Section 6: ZkProver Hash Function

In the context of zkProver, Keccak and Poseidon are two specific hash functions that are used as part of a state machine to handle hash operations. These state machines can be thought of as "automated" versions of these hash functions, meaning that they are designed to automatically handle various tasks related to hash functions without requiring the user to manually perform each step.

Keccak State Machine: Keccak is a cryptographic hash function designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche as a potential replacement for the SHA-256 hash function used by Bitcoin and some other cryptocurrencies. Keccak is the algorithm that won the NIST (National Institute of Standards and Technology) SHA-3 cryptographic hash function competition. It is designed to be highly flexible and scalable and can adapt to different security levels and application scenarios.

Poseidon state machine: Poseidon is another cryptographic hash function that is specifically designed for zero-knowledge proofs. Poseidon hash functions are designed based on the needs of SNARKs (Succinct Non-Interactive Arguments of Knowledge) and other advanced cryptography techniques. Its goal is to provide efficient hashing operations while maintaining sufficient security to support complex cryptographic applications. Poseidon has optimized computational performance and memory usage, making it ideal for building efficient zkProvers.