Devcon 5

A Conservative Approach to a Radical Roadmap

The current Ethereum 2.0 roadmap is doing a lot of great work on many fronts such as research on VDFs, data availability proofs, and multi-execution environments. However, as an active observer of the Ethereum 2.0 roadmap development over the past 2 years, I am concerned with some of the choices in roadmap strategy, particularly its approach to radically transforming a network with over $30B of value and hundreds of applications depending on it. In this talk, I will present an alternative, more conservative view of how to approach the Ethereum 2.0 roadmap. Some of the topics covered will include: - Radical vs Conservative technological upgrade paths. - We should use Ethereum 1.x as the beacon chain instead of launching a new beacon chain. - Proof of Stake is highly experimental. We should test Proof of Stake on shards before using it on the beacon chain. - Why requiring a 1-way peg burn of ETH to stake is scary. - Learnings from 3 months of Proof of Stake on Cosmos - Why we NEED delegation *in-protocol* - Why sharding doesn't solve social scalability.

A journey to the center of the eth: How the Gas Station Network improves the UX in Ethereum

The Ethereum developer ecosystem is in constant change. Undoubtedly, teams have started to leave the development of Smart Contracts in the background to focus on the development of decentralized applications, and on how to eliminate friction points between users that might not know anything about Blockchain but still need to interact with it. But developer tools are still important and they have to be simple and secure to use. In this talk we will explore how the Gas Station Network is implemented to redefine the interaction between users and DApps in a way that they don't need to have any knowledge on mnemonics, private keys, transactions or gas costs. Moreover, we will go through a set of tools that the OpenZeppelin team developed to make this transition from regular DApps to gasless DApps in a super easy and fast way.

A Visual Overview of Blockchain Development

“The open-source model is a decentralized software development model that encourages open collaboration. Depending on the license terms, others may then download, modify, and publish their version (fork) back to the community.”Yet the ‘open source way’ doesn’t always abide by the rules and many developers just don’t care enough to choose the right license. Arguably, the more than 80 license types scare developers away. This talk will show us the current state of licenses out in the wild west of open source Ethereum communities- for that, we’ll look at charts, diagrams and maybe even maps- and help you choose an appropriate one when starting a new project.

Accountable Watching Services (PISA)

At Devcon IV, we presented PISA, a solution to help alleviate the online requirements for state channels. Thanks to an Ethereum Foundation grant, the team has taken the idea of an 'accountable watching service' further to help alleviate the online requirement for other off-chain protocols such as Plasma and in general most smart contracts. What do we mean that PISA is usable by most smart contracts? Ideally, if we consider a smart contract where the user has to be online and watching for an on-chain event, then PISA can be hired to protect them (and perform the final step). Our goal is to help improve the UX for most smart contracts as users can simply go off-line and PISA can finish the task in a financially accountable manner. In this talk, we'll discuss the substantial changes to PISA such that it can be generically used for most smart contracts. We'll discuss the implementation of PISA, the open-source project, and how other projects can use our simple API to sign up to the accountable watching service.

A review of short term interest rates of tokens in the Ethereum Defi space, why they exist and how to interact with those smart contracts

This a review of the current interest rate economics in the Ethereum space. A quick look at loanscan.io will show tons of projects interacting with each other to create lending and borrowing opportunities. We are here to review why they exist and show on a practical level how to interact with these smart contracts. Most use cases will be earning a high-interest rate or getting a loan of a cryptocurrency.How do you make sure your money is safe, what risks are you taking, how is this different than lending/borrowing money in the "real" world? We will go through a practical example of taking USD and entering the crypto world, interacting with a smart contract and earning interest. The hope is to teach anyone to do this in 10 minutes.

AKASHA Reloaded: Unifying the Ecosystem with ethereum.world

AKASHA Reloaded introduces the idea of a social media framework. It might help to imagine it as a sort of "Wordpress for social networks." What if we would use this framework to build a social network designed to enhance the collective intelligence and collaboration potential of the Ethereum community as a whole? What if we would use this opportunity to integrate the Ethereum ecosystem of dapps and services into a unified user experience accessible to anyone - from meetup organizers to smart contract developers to researchers and beyond? Moreover, how would this play in the bigger picture where any other social network built with the AKASHA framework will have at their fingertips the equivalent of "Wordpress plugins" but in this case in the form of Ethereum services and dapps? We're almost done with the foundational work at the "framework level" and we plan to start in the next couple of months working on ethereum.world to showcase the potential of a modular, interoperable, open-source, social network powered by Ethereum and complementary technologies like IPFS, Verifiable Claims and DIDs. In the past I tried to encourage more collaboration within Ethereum but I think it was too early: https://blog.ethereum.org/2015/03/20/ethereum-builders-experiment/ https://blog.ethereum.org/2015/04/06/ethereum-builders-supercharging-github/What about now?

An Anthropological Perspective on Ethereum

This talk offers insights on the Ethereum community from an anthropological perspective. Technology and society mutually constitute one another. Despite popular claims that depict blockchain as a “neutral technology”, it is important to critically examine how blockchain expresses itself in different social, economic and political contexts. The famous media theorist, Marshall McLuhan, once stated that technologies are extensions of the human; this means that blockchain as a technology, reflects our values, beliefs, and biases. It is thus important to critically reflect on the kinds of narratives and values we prescribe to blockchain and how in turn, actors within the blockchain community and beyond are influenced by them. Topics in this talk range from exploring the relationship between Ethereum protocol design and ideologies, the dangers of techno-utopianism, techno-colonial solutionism, and general recommendations for how Ethereum builders can adopt more socially-minded frameworks in their work to create a more ethical and accessible Ethereum ecosystem.

A trustless Ethereum mixer using zero-knowledge signalling

Since Ethereum transactions are fully visible on-chain, it is possible to trace value transfers and surveil users' financial activity. This state of affairs deprives users of privacy beyond mere pseudonymity. Some workarounds, like using a centralised exchange wallet or a custodial mixing service, however, introduce a high degree of counterparty risk. The Ethereum ecosystem needs a noncustodial mixer which works through strong cryptography, rather than blind trust. To solve this, we present a trustless mixer for Ether and ERC20 tokens. It builds upon Semaphore, a zero-knowledge signalling system by Barry WhiteHat and Kobi Gurkan. Additionally, it employs a burn relay registry which incentivises third parties to pay gas fees on behalf of mixer users. In this presentation, I will show a high-level architectural overview of the mixer, dive into its underlying zero-knowledge circuits, and discuss other applications of zero-knowledge signalling.

An Examination of Quadratic Voting

Quadratic Voting advocate Masahiro Yasu (CEO of ALIS Co., Ltd.), who, upon request by RadicalexChange co-writer, Glen Weyl, founded the Japanese division of Radical Markets,  and Sota Ishii (CTO of ALIS Co., Ltd.) implemented and tested multiple Democratic Voting Mechanisms such as Majority Judgement and Quadratic Voting using his own Web3 community. The Economics Design involved in these experiments was supervised by Mechanism Design scholar and Professor of Economics at Keiou University, Professor Sakai. In this talk we will go over the findings done in these experiments that were based on economic theories, on an advancing Web3.

An introduction to privacy and anonymous communication: A hands-on workshop

This workshop will go over the basics of privacy, starting with anonymity and unlinkability. We'll show that privacy is a 'holistic' systems-level concept, and not just an application of zkSNARKs on-chain. Various types of privacy notions (unlinkability, undetectability), and threat models, will be explored, as well as the various levels where privacy leaks happen (layer 0 on the network level, layer 1 on the chain, and layer 2 application issues). The workshop will then invite coders to describe their own privacy problems, and we'll offer advise and hands-on work through with systems like mix-networks (Loopix), anonymous credentials (Nym), and other systems.

An EVM-based formal Rules Language

Smart contracts are immutable programs on the blockchain. They are automatically executed based on pre-defined rules. However, complex and inferencing rules could be extremely difficult to program, test, and validate, using standard programming languages like Solidity. The long sequences of highly nested and intersecting IF / THEN statements are fragile and error-prone. The problem is compounded by the need to frequently change rules based on business requirements. Enterprise software developers have long relied on Business Rules Engines (BREs) to solve this problem. BREs allow business analysts to write transactional (state changing) programs in a specialized programming language called formal rules language, which can be generated by graphical user interfaces. BREs automatically evaluate, re-evaluate, and execute those rules. They have been proven successful in traditional financial services. The Open Source Lity project developed extensions to Solidity so that the EVM could support BRE for smart contracts. In this presentation, I will discuss the benefits and use cases of rules language and engine for smart contracts especially in the context of financial services and e-commerce applications. I will further describe how the rules language extension for Solidity, modeled after Drools,  is designed and implemented, including compiler and runtime support.

Analyzing decentralized exchange liquidity with DexIndex

DexIndex is a free, open source library for developers working with Ethereum decentralized exchange data.  It launched in February of 2019 and has seen spectacular growth since then, with almost half of all new commits coming from outside contributors!  In this lightning talk, we'll go over what DexIndex is and how you can use it your applications and APIs with just a few lines of code. https://medium.com/fluidity/introducing-dexindex-93dc0bac77d0

Analyzing The Security Of Casper

From the beginning of this year, we have been working on the security analysis of Casper FFG/CBC, resulting in findings of attacks and formal proofs of properties. In this talk, I'll share a few tips towards the secure development of cryptoeconomic protocols, as well as our research on Casper.

An Examination of the Evolution of Staking and Validators

Ethereum 2.0 Phase Zero is rapidly approaching. Extensive research has been conducted on Proof-of-Stake, along with multiple tests and debates to discuss the economics of how this transition will play out. However, there are a few real world data points worth observing in order to understand how Ethereum 2.0 staking and validator markets will play out. stake.fish has been in operations for a year supporting projects like Cosmos, Tezos, and Loom Network. We would love to share how these staking projects evolved along with the stakeholders around them. We can't wait for Devcon 5 and for Ethereum 2.0 :)

Architecting a Decentralized GitHub Backup

When it comes to building dApps, there is a key part of the process that remains very centralized. The tools we use for version control, like GitHub, are centralized, leaving dApp builders and communities at the mercy of providers and prone to censorship. By building a decentralized backup of GitHub in case of censorship, downtime, or other sudden loss of source code access, dApps can better decentralize access to their codebase. This presentation will outline the architecture behind a decentralized GitHub alternative and demo the proof of concept.

Assessing Risk/Trust in Decentralized Finance

In the last year, we have seen an explosion of smart contract based lending/borrowing, which has become the biggest sub-category of DeFi by far. But not all lending protocols are created equal. Different protocols have different risk/reward profiles, and comparing their rates are often apples to oranges comparisons. I would like to present a model I have been developing to assess the risk of different decentralized lending protocols that takes into account elements of both smart contract risk and liquidity risk. This model will be consumer facing, and will attempt to better inform protocol's users as they make important financial decisions. If we want people to be their own bank, we will need to provide tools akin to what current banks have when making financial decisions.

Autonomous Ethereum mixers

I demonstrate how to build a profitable, self-sustaining Ethereum mixer. I use zkSNARKs as the core mixer mechanism [1], and invest the shielded money pool into a risk-free DeFi application to earn interest [2].  The mixer complies with Vitalik's interface proposal [3]. The general privacy setup is similar to ZCash: a "shielded" pool, which contains all the ETH deposited by people who desire anonymity, and "notes" that can be withdrawn without revealing any connection to the deposit transaction. Importantly, this provides K-anonymity for K → ∞, unlike ring signatures or MimbleWimble, providing K-anonymity for K < 15 (ring signature size in Monero, block size in MimbleWimble) and thus prone to several attacks [4, 5]. The pool of ETH deposited into the mixer and awaiting withdrawal is supplied into the Uniswap WETH converter (~4%/year ROI). Unfortunately, that revenue cannot be supplied to the users, since the exact amount would give away precisely when the deposit was made. On the other hand, it can be used to subsidize infrastructure and "keepers" that made the withdrawal transactions for clients – a known problem for all previous mixer designs. [1] https://github.com/barryWhiteHat/miximus [2] https://zumzoom.github.io/analytics/uniswap/roi.html ETH-WETH pair [3] https://hackmd.io/@HWeNw8hNRimMm2m2GH56Cw/rJj9hEJTN?type=view [4] https://ipfs.io/ipfs/QmWYTeggKeL8xBitA8uQWAaNDWfFrUHXAxBXkvmnisdDw7 [5] https://eprint.iacr.org/2019/455.pdf

Batched Bonding Curves: Grieving DEX Frontrunners

It's been widely publicized that front-running is rampant across decentralized exchanges. Billy Rennekamp describes the technique developed to stop the parasitic behavior by using batched orders in tandem with bonding curves and how it's being used in a new fundraising app by Aragon Black.

Better than free? The end of FAANG.

Revolution started with home PCs. Then the cloud came and freed us from storage worries, backups and availability but at the cost of privacy and surveillance. In this talk we suggest that the solution is a personally-owned distributed cloud. Home servers with redundancies that ensure availability and provide space and computation for other users to use in exchange for infrastructure usage payments. But FAANG (except Netflix) offer their services for free in a model where User Data is the revenue maker. They offer genuinely great UX for users, that happily trade their privacy away. How to compete with their millions of $ of R&D and market share? Many technologists in the Ethereum space agree that decentralization is inherently better, but in the past many projects have claimed to be better than the current alternative and failed. The 10x rule (loosely adapted) states that in order to challenge the status quo, something needs to be 10x better. So what’s better than free? Getting paid for using it. Incentivization models and a robust distributed infrastructure layer are key. In our talk we put incentivization, TCRs, secure distributed computation and node federations together for the 10x next stage.

Beyond Burners - How to Make Web3 Feel Like Web2

While working at Spankchain, James experienced firsthand the difficulties of creating a Web 3 product that users felt compelled to return to. The fact is, there is an incredibly high dropoff rate for dapps today. A large part of this issue revolves around key management. Austin Griffith put the onboarding technique of using a burner wallet in the spotlight half a year ago, and has proven to be the most effective on-boarding solution to date. In Beyond Burner, James will expand on an idea he began building in early 2018 describing how to create an intuitive account management experience by utilizing a contract that contains multiple ephemeral (burner) keys. He likens this method to the Impossible Burger narrative, where environmentally friendly meat alternatives have become as good or better than the real thing. Beyond Burner describes the way counterfactual account contracts and burner keys can create an intuitive Web 2-like experience while keeping the benefits of Web 3. Come learn about the future of dapp UX!

Beyond CryptoKitties: building tradeable, interoperable ERC721 digital assets

ERC721, a standard for non-fungible tokens pioneered by CryptoKitties, is the new standard on the block, somewhat less well understood than the more mature ERC20. ERC721 has a variety of emerging use cases, including pure collectibles, game items, event tickets, naming systems, and even physical assets like real estate. This workshop will guide participants through the process of creating a new ERC721 contract from start to finish, with functionality beyond simple collection and trading. It will cover a range of tools for building robust, useful ERC721 assets, including decentralized file systems like IPFS for metadata storage, integration with marketplaces like OpenSea, interoperability with virtual worlds like Decentraland and CryptoVoxels, ERC20-compliant wrapped ERC721's, and ties to off-chain data with Oracles like ChainLink. The workshop will leverage existing Ethereum infrastructure like Truffle and Infura, allowing the user to deploy a fully-functional ERC721 contract that could then be launched alongside a dapp on the Ethereum mainnet. The workshop will also discuss extensions to the ERC721 contract, as well as newer standards like ERC1155.

Beyond DAOs: Evolving Human Organization

The hegemonic approach to human coordination (i.e. nation states, corporations) is being challenged as those underserved and disempowered by the current system search for more open, adaptable, and representative solutions. With the emergence of DAOs, decentralized governance, and token economics, we now have a new design space to engineer incentives and mechanisms that align human behavior. Projects like Aragon, DAOstack, Fairmint, Gnosis, Gitcoin, Commons Stack, and MolochDAO are all building, experimenting, and testing new ways to fund and govern human organizations. We want to build organizations that encourage sustainability over profit, stimulate regeneration instead of scarcity, and eliminate stakeholder misalignment seen in current cooperative models. To truly impact those outside the Ethereum ecosystem, we should be strategically aligning experimentation around counter-hegemonic goals and visions. Only then will we be able to move 'beyond DAOs' into an evolved future of regenerative, sustainable, and cooperative human organization. This workshop aims to: -Spark discourse and discussion on what future we're ACTUALLY building towards - Get those experimenting with new organizational models in the same room to discuss collaborative strategy, insights, and roadmaps - Workshop common frameworks and visions for new organizational models to eliminate project silos, form counter-hegemonic strategies, and move the whole ecosystem forwards.

Blockchain × 3D data, Publishing NFT for whole body 3D scanned data.

The development and diffusion of VR and AR technology has made 3D data familiar.However, 3D data can be copied, and there are challenges in protecting copyrights and portrait rights. Also, monetization can be difficult.By publishing NFT of the original 3D data and providing the benefit that only the owner of the NFT can enjoy, we aim to create an eco-system that the value of the NFT will increase when the data duplicated.We(BlockBase,inc, DiGITAL ARTISAN, and MiraCreative) started a project to publish NFT of Whole body 3D scanned data of Japanese celebrities.

Birthmarking Your Smart Contracts For Vulnerability Search

In this talk, we will highlight an automatic vulnerability search technique for smart contracts. In the context of security, vulnerability search enables us to make quick response to new threats and zero-day exploits. In those cases, well-designed analysis is far from prepared to deliever precise detections. Our vulnerability search technique can act as a complement in this setting to efficiently identify potentially vulnerable contracts without heavyweight in-depth reasoning and analysis.The key insight is to "birthmarking" a smart contract by abstracting its programming intents. Generally, the generation of birthmarks is realized via symbolically executing the bytecode of a smart contract and building global dependency on the fly. More specifically, both syntax features (e.g., number and type of instructions) and semantic features (e.g., load and store at the same storage) are considered in birthmarks. Then, the task of searching for a known vulnerability is converted to computing a similarity between a target contract (with the vulnerability) and a candidate contract (may/may not have the vulnerability). We have implemented a prototype to search for known vulnerabilities and conducted large-scale evaluations on real-world security issues. Particularly, we will use CVE­-2018-­10376 to explain how the search technique can help existing security analyzers

Blockchain & The Law: interfacing the rule of law and the rule of code

This panel will feature prominent members of the COALA (http://coala.global) community. It will address the work that is currently being undertaken at COALA, with regard to interfacing the blockchain world with the legal world. It will focus in particular on the notion of "alegality" and how we can create legal APIs in order to help blockchain-based systems interact with legal persons. It will also discuss the need for legal reforms in order to accommodate the new opportunities provided by blockchain technology, and how the notion of "functional equivalence" can be used as a means to rely on blockchain technology as a "regulatory technology" in order to achieve similar regulatory or policy obec

Blockchain from the bottom up: Lessons from creating financial empowerment in remote pacific-island communities

For as long as the technology has existed, Blockchain has promised financial inclusion and empowerment for underserved communities. For the most part however, this promise is yet to be realised - projects to date have largely served people living in wealthy countries. If blockchain will truly create positive impact for those who need it most, we need to start working deeply with underserved communities, having real conversations to discover their dreams, aspirations and the challenges they face. In early 2019, international NGO Oxfam and social impact startup Sempo collaborated to launch the first stablecoin-powered humanitarian cash assistance program. Working alongside communities in the highly remote and disaster prone pacific nation of Vanuatu, we used vouchers collateralised by Dai to empower over 200 vulnerable people to buy what they needed, from local vendors, on their terms. The entire project was delivered working with communities with limited access to smartphones, banks, and where internet would go down for days. This talk is a joint presentation between Oxfam and Sempo. We will cover how we addressed the challenges we faced working in such an extreme environment, what the project meant for the people participating, and our vision for the future of financial inclusion.

Breaking Smart Contracts

Some of the most financially devastating hacks in recent years have happened on the blockchain. In this workshop, we will walk through a series of simple Solidity coding challenges and common mistakes, where participants are asked read code, understand and try to break them. Regarding each challenge, we will talk about the history of the hacks involving that family of bug. We will talk about the attacks and possible solutions.

Bridges to...Somewhere?

Interoperability

Build a constraint system, prover and verifier using OpenZKP Stark

There are great tools and tutorials for R1CS proof systems (aka Snarks) but not much is known about programming Starks. Starks have a much more complex constraint language, but in return you can achieve a much better performance. In this workshop we will * learn about the mathematical underpinnings of Stark proofs, * use 0x's OpenZKP library to generate and verify proofs, and * implement a Stark constraint system.

Building a Decentralized BitMEX Using an Optimistic Financial Contract (OFC) Framework: New Tools for Fast and Secure Financial Contracts on Ethereum

We introduce the Optimistic Financial Contract (OFC) framework, a novel approach to financial contract design that allows for hyper fast, secure, and scalable DeFi contracts *without* requiring an on-chain price feed. This framework makes it easy for developers to build otherwise complex synthetic financial derivatives on Ethereum. We show how this design can be used to build a decentralized derivatives exchange (aka BitMEX) that can be as performant as the centralized alternatives. How it works: optimistic contracts work by assuming contract participants will act optimistically to avoid penalties. This formalization borrows heavily from Plasma and state channel research. “Long” contract participants enforce that “shorts” remargin contracts on a timely basis (and vice versa). Surprisingly, no on-chain price feed is required—an oracle is *only* needed to resolve disputes in what is conceptually similar to Plasma’s exit games. This simple framework works at both the L1 and L2 levels and can be extended to create almost any type of financial contract developers can imagine.

Building Ethereum 2.0 On Substrate

Wei Tang presents Building Ethereum 2.0 on Substrate.

Building a Formally-Verified DApp with the Reach DSL, today!

In this hands-on workshop, we introduce Reach, take participants on a walkthrough of an example program, and guide them through implementing a basic DApp on their own. Reach, a new domain-specific language for decentralized applications, provides automatic solutions to the key problems faced by blockchain developers: ensuring the smart contract is consistent with client-side software, verifying the DApp is trustworthy, and abstracting over different blockchains. We then take a guided tutorial consisting of an example Reach program that implements a formally-verified two-party wager DApp. We explain the structure of the ~50 line Reach program and the structure of the ~50 line JavaScript frontend, and take a deep dive into properties that Reach formally guarantees. Participants will then work through a series of exercises implementing a different DApp with a similar structure to the sample program. They will leave with concrete experience using Alacrity that will enable them to build their own DApp. Prerequisites: Experience programming in JavaScript, have Docker installed on their machines to install the image of the Reach compiler and demo. It is recommended participants download and install this image before the workshop at: https://bit.ly/ReachIsTotallyAwesome. Experience with formal verification or stating DApp properties is NOT required.

Building Mainstream-Ready dApps

Matt Slipper speaks about building mainstream-ready dApps.

