Disarming Fiat-Shamir footguns

By Opal Wright

The Fiat-Shamir transform is an important building block in zero-knowledge proofs (ZKPs) and multi-party computation (MPC). It allows zero-knowledge proofs based on interactive protocols to be made non-interactive. Essentially, it turns conversations into documents. This ability is at the core of powerful technologies like SNARKs and STARKs. Useful stuff!

But the Fiat-Shamir transform, like almost any other cryptographic tool, is more subtle than it looks and disastrous to get wrong. Due to the frequency of this …

block building computation conversations documents fiat important knowledge mpc non opal party protocols technologies transform zkps