merkle_authentication_path_variable.tcc

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/**
 *****************************************************************************
 * @author     This file is part of libsnark, developed by SCIPR Lab
 *             and contributors (see AUTHORS).
 * @copyright  MIT license (see LICENSE file)
 *****************************************************************************/
 
#ifndef MERKLE_AUTHENTICATION_PATH_VARIABLE_TCC_
#define MERKLE_AUTHENTICATION_PATH_VARIABLE_TCC_
 
namespace libsnark
{
 
template<typename FieldT, typename HashT>
merkle_authentication_path_variable<FieldT, HashT>::
    merkle_authentication_path_variable(
        protoboard<FieldT> &pb,
        const size_t tree_depth,
        const std::string &annotation_prefix)
    : gadget<FieldT>(pb, annotation_prefix), tree_depth(tree_depth)
{
    for (size_t i = 0; i < tree_depth; ++i) {
        left_digests.emplace_back(digest_variable<FieldT>(
            pb,
            HashT::get_digest_len(),
            FMT(annotation_prefix, " left_digests_%zu", i)));
        right_digests.emplace_back(digest_variable<FieldT>(
            pb,
            HashT::get_digest_len(),
            FMT(annotation_prefix, " right_digests_%zu", i)));
    }
}
 
template<typename FieldT, typename HashT>
void merkle_authentication_path_variable<FieldT, HashT>::
    generate_r1cs_constraints()
{
    for (size_t i = 0; i < tree_depth; ++i) {
        left_digests[i].generate_r1cs_constraints();
        right_digests[i].generate_r1cs_constraints();
    }
}
 
template<typename FieldT, typename HashT>
void merkle_authentication_path_variable<FieldT, HashT>::generate_r1cs_witness(
    const size_t address, const merkle_authentication_path &path)
{
    assert(path.size() == tree_depth);
 
    for (size_t i = 0; i < tree_depth; ++i) {
        if (address & (1ul << (tree_depth - 1 - i))) {
            left_digests[i].generate_r1cs_witness(path[i]);
        } else {
            right_digests[i].generate_r1cs_witness(path[i]);
        }
    }
}
 
template<typename FieldT, typename HashT>
merkle_authentication_path merkle_authentication_path_variable<FieldT, HashT>::
    get_authentication_path(const size_t address) const
{
    merkle_authentication_path result;
    for (size_t i = 0; i < tree_depth; ++i) {
        if (address & (1ul << (tree_depth - 1 - i))) {
            result.emplace_back(left_digests[i].get_digest());
        } else {
            result.emplace_back(right_digests[i].get_digest());
        }
    }
 
    return result;
}
 
} // namespace libsnark
 
#endif // MERKLE_AUTHENTICATION_PATH_VARIABLE_TCC