Building on Uniswap

Uniswap is an automated market maker on Ethereum. It can be used directly as an exchange, but arguably its most interesting use is as a building block for other protocols and applications. This talk will discuss how Uniswap was designed to favor composability, including offering synchronous contract-accessible liquidity, turning pooled market maker liquidity into its own fungible asset, and aiming for simplicity and efficiency rather than completeness. The talk will demonstrate ways in which Uniswap can be composed with other protocols to create new kinds of on-chain financial products. The talk will also preview some future features of Uniswap—ERC20-ERC20 pairs and Uniswap-based price oracles—and show how they would expand Uniswap’s usefulness as a building block of decentralized finance.

Building Synthetic Derivatives on Ethereum

This workshop will teach participants how to build best-in-class financial contracts on Ethereum that can support a wide array of DeFi use cases. Using concepts borrowed from fiat financial derivatives, participants will learn—with real, interactive examples—how to design and create their own decentralized financial contracts that are self-enforcing, permissionless and universally accessible. Participants will learn common design patterns for a wide range of financial products, including contracts for synthetic asset tokenization, decentralized margin trading, and interest rate swaps. We will also discuss how to implement these design patterns using the Optimistic Financial Contract framework, a new approach to financial contract design that allows for fast, secure, and scalable DeFi contracts. With examples and real-life code, participants will learn how to design new, scalable DeFi products, including a simplified design for a decentralized derivatives exchange (aka a decentralized BitMEX).

Building dApps and IoT using the Incubed Ultra Light Client

The Incubed protocol is an incentivized, secure and fully decentralized protocol for stateless ultra light clients. It is specially designed for devices or applications which are restricted in available resources like memory, calculation power, connectivity or bandwidth. During the workshop, we will discuss the advantages and disadvantages of non-synchronizing (stateless) clients and demonstrate with comprehensible programming examples how mobile apps, web applications and especially IoT applications can be realized with minimal resource consumption using the Incubed client. In the second part, we will take a closer look at the proofs used by the Incubed protocol to verify the correctness of blockchain information. In a programming challenge, we will examine how those proofs work in the application context.

Catching exceptions in Solidity

When a revert happens in solidity, all the state changes done in that transaction are rolled back. All the changes done in sub calls are also rolled back. If a contract A tries to do a token transfer in contract B but contract B reverts, all the changes done by contract A will also be rolled back. This is fine for some cases but sometimes there might be a need to ignore or handle this revert in the smart contract itself. The talk will demonstrate how reverts and other exceptions can be caught in Solidity.

Chainalysis: Building Trust in the Ethereum Blockchain

Mikkel Jensen & Surya Rastogi give their talk on Chainalysis & Building Trust in the Ethereum Blockchain

Choosing composition over inheritance wherever possible: is that right?

Composition over inheritance is a staple in object oriented programming since the early 1990s. Developing with Solidity on the EVM has forced me to re-examine several programming paradigms. With Ethereum, there are other considerations given that smart contracts are typically immutable and gas costs become a more important factor. I wanted to take some time talking about this design pattern and sharing some examples with the community.

COALA Workshop: Model Law for DAOs

The number of DAOs is growing, and yet most of these DAOs still cannot interact with legal entities, because they do not have legal personality or legal capacity. This workshop is aimed at drafting model legislation for governments to recognize DAOs as legal persons, provided that they possess specific characteristics that facilitate interaction with third parties, and that they provide minimum guarantees of soundness, oversight and accountability. The goal is not to create new types of corporate entities that could accommodate a DAO (c.f. the approach taken by Vermont and Malta), but rather to carve out some kind of legal recognition to DAOs that subsists in an “alegal” state (a.k.a in the blockchain world) and not in a particular geographic jurisdiction in which they would otherwise need to be incorporated. To the extent that blockchain technology has newly endowed DAOs with both technical and economic agency (c.f. their ability to own crypto-assets and to enter into smart contract relationships), it has become crucial for national jurisdictions to recognize these new technical opportunities, and grant DAOs with some kind of legal personality and legal capacity in order to enable these technical affordances and match them with newfound legal affordances. This work requires building a definition of who are the DAOs that should be recognized as legal persons, and what are the legal or technical requirements they should comply with to avail themselves of legal personality and legal capacity. Once this preliminary work has been done, we will work on drafting a model law for DAOs that could be adopted by a variety of national jurisdictions.

Competing With Non-Crypto Products Without Losing Crypto's Philosophies

Taylor Monahan discusses competing with non-crypto products and keeping crypto's philosophies in place.

Complementing DApps with Trusted Computing: The Challenge of Designing Rock Solid Oracles

Decentralized Applications aim to change the way verticals across multiple industries work. An important element for this to happen is for smart contracts to access real-world data. Problem is, blockchain is a walled-garden and smart contracts cannot natively fetch data from the outside world. Blockchain oracles enable DApps to overcome this limitation. Designing such a tool is quite a challenge - elements such as security, decentralization and feasibility must be kept into consideration. Is blockchain a self-standing technology? Security-focused techniques such as Trusted Computing or ZKSnarks are being explored as a complementary technology enhancing the power of decentralized tools. How do those technologies complement each other? What’s the benefit for blockchain oracles to rely on both? And what’s the benefit for users?

Conditional Tokens - Road to Futarchy

Conditional tokens are a new crypto primitive which in the broadest sense allow for the incorporation of conditions into fungible assets. There are a myriad use cases for these conditional tokens, ranging from conditional payment to synthetic derivatives and event futures. Conditional tokens also elegantly capture the fundamental concept behind prediction markets: Conditional tokens allow tokenization of future events and make their outcomes tradable. We developed a new smart contract framework for conditional tokens which allows seamless combination of conditions for multiple future events. This concept lays the foundation for taking prediction markets beyond the PoC stage by natively allowing (1) markets to show dependencies between events in a scalable manner and (2) showing how the value of a specific asset is impacted by a possible future. Showing these dependencies is one of the core mechanisms used for Futarchy, a governance model reliant on decision markets. In our presentation we will explain the implementation of our framework and how it can be utilized for Futarchy.

Complexities in Aggregation at Scale

Mikhail Kalinin presents Complexities in Aggregation at Scale.

Connecting Decentralized Liquidity

The talk will introduce decentralized liquidity, its role in the ecosystem and how several defi projects are utilising the decentralized liquidity in different ways. The talk will also touch base on what Kyber does to connect different decentralized liquidity sources to make them available for the defi ecosystem.

Conquering the Nonce

The nonce - just a single, incrementing integer that lets you send your transactions to the Eth network. Simple, right? Our experience working with hundreds of dApp developers tells a very different story - thousands of failing RPC requests, transactions that never get mined, and dozens of hours spent debugging with nothing more to show than a fragile work around. Overlooked and under considered, nonces have been the single biggest pain point for tons of Ethereum developers. In this talk we will share all of the techniques and best practices we’ve gathered in our hundreds of hours helping DEXs, dApps, and more solve exactly this issue. A few thoughtful design choices and properly handled nonces can lead to better products and significantly higher quality of life for developers.

Creative Constraints for DApp Development

Can the challenges of blockchain development — gas limitations, storage scarcity, and decentralized computation — create conditions for creative DApp development? Are the parts of Solidity that often confound developers actually starting points for creative thinking? 20 minutes: Survey of Creative and Whimsical DApps We will review games and whimsical DApps, from CryptoZombies and CryptoKitties, ERC721 collectables, to some of my personal projects, including a fruit-backed cryptocurrency, and a blockchain treasure hunt. 20 minutes: DApp Idea Generation We will brainstorm how to make fun and whimsical DApps. The room will break into small teams and draw random cards as idea prompts. One set of cards will contain Solidity features, others will contain game types and themes. 80 minutes: Build-a-long The next 80 minutes will be a hands-on DApp build-a-long of a Japanese-style treasure hunt known as a “Stamp Rally” in Solidity. (Sample code: https://github.com/ann-kilzer/blockchain-stamp-rally). Participants will build key parts of the app in Remix, and interact with a publicly hosted version of the UI. If participants want to continue learning and experimenting afterwards, there will be extensions in the repo. My goal is to show participants that blockchain development can be fun, creative, and approachable.

Conversational design: the low-cost way to design your dApp

Have you ever been told that your dApp is difficult to use or understand? Have you had to write a tutorial on Medium or Kauri just so users can make it through a flow? Well it's time to put an end to that. In this workshop you'll learn how to quickly and cheaply ensure you're building something that your users will really understand. By starting with a script as an early, low fidelity prototype you'll realise your interface is more than a container of content, it's a conversation between your system and the user. This will help you: - appeal to more users by removing the jargon and technical language from your front end - build interfaces in a more logical order with clearer content hierarchy - identify edge cases before development even starts - reduce iteration in-browser - get better feedback from usability testing We'll go through the entire process: from some quick guerrilla research through scripting onto sketching and iterating. So you'll get a chance at levelling up some of your other design skills too. You'll leave this workshop with both a new way of thinking about products and a powerful new tool for designing and building one.

Crypto for Activism

Micah White and Amir Taaki give their talk on Crypto for Activism.

Creating Type Safe DApps with TypeScript and TypeChain

Lately, we've seen a huge spike in TypeScript popularity, wouldn't it be great to be able to leverage it for DApp development?In my talk, I want to show how to use TypeScript and tool that I created called TypeChain to achieve fully type-safe communication with Ethereum smart contracts. This speeds up development process, helps to find bugs in compile-time and warns about breaking changes.TypeChain is not only useful during DApp development but it integrates with Truffle Suite as well which makes writing tests for smart contracts in TypeScript possible.

Dapps Ain't Easy

Along with my job at OpenZeppelin, I spent the last year writing a book on Ethereum for traditional web developers new to the space. While writing, I found that many things that we take for granted when coding on Ethereum are much more difficult to get right than we think. On this lightning talk, we will briefly present overlooked challenges on gas estimations, handling reorganizations, and even managing subscriptions. Though there will be no silver bullet solution to close, we will discuss what we can do as an ecosystem to mitigate these problems.

Cryptoeconomics In 30 Minutes

Vitalik gives a quick overview behind Cryptoeconomics.

Daily: An easy, open source dollar wallet for Venezuelans

We'll quickly go through the user experience decisions we took when building Daily, a wallet that Venezuelans can use to send digital dollars from one phone to another. We'll talk about the Linkdrop protocol, supporting old Android versions, and the importance of connecting deeply with liquidity sources.Daily is a project supported by MakerDAO and Binance Labs.

Data privacy and provenance with OpenAttestation

OpenAttestation is the framework powering the nation-wide blockchain based digital education credentials solution, OpenCerts, in Singapore. OpenAttestation turns documents into structured verifiable claims and allow the provenance of the documents to be verified on the Ethereum blockchain. These documents put users in control of their own data by allowing them to selectively obfuscate parts of the data in the document without compromising on the integrity of the document. This presentation will focus on key learning point from deploying such solution at a nation scale: Batch issuing large number of documents Selective disclosure of data Decentralized document templating and rendering Demo: https://opencerts.io

DAO Design Canvas

One of the most interesting innovations to come out of the cocreation in the Genesis Alpha DAO (DAOStack's first DAO) - The DAO Design Canvas Workshop utilizes a canvas-like tool developed by me to guide groups through the process of making the most vital decisions they face in the process of designing a DAO, soft and hard governance, on and off chain, no matter what platform. The process of exploring the purpose of groups with the canvas yields well defined use cases, powerful educational experiences and high quality dialogue that often leads into action. DAO Design Canvas has been used in all 5 continents and has been used to design the CuraDAO, the dHack DAOs amongst others.

David Chaum

David Chaum gives a brief history of his experience in Cryptography, and presents Elixxir and Praxxis.

Decentralized Federated Learning on the Oasis Network

Machine learning is being adopted more and more broadly in technology. Such success is largely due to a combination of algorithmic breakthroughs, computation resource improvements, and the access to a large amount of diverse training data. The collection of data can raise concerns about siloing, security, and user privacy. In this talk, I will highlight a new blockchain-based machine learning technology that allows users to share their data, train models in a fully decentralized way, and incentive end users to keep their data on the network using the Oasis network. This technology, called HiveMind, leverages a federated learning framework to reduce overhead both in communication and computation. In addition, the talk will highlight the benefits of a novel blockchain-based secure aggregation protocol that ensures client-level differential privacy, and thus prevents information leakage from trained model parameters.

Decentralized UX Problem-Solving with The Bounties Network and Rimble

The Bounties Network and Rimble are kicking off an experiment in decentralized problem solving. The Rimble team continuously researches critical UX problems that are hindering dApp adoption and usability. Through this initiative, we are incentivizing the generation of creative and effective solutions to dApp UX challenges through the use of bounties. Rimble will validate and iterate on the best solutions, ultimately incorporating them into open-source resources that make it easier for developers to build dApps for broad usability. This session is for developers (primarily front-end/React), designers, and anyone interested in contributing their ideas and concepts with the aim of advancing the dApp experience with accessibility in mind for new and current users of the decentralized web. We will be offering bounties as an incentive for participation as well as for providing feedback about the session and and the resources/tools used throughout. We want to see designs, prototypes, and working demos addressing some of the most critical segments of the dApp experience: On-boarding new usersSmart contract interactionTransaction statusAddress exploration Important aspects we will be considering are accessibility, color contrast, and error handling. Specific criteria will be posted on each bounty for participants to fulfill. The challenge doesn't end during the workshop. The workshop bounties will be active for the duration of the conference, and possibly beyond. At the conclusion of each bounty deadline we will determine winners and/or submissions to award based on criteria that we define, and based on the quality of execution and content of each submission.

Decentralizing Ethereum Data with VulcanizeDB

Ethereum is a robust platform for decentralized applications, but the same data structures and encodings that make it effective and trustless also complicate data accessibility and usability. How do you know token balances were updated correctly after you sent your transaction? Is an address authorized to seize your assets? How have system parameters changed over time? To answer these questions, we’ve traditionally depended on centralized APIs and block explorers to capture and serve historical data in a performant way. But what if those services shut down or returned modified results? VulcanizeDB has been working hard to address this problem - aiming to make it easier for anyone to set up, maintain, and query their own data directly. The good news: it is possible to keep track of the historical state of smart contracts without storing petabytes of data! The tricky part: you need to be intentional about how you track information, and you need to aggregate data from disparate sources to provide a holistic view. This workshop will provide a demo and hands-on experience walking through how VulcanizeDB simplifies the process of developing and interacting with smart contracts while keeping our applications and data independent of centralized third parties.

Decentralizing Transaction Abstraction for On Chain Privacy

Transaction abstraction (or meta transactions, if you prefer) isn't a new idea in Ethereum. The idea, roughly, is that users sometimes want a 3rd party, called relayers, to pay gas for their transactions for them. To support on-chain privacy apps like the MicroMix mixer, we've designed a decentralized transaction abstraction system with 2 particularly novel ideas:a transaction simulation engine that allows anyone to run a relayer with minimal configurationa trustless reputation/spam-prevention system for relayers, that we call the 'burn registry' In this talk, I'll:present the design space of transaction abstraction and some of the crypto-economic challenges in building such a systempresent the solution we've built for MicroMix and finally, share software that you can run today to be a relayer on our network.

(Defense Against) The Dark Arts - Contract Runtime Mutability

Smart contracts are no longer guaranteed to have immutable runtime code, and can be redeployed with new code using a variety of methods involving the CREATE2 and SELFDESTRUCT opcodes. In this presentation, we will investigate how this is done and how to protect against malicious mutable contracts. We will also explore ways these new techniques can be applied in order to enable new use-cases and to improve the user experience.

Delightful Developer Experience with Solidity Hot Loader

Mass adoption of Ethereum requires attracting both users and developers. Developers trying to enter Ethereum are often pushed away by unstable libraries, lack of documentation and poor developer tools. The typical Solidity development cycle is: change a Solidity code, compile the code, restart a local node, apply an initial state, and restart a frontend app. It can be reduced to just saving Solidity source code and all the changes will propagate automatically. We present a practical implementation of Solidity Hot Loader as well as a generic approach to enable it across the entire Ethereum developer space.

Demystifying libp2p gossipsub: a scalable and extensible p2p gossip protocol

ETH2.0 is evaluating libp2p gossipsub as a decentralized, peer-to-peer publish/subscribe mechanism for validators, proposers and attesters to quickly disseminate data throughout the entire network. This talk covers the technical design, tradeoffs and functionality of gossipsub, aiming to deliver foundational knowledge to everyone interested in learning more about this potential building block of the ETH2.0 network. Gossipsub was incubated in the libp2p project as a replacement for the naïve floodsub pubsub router (which simply broadcasts messages to all peers we know are interested in a topic). It maintains stable reciprocal meshes via explicit link grafting, while preserving random gossip to disseminate metadata, and to provide cues to aid message deliverability. It also features a piggybacking algorithm to minimise the overhead of control messages; allows developers to attach custom per-topic validator functions; and more. Come to learn more about how gossipsub works, and to hear about the state of the art of p2p pubsub protocols!

Designing before building - Find out if you're building the right thing for users before you start to build

Blockchain development takes longer than Web2 product iteration cycles. This means teams don’t know if they’re building something users want until after a costly and time consuming development cycle. We use Design Sprints to prototype, test and learn from real user feedback — fast. Bringing product design methodologies to Dapps and DeFi developers. At Deep Work Studio, we've used the Design Sprint process to find out if a product is worth developing, if a feature is worth the effort, or if the value proposition is really valid. With teams from ConsenSys, Molecule, Wyre, Hummingbot, Ramp, Pillar and more. In this talk, we'll talk through the process. Showing how any team can design, prototype and test a product within a few days. Too often we've seen extensively build products launch to little user or market need. At the end of the talk, teams will have insights on how they can: - Validate products and features before a costly building phase. - Increase speed to market. - Increase chances of product success. With real user feedback in days not years!

Designing Awesome Developer APIs for Protocols

The growth of your protocol ecosystem is rooted in the ease at which developers can build applications using your tools. How do you create intuitive, powerful developer experiences to encourage people to build a vibrant application ecosystem?We share the behind the scenes of what really goes into powering marquee developer communities. In this talk, we cover the design and implementation of custom APIs for some of the most popular applications: CheezeWizards by CryptoKitties, Kyber, and more.

Decentralize All The Things: Deploying Your Own Node Infrastructure

Many developers rely on third-party node services to make dapp development easier and reduce user onboarding challenges, but this can lead to single points of failure and systemic weaknesses in web3 infrastructure. This presentation will go over some of the weaknesses in different ethereum node implementations and show you how to mitigate against them in your own resilient node service, including how to reduce node start times with efficient state replication and how to protect against DDoS attacks. Reduce your dependence on third parties and make sure your dapp or blockchain-related service can take a beating. Blockscale used these same techniques to help MyCrypto significantly improve the performance and cost-effectiveness of their node services. This presentation includes code examples and deployment demos.

Designing Smart Contracts With Free Will

A range of bribery attacks, collusion possibilities, and other economic vulnerabilities plague our smart contract design.  Unlike with simple anti-patterns like recursion, these security vulnerabilities have no obvious fix.  Join us for a deep dive into the state of the art bribery attacks that are technically feasible on cryptocurrency today, and their countermeasures.  We will introduce and explain new signature schemes that resist the ability for users to be bribed on Ethereum-based smart contracts.  We will teach developers of smart contracts how to build contracts that are maximally resistant to bribery, and provide practical tips for the protection of your users.Lastly, we will show and launch a toolkit that provides signatures with protection from an advanced form of bribery known as the Dark DAO, in which users are bribed undetectably.  Our toolkit provides a simple API for any Ethereum contract to ensure the free will of their users through an easy to use library.Building bribery resistant smart contracts is of critical importance for voting schemes, oracles, prediction markets, proof of stake and other consensus protocols, randomness generation, and more.  Join us in ensuring the protection

Devcon50 preparation on the moon

Cyber-physical systems (CPS) are change the world right now. Thousands of robots makes billions useful things every day. The power of Ethereum is lifting computing to decentralized world. Robonomics Network as L2 solution use Ethereum to control CPS over the world. Most efficient mechanism for this purpose is open market for service-oriented systems. On this workshop participants will try to build space station using autonomous robots on the moon.

Doing Business with the Blockchain

How to explain the blockchain to C-level managers. How to convince companies to become more competitive and grow their business by adopting the blockchain technology How to avoid  the major pitfalls of the enterprise mindset .

Driving engagement in web3 communities!

Andreas Wallendahl speaks about driving engagement in web3 communities.

Economics of Ethereum 2.0

This will be a presentation reviewing the Ethereum 2.0 Economics for an average validator. The talk will highlight the validator economics based on the current spec that can be expected for Phase 0 and Ethereum 2.0 at a mature state. The presentation will result in a call for community feedback on the proposed economics, which will be done through a public facing Ethereum 2.0 calculator built by the EF and ConsenSys.

Ending Planned Obsolescence in Tech

The apps we love are built to die. Planned obsolescence, a term most people associate with cheap physical goods, is just as problematic in the software industry, where it hurts users and stifles innovation. It should seem counterintuitive that a product consisting primarily of ones and zeros could have a built-in expiration date, and yet the applications we rely upon shut down or become defunct all the time. Just this year already two applications that our team relied upon and were willing to pay for, shut down, despite having large active user bases. How is it that products and services with almost zero marginal cost of distribution, can shut down amidst the protests of loyal users? In contrast to the manifestations of obsolescence were used to, the flaws here are subtle economic and technological shortcomings, rather than obvious physical defects. In this talk I will explore the history of planned obsolescence, the root causes for it in the information technology sphere, and how a long term shift in how we think about building software is poised to deliver something in the world of bits that we could never imagine in the physical world: permanent products.

EIP 2020, E-money Token Standard: A standard for financial payments and operations for tokenized money

The EM Token builds on Ethereum standards currently in use such as ERC20, but it extends them to provide few key additional pieces of functionality, needed in the regulated financial world: Compliance: EM Tokens implement a set of methods to check in advance whether user-initiated transactions can be done from a compliance point of view. Implementations must `require` that these methods return a positive answer before executing the transaction Clearing: In addition to the standard ERC20 `transfer` method, EM Token provides a way to submit transfers that need to be cleared by the token issuing authority offchain. These transfers are then executed in two steps: 1. transfers are ordered 1. after clearing them, transfers are executed or rejected by the operator of the token contract Holds: token balances can be put on hold, which will make the held amount unavailable for further use until the hold is resolved (i.e. either executed or released). Funding requests: users can request for a wallet to be funded by calling the smart contract and attaching a debit instruction string. Payouts: users can request payouts by calling the smart contract and attaching a payment instruction string. https://emoneytokenstandard.org/

Enterprise Ethereum is a Team Sport

The World Economic Forum's Centre for the Fourth Industrial Revolution works with public and private sector around the world to deploy Ethereum solutions in a fair, inclusive and well-designed way and to maximize the benefits for society. From investigating the use of the technology to increase transparency and accountability in government processes to reduce corruption, to encouraging inclusive supply chain deployments to moving ahead decentralized global trade identities. As an impartial party to a number of industry-wide consortium efforts to solve key global issues, it is clear that collaboration, fair and well-designed governance systems are a key barrier to Ethereum adoption. I will share and explore lessons and insights learnt from existing and in-progress industry consortiums, together with what good consortium collaboration and governance looks like in a decentralized setting. While the rewards from collaboration can be high, agreeing on what constitutes a fair and well-designed consortia governance system, let alone a joint blockchain platform, can be challenging. This is where many industry collaboration efforts have fallen apart. The presentation will focus on insights to foster industry- and ecosystem-wide blockchain collaboration - to increase the likelihood of success of Enterprise Ethereum adoption and thereby maximize the benefits of blockchain.

