proof-cat-core

Field-agnostic proof-system primitives, factored out of proof-cat so that both PLONKish and STARK-flavored downstreams can share them without inheriting either constraint vocabulary.

What's in here

Module	Purpose
[`transcript`]	Functional Fiat-Shamir transcript over SHA-256
[`commit::merkle`]	Hash-based vector commitment with leaf-index domain separation
[`poly`]	`MultilinearPoly<F>` evaluation tables on `{0,1}^n` with partial evaluation
[`sumcheck`]	Sumcheck prover and verifier for multilinear polynomial sums
[`error`]	The shared [`Error`] enum

What's NOT in here

The Field and FieldBytes traits or any concrete prime field. Those live in field-cat.
The PLONKish constraint system (ConstraintSet, Expression, Wire). Those live in plonkish-cat.
The bridge from PLONKish constraints to sumcheck. That stays in proof-cat as its sole remaining responsibility.

Why a separate crate

Each of transcript, commit::merkle, poly, and sumcheck is independent of any particular constraint system. Lifting them out lets a STARK frontend (AIR + FRI + sumcheck, in a future stark-cat) consume them directly, without taking a transitive dependency on plonkish-cat's ConstraintSet / Expression / Wire vocabulary.

Quick start

use field_cat::F101;
use proof_cat_core::{MultilinearPoly, SumcheckClaim, Transcript, sumcheck_prove};

let poly = MultilinearPoly::from_evals(vec![
    F101::new(1), F101::new(2), F101::new(3), F101::new(4),
])?;
let claim = SumcheckClaim::new(poly, F101::new(10));

let (_proof, _challenges, _transcript) =
    sumcheck_prove(&claim, Transcript::new(b"example"))?;
# Ok::<(), proof_cat_core::Error>(())

Building

cargo build
cargo test
RUSTFLAGS="-D warnings" cargo clippy
cargo doc --no-deps --open

Conventions

See CLAUDE.md: functional, type-driven, hand-rolled Error enum, no unwrap, no as casts, no mut, no dyn, no loop/for, no path dependencies.

License

Licensed under either of:

Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

proof-cat-core 0.1.0