Fraud Proofs: Maximising Light Client Security and Scaling Blockchains with Dishonest Majorities
Duration: 00:26:05
Speaker: Mustafa Al-Bassam
Type: Talk
Expertise: Intermediate
Event: Devcon
Date: Jul 2026
Light clients are nodes which only download a small portion of all of the data in a blockchain, and try to use indirect means to verify that a given chain is valid. Typically, instead of validating block data, they assume that the chain favoured by the blockchain's consensus algorithm only contains valid blocks, and that the majority of block producers are honest. By allowing such clients to receive fraud proofs generated by fully validating nodes that a block violates the protocol rules, we can eliminate the assumption that the majority of consensus-participating nodes are honest, and instead assume that there is at least one honest fully validating node that can distribute fraud proofs within a maximum network delay, and a minimum number of honest light clients to reconstruct missing data from blocks. Fraud proofs and data availability proofs are key to enabling on-chain scaling of blockchains (e.g. via sharding or bigger blocks) without significantly reducing the ability of end-user wallets to have assurance that all on-chain data is available and valid. We present, implement, and evaluate a novel complete fraud proof and data availability proof system. Research paper draft (work-in-progress): https://www.dropbox.com/s/3zj3burdfrw5v69/fraudproofs-paper.pdf Data availability code: https://github.com/musalbas/rsmt2d Fraud proofs prototype (work-in-progress): https://github.com/asonnino/fraudproofs-prototype