ERC 20 Test Suite: Towards Decentralized Security

Nowadays, a lot of Dapps and exchanges interact with ERC20 tokens and they expect certain behavior from those contracts. It is crucial to make sure that the token fully complies with ERC20 standard to avoid loss of funds and reputation. The problem is that one cannot easily verify this compliance. This can be done only by ordering an audit or writing and running a bunch of tests. However, these options are expensive and not scalable. In my speech, I will tell about a decentralized tool that we created to help developers solve such problems. ERC20 Test Suite is a service that runs a series of tests for ERC20 standard compliance in the form of on-chain transactions. The final test results are recorded in a smart contract. Test Suite cannot fake the test results as each test is a transaction recorded in the blockchain. SmartDec ERC20 Test Suite is open source: https://github.com/smartdec/testsuite Also, we have deployed our centralized instance of the tool here: http://testsuite.net/ropsten/

ERC725 - The future of on chain interaction

One of the biggest problems for blockchain its is difficulty to store and secure assets and manage interacting with a blockchain. The main cause is the use of private keys for the source of interactions on-chain. ERC725 is a standard proposed to make abstract accounts from keys to a smart contract account. This not only makes security upgradable, but lets accounts become information holders. Fabian Vogelsteller the author of ERC20 and ERC725, the Mist browser and web3.js will talk about how on-chain interaction should look like.

Eth 1.x Explained

Ethereum 1.x isn't as sexy as Eth 2.0, but that doesn't mean it isn't important! In this talk we go over the history of Eth 1.x including its Devcon4 origins and what it means for Ethereum today.

Eth 2.0 light clients: How light is light?

Ethereum 2.0 has been designed from the ground up to be friendly for "light clients" - blockchain clients requiring vastly reduced computational resources that can easily be run in the browser, in embedded devices, and even inside other blockchains! We discuss how light clients work in Eth2.0, why light clients are lighter than full nodes, and get to the bottom of just how "light" these clients can be.

Eth 2.0 Minimal Execution AMA

A fishbowl style conversation with lead researchers and passionate contributors to Eth 2.0, but allowing anyone from the audience to stand up and lead a topic. The intent is to discuss certain key topics around the design of the Eth 2.0 shards and how they can be used by the everyday dapp developer. This session aims to bring everyone interested in Eth 2.0 execution to a friendly discussion.

Eth 2.0 on a Pi

Throughout the years, one of the main complaints of blockchains and Ethereum has been how much energy it consumes to secure transactions. Thus, blockchain is often associated with energy waste in mainstream views. Eth 2.0 with its proof-of-stake consensus promises significantly improved energy consumption. It also brings back validation power to common hardware while proof-of-work increasingly requires interested parties to invest in specialized hardware, space and location. Let's dive together to see if the beacon chain holds those promises and run it on one of the most accessible hardware: the Raspberry Pi.

Eth 2.0; tldr

High level overview of the work that has gone into Ethereum 2.0 since last devcon, the major milestones achieved, the landscape of research, and where we're going in the next 12 months. This serves as an overview talk for the track to get devcon attendees acquainted with the space in general and ground them for the range of more technical talks throughout the conference.

Eth2 Collaboration Culture

We discuss the trend of collaboration within the blockchain industry, presenting specific examples from Ethereum 2.0 R&D. This talk will highlight the hard Eth2 problems that are being tackled with other blockchains, academic teams and companies.

Eth2 Phase 0 Technical Deep Dive

Seminar style deep-dive on phase 0 of Ethereum 2.0. Content includes explanations, diagrams, Q&A, etc. Session will open with a high level overview, followed by a deep-dive explanation and analysis of the various components of the system ultimately showing how all of the pieces fit together. Various researchers and developers to present on sub-topics related to their expertise.

Eth2.0 Client Panel

Panel discussing the short-term future for Eth 2.0 clients.

Ethereum 2 Network Spec and Structure

Zahary Karadjov speaks about the Eth 2 network spec & structure.

Ethereum 2.0

The Ethereum Magicians discuss Ethereum 2.0

Ethereum 2.0 Phase 1&2 Developer Experience

In this breakout session, we would invite some prominent Dapp developers to discuss the developer experience with Ethereum 2.0 researchers and client implementers. The goals of this session: Phase 1 will enable some layer 2 scaling framework to be much more useful! What would the developers need to know? And what are the edge-cutting tools they can start to dig?Till today, the most promising Phase 2 proposal is the execution environment abstraction by Vitalik Buterin (https://notes.ethereum.org/s/Bkoaj4xpN). While this scheme would only add minor cost to migrate the existed Dapp, it would be great to understand the requirements from the perspective of developers.What's the user experience regarding cross-shard transactions?To get some more concrete ideas of the Eth2 tooling we will need.

Ethereum 2.0 Security Considerations

Ethereum 2.0 is fast approaching with multiple implementations underway. We examine the attack surface of Eth2, specifically:  -Networking (eclipse attacks, transport encryption, discovery protocol, anonymity)  -Software vulnerabilities (DoS, code integrity, inconsistent state transitions) -Consensus assumptions (honest majority, liveness) -Efforts underway (fuzzing, code review, external assessments)

Ethcon: build your local community's developer conference just like building an opensource together

Korean Ethereum community successfully hosted a local community-driven Ethereum developers' conference in May 27th-28th, 2019. 60 speakers, 500 participants, 16 donators, 16 sponsors, 11 media partners, and 20 volunteers made the conference together. Also, 'Ethcon Korea' could get grants from Ethereum Foundation for the effort to focus on the local voices and shed light on them. This speech tells about how we built that solely run by volunteering like building an open source together. To be more specific, we want to share our experience with other local communities and encourage them to make their own Ethcons through the following agendas: Why we started the conference How we prepared the conference in a decentralized manner What happened so How to make a community's own 'Ethcon'?

Ethereum 2.0 Trustless Staking Pools

One of the goals of the Ethereum 2.0 protocol is to allow for trustless staking pools. The main difficulty that had to be overcome to achieve this was the proof of custody construction, which we specifically changed to use a very MPC-friendly cryptographic primitive, the Legendre symbol.

Ethereum 9¾: MimbleWimble for ERC20 with ZK Snark

Ethereum 9¾ is an entrance to the magical world to send ERC20s privately. It hides the transaction histories using MimbleWimble and ZK Snark. A user enters into the magical world by depositing ERC20 tokens with a valid MimbleWimble output. As Ethereum 9¾ appends it as a coin-base to the Merkle Mountain Range tree, the user becomes able to use MimbleWimble spell to send ERC20 privately. The contract only accepts MW spells which include an unlinkable spent tag, result outputs, and a ZK proof. The proof should pass the ZK-circuit which ensures that the tag is derived from an output which definitely exists in the MMR tree while the sum of spent and resulting outputs satisfies the MimbleWimble equation. Then, the spent tag prevents double-spending and ZK Snark secures deposited ERC20s by proving that the sum of inflow and outflow is zero by MimbleWimble protocol without revealing details. Or the user can go back to the muggle world anonymously and withdraw ERC20s by providing an unlinkable spent tag and a ZK proof. Because MimbleWimble doesn't reveal the value during transactions and we also don't know which output has been spent, it becomes hard to link the deposit and withdrawal.

Ethereum roadmap 2020 EEA Meets With Ethereum Community

Overview: The Enterprise Ethereum Alliance (EEA) is interested in growing our relationship with the Ethereum Community and building a bridge for ongoing communication. We invite you to participate in an open forum co-hosted with the Ethereum Foundation, Ethereum Magicians, and Ethereum Cat Herders such that EEA can better collaborate to serve users of Ethereum Mainnet. The goal of the workshop is a moderated large-group discussion where everyone in the room feels they have a voice.

Ethereum Roadmap 2020 Say Hello and Opening Ceremony

The Ethereum Magicians open Devcon 5.

Ethereum Roadmap 2020 Eth1 to Eth2 Transition

The Ethereum Magicians give an update and a Roadap for Ethereum in 2020 and beyond, looking ahead to the transition to Eth 2.0

ethers.js - A Complete, Simple and Tiny Ethereum Library in JavaScript

The ethers.js library provides a complete, easy-to-use JavaScript library for developers to create dapp frontends and backends, Ethereum frameworks, tools and wallets.It provides all the APIs and utilities needed to query and connect safely and securely (optionally infrastructure-free) to a variety of backends, create JavaScript objects representations of  smart contracts and their state, sign and manage transactions and format content for display logic and parse user input.This talk will quickly cover many of these features, provide examples of common tasks, and demonstrate a few less-obviously-dangerous, but easy-to-make mistakes  (with solutions).

Ethical design practices for web3

In this talk, we'll share the MetaMask Permission System, a set of agreements between web applications and users that could help make new/emerging web user experiences more trustworthy.  We now have enough evidence that illustrates how users’ trust is being broken by today’s web, and how user experience is fundamentally broken due to lack of user control, lack of choice, unethical data sharing practices, and use of dark patterns by websites. Web3 has attempted to address some of these issues, but so far our user research points to a lack of maturity in creating useful & engaging experiences. We'll share applied design practices that help keep users in-charge (e.g., design suggestions for informed consent, aid decision making, privacy & security by default, etc.), without interfering in enjoyable browsing experiences.

ETHLagos: onboarding developers and laying a foundation for 1billion + people

Through firsthand experience, our group of EF devs realized that hackathon participants often lack sufficient knowledge to create meaningful projects within the short timeframe of a hackathon event. This has led us to create a concept called ETHimpact. ETHimpact is introducing a novel approach to solving social and global challenges. By creating an inclusive environment and bringing together developers, designers, and industry experts into a week-long program to learn and co-create decentralized solutions for social impact, we effectively break down barriers between groups with a shared vision to drive towards a sustainable future. Our team is now made up of motivated individuals from all walks of life. We are supported by the EF, the German Development agency (GIZ), as well as local initiatives like the Africa Blockchain Alliance. We do not only end our engagement with the hackers after the hackathon/event, but will continue to work with the winning teams to build out the solutions into sustainable impactful projects. ETHLagos is the first iteration of this concept, and we would like to introduce it to the world at Devcon. In this first edition, we will focus on decentralized energy solutions: an area of prime importance for Nigeria in the wake of its current energy crisis. We chose Lagos because it is a thriving techhub in Africa, and because we’ve realized that decentralization is not a new concept to Nigerians and Africans in general. Ancient civilizations within Nigeria and Africa have governed themselves using decentralised concepts for centuries. Examples include consensus mechanisms, oracles and state channels. The ancient civilizations of Ife, Benin and Igbo communities within Nigeria have used these concepts and still use them today. This has also made it easier for the concepts of decentralization to be understood and accepted across Africa and helped in building a thriving community of blockchain enthusiasts on the continent through the Africa Blockchain Alliance.  One of the fruits of the African community effort is the Ribbon Blockchain built on Ethereum. Ribbon seeks to automate public health through tokenized incentives. Ribbon enables crowdfunding for public health programs, then distributes proceeds as incentives to patients and healthcare practitioners to encourage healthier lifestyles and quality healthcare delivery. Funding is sent directly to patients, community health workers and healthcare practitioners; where the funding is used for preventative care, adherence to medication, quality care delivery and overall population health outcomes. A demo of the incentives app will be showcased.  We believe that many more impactful projects in the energy space and more areas will emerge from this concept which we will keep supporting in solving some of the world’s most pressing challenges.

EVM Roundtable: everything you wanted to ask, but were afraid to

A fishbowl style conversation with passionate contributors to the EVM, but allowing anyone from the audience to stand up and lead a topic. The intent is to discuss certain key topics, such as how to evolve the EVM, what the most pressing issues are, and dissecting a handful of EVM proposals.

Ewasm 2.0 - State Execution in Eth 2.0

This session aims to bring clarity to what execution on Eth 2.0 means. It will be presented by multiple members of the Ewasm team, starting with a historical overview of how Eth 2.0 designs evolved around execution, followed by deeper technical topics. We will cover: - Scout (an Eth 2.0 execution engine) - Different execution environments (such as the "Eth1 shard") - In-depth presentation of different designs used in the Eth 2.0 stateless model - An Eth 2.0 execution testnet If you are interested in stateless contracts and Merkle proofs, this is the session to attend.

Extending Ethereum’s Account and Transaction Models in Klaytn

Ethereum has usability limitations that hindered mass adoption. To solve the issues, Klaytn, an Ethereum-forked blockchain platform, extended account and transaction models while preserving compatibility. Blockchain user accounts have been a technology adoption barrier. There are two pain points that Klaytn aims to solve. 1) A random hex string as an account address that is not human readable. 2) A single private key that is permanently attached to an account. Klaytn supports the creation of alphanumeric account address and update of the private key of an account. On top of that, the native support of multi-sig and role-based keys, which is needed by industry, will expedite the blockchain mass adoption. Klaytn refined the transaction model as well so that each transaction type serves a specific function. This separation of concerns gives more opportunities for performance and storage optimization and makes it easy to add or extend platform features. Utilizing this design, several new transaction types are introduced in Klaytn without breaking backward compatibility to support the transaction-fee delegation and the extended account management features mentioned above. We believe that Klaytn's new account and transaction models are applicable to other Ethereum-compatible blockchain platforms to increase usability and performance.

Ewasm: Past, Present, Future

Starting with a brief introduction, we explain the challenges, design directions, and the work done in the last 12 months. We conclude with a roadmap of Ewasm. The session will consist of four parts: 1. Introduction 2. Speed, Size, and Extensibility – a honest report of Wasm in Ethereum (aka "The Benchmarking Report") 3. Is Wasm suitable for blockchain? This part will explain the changes (if any) needed for Wasm, questions relevant to blockchain, and solutions developed and proposed. 4. Roadmap

(e)WASM code golfing - below par with Nim

On the horizon of Ethereum2, WebAssembly being proposed for phase 2 execution. Just like with the EVM, we'll be paying for gas and storage, and thus it's important that you're able to use contract space efficiently.In this presentation, we'll go over the WASM pipeline from program code to assembly bytecode, looking step by step at:* where storage goes* tricks and techniques to optimize for size, speed or both* how the compiler looks at and reasons about your code* what tooling is available to help you!* how the choice of programming language might affect the efficiency of your codeFor our examples, we'll be using NimPlay - an easy to use smart contract development environment currently being researched at Status.

Finding the Simplest Path to Digital Sovereignty & Security

Paul Gardnerstephen presents his talk on Finding the Simplest Path to Digital Sovereignty & Security.

Formal verification of smart contracts made easy

In this hands-on workshop, we will go through the process of formally verifying smart contracts. The attendees will learn (1) how to formally specify relevant functional requirements of Ethereum contracts, such as "the sum of deposits never exceeds the contract’s balance", and (2) how to verify these using existing analysis tools for Ethereum. First, we will show how to formally specify the intended behavior of smart contracts. We will look closer at safety temporal properties, an expressive class of properties for capturing which sequences of contract states are considered correct. We will present common requirement idioms, including access control, state-based properties, multi-contract invariants, and others. Next, we will provide an overview of existing testing tools, such as tools based on symbolic execution and fuzzers. The goal is to understand how they can be used to identify violations of the formalized properties as well as their limitations in providing unbounded formal guarantees. Finally, we will learn how formal verifiers go beyond testing and can provide unbounded formal guarantees (for any sequence of transactions). We will take a closer look at the specification language used by VerX and its automated verification method, which is easy to use and does not require in-depth knowledge in formal verification.

Formally verified EVM golf and reverse bug bounties

With the formalized semantics of the EVM in the K framework (the Jello paper), a new arsenal of analysis tools has become available for Ethereum smart contract development. This workshop will demonstrate how this tooling can be used to verify the complete behavior of smart contracts, sharing the techniques and tools used to verify the core contracts of multicollateral dai.We will demonstrate the power of formal verification by presenting the Ethereum community with two challenges:In the first one, we invite the workshop participants to a round of formally verified EVM golf. The most gas efficient implementation of an ERC20 contract which provably matches the specification wins!In the second challenge, the task is to challenge the specification itself, by writing a passing adversarial smart contract. In this "reverse bug bounty", participants are invited to poke holes in a specification by writing smart contracts which satisfy the postulated requirements but are otherwise faulty in some way.

Funding as Medium and Message: How We Get Capital and its Influence on #BUIDL

Access to capital is likely one of the most fundamental tools to #BUIDL anything. But do we ever think of funding as a core tool and the implications that it has? And how does our choice of funding affect our message? Funding has many sources, both centralised and decentralized, and many legal implications. And funding strongly affects incentives, human behaviour, how we communicate and collaborate with a community. This workshop will explore a topic that often feels taboo: namely how and why we obtain funding and what it means in a decentralized world. We will explore centralised funding (equity), non-profit funding (grants), decentralised funding (tokens), continuous funding (DAOs and bonding curves) and many more. More importantly, though, we explore what teams and developers should be aware of when looking for funding decentralized solutions, educating attendees on what sources are available in the Ethereum ecosystem, and what philosophical and behavioural implications funding actually has.

Funding ETH 1.x With Network Upgrade Sponsors

In this lightning talk, we will propose an auction mechanism to sponsor Ethereum Network Upgrades and use the proceeds to fund Ethereum 1.x initiatives. The talk will (quickly!) go over the proposed auction scheme, distribution of funds, and common objections to & potential pitfalls of this model.

Future of Open Hardware in a (Verifiable) Decentralised World

Matthias Tarasiewicz present his talk on the Future of Open Hardware in a (Verifiable) Decentralised World.

Functional programming for Ethereum

Statically typed functional programming has received more attention in the age of blockchain than perhaps ever before. Languages like Haskell and PureScript were once thought to have a more natural home in academia than in industry. Now their powerful static analysis and security guarantees allow blockchain developers to prove more about the correctness of their programs. This is especially important as we move into the era of application-specific blockchains and scaling solutions written in ordinary languages.We’ll walk through the state of Ethereum libraries and tooling in Haskell and PureScript to highlight some of their interesting features, as well as compare and contrast them with their counterparts in non-functional languages. We’ll also discuss the ongoing work on hs-abci, the Haskell bindings to the Tendermint ABCI protocol, which enables Haskell developers to write application specific blockchains backed by cosmos/Tendermint.The session will be a mix of live demonstrations and slides. There will be a repository to follow along with for the interactive portions.

Fully automated inductive invariants inference for Solidity smart contracts

One of the hardest challenges in formal verification is handling loops in a fully automated way. A common approach is to compute inductive loop invariants, properties that formally capture the essence of the loop independent of the rest of the program. These sound loop summaries are then used to check further desired properties from a specification. In the context of Solidity smart contracts, properties over state variables can also be seen as loop invariants where one loop iteration is one transaction. We developed a technique using systems of Horn clauses to infer state and loop inductive invariants at compile-time in a fully automated way, while proving safety properties. The algorithms are released as part of the SMTChecker module inside the Solidity compiler. Thus, the process is seamless to the developer and requires nothing more than the source code. The generated inductive invariants can be used by the compiler and other tools to check properties more easily, to confirm/correct external specifications, and to provide potentially hidden program logic insights to the developer. The goal of the talk is to present the technicalities and use cases of our approach, and to continue discussions around formal verification and inductive invariants.

Fuzzing the Solidity Compiler

Since the Solidity programming language does not have a formal specification, testing the compiler implementation is an important way to obtain assurance about the correctness of code generated by the compiler. Fuzz testing is well-suited for this setting. However, applying fuzzing in the traditional manner (random input generation that is coverage-guided) is inefficient for testing compilers because a significant fraction of randomly generated code is syntactically invalid. If the fuzzer does not generate syntactically correct Solidity programs, the compiler will simply reject it. As a consequence, code optimization and generation subsystems of the compiler will not be tested. The approach adopted by us is to define a grammar for the Solidity programming language and automatically generate inputs based on this grammar. Grammar based fuzzing ensures that generated programs are successfully parsed by the front-end parser. We make use of libProtobuf and libProtobufMutator for defining the grammar and performing grammar-based mutations, and libFuzzer as the underlying fuzzing engine.

Governance Schizophrenia of Decentralized Protocol

Decentralized protocol has conflicting needs of governance during its life-cycle. In the early stages, the protocol needs fast, flexible and focused development. Such is usually achieved by the founding team controlling both roadmap and team composition. Autocratic leadership enables the protocol effective bootstrapping and fast time to market. As the protocol matures, more and more people become dependent on it. Characteristics of being fast, flexible (and centralized) transforms from an advantage to the unwanted feature. People who build their businesses and lock-in their future on chosen platform are not willing to undertake risk of their lives being governed by nontransparent organization. So, how can it be addressed? Building decentralized protocol with the governance transformation process in mind (from day one) is the answer. Let's elaborate on the most efficient and non-destructive governance transformation model that would put order to the noise of the protocol schizophrenic needs. From foundation to algorithmic democracy (DAO)...

Grantee Exposé Lightning Talk 1 - Formality: An efficient proof language

Formality is a dependently-typed functional programming language similar to Agda that compiles to a non-garbage-collected, parallel runtime based on interaction combinators and Lamping's optimal reduction algorithm. The language is suitable both as a formal proof language as well as a fast low-level systems language, which allows it to be used to write verifiably secure software at every level of the stack, from hardware drivers to smart contracts and everything in between. Formal proofs are of particular interest for smart contracts applications, given that they often have large amounts of capital depending on the safety of relatively small code bases.

Grantee Exposé Lightning Talk 1 - Sustaining Open Source Software GITCOIN

As end-users join us on the journey from Web 2.0 to Web 3.0 they will encounter a new suite of tools, terminology, and ways of thinking. The way you architect your app will have massive implications for your users, and developers need to balance the tradeoffs between decentralization and maintaining a good user experience. In this talk, Gitcoin VP of Engineering Dan Lipert will discuss the tools and techniques Web 3.0 developers can use to make their users' lives easier, while still maintaining decentralization and privacy. He'll go over the advantages and disadvantages of tools like decentralizated storage, blockchain metadata caches, running your own nodes, and using public blockchain explorers. As you create your next generation web application, you'll need to decide how to keep your userbase's data safe and private, without sacrificing usability - come to this panel to learn about the tools available to you and how best to utilize them.

