hash.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 "barretenberg/common/assert.hpp"
#include "barretenberg/common/net.hpp"
#include "barretenberg/crypto/blake2s/blake2s.hpp"
#include "barretenberg/crypto/pedersen_commitment/pedersen.hpp"
#include "barretenberg/crypto/pedersen_hash/pedersen.hpp"
#include "barretenberg/crypto/poseidon2/poseidon2.hpp"
#include "barretenberg/numeric/bitop/pow.hpp"
#include <vector>
 
namespace bb::crypto::merkle_tree {
 
struct PedersenHashPolicy {
    static fr hash(const std::vector<fr>& inputs) { return crypto::pedersen_hash::hash(inputs); }
 
    static fr hash_pair(const fr& lhs, const fr& rhs) { return hash(std::vector<fr>({ lhs, rhs })); }
 
    static fr zero_hash() { return fr::zero(); }
};
 
struct Poseidon2HashPolicy {
    static fr hash(const std::vector<fr>& inputs)
    {
        return bb::crypto::Poseidon2<bb::crypto::Poseidon2Bn254ScalarFieldParams>::hash(inputs);
    }
 
    static fr hash_pair(const fr& lhs, const fr& rhs) { return hash(std::vector<fr>({ lhs, rhs })); }
 
    static fr zero_hash() { return fr::zero(); }
};
 
inline bb::fr hash_pair_native(bb::fr const& lhs, bb::fr const& rhs)
{
    return crypto::pedersen_hash::hash({ lhs, rhs }); // uses lookup tables
}
 
inline bb::fr hash_native(std::vector<bb::fr> const& inputs)
{
    return crypto::pedersen_hash::hash(inputs); // uses lookup tables
}
 
inline bb::fr compute_tree_root_native(std::vector<bb::fr> const& input)
{
    ASSERT(numeric::is_power_of_two(input.size()), "Check if the input vector size is a power of 2.");
    auto layer = input;
    while (layer.size() > 1) {
        std::vector<bb::fr> next_layer(layer.size() / 2);
        for (size_t i = 0; i < next_layer.size(); ++i) {
            next_layer[i] = crypto::pedersen_hash::hash({ layer[i * 2], layer[i * 2 + 1] });
        }
        layer = std::move(next_layer);
    }
 
    return layer[0];
}
 
// TODO write test
inline std::vector<bb::fr> compute_tree_native(std::vector<bb::fr> const& input)
{
    ASSERT(numeric::is_power_of_two(input.size()), "Check if the input vector size is a power of 2.");
    auto layer = input;
    std::vector<bb::fr> tree(input);
    while (layer.size() > 1) {
        std::vector<bb::fr> next_layer(layer.size() / 2);
        for (size_t i = 0; i < next_layer.size(); ++i) {
            next_layer[i] = crypto::pedersen_hash::hash({ layer[i * 2], layer[i * 2 + 1] });
            tree.push_back(next_layer[i]);
        }
        layer = std::move(next_layer);
    }
 
    return tree;
}
 
} // namespace bb::crypto::merkle_tree