Crate poseidon_hash 

Poseidon Hash (Goldilocks)

Rust implementation of Poseidon2 hash function and Goldilocks field arithmetic.

⚠️ Security Warning

This library has NOT been audited and is provided as-is. Use with caution.

• Prototype implementation focused on correctness
• Not security audited - do not use in production without proper security review
• While the implementation appears to work correctly, cryptographic software requires careful auditing
• This is an open-source contribution and not an official Lighter Protocol library
• Use at your own risk

Overview

This crate provides essential cryptographic primitives for Zero-Knowledge proof systems:

• Goldilocks Field: A special prime field (p = 2^64 - 2^32 + 1) optimized for 64-bit CPU operations
• Poseidon2 Hash: A ZK-friendly hash function designed for low constraint counts in ZK circuits
• Fp5 Extension Field: Quintic extension field (GF(p^5)) for elliptic curve operations

Features

• Fast field arithmetic with optimized modular reduction
• Efficient Poseidon2 hash implementation
• 40-byte field elements for cryptographic operations
• Production-grade performance and security

Example

use poseidon_hash::{Goldilocks, hash_to_quintic_extension};

// Field arithmetic
let a = Goldilocks::from_canonical_u64(42);
let b = Goldilocks::from_canonical_u64(10);
let sum = a.add(&b);
let product = a.mul(&b);

// Poseidon2 hashing
let elements = vec![
    Goldilocks::from_canonical_u64(1),
    Goldilocks::from_canonical_u64(2),
    Goldilocks::from_canonical_u64(3),
];
let hash = hash_to_quintic_extension(&elements);

Modules

merkle

Binary Merkle tree built with the Poseidon2 hash over the Goldilocks field.

Structs

Fp5Element

Fp5 extension field element.

Goldilocks

Goldilocks field element.

Functions

empty_hash_out

Returns an empty hash output (all zeros). Equivalent to Go’s EmptyHashOut function.

hash_n_to_one

Combines multiple hash outputs into a single hash output. Equivalent to Go’s HashNToOne function.

hash_no_pad

Hashes a slice of Goldilocks field elements, producing exactly 4 output elements. Equivalent to Go’s HashNoPad function.

hash_out_from_bytes_le

Deserialises a HashOut from 32 little-endian bytes.

hash_out_to_bytes_le

Serialises a HashOut to 32 little-endian bytes.

hash_to_quintic_extension

Hashes a slice of Goldilocks field elements to a single Fp5Element.

permute

Applies the Poseidon2 permutation to a 12-element state array.

Type Aliases

HashOut

Hash output type: 4 Goldilocks elements (32 bytes) Equivalent to Go’s HashOut type