Grantee Exposé Lightning Talk 1 - The Web3j-SDK

This talk at Devcon will be used to announce the release of the web3j SDK (final name TBC), which provides a fully integrated development and deployment environment for Java/Android/Kotlin/etc developers working on Ethereum. It also includes a smart contract registry and blockchain explorer for ongoing smart contract management and support.

Grantee Exposé Lightning Talk 2 - Perun’s research on off chain protocols

Lisa Eckey presents Perun's research on off-chain protocols.

Governance Strategy for Maximum Fork Readiness

In this workshop, we will present a case which will concern a fictional blockchain with characteristics similar to Ethereum and a potential fork of that blockchain. Based on an imaginary event, but with realistic elements, the fork will be linked to the phenomenon of tech giants issuing their own currency. We will present all the known facts of the case, important stakeholders, relevant circumstances of the fork, actions taken by individuals and the community as well as the rest of the information that influenced decisions taken by the involved parties. We will create three claims for each party which together form a dispute between primary blockchain community and the forked community. Attendees will be asked to form argumentation for both sides, analyzing and applying current customs, norms, and protocols with respect to crypto law and already existing practice in the blockchain community. The objective of the workshop is to form an interdisciplinary cooperation and practice combinations of expertise needed to create persuasive and complex argumentation. They will take into account practicalities, e.g. protocol design, the politics and efforts of stakeholders as well as the usual scenarios, communication management, expected public relation management, intellectual property hacks, and standard business ethics.

Grantee Exposé Lightning Talk 3 - Academic Research on Casper

CBC Casper is a promising protocol for the future of Ethereum. However, the research of CBC Casper is still in progress, even about its fundamentals. For example, Casper has been criticized for the lack of liveness proof for a long time. Therefore, we first introduce our liveness proof. Then, we analyze CBC Casper in both its performance & incentive to persuade the audience why CBC Casper matters.  This presentation is based on our unpublished work, which we expect to publish by the time of DEVCON5. The more detailed agenda is: (1) Liveness: We first introduce our liveness proof, which is applicable to each family of CBC Casper. (2) Performance analysis:  We compare CBC Casper with other existing protocols about  TPS and latency, both of which are important performance measures of consensus protocols, showing the advantages of CBC Casper. (3) Incentive analysis: CBC Casper is designed to satisfy economic properties desired for a public ledger. In particular, the notable feature of CBC Casper is "subjective finality", where validators can pick up their own fault threshold. We discuss how this feature affects cartel resistance.

Grantee Exposé Lightning Talk 3 - Twitch Plays Pokemon on Plasma

Tom Nash presents Twitch Plays Pokémon on Plasma.

Grid: tools for the ETH 2.0

In this lightning talk we'll show how Grid lets you safely download and manage ETH clients and interact with the ETH 2.0 beacon and validator chains.

Grantee Exposé Lightning Talk 2 - What’s next for GSN

Liraz Siri speaks on what's next for the Gas Station Network.

Grid: your new personal Ethereum infrastructure

Grid provides new and experienced users alike with a powerful tool to help them find, download, configure, and use Ethereum clients and tools in a secure way, enabling them not only to become participants in the Ethereum network, but also strengthen the core philosophies. Grid tries to make the Ethereum ecosystem, and access to powerful financial and cryptographic applications, more inclusive and accessible for everyone.

Growing The Way We Support

What we're up to, what's different from last year.

Guidance on Assessing a Blockchain Platform

Blockchain platforms are maturing to enable decentralized architecture but vary in design depending on deployment environments, such as open digital ecosystems or contained multiparty environments. In this session we provide a summary of Gartner's observations on blockchain platforms adoption, a functional framework for assessing blockchain platforms, and future projections on blockchain platforms technical evolution.

Handel: Practical Multi-Signature Aggregation for Large Byzantine Committees

We present Handel, a Byzantine fault tolerant aggregation protocol that allows for the quick aggregation of cryptographic signatures over a WAN. Handel has logarithmic time and polylogarithmic network complexity and needs minimal computing resources. We implemented Handel as an open source Go library with a flexible design to support any associative and commutative aggregation function. We tested Handel with a BLS multi-signature scheme for BN256 on 2000 AWS instances running two nodes per instance and located in 10 AWS regions. The 4000 signatures are aggregated in less than 900 milliseconds with an average per-node communication cost of 56KB. This work can be used to improve Ethereum 2's latency to finality.

Hands-on applications of zero-knowledge signalling

Semaphore is a generalised zero-knowledge signalling system which can be deployed to fulfil various privacy use cases, such as a mixer and anonymous whistleblowing. This hands-on workshop will guide participants through a high-level explanation of how Semaphore and zero-knowledge proofs work, and guide them through an anonymous chat app integrated with POAP tokens which can generate and verify said proofs. No programming or zk-SNARK knowledge is needed.

Holly Atkinson: from zero knowledge to zero knowledge proof

Holly Atkinson left her role as Lead Business Developer at a green energy company on 31 October 2018, to pursue a new career as a software engineer. Holly now works as Frontend Engineer at Tracr, a company that is bringing the benefit of the Internet of Things to the Diamond Industry, and plays an active role London’s blockchain community. She will share her technical pathway to date, her perspectives on the two types of role and her reflections on turning from a user of technology into a creator.Specifically, Holly will share her story about how and why she became a developer, useful resources, getting into Ethereum in London, observations on the differences between old and new career, key learnings from being a mentor to women in tech and her vision for the future.

How are projects working with the international development sector? Perspectives from Ukiyo Conference

How are projects securing and scaling use cases in humanitarianism, working with the international development sector and better understanding the needs, risks and challenges of end-users?Hear from the people & projects:- use cases in direct cash transfers, digital identity, community currencies by projects + aid organisations. - researcher perspectives on design, data, privacy and the risks and challenges of deploying emerging technology.- feedback loops with the communities projects intend to serve to understand and test the needs, complexities and impacts of solutions being designed and built. [Ukiyo Conference occurs the day before Devcon in Osaka with the aim of designing and deploying solutions that consider the consequences and complexity of emerging technology.]

How do we make dapps as secure as the underlying Ethereum?

Web3.js is a Javascript API for web applications (dapps) to access Ethereum blockchain. However, its security assumption inherited the security assumption of an Ethereum node, which is entirely open to the node's owner. The privacy and security consequences of that assumption are two-fold. First, a web application can learn sensitive information about the user. Second, the web application can feign a representation of blockchain data to be another or even tricking users to signing obfuscate transactions. A website which simply draws a crypto kitty would look no different than another which reads the user’s kitty from Ethereum smart contracts. Much makeshift work has been down for this underdesigned infrastructure. For example, MetaMask resorted to hardcoding CryptoKitty and requesting permission to read the user's address. However, only so much patches could do. Furthermore, such patches weren’t designed with abstraction to accommodate next-generation blockchains with privacy and efficiency improvements. For example, failing to find truth quickly using the low-level interfaces provided by web3.js, many dapp browsers resorted to relying on a centralised token status database. The speaker presents a design which abstracts token interface away from low-level Eth-node interface, remodels the basic web code trust inheritance for practicality and security. It involves high-level API for web applications and a secure, WebAssembly based sandbox running signed code designed to embed in the Web itself.

How ENS is taking Ethereum to the rest of the Internet

ENS is forming a bridge connecting the Ethereum and legacy Internet communities. We are doing this with DNS domain integration; support for other cryptocurrency addresses; resolution for IPFS and Tor .onion addresses; working on securing a new DNS record type for Ethereum addresses; relationships with ICANN, IETF, et al; and working on support for DNS records and other cryptocurrency addresses. This helps to further entrench ENS and therefore Ethereum as a basic piece of Internet infrastructure, used widely by people whether they are a part of the blockchain community or not.

How Microsoft engineers build enterprise Blockchain apps on Ethereum Networks

Enterprise Blockchain applications have different constraints and challenges to ones on public networks. Come see how Microsoft engineers architect based on market segment (B2B / B2C), and use serverless compute to integrate systems onto Ethereum networks. This will be a demo heavy presentation showing real world engineering used at top enterprises, such as DevOps, unit testing, serverless compute, VS Code scaffolding.

How much gas does it use interacting with this smart contract?

Developing a smart contract is easy. There are a lot of tutorials and examples on how to write a smart contract. In some cases, it is even possible to simply copy the code. Afterwards compile it, deploy it and let the users use it. But has it been optimized before the deployment or does it waste the user’s gas?We present a tool which analyzes the bytecode of a deployed smart contract based on the rules presented in Chen et al. (2018): “Towards Saving Money in Using Smart Contracts”. A user can enter a transaction hash and the tool reveals if the smart contract has been optimized. For non-optimized cases the user sees how much gas is wasted by using the functions. The estimation is based on the analysis of the OP codes. Thus, is not necessary to provide the ABI or the source code. This gives users the possibility to verify that smart contracts do not use too much gas and forces developers to optimize their smart contracts.

How scaling impacts privacy

This will be a presentation or panel discussing the positive and negative privacy consequences of scaling to mainstream use. By considering the data stored on blockchains, now, we can speculate about the use of it in the future and how it can be analyzed at scale. We will explore specific data types and common use cases, including data mining. The goal of this session is to help the community know how privacy will be impacted when cryptocurrency reaches mainstream use and explore the societal consequences of personal data collection and decentralization of systems.

Hodor - open source zkSTARKs library by Matter Labs

"Hodor" (let's be original and don't use Marvel Universe) is an open source implementation of zkSTARKs over prime field (initially) that is currently being developed by Matter Labs and expected to be released early-mid September. In this workshop I'd like to cover some information about zkSTARKs such as arithmetization and prover/verifier work, as well as give concrete examples how to use "Hodor".

How to Integrate Ultralight Beam

The objective of Ultralight Beam ("UB") is to provide a simple and extensible messaging format for applications to transmit arbitrary data over a mobile ad hoc network (MANET). MANETs are devices that come together to form a network without relying on any infrastructure. In the context of Ethereum, this allows for transactions to be broadcasted and state channels to be formed, but offline. This workshop aims to show how a developer could integrate Ultralight Beam into their application to allow for offline interactions as described above.

How to make ethereum really trustless?

Every month, more than 1.5 million smart contracts are published to the blockchain.Every day, more than 1.2 million calls are being made to smart contracts.There are more than 10 million smart contracts on the blockchain already.At the same time, there are less than 1000 publicly verified source codes.Without verified source codes, users who interact with smart contracts directly or through the use of DAPPs, have to trust that the contracts actually do what they promise to do and don't contain any malicious parts.We would like to host a session to discuss how to motivate smart contract creators to publish/verify their source code. Furthermore, we would like to discuss to store verified source code in a decentralized way.

How To Onboard A Staking User in Under 5 Minutes

1) Staking problem overview As dPOS becomes a popular design pattern, staking tokens is an activity that end users for dapps and protocols are increasingly exposed to in order to get the required network participation. Since user interfaces for dPoS is still quite new for most, we hope to help you with your own design research by sharing some of our challenges and learnings unique to designing dPoS staking applications. At Livepeer, we employ a dPOS approach to ensure the quality and security of the video transcoding services that our platform provides. Past studies showed that it took from 30 minutes up to 3 days for new users to figure out how to stake. This led us to ask the question: how can we make the experience so intuitive that even new users can go from signing up with a wallet to staking token in under 5 minutes? 2) Research and design A) We conducted 15 user interviews with current and new users and constructed a user journey of the current staking experience. B) Noting the pain points and feature requests from these initial talks, we then went on to do competitive analysis across 10 staking apps for prominent blockchain projects, taking inspiration from the best elements of each. C) Due to feedback about user confusion, while navigating our staking app, we asked users to card sort features on the current application to help us redesign information architecture. D) Lastly, we iteratively tested our redesign with clickable prototypes to create a brand new onboarding experience and a brand new staking platform. 3) Results Our A/B test of the prototype showed a significant improvement in the amount of time it took for users to go from signing up to staking token. 60+% participants were able to complete the new staking prototype in under 5 minutes*! *Given that the user has already installed a wallet and have acquired Livepeer token.

How to Develop Generalized Applications on Layer2

Cryptoeconomics Lab has been researching generalized Dapps using the second layer technology especially Plasma and building a framework with developer tools for them. The final goal of our R&D is to produce more viable applications running on top of Ethereum by enabling developers to build secure, scalable, and usable Dapps with better developer experience. In this talk, we will first clarify what it’s like to build L2 applications based on the design of the Optimistic Virtual Machine, our latest research focus, which enables the generalization of various Layer2 constructions. Then, we will showcase example L2 applications, such as a payment application with instant finality using Plasma and payment channel and DEX supported by Atomic Swap technique.We hope that we can contribute to the Ethereum ecosystem by sharing our research outcome and its implementation as a library with all the other research teams and create more of the application use cases on Ethereum cooperatively.

Increasing adoption, the hard(ware) way

Everyday we use tremendous amount of computer power. However, nowadays all of this processing needs are fulfilled by 3rd parties and it is damn convenient to do so, even if it means sacrificing privacy and security. In the short term it is not very likely that families have servers at home that fulfil all their computing needs 24/7, let alone the nodes to run blockchains! The mass market is already buying and running, of their own volition, hardware that provides them with a service they extract direct value from: a smart hub home, a voice assistant, AI bots monitoring all sorts of data… These are entering the consumer market by the storm, but they are missing one key piece: a means to transfer native value within the networks they form. Can we leverage the hardware people are already accepting into their homes and give them more functionality? Can we equip these devices with nodes and increase node count? What needs to happen for this to become a reality? An incentivization layer, a more data-conscious cyber-culture and direct value to the user would get us there. This talk will explore how to put a node in every home.

Infura's Open Architecture Initiative

Infura engineers have found unique ways to utilize tools openly available in cloud provider offerings to reduce the time to sync Ethereum nodes and run them reliably. At DevCon5 we’d like to share this new architecture paradigm so that other development teams will be able to utilize the same tools that we do to run their own reliable infrastructure. We first launched at Devcon2 as a handful of nodes and a simple architecture. We’ve scaled and iterated on our architecture for API traffic that grew from millions to billions of requests per day-- serving applications like Metamask, MyCrypto, Coinbase Wallet, Opera, and Brave Browser. Infura makes it easier for developers to build on Ethereum. During this talk, we’ll share our findings on scaling access to blockchain data. We’ll also discuss ways on how to efficiently cache blockchain data for the JSON-RPC API. We’ll talk about what worked and what didn’t so that others can learn from our applied research.

Improving the federated 2-way peg: A new sidechain design for trustless bridges on Ethereum

In this talk, we'll introduce a novel mechanism to maintain 2-way pegs, as well an initial implementation of a Bitcoin peg on Ethereum. ## Problem Bitcoin's stable codebase is a strength. Developers are loathe to introduce significant changes, reasoning that a store of value should prioritize stable operation. While this cemented Bitcoin's place in the market, we all know the costs- Bitcoin's ossification at the expense of public experimentation and diverse use cases. In 2014, the answer to this problem was "sidechains". Trustless sidechains are the ultimate vaporware- and since 2014 the goalposts have moved. ## Approaches Blockstream's Liquid touted itself as the "first production sidechain", built on a multi-sig federation. No hashpower validates the sidechain-- funds are fully trusted to 15 Bitcoin multi-sig participants. BitGo's WBTC takes a similar tact-- but instead of building a new chain, custodians operate on Ethereum. Neat! Unfortunately, they require KYC :( These centralized projects have a few custodians that can be convinced by governments-- or their own interests-- to censor or seize funds. ## Design We propose a new approach-- the *bonded, multi-federated peg*. We believe this is the best candidate for a sufficiently trust-minimized alternative, unlocking Bitcoin for use in DeFi.

Is Market Capitalization an Objective Measure of Cryptoassets’ Value?

The cryptoasset industry is fixated on market capitalization as a metric in determining the success of any particular project. In this talk, we will shed some light on how market capitalization can be easily manipulated and is not entirely the best metric to value cryptoassets. More due diligence should be applied before trusting any market capitalization number published anywhere.

Janus Platform

How to publish websites in a decentralized way and index it using Ethereum Smart contracts. After is possible to search keywords in the websites. In this talk will be presented tools to register, store and explore the Web 3.0.

Japanese, Human-Readable Smart Contracts

This workshop invites native or fluent Japanese speakers to create a Japanese-based smart contract language to create Ethereum smart contracts with that can be read by anyone who understands Japanese, and deployed directly to the Ethereum mainnet. Speakers of other languages who are interested in facilitating a Lexon variant based on their language are also invited to understand the process of adaption. The attempt is based on the Open Source, human-readable smart contract language Lexon that is a subset of natural English. This workshop is a hackathon-like event where the Lexon compiler source code and grammar is altered to see if a Japanese version of Lexon is possible. Coding skills are NOT required from participants. Lawyers and impact-oriented participants are highly welcome. Only one or two programmers — likely the tutor — will be working on code. The actual work will be for the audience to understand how the Lexon grammar is structured and to propose what has to be changed to make it work with Japanese. The result may be a working Lexon compiler for smart contracts written in Japanese, that anyone who can read Japanese can understand, and that can be compiled and run on the Ethereum main- and testnet immediately. This is possible because the Lexon grammar is relatively concise and changes to it can be made in a straight forward way that could lead to immediate results. At the least some experimental output should be achieved from an alpha version of a Japanese Lexon compiler. This is a different proposal from the workshop that teaches people how to write human-readable smart contracts in English. This Workshop is complementary, hands-on research part to the proposed 20-minute session about Human-Readable Smart Contracts. It will allow participants to shape the way forward for the project. (For your convenience, the following is a repeat from the complementary 20-minute session application that focusses on reading and the science behind it. 'Human-readable' smart contracts expand the audience of people who can read smart contracts by a thousand times. They democratize them beyond the ranks of developers and provide a means for expert validation, human debate and consensus. Lexon is a new type of program language that can be read by anyone without any preparation, made to create smart contracts that run on the Ethereum mainnet. It has been built from the ground up, over the course of two years, to allow lawyers and non-programmer experts to understand first-hand what a smart contract means. The result turns out to be enlightening for any community that wishes to allow their non-technical members to read for themselves what its DAO or smart contract code actually means. Turns out that's everyone except re-centralizing start ups. LEX Escrow Contract. “Payer” is a person. “Payee” is a person. “Arbiter” is a person. “Fee” is an amount. The Payer pays an Amount into escrow, appoints the Payee, appoints the Arbiter, and also fixes the Fee. CLAUSE: Pay Out. The Arbiter may pay from escrow the Fee to themselves, and afterwards pay the remainder of the escrow to the Payee. CLAUSE: Pay Back. The Arbiter may pay from escrow the Fee to themselves, and afterwards return the remainder of the escrow to the Payer. The enclosed paper draft explains the concept in-depth and has longer examples. Lexon is an Open Source project by the Lexon Foundation. It was created by the presenter and implemented by Marcelo Alaniz, Nicolas Guzzo and him.

(In)Stability for the Blockchain: Deleveraging Spirals and Stablecoin Attacks

We develop a model of stable assets, including noncustodial stablecoins backed by cryptocurrencies. Such stablecoins are popular methods for bootstrapping price stability within public blockchain settings. We demonstrate fundamental results about dynamics and liquidity in stablecoin markets, demonstrate that these markets face deleveraging spirals that cause illiquidity during crises, and show that these stablecoins have `stable' and `unstable' domains. Starting from documented market behaviors, we explain actual stablecoin movements; further our results are robust to a wide range of potential behaviors. In simulations, we show that these systems are susceptible to high tail volatility and failure. Our model builds foundations for stablecoin design. Based on our results, we suggest design improvements that can improve long-term stability and suggest methods for solving pricing problems that arise in existing stablecoins. In addition to the direct risk of instability, our dynamics results suggest a profitable economic attack during extreme events that can induce volatility in the `stable' asset. This attack additionally suggests ways in which stablecoins can cause perverse incentives for miners, posing risks to blockchain consensus.

Interblockchain Communication & Interchain Topology

The interblockchain community protocol will faciliate permissionless interoperation between smart contracts on Ethereum 1.0/1.x & Ethereum 2.0, Cosmos zones, Polkadot parachains, Bitcoin & more. The first half of this talk presents the protocol construction, notes security properties & consensus requirements, explains the message channel interface exposed to smart contracts & modules, and discusses special techniques for bridging Nakamoto proof-of-work consensus blockchains such as Ethereum 1.0/1.x to chains with finality. The second half embarks on a speculative exploration of what the future topology of interconnected blockchains might look like: what economic constraints might shape cross-chain design choices, what kinds of applications might most benefit from cross-chain logic, and what shared ecosystem standards might most effectively facilitate positive-sum interoperation, with particular attention to integration into the Ethereum 2.0 specification process.

Keymanagement: Multisig based Custody as Enabler for Mass Adoption

Key management is a fundamental challenge in the widespread use of blockchain technology. Especially when it comes to managing large tokenized values, a suitable custody service is essential. While many existing custody services are primarily based on technologies such as Shamir's Secret Sharing, it makes sense to use a Smart Contract based Multisig to manage the rules such as access, what signatures are required, time delay, recovery of lost accesses, etc.

K Semantic Model of Beacon Chain

Daejun Park gives an overview of the K-Semantic Model of the Beacon Chain.

How We Think About Storing Crypto is Broken

The original sin of cryptocurrency is not transaction speed, poor anonymity, volatility or a high Gini coefficient -- it's a digital format which is confusing to use, easily delegated to centralized exchanges and, most importantly, reliant on multiple layers of software and hardware trust. What if instead Bitcoin and Ethereum were like cash, a physical format that billions of people are intimately familiar with? To achieve a viable physical cryptocurrency, however, we need radically open hardware with cryptographically-secured guarantees of their face value and uniqueness anchored in silicon. We propose a novel, low cost, physical format for cryptocurrency -- more appropriately "cryptocash" -- that's intuitive to use and allows for free, anonymous, and instantaneously final transactions. By isolating cryptographic key material and operations from software and firmware in secure silicon, we can build a new hardware foundation that supports not only self-ownership of crypto assets, but broadly serves to secure the secrets users need for participation in the decentralized web. We'll hone in how shared trust in hardware and chips must ultimately be quantified through crypto-economic incentives such that we can move away from manufacturers that willfully or ineptly include backdoors in their products.

Kicking Our Infura Addiction: A Quick-Launch Client

How do you connect to mainnet? To minimize effort, there is one obvious answer: Infura. Infura has its place, but using it everywhere means giving up so many of the core promises that Ethereum makes. So how can we make it easier to run your own node and actually deliver on Ethereum's promises? One of the worst parts of starting up your own node from scratch is the launch time. If you're very lucky, you can count launch time in hours. Any less lucky, and you'll be counting in days. In this talk, I explore how to reduce cold-start launch time to minutes. I cover the approach of downloading just the state required to execute the most recent blocks. It requires a new execution strategy, and is significantly accelerated by a supplemental network protocol. I show the progress in a client that I prototyped it in: Trinity.

