Crate starkom_poseidon2 

Poseidon2

Overview

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

This crate uses version 2 of the permutation. For version 1 see the starkom-poseidon crate.

The implementation is generic and works on any prime field.

Configurations for the BLS12-381, Goldilocks, and BlueSky prime fields are provided; the BLS12-381 and BlueSky configurations support T=3 and T=4, while the Goldilocks configurations support T=12 and T=16.

[!NOTE] All predefined configurations are gated behind feature flags to avoid including all constants in all builds. The currently defined feature flags are bls12_381, goldilocks, and bluesky, all disabled by default.

Usage

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

use starkom_bluesky::Scalar;
use starkom_poseidon2;

fn hash_t3(inputs: impl IntoIterator<Item = Scalar>) -> Scalar {
    starkom_poseidon2::hash::<starkom_poseidon2::bluesky::BlueSkyConfig3, Scalar, 3, 2, 1>(inputs)[0]
}

fn hash_t4(inputs: impl IntoIterator<Item = Scalar>) -> Scalar {
    starkom_poseidon2::hash::<starkom_poseidon2::bluesky::BlueSkyConfig4, Scalar, 4, 3, 1>(inputs)[0]
}

Re-exports

pub use bluesky::*;

pub use bls12_381::*;

pub use goldilocks::*;

Modules

bls12_381

bluesky

goldilocks

Structs

Decryptor

Decrypts an arbitrary number of field elements in batches of R using the Poseidon permutation with state size T.

Encryptor

Encrypts an arbitrary number of field elements in batches of R using the Poseidon permutation with state size T.

Traits

Config

Poseidon2 instance configuration trait.

Functions

hash

Generic Poseidon2 implementation over the prime field F with state size T.

hash0

Convenience function for hashing with Poseidon2 and squeezing the first element.

permutation

Runs the Poseidon2 permutation.

sbox5

Standard x^5 S-box.