Yesterday I wrote about the cheater checking problem: how to make sure that parties who are supposed to be checking others’ computations are really doing so, rather than lazily guessing/assuming that the…

Our team at Offchain Labs was happy to see that the new Flow blockchain proposed by Dapper Labs tried to address the Verifiers’ Dilemma. We think that’s an important problem. Unfortunately their solution fails to solve the Verifier’s Dilemma, for two separate…

Dapper Labs has responded to our previous post about flaws in their new Flow protocol. They graciously thanked us for our critique and offered some kind words, both of which are appreciated. But unfortunately the changes to their design don’t fix all of the problems with Flow.

Smart contracts on Ethereum often want to set deadlines for clients to act. For example, Layer 2 protocols like Arbitrum give parties a time window in which they can challenge some claim by another party. To enforce a deadline, the only reliable clock available is…