KWasm: Executable (E)Wasm semantics for verificaton and profit

KWasm is a project for specifying Wasm in the K framework, much like the EVM was specified with KEVM. KEVM has been used extensively for verifying smart contracts, and as Ethereum transitions to Wasm, it's time to get ready to verify Ewasm contracts. With KWasm complete, the new focus is embedding it into KEwasm and other blockchain execution interfaces. This talk is a quick introduction to the power of K, our roadmap and how you can use KWasm to start verifying Wasm code.

Keycard - An open source Smartcard hardware wallet framework

Keycard is an open source smartcard framework and API to build smartcards for cryptocurrency. We propose a workshop where developers can learn everything about using Keycard hardware and software. Using Android, iOS or Go SDKs they will quickly learn how to integrate Keycard with existing applications on both mobile (iOS/Android) and desktop. Interacting with the Keycard applet, they will able to integrate a smartcard hardware wallet that implements all the features of an HD Wallet. Using the Keycard Cash wallet, they will learn how to interact with a smartcard “burner wallet” that enables quick onboarding with “pre-paid/pre-loaded” cards and ready to use NFC enabled smartcard to tap and pay at Point of Sales devices. Keycard applets run on standard javacard smart cards, the same platform used by credit cards or SIM cards, and turns them into a hardware implementation of a BIP-32 HD wallet that supports key generation, derivation and signing. [full text + links/projects/integrations in the PDF attached because of words count limits here]

KeySpace: End-to-End Encryption using Ethereum and IPFS

One of the interesting side effects of the number of developers coming into the blockchain space is that as more engineers come to understand & play with cryptographic tools, they are more likely to come up with solutions to new user experience issues by creatively applying these cryptographic primitives. At AirSwap we wanted to enable conversational, messaged-based trading for users, and support dependable message delivery, without compromising their privacy. Since we knew that all dApp users have access to a persisted public-private key-pair through their wallet, we built a system that allowed them to derive secondary PGP keys which were deterministically tied to their address, and allowed for encryption & decryption of messages, and also signatures and signature verifications. (more detail here: https://medium.com/fluidity/keyspace-end-to-end-encryption-using-ethereum-and-ipfs-87b04b18156b)In this workshop, I’ll help participants walk through the creation of their KeySpace key pairs using their Ethereum wallet of choice (Trust, Coinbase Wallet, Ledger, Trezor, etc) via the functionality provided in the AirSwap.js library (https://github.com/airswap/AirSwap.js). Afterwards they will be able to validate identities in decentralized messaging systems, encrypt & decrypt messages sent over IPFS (via OrbitDB), and build the foundation for permissioned, off-chain applications.Participants will need a laptop, understanding of git, and basic javascript development skills (installing from NPM, writing code in an IDE of choice).

Learn how to secure your code as you write it

The Ethereum Virtual Machine and the Solidity language are not trivial components to build with. When you code, you need to consider many more things than with other traditional languages. Things like execution cost, storage and the most importantly: Security. Also, using a code style guide is a must. It will help any current programmer in a project adhere to the rules pre-established by the team, and enormously help a newcomer avoid some undesired writing styles, impacting on code review quality and speed. I will introduce you to one of the most used open source linters in the ethereum ecosystem: Solhint. Solhint allows for detecting syntax-related security code vulnerabilities. Covering a wide range of validation rules, the tool also enables developers to add new ones, while complying with the Solidity style guide and granting 2x–4x boost in performance. By attending to this workshop you will go through the journey of using Solhint. From integrating it to your preferred IDE all the way down to get the most out of its functionality. I will close the workshop sharing best practices that are hard to port - and are still yet to be implemented into Solhint.

LavaMoat: MetaMask's approach to secure apps

Cryptocurrency is a juicy target for attackers: just grab the coins and run! As app developers, how can we protect our users? Especially given the new trend of "supplychain attacks" where the attackers get into your own app code! LavaMoat is a set of tools to help keep invaders at bay.

Legal troubleshooting for DeFi projects

This will be a practical course and discussion around navigating decentralized finance projects through troubled waters of global regulation. It will cover issues universal for many DeFi areas, as well as those specific to most popular products (DEX-es, stablecoins, etc.), in a cross-jurisdictional context. The goal is to cover many topics neglected in mainstream media discussion, yet crucially relevant for DeFi projects creators. Not planned to be a lecture delivered ex cathedra, but an actual workshop for all DeFi movement participants present at devcon.

Lessons Learned From Phase 0 Testnets

Preston Van Loon discusses lessons learned from Phase 0 testnets.

Layer2 Design Patterns - (enhanced from previous submission #1251)

Continuing previous research I’m interviewing all Layer2 solution providers, exploring current solutions, their problems, the UX patterns and user-research being done. The interviews are focused on extracting knowledge from the companies own user-research, if available: only a few of these projects have actually launched and have real users and even less have performed real user-research. The only company I’m partially affiliated with, Abridged, will launch 7 apps by EthBerlin and there are 13 more launching in September. For once Layer2 tech allows to have direct user contact since most flows ask for user emails.I hope there will be enough users to gather some data which I’d like to share at Devcon, although at this time I can’t guarantee it. Even so, this talk will allow viewers to quickly learn about all Layer2 UX patterns in one session, learning about the differences between the UX mechanics of payment channels, Plasma, (Generalized) State Channels, maybe sidechains, their pros-and-cons, how users enter and exit these systems, how and what they understand about decentralization, what are the open design problems of the space, and accelerating their knowledge of Layer2 solutions which hold the promise to onboard real users onto the decentralized web

libp2p ecosystem: what’s up and what’s next

The libp2p networking stack is becoming a foundational element in many decentralized systems (including ETH2.0). In this session, we'd like to: walk the audience through the current state of the ecosystem, and the 7+ language implementations.explain the toughest problems the core team and community is currently researching and hacking on, e.g. decentralized NAT traversal, slimming down protocols, censorship and deep packet inspection, DHT scaling, traffic shaping, resource control, etc.present what features, subsystems, protocols and redesigns are coming next in libp2p.call out for help and participation in areas where input, feedback and help from contributors is appreciated.Join us, and let's advance the state of the art of p2p networks together!

Least Authority’s ProgPoW Audit

Least Authority will present the results of the ProgPow security audit, including the auditing process used, the findings of the review and outstanding areas for further discussion. The goal of the presentation or panel would be to increase the transparency of the ProgPow audit that was performed on behalf of the Ethereum Cat Herders for the larger Ethereum community. The discussion could also extend into lessons learned by the community and how to most effectively incorporate security reviews into the development and governance processes in the Ethereum community.

Lightning fast light clients for the future of Ethereum

The presentation focuses on recent developments of the Go Ethereum light client project (LES) and their relevance for both ETH1.x and ETH2.0. Significant progress has been made towards an efficient and truly decentralized network incentivization model. In addition to solving the hard problem of LES service availability, it can also serve as a PoC for our future networks where a proper incentivization layer will be key to a scalable and reliable infrastructure. The talk covers the following topics: - the challenges of creating a healthy service market in a low-trust environment - building trust between pseudonymous participants without central authorities - guarantees for good performance and quick response times - a two-layered model that allows using different pricing schemes on top of a common simple base layer - more advanced applications and network topologies - a quick demo of how you can already use micropayments with LES

Living On Defi

Living in Argentina but getting paid in Dai, I can access financial systems that are usually not available to us. I want to show how Ethereum's DeFi movement has been working fine for the last 2 years, by leveraging Dai and secondary lending platforms, and how that is changing the financial reality for people in developing economies. Someone in South America getting paid in crypto can access more stable currencies than their local ones, with better interest rates, and this is all happening right now, and scaling right now.

Load Balancing in Eth2

Joe Delong from Pegasys gives an overview of the Artemis Architecture.

Lessons Learned to Build a Dapp On a Light Client

Builders on Ethereum are concerned by centralization, otherwise they wouldn't build on Ethereum right? Still, most Dapps today rely on trusted 3rd party nodes. We need to change this. Over the past months, we have built Fether, a wallet based on a light client. We will show in this presentation the lessons learned and share our takeaways on how to best build an application on top of a light client. We will present light.js, the library we've built to enable builders to use good practice and have a Dapp that is truly decentralized.

Machine Learning Resistance for Human Rights on the Blockchain.

Bitcoin’s original white paper description of “one CPU one vote” (Nakamoto, 2008) shaped the software industry to think governance centered around machines, instead of humans. Although a fundamental right to privacy bent early blockchain design toward anonymity, this property facilitates the malicious use of Sybil Attacks (Douceur, 2002) significantly undermining the governance capacity of protocols. The importance of formalizing human identities can be inferred from centralized networks: major social media platforms were established when they achieved a sufficient level of consensus over their identity protocols, thus creating a trust layer on top of which a myriad of social applications could be built. This networked social infrastructure has in turn facilitated the emergence and spread of multiple borderless political movements. However, being highly vulnerable to several artificial intelligence exploits such as addictive algorithms, bots and deep fake technology, the underlying architecture of current protocols exposes society to political manipulation as well as data theft. On this talk we'll explore the different approaches to reach a “one human one node” graph, providing protocol specifications able to serve as a source of legitimacy in the governance of digital networks and strategies that can keep these protocols free from AI.

Make the tests feel the user's pain - E2E testing for DApps

With the move from protocol development to more user-focused products, the decentralized applications are in a stage where frontend testing is not an easy task due to the lack of tools and experience in the field of Web3. Protocols have strong testing and auditing, but their user-facing apps lack a simple way to do so. In this workshop, we aim to explain how to start focusing on the user and ensure that they get what we expect even when the chain behaves unexpectedly. The main things that we will touch in the workshop will be: - Classic E2E tools (Puppeteer and Cypress) - Why they don't work the same way in DApps - How to use them with Web3 injectors like Metamask and connect to different testnets - What are the key pieces to test The workshop will start with a bit more of theory around testing and then we will move to a practical exercise where we will set up the architecture needed to properly test our decentralized app.

Mary Maller

Pair-based SNARKs?

Measuring Decentralization of Blockchain Networks

We introduced the concept of measuring "decentralized transactions per second" in this paper (https://consensys.net/research/the-maximally-decentralized-settlement-layer/) and have invited the community to help us define it. We will have data and insights to share at the time of DevCon V. Decentralization is a fundamental blockchain concept, but how to actually determine or quantify decentralization—and consequently, how to value one blockchain’s potential over another—is more complicated. Currently, transactions per second throughput is the most popular competitive metric for comparing blockchains, but this emphasis on speed ignores the essential feature of decentralization. In Balaji Srinvasan’s 2017 "Quantifying Decentralization," he proposed the use of the Gini and Nakamoto coefficients to attach an objective measure of decentralization to a blockchain. By applying Srinvasan’s logic of measuring comparable blockchain characteristics (i.e. node decentralization) and representing it numerically, we propose a measurement we can call DTPS, or decentralized transactions per second. The purpose of DTPS is to factor a blockchain’s decentralization into the ecosystem debate of judging one blockchain’s transaction throughput against another’s. There does not exist, however, a way to factor all that information into a single comparable statistic that factors in near-objective decentralization with objective TPS.

Meta Transaction Relayers at Scale

Earlier this year Bloom’s smart contracts were consuming over 2% of all gas on Ethereum mainnet. All coming from one meta transaction relayer. In this talk we will cover the techniques implemented in Bloom’s transaction broadcasting service to meet strict requirements of transaction ordering, fee management, chain reorg detection and alerting. We will also cover the challenges of moving a Meta transaction service from test nets with low, consistent volume and quick confirmation times to main net with irregular costs and spiking periods of congestions.We will officially open source the service at Devcon and discuss future work involving how to reliably cache and batch transactions to further reduce meta transaction costs.

MakerDAO Oracles: The Backbone of Decentralized Finance

For the past two years, MakerDAO's Oracles have been running on Mainnet, powering not only the 500 million Dollar Dai Credit System, but most of the Decentralized Finance projects that run peripheral to it, like secondary lending platforms.In this presentation, you'll learn about the history of MakerDAO's Oracles, what worked, what didn't, and get a good look at the Version 2 Oracles that will power Multi-Collateral Dai and the rest of Decentralized Finance on Ethereum.

Mapping finite state machines to zkSNARKs

Fabrizio Romano Genovese speaks about Mapping finite state machines to zkSNARKs.

Mixing based privacy mechanisms are insufficient

Mixing based privacy-preserving mechanisms like trustless coinjoin used by Wasabi wallet and ring signatures used by Monero are noble and might work for the average Joe, but they don't provide privacy required for mission-critical things. The talk will briefly cover some of the attack vectors against such mechanisms and provide tips on improving your privacy within such systems.

Monitoring an Ethereum infrastructure

Have you ever wondered what goes on under the hood of an Ethereum node? Frankly, most people don't care. If you are, however, running production systems with multiple nodes across geographical locations, knowing what your nodes do internally is more important than you might think.It is a general fallacy to believe that a software either works, or does not. In reality, there is a whole spectrum in between. A software almost never works perfectly, rather there are quirks that may or may not affect your use case. These quirks may manifest only above a certain load or compound as time passes. The only way to build out a robust infrastructure, is to accept that your nodes are quirky. Instead of getting surprised when they break - having no idea what caused it - you must always be aware of buildups and correlations to external stimuli. This talk will present the suite of metrics that Geth exports for monitoring, highlighting why these have been added and why they might be important to you. By correlatinh your own load and use case with Geth's internals, you'll be able to gauge issues before they ever get strained enough to cause catastrophic meltdowns.

Money At The Edge: How People Stay Afloat in Venezuela

The Open Money Initiative has gone into the field to understand how Venezuelans survive in the midst of heavy capital controls, criminalization of free markets, and hyperinflation. We'll share stories from places like Cúcuta, where worthless bills are used as art and home decor, and Caracas, where individuals are saving in bitcoin, trading it for local currency only at times of essential purchases. We'll discuss concepts for products and services in places where regimes have a tight grip on society, and how they relate to cryptocurrency.

Minimum Viable Privacy: Introducing Hopper

Hopper is an Open-Source Mixer for Mobile-friendly private transfers on Ethereum. It allows the private transfer of value from one Ethereum account to another, via an iOS client. Users can deposit notes of 1 ETH into a mixer smart contract and withdraw them later to a different account by only providing a Zero-Knowledge proof (zkSNARK) that they previously deposited a note into the mixer, without revealing from which account that note was sent. Relayers are used to post transactions to the blockchain so that the recipient of a private transfer can withdraw a private note from the mixer without needing any prior ether. This project is based on previous work on trustless Ethereum mixers by @barryWhiteHat and @HarryR. This talk will discuss the development of Hopper, how others can contribute, and the next steps to make it a true utility for the community.

Network level privacy with HOPR - fixing Ethereum's Achilles' heel

Multiple projects currently focus on on-chain privacy but at network level, Ethereum utilizes broadcasting of messages in a P2P setting which is known to have inferior privacy-guarantees compared to mixnets. Beyond the core layer, dapps running on top of Ethereum or users interfacing these dapps and communicating with one another need a go-to protocol that allows them to exchange data without leaking private metadata that allows for de-anonymizing them while using a dapp.In this talk we highlight some attacks that collect network metadata in order to de-anonymize senders of a transaction. We then show how a mixnet like HOPR can be used to establish network-level metadata privacy. HOPR is a mixnet that allows participating nodes to earn ETH for relaying messages and thereby provide privacy. As HOPR requires cooperation of downstream nodes to unlock a payment, traditional payment channels would lead to race conditions that allow relayers to exploit the network. We will present an alternative to common payment channel implementations, building on commutative properties of elliptic curves for efficiently closing payment channels.

Networking in ETH2.0

The Whiteblock team has been working on several ETH 2.0 related projects over the past year. These projects include: An analysis of Libp2p’s gossipsub in collaboration with the ETH Research team, The development of protocol-specific tooling and utilities, constituting the basis of the ETH2.0 test runner (developed in collaboration with Moloch DAO and provided to the community as open source software), as well as Contributing to the specification for the currently implemented wire protocol. I propose to deliver a 15-minute presentation, consisting of two parts: A brief 7 minute overview of the tools and protocols, such as Hobbits, a lightweight wire protocol designed to allow Eth2.0 clients to exchange information, developed to accelerate the testing of Eth 2.0 client; and an 8 minute summary of Whiteblock’s most recent analyses on Eth2.0 networking protocols such as libp2p.

New Application Design Principles in Ethereum 2.0

With the Phase 0 spec freeze and Phase 1 in progress,  the mechanics of Casper FFG and  sharding of data availability has received plenty of attention. On the other hand, the mechanics of Ethereum 2.0 for application developers hasn’t received the same amount of clarity from the implementors nor scrutiny from the community. This talk will focus on how application design will (and will not!) evolve in the context of three trends in application design right now: DeFi, zero knowledge proofs, and layer 2 solutions.

Money and Debt and Digital Contracts

Brewster Kahle presents his talk on Money, Debt, and Smart Contracts.

New Markets In The Arts

This presentation explores new markets to facilitate the arts, breaking it down into three broad categories. 1) Patronage & The Always-On Auction Through Harberger Tax. 2) New Generative Economics & The Creation of Autonomous Artists. 3) Markets As Arts. Exploring New Arts Through Markets-As-Medium.

Open Community Discussion

An open community discussion featuring many voices from the Ethereum ecosystem & developers.

Off-Chain Trusted Compute Overlay testnet for Blockchain Privacy, Scalability and Adaptability.

During Devcon 4 we introduced potential for Trusted Compute as an option for addressing scalability and privacy challenges faced by blockchains. Since then Enterprise Ethereum Alliance (EEA) has released version 1.0 of Off-chain Trusted Compute specification. As part of the workshop we will introduce an Enterprise Ethereum network connected to EEA compliant Trusted Computing pool; both hosted on Azure cloud. In addition we will demonstrate one sample real-world usage scenario and give examples of more. During the workshop developers will be provided scripts to recreate the setup on their local laptops and guidance on how to create private test setups on Azure cloud. Developers will walk away with background on leveraging Trusted Compute in context of their decentralized applications for addressing privacy, scalability and/or adaptability.

Opportunities for Collaboration: ETH1x and Ethereum Classic

Join us to consider options for collaboration between the Ethereum and Ethereum Classic communities. As a result of significant changes underway in ETC, there are several new and positive sum opportunities for cooperation. Ethereum Classic Labs and it’s core development team is committed to contributing to the Ethereum Classic and Ethereum ecosystems. ETC has been adopting ETH upgrades on ETC to ensure compatibility; and both the ETH and ETC communities have been building bridges and identifying mutually beneficial and complementary activities. We will discuss specific paths for technical development and community engagement going forward. We will also announce several new and exciting developments.

Optimistic Execution: Putting the Internet on Ethereum

Ethereum can serve as an arbiter of trust for the entire internet. To make this a reality we'll have to scale. Our best bet to scale is constructing a comprehensive layer 2.What do plasma, state channels, optimistic rollup, & ETH2 have in common? Optimistic execution! Or in other words, they each make inferences about future Ethereum state based on local information--think fork choice on top of a state machine. Using this concept we construct the Optimistic Virtual Machine (OVM), baking inference logic directly into wallet & application software. In this talk we discuss how the key role trust will play in the internet--from DeFi to timestamping--and how we can build the underlying infrastructure to support internet scale. These are exciting times for blockchain infrastructure. Now we just need to solve identity & UBI -- easy!

Optimization techniques for EVM implementations

A number of optimization techniques for Ethereum Virtual Machine implementations are going to be presented along with examples and benchmarks based on evmone and EVMJIT projects. Based on performed benchmarks, the presentation will show ~10x speed improvements in evmone comparing to other EVM implementations. While evmone is build in C++, the optimizations are not limited to C++. All of the optimizations are applicable to any compiled language, some of them even to interpreted languages.

Nightfall - The Open Source Privacy Solution for Ethereum

We believe that public blockchain is the future of business to business transactions. However, two issues - privacy and scalability - will need to be solved if this vision is to be fully realised. This talk will explain the motivations behind the open-source nightfall code and how it is intended to tackle the first of these issues. We cover the operation of the protocol, the method by which it provides complete privacy, and how developers can use it to build their own applications by making use of its smart contract infrastructure and the ZoKrates framework. We will also present our modelling of transaction costs, which shows that nightfall can already provide a cost-competitive alternative to private blockchains for many situations and how that will be true for a growing number of use cases in the near future.

Optimizing Eth2

Michael Sproul from Sigma Prime discusses Optimizing Eth2.

Opting Into The Surveillance State: The UX of Informed Consent

There is a saying among IT security professionals that the most vulnerable part of any system is the human. Additionally, it just so happens that when you want to exploit human behavior, product designers can be the most effective attackers. We have seen this be the case in such high profile instances as the Cambridge Analytica/Facebook scandal, and with Libra looming on the horizon, the situation is only becoming more dire.As we move into a future where digital identities can be sovereign and people truly have both the power to control the the data they share, but also the responsibility that comes with this power, what role do product designers play in helping to bring about the future that the self-sovereign identity movement promises?This talk will will explore the importance of ethics in design as it relates to data sharing and also examine some of the common "dark patterns" that are currently exploited. It will also present examples and suggestions for best practices when interacting with user data, how to gain informed consent from users, how to solve the "privacy paradox", how to design dApps that are GDPR compliant, and other related topics.

Overcoming the smart contract size limit

EIP 170 introduced a limit of 24KB on bytecode size of smart contracts in Ethereum. This talk will explain the rationale behind the decision and then talk about overcoming or playing around the limit. The talk will cover ways like proxy patterns and libraries for working around the limit. Tips on optimizing code for reducing bytecode size will also be shared. The talk will then explain new proposals for removing the contract size limit while still fixing the original problem.

p2p - where are we with the ecosystem and how to push it forward?

p2p and Ethereum need each other a lot in order to bring decentralized future, but we're not working together very well. Leaders of p2p projects and core blockchain/dapp developers in the same room to build bridges and align plans on day0.Blockchain/dapp people don't know too much about p2p projects and don't have access to p2p stack that they need to build real decentralized applications. p2p people can't navigate blockchain ecosystem, don't know what's needed, don't have access to funding.We've set out to fix all of this in 2019. 3 phases:1.p2p Ecosystem report. Directory and assessment of what works right now.2.p2p ecosystem position paper. How to design p2p ecosystem from first principles and how should we get there, what are the priorities for reasearch/funding.3.p2p infrastructure DAO. Experts from both p2p and Ethereum allocating grants together. $400k already committed to grants. This breakout session would briefly present findings of the p2p ecosystem report, but would focus on designing perfect p2p ecosystem that would make deliver everything needed to make Ethereum ecosystem happy. We're also submitting a 20-minute talk proposal "State of p2p" where leaders of key p2p projects we would present learnings from this workshop on day1.

