poseidon2_permutation.hpp

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// === AUDIT STATUS ===
// internal:    { status: not started, auditors: [], date: YYYY-MM-DD }
// external_1:  { status: not started, auditors: [], date: YYYY-MM-DD }
// external_2:  { status: not started, auditors: [], date: YYYY-MM-DD }
// =====================
 
#pragma once
#include <array>
#include <cstddef>
#include <cstdint>
 
#include "barretenberg/crypto/poseidon2/poseidon2_permutation.hpp"
#include "barretenberg/stdlib/primitives/circuit_builders/circuit_builders.hpp"
#include "barretenberg/stdlib/primitives/field/field.hpp"
 
namespace bb::stdlib {
 
template <typename Params, typename Builder> class Poseidon2Permutation {
  public:
    using NativePermutation = crypto::Poseidon2Permutation<Params>;
    // t = sponge permutation size (in field elements)
    // t = rate + capacity
    // capacity = 1 field element (256 bits)
    // rate = number of field elements that can be compressed per permutation
    static constexpr size_t t = Params::t;
    // d = degree of s-box polynomials. For a given field, `d` is the smallest element of `p` such that gdc(d, p - 1) =
    // 1 (excluding 1) For bn254/grumpkin, d = 5
    static constexpr size_t d = Params::d;
    // sbox size = number of bits in p
    static constexpr size_t sbox_size = Params::sbox_size;
    // number of full sbox rounds
    static constexpr size_t rounds_f = Params::rounds_f;
    // number of partial sbox rounds
    static constexpr size_t rounds_p = Params::rounds_p;
    static constexpr size_t NUM_ROUNDS = Params::rounds_f + Params::rounds_p;
 
    using FF = typename Params::FF;
    using State = std::array<field_t<Builder>, t>;
    using NativeState = std::array<FF, t>;
 
    using RoundConstants = std::array<FF, t>;
    using RoundConstantsContainer = std::array<RoundConstants, NUM_ROUNDS>;
    static constexpr RoundConstantsContainer round_constants = Params::round_constants;
 
    static State permutation(Builder* builder, const State& input);
 
    static void matrix_multiplication_external(Builder* builder, State& state);
};
 
} // namespace bb::stdlib