p3-challenger

A Fiat–Shamir transcript and challenger framework, used to derive random challenges from an IOP's transcript.

Key items:

• CanObserve, CanSample, CanSampleBits, FieldChallenger — the observe/sample trait family
• DuplexChallenger — sponge-based challenger over a cryptographic permutation
• HashChallenger — challenger built from a generic hash function
• MultiField32Challenger, SerializingChallenger32/64 — challengers bridging fields of different sizes
• GrindingChallenger — proof-of-work witness generation and verification

Prover and verifier must observe and sample in the exact same order; every proof object is bound to the transcript before any challenge it influences is sampled.

Part of Plonky3, dual-licensed under MIT and Apache 2.0.