PANEL: Emerging Technology and Social Progress

Natalie Cargill, Will Ruddick, Adam Bornstein & Lucas Geiger discuss Emerging Technology & Social Progress.

PANEL: Community Interoperability

Vitalik Buterin, Terry Culver, Josh Swihart & Jae Kwon discuss Community Interoperability.

Path to Seedless Recovery

Private key management is one of the key issues to be solved on the road to mass adoption of blockchains like Ethereum. Smart contract based wallets like the Gnosis Safe are laying the foundation to solve this problem by allowing different types of access control. The talk gives an overview of the different approaches developed to allow account recovery beyond seed backups and explains how to implement social recovery to ensure recoverability without compromising privacy.

Peers and Intermediaries in Indonesia’s P2P economy

While ‘peer-to-peer’ emerged as a technical term, growing traction means it is increasingly used to describe a wide variety of complex socio-economic transactions. Anthropologist Keith Hart observed that “A lot more circulates with money than the goods and services it buys. Money conveys meanings and these tell us how we make the communities we live in.” Arguably, the exchange of digital money also comprises far more than a simple financial transaction, and far more than can be summarised in an elegant acronym. Who are these so-called peers? Who are these (multiple) intermediaries, subtly obfuscated behind the ‘2’, and why do people rely on them? And what does disintermediation mean in such a context? This talk unpacks these questions, by drawing on ethnographic research on the use of digital payments in Yogyakarta, Indonesia. It analyses the various relationships between different types of users and the power and responsibility that the intermediaries have in configuring socio-economic dynamics when developing technology. The talk shows how ‘access’ to financial services and technologies is neither a binary nor static category. Rather, providing a viable technological alternative to conventional financial services means supporting people’s ability to transition flexibly between forms of digital and tangible money.

Pentesting Ethereum Contracts: Exploring a honeypot contract using Ganache

In this workshop we will demonstrate some of Ganache's advanced features to instantly fork Ethereum Mainnet, granting developers a safe, secure, and risk-free environment. We'll explore what a re-entrancy attack is, review historical re-entrancy attacks (like the DAO hack), as well as the narrowly avoided re-entrancy attack vector that would have been introduced by the original Constantinople hardfork proposal. Attendees will attempt to perform a re-entrancy attack against an actual Mainnet-deployed contract that has been cleverly crafted to trick aspiring exploiters into becoming victims. We will utilize Ganache's forking feature to safely discover how it works, and how to write better — and more secure — contracts.At the end of the workshop we'll play a game of Capture the Flag, where you'll have a chance to exploit a real contract, earning actual Mainnet Ether if you are the the first to execute the exploit! But you'll have to be careful as things aren't always as they seem! Ganache is a fast, lightweight development blockchain, and is part of the Truffle tool suite. Ganache forking is a feature that enables developers to read from Mainnet, while transacting against a local development chain, enabling fast, sync-free development and penetration testing.

Polkadot's Data Availability and Validity Scheme

How can we make blockchains secure at scale? We suggest a data availabilitty and validity scheme that make sharding efficient in terms of the number of validators and validating resources. We first describe the Polkadot data availability and validity scheme and consider its applicability to other sharded systems (e.g. ETH2.0). In Polkadot we tie an erasure coding data availability scheme with consensus, where we can not finalise an unavailable block. Moreover, reports of unavailability or invalidity trigger extra checks. The aim is that, with high probability, we do not finalise an unavailable or invalid block provided that there are enough honest actors to report. The key advantage of this scheme is that we need fewer validating actors per shard and in turn less total computational and especially networking resources. This softens the trade-off between scalability and security.

Practical design patterns for DApp developers

Used to building apps in Python or Ruby on Rails, but new to blockchain? This talk is aimed at experienced developers who are new to Ethereum. My goal is to give developers practical frameworks for architecting their decentralized applications, that will minimize gas costs, reduce the attack surface and simplify upgrades. Decentralized applications require a new way of thinking. I want to share some templates for developers who are making the jump to decentralized applications and aren't familiar with the quirks and limitation of the Ethereum EVM. We will look at the following Solidity design patterns: Approve and call Factory contracts Proxy contracts Name registry Upgradability As well as ways to reduce gas costs without compromising on security, including: Event sourcing Using IPFS effectively Building decentralized applications is hard. The stakes are high and there are a lot of ways to get things wrong. Mistakes can be expensive, either from security losses or high gas costs. I’m looking forward to sharing some of the lessons Origin’s engineering team has learned over the past two years building peer-to-peer marketplaces on top of Ethereum.

Preventing Disaster: Advances in Smart Contract Vulnerability Detection

What do the DAO, Parity MultiSig wallet and Beautychain have in common? 1. All three were hacked with disastrous consequences, 2. in each case, the bugs could have easily been spotted in advance using automated analysis techniques. In this talk, we'll investigate the above exploits in depth and show how to use a combination of multi-transactional symbolic execution, taint analysis and greybox fuzzing to detect similar bugs with high accuracy and a low false positive rate. Well' also introduce optimization tricks that enable fast detection of "deep" vulnerabilities - exploit conditions that are triggered over a longer sequence of highly specific transactions. Finally, we'll show how developers can apply these security analysis methods to their own contracts using MythX and Mythril.

PoS Security and Ethylene

Emin Gün Sirer gives his talk on PoS Security & Ethylene.

Privacy by design in a world with universal SNARKs

ZK-SNARKs are an innovative method of verifying that a computation has been performed correctly. They form the backbone of many proposed scaling and privacy solutions for Ethereum. PLONK is a new ZK-SNARK construction, developed by AZTEC and Protocol Labs, that is 'universal'; only one 'trusted setup' is required, and different ZK-SNARK programs do not require additional trusted setups to be performed. This construction is the first universal ZK-SNARK construction that is practical enough for use in smart-contracts. In this talk, we will provide an overview of how ZK-SNARKs can be used to solve Ethereum's scaling and privacy challenges, and how PLONK opens up a world of zero-knowledge dapps.

Privacy in Ethereum

From mixer to anonDAO, anonSocial media to journalism under authoritarian regimes ethereum offers ways to provide privacy to people who need it most. Come hear what we have done and what we want to do. How *YOU* can help us move forward.

Private and Reliable Data Sync for Messaging Over Whisper

How do we achieve user friendly data sync in a p2p network for resource restricted devices? In this talk we go over the problem space, do a brief survey of existing work, and propose a solution combining several of the most promising technologies. This talk will include a demo of a data sync protocol being developed. We’ll also cover things such as: - dealing with mostly-offline devices, - dealing with large sync contexts, such as group chats - making the protocol transport-agnostic. Finally, we’ll show how data sync fits into the larger picture, from transport layer to end user applications, and highlight some of the work that still needs to be done, and who is working on it.

Protocols: the control structures of decentralised networks

Protocols are essential for the formation of (decentralised) networks, both for humans and machines. Protocol designs directly influence the interaction between agents and also the kinds of networks that are able to form. This is especially important when trying to build inclusive and open networks. This talk will give the audience a glimpse into the protocol design world and should serve as an entry point for people to get interested in the topic. I will cover some philosophical angles, what it actually means to design protocols; provide motivation as to why making a conscious effort to design protocols is necessary—also motivated by the growing popularity of DeFi applications and their influence on all levels of the blockchain stack—and give pointers for things to watch out for when it comes to writing specifications.

Psychology of UX and adoption

This talk is aimed at bringing depth to the conversation of mass adoption by defining concepts such as ‘UX’, ‘Education’, and ‘User’. It is commonly pointed out that in order to drive mass adoption, “UX is critical” and “We need to educate users”. Is this true? What does this look like in practice? And what can we do to get the UX right? In this talk I’ll provide actionable suggestions based on stablished frameworks on the psychology of technology adoption as well as anecdotes from UX research at Status; where over the last year we have surveyed over 300 people, talked to ca. 50 people in usability testing and field research, and received numerous valuable requests in Status’ public channels. Suggestions include for example how to design user interfaces in which people can safely learn from mistakes and interactions that satisfy the human need to connect with family and friends.

Protecting The Baselayer - from Shanghai to Osaka

Most people know that Ethereum runs smart contracts and move ether around. However, "Ethereum Security" involves a lot more than only smart contracts, mining difficulty and managing private keys. This is a talk about the base layer security. There is a peer-to-peer stack, with it's own separate discovery protocol and p2p protocol, which can be used for eclipse-, DoS- and amplification attacks. There's a consensus engine which encompasses a lot more than only the EVM. In this talk, Martin Holst Swende will talk about vulnerabilities, attacks and hotpatching the mainnet -- lesser known incidents, hiccups and close-calls that have occurred on the road from Shanghai (Devcon2) to Osaka (Devcon5).

Putting Eth2.0 To Work

There is much excitement around Ethereum 2.0 but given the fast pace of the project it can be hard to keep up. The relationship between today's Ethereum and the new system can be murky: does eth2.0 replace eth1.0? And where does eth1.x fit in?This talk answers these questions by sketching the lesser known ways eth2.0 can directly benefit Ethereum 1.x. The two systems in fact complement each other as each phase of eth2.0 paves the way for tangible benefits to the network we all know and love. With Phase 0, we can upgrade Ethereum with the finality gadget, leveraging the proof-of-stake consensus to provide better security for the existing chain. With Phase 1, the proof-of-work chain can use the data-only shards to enhance the scalability of L2 solutions like zk-rollup and Plasma. With Phase 2, we can bring existing dApps into the realm of highly scalable smart contracts on shards with an upgraded virtual machine.Participants will gain a better understanding of the many ways eth2.0 can help scalability in the near term and onward into the future. While the journey there may be dynamic and winding, it is clear that the future of Ethereum is bright.

Quickly develop data driven reactive ÐApps

We present a new developer library that can do serverless event sourcing & automatic data syncing for querying smart contracts that greatly improves creating reactive ÐApps.

RadicalXChange

Audrey Tang, Taiwan's first Digital Minister for Social Innovation, presents the RadicalXChange.

RADON: a domain-specific language for oracles

Oracles are bound to bridge the gap—or abyss—between the realm of smart contracts and data coming from outside the blockchain. But, at the end of the day, achieving such ambitious goal boils down to removing the inherent indeterminism of real world events by aggregating, filtering and reducing multiple data points into a single one in a predictable way. This is no easy task—even more in the case of decentralized oracles. In this talk we will introduce RADON: a domain-specific language that provides a new ontology and semantics to enable smart contract developers to define how external data will be retrieved, aggregated, filtered, reduced and reported to their contracts. In a learn-by-doing manner, we will reflect on the challenges that we faced and the quirky, wicked and hidden incentives that can be accidentally introduced by poorly constructed queries. Finally, we will also demonstrate relevant tooling for ergonomically creating and troubleshooting oracle queries within the context of existing Solidity projects.

Realigning Incentives for Nonprofits with Ethereum

The Nonprofit space is a victim of our incomplete economic model. Our current economy does a great job at assigning value to individual wants and needs, but shared resources (infrastructure, the environment, public goods, etc) and taking care of the less fortunate members in our society are not assigned any value at all. Instead, when entrepreneurs do value calculations (profit projections) they are incentivized to extract everything they can from "externalities" because that improves the numbers on their spreadsheet. This is an impossible battle to win for the nonprofit world. Nonprofits will not out-compete for-profit companies when the economic model is working against them. We need to build new economic models around causes, so that we can actually attribute value to these "externalities" appropriately. I will introduce the various tools we have in the Ethereum space: Harberger Tax, Token Bonding Curves, DAO Governance Models, Escrows, Traceable donations, etc and how they can be used to build parallel economic models to fill the gaps in the current system. We have the tools to design, simulate, test and iterate solutions that can level the playing field for nonprofits! Let's get to work!

Remix New Features and Plug-in Governance

We’ve updated Remix’s architecture so that everything is a plugin. We’ve invited developers out there in "Ethereumland" to make plugins to expand Remix’s functionality to address their uses cases. This workshop will begin with introductions to some of these plugins. Then together, we will go through tutorials using the NEW Remix tutorial framework, to learn the techniques needed to use these plugins.

Rimble presents: the state of transaction states

Whenever we speak to builders they say "the most pain-in-the-ass part of making dApps is those pesky transaction states" (paraphrased). So we decided to do some of the work for you and now we want to share it. Over the last few months we've been turning transaction states inside-out to grasp the do's and don'ts of keeping users in the loop about their on-chain activities. And what this means for how you should build them. We asked ourselves: What do users want to know? What are they thinking after 2 minutes and it looks like nothing's happened? Should we use blockchain lingo? Do users actually trust dApp transaction messages? And what happens if you run out of gas? Plus, plenty more. Then we interviewed, designed, tested, demoed, iterated and repeated in order to get the answers you and every dApp developer needs. At this talk, we'll share everything we've learned and show you how you can turn these user insights into great user experiences for your own projects.

Robotics under Ethereum computer control

Ethereum as a world computer is the best way to control big and complex cyber-physical systems like smart factories, sensors networks or drone bases. The decentralized computer doesn't have a single point of failure and that feature is important when we want to use autonomous robotics systems.

Scalabilty with zKSNARKs

Scalabilty with zKSNARKsThis session will introduce iden3’s zkSNARKs implementation and how it will be used at two scenarios: For the trustless relayer implementation at the identity management environment, allowing the identities to perform claims without cost at big scale.And the rollup project for Ethereum scalability, allowing verifiable computation off-chain to increase transaction throughput

Scaling Ethereum with security and usability in mind

In this talk, I will go through scaling mechanisms and their disadvantages at a user and developer perspective. With our approach at Matic https://matic.network, plasma-fied sidechain, I will explain how we are tackling security using plasma, predicates, and normal state computation on the sidechain. Having specialized DApp specific fraud-proof using predicates, partial confirmations, different fee models allow us better usability for end users. Then will talk about how we are addressing the issue for users when they interact with multiple chains - Ethereum and Plasma sidechain using walletconnect protocol. Overall, it explains how connecting some important dots on Ethereum landscape can help us achieve scalability and usability, and clears our path to mass adoption which we all are aiming for.

Scaling your favourite dapp with ZkRollup

Rollup allows dapps to scale by using ethereum as the data availability layer and using snarks to create an off-chain execution environment where your dapp business logic can run easily. Rollup aggregates transactions so that they only require a single on-chain transactions required to validate multiple other transactions. The snark checks the signature and applies the transaction to the leaf that the signer owns. Multiple users create signatures. Provers aggregate these signatures into snark and use it to update a smart contract on the ethereum blockchain. A malicious prover who does not also have that leaf's private key cannot change a leaf. Only the person who controls the private key can. This is intended to be the database layer of snark-dapp (snaps) where the layers above define more rules about changing and updating the leaves Rollup does not make any rules about what happens in a leaf, what kind of leaves can be created and destroyed.

Scaling Many to Many Payments with Probabilisitic Micropayments

Probabilistic Micropayments, in which a sender pays a recipient with a form of lottery ticket for services performed, present an alternative payment scaling solution to state channels that bring advantages in certain use cases such as stream data processing and distributed compute. In this talk we'll present an overview of this form of micropayments, compare and contrast them to hub and spoke payment channels, show the security model against double-spends, present benchmarks from real world usage within the Livepeer protocol, and showcase an open source implementation.

Securely Connecting Smart Contracts to Off-Chain Data and Events

For smart contracts to achieve mass adoption, they need the ability to securely connect to external off-chain data and existing non-blockchain systems. The reliability with which smart contracts connect to key external systems determines their overall security. This critical security factor determines whether smart contracts will be used to secure the many forms of value beyond tokenization, such as prediction market outcomes, insurance payouts, trade finance, and more. In this talk, we’ll examine what makes a secure oracle mechanism reliable enough to be trusted by smart contracts for external data delivery, access web APIs, and off-chain payments. We’ll review the security risks and failure scenarios to avoid when using oracles and share how developers should set up methods to maximize success. We’ll examine how a decentralized network makes oracle mechanisms more secure, and how decentralization, combined with approaches like Trusted Execution Environments, can enable the highest level of security when connecting with external systems. Finally, we will show the design patterns which leading smart contracts use to remain reliable and provide high levels of overall security while connecting to external systems.

Satoshi Has No Clothes, What About Szabo?: Smart Contracts, Privacy, and Practicality

This talk will explore the possibilities for privacy preserving smart contracts in terms of both cryptography and functionality. It will give an overview of known approaches, including a detailed discussion of zk-proof based schemes such as Zexe (my work) and an overview of other approaches including refereed computation as seen in systems like Truebit and Arbitrum, multi-party computation, secret sharing, and fully homomorphic encryption. More fundamentally, it will explore what a private smart contract really is. Do we need to hide which contract is running? Do we really want privacy in most cases?

Securely storing wallet private keys for application use

Private key management is a complex problem in cryptography. In the last few years, we have seen attacks against cryptocurrency companies that seek to retrieve the private keys of user wallets. Within cryptocurrency, private key management has an additional complexity: the value of stored user funds related to that private key. Truly, key management is a challenge that has plagued secure computing for years.While storing keys is essential, it is equally important to securely use those keys in an application. Without secure use of private keys, applications are vulnerable to attacks to exfiltrate those private keys.In this talk, we will discuss the approach the AirSwap team uses to securely store and use private keys for high value wallets. We will show real world permissions, policies, and code used by our team. We will discuss common attacks against private key management systems and the ways that our implementation thwarts those attacks.This talk is beneficial to any team or company that interacts with the Ethereum blockchain via signed transactions and off-chain custom code. It is essential for any team that wishes to use a private key in their application code securely.

Seeing in Systems: Sketching A Native Ethereum Design Language

We often lament how the "UX of web3 doesn't work more like web2". Those are easy fixes. What we really need is a native web3 design language. One that guides us to design with Ethereum, not against it. To achieve that, we must learn to see in systems. Our world is a complex collection of natural & artificial systems. Our software are systems, too: networks of dependencies, features, users, incentives & interactions. Yet none of our design tooling or "best practices" is designed to help us work in this mindset.  Let's invent the “Third Layer” of the design stack: A systems-first approach that goes deeper than "UI" or "UX", in order to: 1. Create a safer & more inclusive user experience.  2. Understand our work as one part of a larger ecosystem. 3. Develop adaptable interfaces that shape themselves to local culture. 4. And give us new tools & mental models to solve major usability problems.  Seeing in systems won't only help us. It may even enable today's legacy online platforms to solve their major challenges: against attention hijacking, mass data collection, state propaganda, racial violence, radicalization, harassment & exploitation.

Securing Layer 2 Networks with Ethereum, Decentralized Storage, and Shared Fishermen

Running data-intensive applications on top of existing blockchain platforms remains a challenge. Modern blockchains are designed for maximum security and have limited compute and storage capacity, which means they are too expensive to handle nontrivial amounts of data. However, traditional applications often need high transaction throughput and low latency of request processing. I will show how to address the scalability and cost efficiency requirements with a hybrid architecture composed of several layers. Speed layer consists of real-time shards directly talking to a client; security layer provides finality and consists of fishermen verifying past speed layer behavior; dispute resolution is served by the Ethereum smart contract; finally, decentralized storage networks such as Swarm or IPFS provide data availability. In this talk, we will go through the hybrid architecture approach and explore how it can make the cost of running a classical database (e.g., Redis or SQLite) in the decentralized environment comparable to its centralized deployments without compromising security.

Shaky ERC20 Allowances

Sometimes, we can't see the forest for the trees. When not used carefully in dapps, ERC20 token allowances fit that description perfectly. This presentation goes into the story of how I accidentally put over 10,000 DAI at risk for my users, even if they only deposited 100 DAI in the smart contract per se.

Sharding From A Dapp Developer's Perspective

From launching CryptoKitties at the ETHWaterloo hackathon to the rise of KittyVerse experiences and designing Cheeze Wizards to be more extensible, our successes and failures have advised us each step of the way. Join this talk where we will share more about what we learned (sometimes the hard way) in designing for open ecosystems and how iterative improvement on smart contracts has the power to result in stronger development communities.

Sharing Security between 1st Layer Blockchains

Nowadays one of the evolving fields in the blockchain technology is a protocol which shares security between a main blockchain and a child blockchain. A protocol which shares it between main blockchains, however, is not developed yet. To do that, we would like to introduce a new Sybil control mechanism, Proof of Unit. In this protocol, a new concept, “unit” appears. The unit has three features. First, a unit is generated with any works such as mining, staking, computing prime numbers, and so on. Second, the amount of minted unit is in proportion to the consumed cost. Third, a unit is used as vote power in the consensus algorithm. Proof of Unit would make it possible for 1st layer blockchains to share their security.

Shouldn’t we rethink debt? What DeFi can learn from susu’s and immigrant lending clubs

With hundreds of millions collateralized in products like Compound Finance and Maker, the Ethereum community is rightfully rallying around #DeFi. Yet, one could easily draw portentous parallels to the systemic risks of financial innovations in the early 2000s: credit default swaps, hybrid securities, and so on. In this lightning talk I will implore our community to look toward another concept of lending used around the world: the susu. The susu (tanda in Latin America, hui in Asia, or a “rotating savings and credit association: ROSCA), is a type of short-term no-interest loan among members of a small community. Each person in the susu makes the same contribution to the pool of money, and on a rotating basis, one person receives the total amount added to the pool. I first encountered this concept when visiting my partner’s family in Trinidad and Tobago, and am studying how communities in NYC rely on these informal lending clubs to pay for a flight, a home down-payment, or just for fun. If Ethereum will bring greater financial access, we should focus less on imitating the sophisticated financial products of Wall Street and instead look to the ways that communities without financial access already get by.

Shrubs - A New Gas Efficient Privacy Protocol

ERC20 tokens that offer high levels of privacy to their users have been a longtime goal in the Ethereum ecosystem. To implement a privacy protocol that offers very strong privacy guarantees such as those of Zcash, it's necessary to maintain a large Merkle tree of commitments. Unfortunately, doing so in a smart contract can be expensive. For example, to support the same number of total transactions as Zerocash (2^64), one would require a tree depth of 64, and thus 64 storage updates per transaction, which is prohibitively expensive gas-wise. In this work, we introduce a new Merkle tree variant, which is defined not by the root, but by the path to the rightmost non-empty leaf node (or frontier), in a tree filled from left to right. This allows commitments to be inserted with O(1) amortized updates, at the expense of a slightly more complicated zk-SNARK proof, used to prove that the commitment is in the tree. We use this new data structure to create ShrubsToken, a new gas efficient privacy token, with Zcash-like privacy. Based on our experiments, we estimate that Shrubs will use around 500,000 gas per transaction, after the next Ethereum hard fork.

Sidechains Are Not Layer 2

In this talk we argue that sidechains are strictly an interoperability protocol, and any attempt at describing them as scalability solutions is misleading. Proof of Work sidechains require each chain to be individually secure, and thus make a double honest majority assumption. Proof of Stake sidechains rely on DMMS-like mechanisms, but even with proper short-long range attack protection they have a different security model to a Proof of Work chain. On the other hand, Layer 2 is a set of mechanisms which allow state to be manipulated more efficiently than the base layer, while inheriting the base layer's security. This is achieved through fraud proofs and client side validation or validity proofs which enforce valid state transitions.

