Zero-knowledge proof composition and recursion. Part 8: Hashing in public input
In this new series of video, following the series of videos on PLONK ( • How does PLONK work? Part 1: What's PLONK? ) I introduce the different ideas and schemes behind proof composition and proof recursion. In this series of videos we will go through pre-proof recursion schemes like Sangria and Nova, and IVC/PCD schemes following the BCTV14 paper, and later the Halo paper.
This video will talk about hashing data before placing it into the public input. Placing data in the public input is a way to authenticate it to the verifier, but it can be costly, so using a hash function saves us some there. I also mention the Poseidon hash function (https://eprint.iacr.org/2019/458).
Timestamps:
00:00 Public input might be too large
00:50 Using hash functions to get a single public input
01:38 Not always possible
02:40 The Poseidon hash function