Poseidon2

Overview

This is Starkom's implementation of the Poseidon2 algebraic hash.

The implementation is generic and works on any prime field, but we always allocate exactly 1 state element for capacity, resulting in 128-bit security.

We also provide configurations for the BLS12-381 and BlueSky prime fields, for T=3 and T=4.

[!NOTE] The BLS12-381 configurations are controlled by the bls12_381 feature flag, which is disabled by default.

Usage

The following example functions instantiate Poseidon2 with T=3 and T=4 respectively, squeezing a single element from the output.

use starkom_bluesky::Scalar;
use starkom_poseidon2;

fn hash_t3(inputs: &[Scalar]) -> Scalar {
    starkom_poseidon2::hash::<starkom_poseidon2::bluesky::BlueSkyConfig3, Scalar, 3>(inputs)[0]
}

fn hash_t4(inputs: &[Scalar]) -> Scalar {
    starkom_poseidon2::hash::<starkom_poseidon2::bluesky::BlueSkyConfig4, Scalar, 4>(inputs)[0]
}