Simulating Ethereum network with SimBlock

SimBlock is a blockchain network simulator. It was designed as an event-driven simulator wherein each participating node behaves according to generated events, e.g., block generation and exchanging messages. This simulator supports Bitcoin, Dogecoin, Litecoin networks and has already been used in several studies about block propagation delay and fork rate. We are developing to support Ethereum, which will allow Ethereum developers or researchers to obtain more realistic data, such as in setting block generation intervals and designing neighbor node selection algorithms. In this presentation, we will show an experiment on how GHOST improves blockchain security as an application of SimBlock. GHOST is a block selection protocol being developed together with Casper, which is PoS protocol of Ethereum. GHOST has been shown analytically to improve blockchain security, but there is little experimental support. In this experiment, we compare the attack success rate in several parameters with the longest protocol.We would like to introduce a practical simulator and get your opinion on future SimBlock Ethereum support.

Smart Contract as a Service: Using messages to share contracts

Currently, developers deploy multiple copies of the same contract to the Ethereum blockchain. But with a shared global system, why not deploy contracts once and make them available for everyone?Learning from the actor model of message passing and the ERC1066 Status Codes Standard, I will present a model for “smart contract as a service”. This style of contract design can lead to highly vetted and secure contracts that anyone can re-use. Their persistence and re-use means we can also write integrations so that non-smart contract developers can make use of them off chain.

Smart contract interaction out of the coldest of storage

At Coinbase Custody, we provide top of the line security for our client's assets. This security comes at a cost though. Through its very nature, our cold storage process creates friction when broadcasting transactions to the network. For HODLers, this friction is a welcome and blessed thing, as it keeps their funds safe. When our clients want to use their funds to participate in decentralized applications however, we have had to get creative. This talk will focus on the patterns we have developed to facilitate rich and convenient network participation between our clients and the decentralized networks they patronize.

Smart Contracts Design Pattern

Design pattern are essential to create secure and efficient software even more in the smart contract world where every bug can have fatal consequences. This talk features a live demo of the development tool Piet and its plugin to access a catalog of smart contract pattern and anti-pattern. The presented Piet plugin queries existing pattern registries, categorizes them and presents the patterns in an enhanced way. A pattern view in Piet consists of its inheritance graph, an example implementation, a description, curated comments and a graphical interface to interact with deployed example contracts. The curated comments are way to inform the developer regarding issues related to this pattern which are not included in the original description.

Stablecoins

Rune Christensen, Victor Rortvedt, Dan Robinson & Eva Beylin participate in a panel on Stablecoins.

Standardized Incentives on Ethereum: a round-table discussion about StandardBounties

Since it's inception at the beginning of 2017, the StandardBounties "protocol" (group of smart contracts) has aimed to create a generalized and robust interface for dapps on Ethereum to manage bounties. These would be useful not only for work-like incentive schemes (like outsourcing coding or design tasks), but also for more nascent use cases like incentivizing social impact. The goal here was to create shared/open source "order book" of incentives which individuals or teams had put up, with the intention that bounties could be easily created within one dapp, and fulfilled on another.Since then, we've seen great interest in StandardBounties, with the protocol already being used to power bounties on Gitcoin and Bounties Network, while also working with DAOStack, Aragon, Giveth, ETHLance, and other teams to have them integrate and use a shared standard. Although this endeavour has been difficult (owing to the friction of coordinating individuals), we've worked hard to have StandardBounties be a collaboratively crafted, and collectively used protocol. This implies that the protocol isn't "open" just because its code is open source; it's open because multiple competing stakeholders are coordinating around the same contracts to the benefit of their users.This breakout room will be used to facilitate an open discussion among the aforementioned parties (Gitcoin, Bounties Network, DAOStack, Aragon, Giveth, ETHLance, etc) as well as any others who wish to partake, in order to discuss any changes or new features which may be necessary in the contract's evolution, and ensure things are running smoothly between the collaborating parties.

Standards in Ethereum - how do we make them, how should we?

Ethereum, unlike most distributed ledgers, is based on standards, from the Yellow Paper to EIPs. Even the "corporate" technology users in the Enterprise Ethereum Alliance build on the Ethereum standards and extend them with their own standards process designed to avoid fragmentation or divergence. This session will explain the existing standards mechanisms and processes both for Ethereum and the Enterprise Ethereum Alliance, how they work individually and together, and be a collaborative exploration of what we can do to improve the various standards processes and make sure they produce better outcomes for the ecosystems and the variety of stakeholders that Ethereum serves.

State Channels

Over the past several months, Ethereum's leading state channels researchers and engineers have worked to unify their protocols and implementations. The result is a single state channels network, compatible with all major state channel implementations. Liam Horne and Tom Close will introduce the audience to their work, the State Channels Improvement Proposals (SCIP) process, explain how developers can get started building on it, and provide a live demo of the network in action.

STARK: From Paper to Product

In this talk, we will describe how we're building a scalability engine for self-custodial trading and payments. We will also describe how to build a STARK-based product over Ethereum, and our contributions to the Ethereum ecosystem (EIP-2028, STARK-friendly hash functions, etc.)

State of Blockchain Governance Breakout

Governance is a hot topic in Ethereum and other blockchain communities in 2019, and for good reason. Blockchain tech continues to evolve rapidly, but our "social infrastructure" lags and major blockchain communities including Ethereum haven't invested nearly as much in building robust, socially scalable governance as they have in scalable tech. This governance-focused breakout session will invite core stakeholders from major blockchain platforms, including Ethereum, Tezos, Cosmos, Polkadot, Near Protocol, Zcash, Decred, and Spacemesh to present in turn the good, the bad, and the ugly of governance in their ecosystem. It will include talks from academics in fields including economics, political science and philosophy, legal theory, philosophy, and ethics, putting the blockchain governance landscape in the context of the overall evolution of human governance systems since democracy was born in Athens. It will introduce participants to essential governance concepts and challenges such as DAOs, on- and off-chain governance, voting, identity, formal vs. informal governance, governing the commons, and aggregating preferences. The breakout session will include a hands-on "challenge" section where participants need to self-organize and race to solve governance challenges in a decentralized fashion, to appreciate how hard the problem is.

State of Ethereum 2019

We last presented at Devcon 3 Cancun. Fast forward to 2019, we explore how the network has evolved and grown since by looking at the overall top stats. As Developers, to build better dApps it is also essential to understand the user base we are serving. Using analytics data, we look at the changing user demographics of the Ethereum eco-system, learn & discover what the Ethereum "User Persona" looks like today vs 2 years ago, has it changed or largely remained the same over time? And while it goes without saying that building technical infrastructure is challenging, there are also unique non-technical issues in delivering basic essential infrastructure service to the community. We share some of these challenges, scaling issues and what we learned.

State of the ENS 2019

Nick Johnson, lead developer of the Ethereum Name Service, gives an update on ENS - what we've achieved in the last year, where we are today, and what you can expect next from ENS.

Supersonic: Transparent SNARKs from DARK Compilers

Benedikt Bunz presents Supersonic: Transparent SNARKs from DARK Compilers.

Store your keys safely offline - never get online to sign transactions

The best way to keep your private key safe, is to keep it disconnected from the internet. This is usually done in hardware wallet, however most of those wallets are directly connected to a computer, either via usb or bluetooth. What if the wallet was never online and never ever connected to an online device. This is achievable using QR code. We did it with Parity Signer. I will present why we built it, how, do a short live demo, and what we will do in the future.

Swarm - Storage and Communication for a Sovereign Digital Society

Swarm is a core infrastructure to the Ethereum powered Web3. It augments the consensus layer of the blockchain with secure file storage, content distribution, and communication.In this breakout session we explore how Swarm can help scale Eth 1.x and 2.x. We showcase what Swarm can do for dapp developers. We present new research on data encoding and data structures specifically adapted to the decentralised web. We host a workshop on incentivisation in Swarm. We talk about what the team has achieved so far and the challenges ahead.Topics include, but are not limited to:"Infinitely scalable trustless database services""Ethereum State on Swarm""Running and testing large scale Swarm deployments""SWARM - A core infrastructure to augment Ethereum with distributed storage and secure messaging.""When Merkle Met Entanglements""Distributed storage meets incentivization on Swarm"

Tales from the field - using Ethereum for a decentralized ISP in rural America

My rural town of 1800 people suffered from lack of internet access. In this talk, I'll explore how we built a decentralized, crypto powered ISP to solve that problem. Homeowners, businesses and farmers own different components of the network and earn ethereum for forwarding bandwith, instead of using large towers and centrally held infrastructure, Everyday people buy eth on their phones and load it into their routers to pay for internet. Building a network in this agile and versatile way has allowed us to reach people more efficiently and provide cheaper and faster internet service. Which means Linda's flower farm is earning eth just for having a few antennas in her yard, and young Beatrice can do her homework at home now instead of the library.

Taking the DX to the next level: The OpenZeppelin Platform in a nutshell

The Ethereum developer ecosystem is in constant change. Undoubtedly, teams have started to leave the development of Smart Contracts in the background to focus on the development of decentralized applications and UX improvements on them. But developer experience is still important: We need the right tools to minimize the difficulty of working on Ethereum projects, while preserving high security standards. In this talk we will discuss how OpenZeppelin has been working on a frictionless tool for developing, deploying, upgrading and interacting with Smart Contracts and for creating DApps in an easy and secure way, introducing the latest version of the OpenZeppelin Platform.

Taxonomy of DAOs

The term DAO appears here to stay. From its first use, the phrase Decentralization Autonomous Organization conjured an array of potentialities, including legal representation and management for natural systems to imaginaries of independent Skynet-like entities. However, despite the resurgence of DAO projects in 2019, we still lack a common vocabulary for different types of DAOs. From “human-work DAOs” to “superscalable” organizations, this breakout session aims to develop a working taxonomy of DAO projects with differing structures and objectives. We will provide a worksheet for participants to evaluate a specific DAO project instance, based on its decision-making processes, ease of entrance and exit, and broader governance mechanisms, with helpers from each project on hand to provide insight. We will also provide basis for existing organizational forms, such as co-operatives and mutual organizations, that DAOs both mimic and exceed. This breakout session seeks to establish a working group on DAO taxonomy, and chart both existing categories as well as the as yet unknown feats of DAOs.

Technological Sovereignty, Blockchain & Human Dignity

Being aware that the self-determination and freedoms of the peoples of the world will be increasingly linked to technological sovereignty and the preservation of ethnosphere. The Fourth Industrial Revolution challenges us to approach in a multidisciplinary manner the development of Artificial Intelligence, the Blockchain, Robotization and other disruptive technologies so that they are compatible with Human Dignity and Sustainable Development Goals (SDGs). The promotion of democratization and decentralization of technologies, open source software, open data, web neutrality and the adoption of new technologies for the progress and preservation of the tangible and intangible resources of humanity is becoming increasingly necessary. A multidisciplinary response is needed to create pragmatic proposals on the adoption and implementation of the Block Chain in order to preserve human dignity and promote sustainable development.Work at the highest level to advocate the adoption of Blockchain for the preservation of Human Dignity. To adopt this and other emerging technologies, it is necessary to promote a more structured multidisciplinary process of intergenerational cooperation and knowledge management. We build bridges between academia, regulators, civil society and the private sector for the adoption of the Blockchain for the achievement of sustainable development goals and the preservation of ethnosphere.

Testing DApps with Realistic Web3 Mocking

I will demonstrate using a Web3 Mock for UI testing of DApps. It can be difficult to test with actual transactions between the frontend and blockchain. This is because transactions must be signed by a private key, but UI testing frameworks cannot interact with Web3 providers to do so. A Web3 Mock solves this problem by signing transactions with a private key automatically and sending them to the blockchain. This offers developers better experiences writing blockchain apps. It uses open source technology and is compatible with a range of blockchain development environments including Ganache, PoA, and remote APIs like Infura. It is integrated with the popular TestCafe platform to perform full end-to-end DApp testing.

The Augur Master Plan, Part 2

The first Augur master plan from 2017 is almost completed, so it's time to look to what's next. To refresh, the original one was:1. Release a v1 which'll be pretty, slow, hard to use, and expensive 2. Integrate 0x and release a v1.5 that allows partially off chain trading so people can create, modify, and cancel orders quickly 3. Integrate Maker once out and release a v2 (“Soros”) 4. Add automatic rollover contracts 5. Release a v3 with super high transactions per second using sharding and/or raiden (“Simons”)In this lightning talk we'll go over what's next!

The CBC Casper Roadmap

The CBC Casper roadmap is a plan to implement Proof-of-Stake and Sharding for Ethereum using “correct-by-construction” (CBC) software design methodology. This talk will share new CBC Casper research, including specifications for light clients, liveness and sharding. It will include updates on formal verification and engineering efforts, and a roadmap for (eventual) release.

The challenge of implementing Solidity stack traces

Debugging is an unavoidable phase of the software development cycle, and the most frustrating and productivity wasting part of developing smart contracts. The essential tools that a programmer would use to debug code manually in a mature platform are missing or unstable in Ethereum or are unstable. These are easy debug logging (e.g. console.log) and stack traces. In addition, smart contracts development presents extra challenges, like testing code and smart contract code being written in different programming languages. In this presentation, we'll shed some light on how stack traces work in other platforms and the challenges we had to solve for building them for Solidity in Buidler. These include identifying the code behind each contract address, identifying the functions in the stack, recognizing Solidity's compilation patterns to improve error messages, and how to display them from your JavaScript tests.

The Commodification of You

Corporate interests monitor and harvest our every contact and click, exploiting the fact that we rely on the internet for nearly every facet of our lives. They delve deep into our digital selves so that they can commodify our identities. For years, they’ve succeeded with only a whisper of pushback. What can we do to know what is happening to us and take back some control from our digital identities? In this talk, attendees will learn: Recent scandals highlighting the danger of the current collect-predict-sell data monetization model; Where technology can and can’t help us as we navigate our digital lives; What we can do to educate ourselves and others to sway public opinion on privacy.

The DarkTech Renaissance

Amir Taaki gives his talk on the DarkTech Renaissance.

The Divorce of a Lifetime - Separating Money and State

The aftermath of the financial crisis made it evident that there was a real need for non-state money. When explaining the need for cryptocurrencies I draw from the analogy between the freedom to choose one’s religion and the freedom to choose one’s money. Simply put, Ethereum is the separation of State and Money. Growing up in school all of us learn about the separation of church and state, which happened hundreds of years ago. We are taught why it is so important that humans can live in societies where their religion, something very precious to them as individuals, is unethical to leave under the management of the government. In the future, this same philosophy should and will be applied to the freedom of choice towards an individual’s money. Today, one can argue that a separation of money and state might be, if not more important than, freedom of religion. Money is as fundamental to our lives as religion, because it affects almost every aspect of your life. The choices that you make about your finances impact your life and those around you, so to have money controlled by a central entity is comical.

The Future of P2P Applications

The web today is dominated by the monopolies that won the internet land grab. I personally spent 10 years working for these companies, working on Google Cloud infrastructure as well as Gmail and Google's collaboration apps. It's a hard engineering problem to solve, but we should be able to coordinate work on Devcon6 using decentralized tools. To provide people with an alternative where they own their data, we’ve build p2p replacement for Google Docs and Slack that works in the browser. For 18 months leading up to Devcon5 we’ve been working on creating open source network for p2p applications. To build out the underlying p2p stack for the whole decentralized ecosystem, we also led team of p2p projects/experts to create p2p-ecosystem report and  position paper where everyone agrees on highest impact work to be funded. As the next step we've also built p2p focused DAO on Ethereum to distribute grants with initial $400k funding.

The Future History of the Open Internet

Human communication systems have always ebbed & flowed between being open & closed.  From the founding of the Free Software Foundation in 1985, to the beginnings of the open source movement in the 1990s, to the historic battles between Linux & Microsoft, to the publication of the Bitcoin Whitepaper in 2008, to the rise of Github, Google, Facebook, and Amazon, there is a rich history of progress on open, permissionless, systems.The internet is the most powerful human communication system in history.  The internet changed the world because it allowed humans to move information across a network; and now we have the internet of money: the ability to move financial value across the internet.  What will participation in the internet of money look like?  What will the future history of our era of the internet look like?  In this talk, Gitcoin Founder Kevin Owocki will talk about the history of the open internet + project these trends forward into 2020 and beyond.

The Future of Privacy-Preserving Smart Contracts

Ethereum is unable to support the development of privacy-preserving smart contracts in its current state. What do we need from Ethereum 2.0 to build arbitrary privacy-preserving smart contracts? What cryptographic building blocks are required? We’ll begin by diving into recent efforts both in academia and industry towards building PPSCs and some of the fundamental flaws with these approaches. We’ll also cover the trade-offs that need to be considered and the lessons learned from previous attempts in this space. Furthermore, we will discuss the limitations on use cases for each approach.Attendees of the presentation will leave with a better understanding of the state of the art for PPSCs in Ethereum and the wider blockchain space.

The Future of Value

Sep Kamvar speaks about the Future of Value.

The Gas Siphon Attack: The Technical and Economic Realities Behind Hacking Exchanges

The Gas Siphon Attack allows anyone to siphon value from many exchanges in the form of gas refunds, a mechanism built directly into the Ethereum protocol. Users can write a simple script that continuously drains unprotected exchange hot wallets of all of their ETH. Until this was responsibly disclosed, many exchanges were affected with varying degrees of severity. How it happened, who was affected, and the technical details behind the attack are discussed during the presentation. The talk dives into the details of the refund mechanism built into the Ethereum network, and how it can be maliciously abused. The presentation explains who is vulnerable and what they can do about it. A number of these types of technical exploits exist on both centralized and decentralized exchanges, and one may find that responsibly disclosing these attacks are harder than the actual exploit itself. Getting in touch with exchanges, continuous communication with services, and helping fix different systems may be a month-long journey that yields very little in return. Hacks, front-running, misaligned miner incentives, and economic disparities are all issues for exchanges and services that are discussed in this presentation. Finally, the talk covers different ways to protect yourself and your dapp from both known and unknown exploits. Preventative measures are presented that will allow for protection from these types of attacks.

The importance of open assets and their support.

The Internet has a lot of open communities supported by goodwill. Open Source Software, Open Access papers, etc. But communities that have been supported by goodwill are often questioned about their sustainability. If the Open Source Software's system was not a massive ecosystem like today, would Ethereum have been born? This problem is still alive. We considered these communities as "assets" and launched a project to create an economy by securitizing. For assets that previously had no opportunity to be evaluated economically, Ethereum can create its chance. I want to talk about the importance of the many assets where goodwill are considered to be a single point of failure and our solutions to them.

The inner workings of a smart contract decompiler

The workshop will teach some of the most useful algorithms and tricks needed to analyse and decompile an EVM smart contract: symbolic execution, memory modelling, loop handling and so on.Techniques shown during the workshop are useful in anything related to contract analysis - from writing your own decompiler, through using existing tools like Eveem, Mythril or Manticore, to working with formal verification K Lab style. Based on the experience from building Eveem.org decompiler and analysing all the bytecodes on the Ethereum blockchain.

The magic of ethereum addresses

More often than not, people get messed up when writing or copying ethereum addresses. The ENS is supposed to solve that but is not adopted by everyone yet. These errors can have spectacular consequences. Some end up with a happy end.- https://medium.com/bitclave/how-we-sent-eth-to-the-wrong-address-and-successfully-recovered-them-2fc18e09d8f6- https://twitter.com/drew___stone/status/1135703041997516801With the adoption of wallet smart contracts, this issue is only going to grow. This talk will describe where ethereum address comes from, how you could exploit knowledge of these mechanisms, and how you could protect yourself and your users using create2 based factory like the one deployed at 0xfac100450af66d838250ea25a389d8cd09062629.

The Invisible Obelisk: Marshall McLuhan and Media Studies on the Blockchain

The so-called Toronto School media theorists, including Harold Innis, Walter Ong, and, most famously, Marshall McLuhan, pioneered a new way of thinking about media and communication technology. For them, innovations like the telegraph and railroad were not merely faster ways of transmitting the same messages that had ridden horseback a century earlier. Instead, they were fundamental re-fashionings of the core of human life, changing the speed, size, and internal dynamics of society itself.Similar transformative potential has been claimed for blockchain technology, specifically for its ability to create unique, non-duplicable data objects. But little thought has been given to exactly whatkind of transformations we're talking about. The Toronto school gives us tools for thinking about the nature of this pending change in detail, such as McLuhan's work on 'warm and cool' media and Innis' work on 'time binding vs. space binding' media. This presentation will be based on this chapter draft: https://medium.com/@dzanemorris/the-invisible-obelisk-mcluhan-on-the-blockchain-part-1-70b668c3778e. It will argue that blockchain tech, because it is both digital and durable, is a truly novel sort of media technology. It will explore how it is different from what came before, and consider some implications for the future. This application was solicited by Maria Paula.

The Gas Siphon Attack: How it Happened and How to Protect Yourself

The Gas Siphon Attack allows anyone to siphon value from many exchanges in the form of gas refunds, a mechanism built directly into the Ethereum protocol. Users can write a simple script that continuously drains unprotected exchange hot wallets of all of their ETH. Until this was responsibly disclosed, many exchanges were affected with varying degrees of severity. How it happened, who was affected, and the technical details behind the attack are discussed during the presentation. The talk dives into the details of the refund mechanism built into the Ethereum network, and how it can be maliciously abused. The presentation explains who is vulnerable and what they can do about it. Finally, the talk covers different ways to protect yourself and your dapp from both known and unknown exploits. Preventative measures are presented that will allow for protection from these types of attacks.

The MakerDAO Critical Governance Vulnerability

While working on an audit for the Coinbase team, we found a critical vulnerability in one of the DappHub library contracts, which affected the MakerDAO governance system in production. In this short talk, we will provide a beginner-friendly technical description of the issue and its remediation.

The Next Evolution of Web3 Wallets

Metamask’s aim is to empower the web3 ecosystem to create useful and usable applications for users. We have led the way thus far by being a web3 connector and a wallet that serves different types of user groups, and hence juggle their different needs. We are at a critical turning point, where we believe a one-size-fits-all solution is not the answer. We are looking forward to make Metamask modular, more secure, and extensible that dapp builders can use for the specific needs of their end users. We’ll do this with the help of new Metamask APIs, which will empower the developer community to build creative solutions that inherently integrate with Metamask. In this workshop, we will share developer beta version of Metamask APIs! What you can expect from this workshop: - You’ll learn about some new APIs the MetaMask team has been working on. - You'll learn how to use these APIs to enhance your products’ functionality and UX. - We'll bring a few working demos, and facilitate a brainstorm on how these features could help your users, and how we can improve them for you. - Build a simple application that is made possible with these new APIs.

The Next Ethereum Story

The external narrative about Ethereum runs alongside the conversations we have in the community. How much they intersect depends on the day. Members of the Ethereum community influence that narrative, but they are far from the only actors shaping perception. Among these are a motley crew of journalists, government officials, social media personalities, and venture capitalists, with varying degrees of technical savvy, as Ethereum collides with our media environment, market conditions, and geopolitics.Ethereum is young enough that our actions impact its story, which can help or hurt our ecosystem as a whole. With this power should come responsibility. As Ethereum grows and further decentralizes, it's up to the builders of each new generation of projects to write the next chapter.In this workshop, Riley Kim, Asia Pacific PR Lead at ConsenSys, and I will present a history of Ethereum through the lens of public perception up to the present, focused on how media in English-speaking and Asian markets have told its story. Then we will facilitate a collaborative activity to brainstorm a shared Ethereum narrative for the future.

The Optimistic Virtual Machine: an Ov(m)erview

The Optimistic Virtual Machine (OVM) is a language for expressing layer 2 scaling solutions like state channels and plasma as a local fork choice. The language is built on a formal model of logical game semantics, along with a "cryptoeconomic dispute assumption." Composing these primitives allows us to describe complex properties of layer 2 state. These layer 2 systems can be written as OVM "programs" which are compiled into both a client-side "proof checker" (the local OVM) and ethereum-side code. The Ethereum code acts as OVM "interpreter" contract on the Ethereum blockchain, which can interpret disputes for any and all of these layer 2 system (state channels, plasmas, etc.). We will go over the details of both the game semantics and Ethereum smart contracts in this workshop.

The paradox of centralized tools doing accounting for decentralized finance

This talk is going to be about a paradox that has been prevalent since the early days of Cryptocurrencies. Cryptocurrencies were made to empower the individual, to be their own bank and to enable financial freedom without having to rely on centralized institutions. The paradox lies in the contradiction that when people want to do accounting or analytics for this new financial system they happily turn to centralized tools. This act enforces the status quo of finance being managed by centralized platforms and goes against the spirit of decentralization, undermining everything we are building. The talk will present multiple examples of this paradox in the world around us, from the way people do analytics (Blockfolio e.t.c.), to the way they do tax accounting (Bitcoin Tax e.t.c.). There will be some theorizing on why this is the case and underline why this is bad for the ecosystem and exceptionally dangerous for the people who utilize such services. Finally potential solutions to this problem will be presented, showing how a tool that performs decentralized financial analytics, accounting and tax reporting should look like in order to respect user's privacy and fit in this new era of decentralized finance we are now entering.

The Nuts and Bolts of Cross-Chain Communication

Throughout the past years, research into facilitating trustless cross-chain communication has resulted in the proposal of numerous concepts and mechanisms. However, to this date, the work is scattered across blog posts, scientific papers and code. The goal of this workshop is to provide an overview of the fundamentals of cross-chain communication, especially in cross-ledger exchanges and sharding. Our goal is that participants understand the differences between trusted/custodial and trustless/non-custodial approaches, and the challenges we face today.We split the workshop into 2 parts:Theory: Overview: motivation, challenges and different approaches and use cases. Focus on (i) cross-ledger exchanges (atomic swaps and cryptocurrency-backed assets), and (ii) sharding, (different proposals and how they handle cross-shard transfers). Two technical deep dives: chain relays and data availability / fraud proofsPractice:  Interactive coding workshop: participants build their own Bitcoin chain relay. We provide Solidity code with missing code snippets and help participants find the correct solution. In the end, we present our example implementation and discuss the approaches found by workshop participants.  People who do not wish to code or are unfamiliar with Solidity: interactive walk-though for the BTC Relay implementation + detailed discussion of possible attacks to foster adversarial thinking.

The Surprising Things We Can Do with Decompiled Smart Contracts

Over the last year we have seen a lot of development in the field of smart contract decompilation. This in turn has opened up a lot of new possibilities: -better user interfaces -new ways of finding security flaws -making decisions regarding the future of protocol -network analysis. The talk will show some interesting things that were built during the last year.

The Use of Utility Token Staking Rewards

The utility token is based on the concept of user ownership. In principle, token-based voting can empower the users of a utility token project to oversee its long-term development. In practice, however, a very large proportion of circulating utility tokens are held by speculators, rather than actual users. The talk will discuss our efforts to improve the utility token model through the introduction of a staking process that incentivizes user ownership. We will explain the process we followed to map our governance objectives into a specific staking mechanism. The talk will explain how this mechanism incentivizes ownership among a target user group, penalizes socially harmful behaviors, and collects and distributes fee revenue in a manner that satisfies basic fairness norms.

Toward Backward Compatible Ethereum Upgrades

Ethereum's last hard fork Constantinople and the current ongoing Istanbul hard fork all bring in an important topic that wasn't previously strongly considered -- backward compatibility. In this presentation, we will explain why this is an issue, and why when reviewing EIPs for inclusion, only talking about soundness of the EIP is not enough. We will explore techniques that are being proposed to solve this issue -- most importantly, account versioning, and how it enables EIPs being included hassle-free, and also allow us to drastically change the VM in the future. The presentation will conclude with current challenges we are still facing regarding backward compatibility, and if time permits, traits that we can use when reviewing an EIP to understand whether it requires account versioning or not.

The Road to ETH 2.0: How to Build EWASM DApps with Embark v5

In this workshop we will be building step by step a modern DApp step that uses the latest Ethereum 2.0 technologies with the aid of Embark & Cockpit.

Towards Eth2 Developer Tooling

Gregory Markou gives his talk on Eth2 Developer Tooling.

The UX challenges to build on top of a light client

In the past year, we have been building Fether, a wallet based on a light client. Although the connection to a node is a fundamental part of building a DApp, it is often considered secondary as connection can be achieved for free using a 3rd party node. We will present the UX patterns that we have developed in Fether to allow for a great UX, without necessarily have access to a full node.

Transparent Dishonesty: Blockchain Front-running Taxonomy

Front-running has been an issue in financial instrument markets since the 1970s. With the advent of the blockchain technology, front-running has resurfaced in new forms we explore here, instigated by blockchains decentralized and transparent nature. In this paper, we draw from a scattered body of knowledge and instances of front-running across the top 25 most active decentral applications (DApps) deployed on Ethereum blockchain, and an instance of abnormal behaviour of a mining pool to participate in an ICO. We also introduce a taxonomy of front-running attacks on blockchain and map the proposed solutions to front-running into useful categories. Published at Financial Cryptography and Data Security 2019: https://arxiv.org/abs/1902.05164

Towards Better Debugging: Data Format Design Session

On traditional computing platforms, most language compilers output debug information to enable debuggers to decode a program's operation and to enable the user to make sense of their code through hands-on inspection. With smart contract languages, however, this is not yet possible. Existing debugging data formats don't support Ethereum's computing paradigm, leaving debuggers to guess at compiler behavior in hopes of understanding how compiled bytecode reflects user-written source. In this breakout session, we will present the current state of debugging support on Ethereum, an overview of how debugging support exists on traditional computing platforms, and what the disconnects are that make this more difficult for Ethereum. From there, we seek to discuss how to overcome these limitations and how we can make smart contract debugging better. The goal of this session is to lay the groundwork for a new data format, including its high-level design and a clear understanding of the path forward for this effort.

Toward Ethereum 2.0 Sharding Universe

Ethereum 2.0 beacon chain has introduced the basic structure of the sharded networks. This presentation would discuss the current research on the sharded network topology and the strategies of the Ethereum 2.0 clients for the future shard chains.

Universal Chain Registry: EVM + Cosmos ChainIds

We will present a new initiative to list all the ids of EVM and Cosmos-based chains. We will also speak about the ongoing work to provide a standardization of the chainId format and data structures to represent multi-interface blockchains information. Github: https://github.com/UCRegistry Telegram: https://t.me/UCRegistry

Trains, Planes and Network Upgrades: A Regular Release Cadence

How does an Ethereum Improvement Proposal (EIP) get deployed onto the Ethereum mainnet? At times it feels like an ‘80s buddy comedy, but as part of the Ethereum 1.x initiative, the process should become as predictable as a clock. In this talk, we will propose a regularly scheduled process modeled after Linux distributions and the Java platform that Ethereum could use for its future network upgrades. Frequent and regular network upgrades will remove the time pressure to submit and review EIPs, provide predictability to applications building on Ethereum and reduce the burden on core developers to begin implementing improvements that are not ready. Once a network upgrade leaves the station, another one will be coming right around the corner!

Using DAOs to Make Decentralized Protocols Actually Decentralized

Luis Cuende gives his talk on Using DAOs to Make Decentralized Protocols Actually Decentralized.

Validating designs and finding points of failure: Testing ETH 1.x and ETH 2.0 against AI agents

We’ve introduced the notion of machine learning algorithms in our network of simulator: Wittgenstein. We explore the different strategies that can be taken by participants in the network to attack the system or manipulate protocol’s design to increase rewards. We focus specifically in reinforcement learning, and set up different agents that engage in different byzantine behaviours. We present results and guidelines to improve the design of protocols such as PoW, Casper and others.

Universal Login Progress: results in on how to make ethereum on boarding much simpler

This is a followup on last year's Devcon about Universal logins and how we can make onboarding much better by getting rid of private keys, seeds and passwords. I will present progress on the Universal Login standard and how it can help ethereum apps to reach mainstream audiences.

Upgradeability of self governed contract

On-chain wallets offer many features that more traditional private key based account lack. This is why many projects are pushing toward broader adoption of multisig wallets to represent users' identity and improve the UX. Yet, all are different and it's unlikely that any of the multisig available right now will be relevant more than a few years. There are features we haven't even though about that will be important to have in the future.ERC725 proposes to build a minimalistic proxy and change its owner when the users feel the need. This allows you to keep your address and not have to move your token to a new wallet. But with this approach, the ownership logic doesn't own the assets so meta-tx with refund is more complex.A better solution would be to allow the proxy to be the multisig itself while offering the same upgradeability potential. Since EthCC 2019, KitsuneWallet has been building a framework that provides upgradeability by design it an increasing number of project (UniversalLogin, Shipl, ...). With this framework, users can upgrade their on-chain wallet to benefit from new features or even change the entire interface to move from one UX to another.

Vulnerability Coordination and Incident Response in a Decentralized World

There’s one question that every team of core blockchain developers has discussed at least once: what are we going to do when a critical vulnerability in our software is surfaced? By definition, everything we create is likely to include a vulnerability or code flaw and the difficult legal, ethical, and business issues arise when bugs show up in code. While decentralization does not require us to reinvent the first principles security, it does force us to challenge ourselves to manage significant complexity to reduce harm to those who depend on our code. This talk will discuss the CosmosCERT as a model for how teams can successfully coordinate vulnerabilities and respond to incidents in decentralized environments using on-chain governance mechanisms in a way that ensures stakeholders have a dedicated emergency response capabilities ready to go when the worst happens.

User Research: How to get out of our bubbles by talking to users

In this workshop targeted at anyone building blockchain products or services, an experienced User Research team will help you step out of your comfort zone; by learning to interview and observe end users. Georgia and Sasha will explain the benefits of doing user research, what it looks and feels like when we talk to people who are different from us, with some "tales from the trenches". Then we will help groups 1) identify and find the right users for your research, 2) work out what to ask them 3) practice interviewing people to get to the core insights. Attendees will leave the workshop with a taste for conducting their own future user research, as well as increased confidence to challenge their own biases and blindspots.

We Come in Peace: Why VC Matters to Ethereum

Jehan Chu speaks about VCs in the ecosystem.

Weak Subjectivity and Eth 2.0 Sync

Hsiu-Ping Lin speaks on Weak Subjectivity and Eth 2.0.

UX Awards

Amy Jung, Alex Orchowska, Graeme Blackwood and Benny Giang present & take part in the UX Awards.

Weaving Cultural Fabrics With Tokens

Many people in the crypto ecosystem have long operated under the same assumptions that Satoshi operated under in his original white paper: that we should assume that there's no trust among actors within an ecosystem, and that they'll make purely rational decisions to benefit themselves. Since then, we've seen the flourishing of tokens, each of which has their own communities with individuals orbiting at various distances. What we've seen practically is that in reality these actors do end up trusting each other in various ways (such as the way that BTC holders all trust each other to enforce a 21M supply cap), and that similarly, actors don't always act rationally (the proof for this point will be left as an exercise for the reader). In light of these updates, it would serve us well to begin thinking of our protocol designs in a manner that not only incorporates the "hard" side (the one which treats actors like rational machines), but also the "soft" side: the one which takes into account human actors, their emotions, and the cultural fabric or "soft layer" which can sit atop the "hard layer" for a system to work in its entirety. This "soft layer" already exists informally-- on crypto-twitter, in telegram groups, through memes, and at the myriad of conferences which take place year-round in our space. However, there would be significant benefits for us as protocol designers to begin intentionally designing these soft layers alongside the hard layers (even though doing so will necessarily require the input of social scientists and not computer scientists).While many perceive extrinsic incentives (like reputation or value) as being at-odds with intrinsic incentives, this talk will illustrate (with examples) how the issuance and distribution of tokens can enable humans to connect with each other in a decentralized fashion, creating a force which unites them around a set of shared principles or goals. By using tokens not just for utility or fundraising but rather as focal points around which communities may organize, we may begin to intentionally weave these cultural fabrics, to be more successful in building new communities and protocols.

Welcome Ceremony

The opening ceremony to Devcon 5.

What Do We Do About Libra?

Lucas Geiger talks about Facebook's Libra & its impact.

What is happening with Ethereum Classic?

2019 has been an exciting year for the Ethereum Classic community. Three years on from The DAO the focus is on developer experience, on coordinating hard forks to bring Byzantium, Constantinople and Istanbul changes to ETC, and looking forward to opportunities for collaboration with ETH 1.x. This presentation gives an overview of the ETC ecosystem, progress in the last year and some ideas on how ETH 1.x and ETC can work together for mutual benefit. Bob has worked at the Ethereum Foundation, ConsenSys, Enterprise Ethereum Alliance and now at the Ethereum Classic Cooperative.

Welcome to the Samsung Blockchain Galaxy

The ideological value of the Blockchain is similar to the chracteristics of Blockchain technology itself. Both the real world as well as the technology are both creating and inspiring new values to communicate to one another. At DevCon5, we look forward to sharing Samsung's vision of Blockchain along with its technical features. We'll explains the background of Samsung Blockchain Keystore launch from a security perspective along with why Ethereum was the first choice for solving the security and tech challenges many face. We'll also look at how the Ethreum ecosystem has allowed Samsung to strategize our blockchain strategy when it comes to regional launch selections, vertical segments, and future roadmap. Samsung would also like to share our market leadership by voicing why we, as the global OEM leader for smartphones, are making the leap into the Blockchain community by making SDK's available for developers and welcoming developers to embrace the platform from a mobile perspective. and welcoming them to partner with us and create amazing decentralized applications. Our scale and market position combined with the dev community's insight and know-how will be very exciting!

What's Next for DeFi?

The DeFi movement, which rethinks the conventional financial services and builds them in a decentralized manner, has enjoyed great momentum. After the humble beginnings in 2018, this year was fruit-bearing: building blocks for open financial protocols have been laid out. Looking forward, we have to challenge ourselves – what are the missing pieces to make this movement truly accessible and how can we achieve global financial inclusion? MakerDAO is one of the oldest projects in the Ethereum space that has, aside from bringing the first decentralized stablecoin build on this blockchain, introduced a powerful decentralized credit system. Maker Protocol transitioned into both: a DeFi bedrock and a building block in the set of services never seen before. Look ahead with the project founder Rune Christensen – he has a major revelation planned to finish off the keynote - more on this TBD.

When 1 Million Eth Devs?

The Ethereum ecosystem has achieved a lot over the past year with respect to core development, adoption, defi, and improving scalability. Ethereum’s main advantage in the blockchain space is the community of developers that continues to build and grow the network. Joe Lubin’s talk will discuss the state of development on the Ethereum blockchain, set some benchmarks for the next year, and propose a common goal: When 1 Million ETH Devs?

When blockchain meets legal design: UX challenges in the world's first decentralized court.

Legal technology guru Richard Susskind said: 'Online courts are not an alternative to the justice system. They are the justice system. In 10 years, more cases will be settled online than offline'. Decentralized courts built on blockchain technology will play a key role in this transformation. But this will pose great challenges, as people aren't used to online trials. This talk will explore the role of UX design to contribute to this transition. In particular, it will focus on the intersection between UX design and legal design, a breakthrough method developed at Stanford’s Legal Design Lab which advocates the use of design thinking principles into legal software products. We will illustrate concepts with examples of UX challenges faced at Kleros, a blockchain dispute resolution DApp, and discuss the design decisions, what worked and what didn't. Finally, we will distill some UX insights for creating user-friendly, accessible, and engaging solutions for the coming age of legal Dapps

Why Dapp Users will Hate Cross-Shard Communication (and what you can do about it)

ETH2 is approaching, and initial indications are that substantially all dapp experiences will suffer. Some problems may be addressed with significant changes to design and development processes, but several tradeoffs are unavoidable without sacrificing scale, security, or decentralization. For example, essentially all popular dapps rely on the fungibility of Ether in a managed pool (e.g. Uniswap, Augur, Maker). In a sharded ecosystem, Ether is meaningfully non-fungible across shards, and users will bear monetary and management costs as a result.This talk will give an overview of cross-shard communication strategies and discuss their impact on developer and user experience. These include merged consensus, shard relays, consensus introspection, and credit markets. For each mechanism, we'll discuss expected impact on user experience metrics like execution time, transaction outcome, and price slippage.The talk is not all bad news. We've discovered some elegant new approaches that give dapps a variety of communication choices. The last section of the talk will discuss specific communication strategies that are amenable to specifi

Will Design Ethics Save Software?

Cade Diehm presents his talk on Design Ethics & Software.

You Too Can Build a Ethereum Mixer!

Cryptography is maths, and maths is scary. There's information overload, you don't know where you start, there's smarter people telling you how your solution(s) isn't perfect and how it has a theoretical limit / flaw / weakness, and how it's not "safe" to do xyz.So how can one with no academic background in cryptography start building cryptographic protocols to be then ultilized in higher-level applications? This talk will focus on my anecdotal process of building a Heiswap, Ethereum Mixer, with a Research vs Engineering perspective.

Zerochain: Using zk-SNARKs for an account based privacy-preserving blockchain

Zerochain is a privacy-protecting layer on top of any smart contract platforms like Substrate and Ethereum. As a high-level overview, Zerochain is based on Zether protocol(https://crypto.stanford.edu/~buenz/papers/zether.pdf) which is privacy-oriented payment protocol on top of smart contracts. Though this original specification uses Sigma-bullets as zero-knowledge proving systems, instead we use zk-SNARKs for the efficiency reason. I would like to talk about how it works, how we can integrate privacy into the account-based approach.Currently supported for the only Substrate, but it can be supported for Ethereum as well because Zerochain and Zether protocols can be compatible with any smart contract platforms. Here is our GitHub page: https://github.com/LayerXcom/zero-chainand blog post: https://medium.com/layerx/announcing-zerochain-5b08e158355d

Workshop: Building on top of Golem with gWasm and Unlimited

Are you ready for a thrill of doing something new and exciting? Would you like playing with WebAssembly on Golem Network? During the workshop, we will demonstrate a set up of a Golem Unlimited cluster - including machines brought by the audience. We will showcase how to distribute the execution of existing apps within the ad-hoc infrastructure. You will have an opportunity to run 3 apps with source-code available and code your own app using the simplistic API and cross-compile to Wasm target. Attending the workshop will give you the tools and knowledge to tackle our white-hat hacker challenge. Stay alert! To fully experience hands-on experience in the workshop, please install the docker on your machine and do `docker pull golemfactory/gwasm-tutorial`beforehand.

ZETH: On Integrating Zerocash on Ethereum

Transaction privacy is a hard problem on an account-based blockchain such as Ethereum. While Ben-Sasson et al. presented the Zerocash protocol [BCG+14] as a decentralized anonymous payment (DAP) scheme standing on top of Bitcoin, no study about the integration of such DAP on top of a ledger defined in the account model was provided. In this paper we aim to fill this gap and propose ZETH, an adaptation of Zerocash that can be deployed on top of Ethereum without making any change to the base layer. Our study shows that not only ZETH could be used to transfer Ether, the base currency of Ethereum, but it could also be used to transfer other types of smart contract-based digital assets. We propose an analysis of ZETH's privacy promises and argue that information leakages intrinsic to the use of this protocol are controlled and well-defined, which makes it a viable solution to support private transactions in the context of public and permissioned chains.

Yul, eWasm, Solidity: Progress and Future Plans

Over the last months, the Yul language has matured and proved its flexibility. The Solidity team has implemented an optimizer and an eWasm dialect and is now full steam working on rewriting the Solidity code generator to produce Yul code to replace sequences of EVM instructions.The Yul optimizer now matches the old EVM optimizer and already surpasses it with features like function inlining and cross-function optimization. This is also the main reason why the new code generator can be written in a super-modular way. Furthermore, it can equally operate on EVM- and eWasm-flavoured Yul code, which is important to cope with the 256- to 64-bit translation.Through this, the Solidity compiler can now output eWasm code, which makes efficient use of 64 bit types. Furthermore, the new code generator includes automated overflow checks everywhere, again something that would have destroyed the old optimizer. Future work:We plan to use a more intricate formal system to remove redundant operations and checks based on range-relations between variables. The introduction of memory area types will help optimizing memory allocation. Finally, a super-optimizer could prove useful, since it is worth spending extra time on compilation to save gas.

ZoKrates - Privacy for dApps

In this talk, we provide an update on the state, future, and vision of ZoKrates, the programming language and toolbox to bring zkSNARKs to Ethereum developers to enable privacy and scalability of their dApps. We describe the evolution of the ZoKrates language, standard library, and tooling before outlining our view on ZoKrates’ role within the Ethereum ecosystem of the future. To support this vision, we share insights gained from use case implementations where we enhanced the privacy of decentralized applications with ZoKrates.

Zero Knowledge: Privacy and Transparency's beautiful co-existence

Zero Knowledge Systems are often imagined as the enabler technologies for a privacy-centric world in which an individual can operate freely, away from public scrutiny. In these proposals, we focus primarily on an individual's right to own and protect their private data. While this is an important topic to us all and a model that is already being explored by projects like Zcash, I believe that the Zero Knowledge paradigm actually offers an opportunity for something even more powerful: that is secure systems providing both privacy and at the same time transparency for individuals and organisations. In this talk, I aim to explore what this balance can look like using zero knowledge systems, how valuable this could be in our personal and business lives, and showcase projects aiming to develop tools in this spirit.