forked from lthn/blockchain
112 lines
3.9 KiB
C++
112 lines
3.9 KiB
C++
// Copyright (c) 2020 Zano Project (https://zano.org/)
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// Copyright (c) 2020 Locksmith (acmxddk@gmail.com)
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// Copyright (c) 2020 sowle (crypto.sowle@gmail.com)
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#pragma once
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//
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// This file contains the implementation of L2S membership proof protocol
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// and a linkable ring signature scheme based on it.
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//
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point_t ml2s_rsum_impl(size_t n, size_t N, std::vector<point_t>::const_iterator X_array_bg_it, const std::vector<scalar_t>& c1_array,
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const std::vector<scalar_t>& c3_array, const scalar_t& cn)
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{
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if (n == 1)
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return *X_array_bg_it + cn * *(X_array_bg_it + 1);
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// n >= 2, N >= 4
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return ml2s_rsum_impl(n - 1, N / 2, X_array_bg_it, c1_array, c3_array, c1_array[n - 2]) +
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cn * ml2s_rsum_impl(n - 1, N / 2, X_array_bg_it + N / 2, c1_array, c3_array, c3_array[n - 2]);
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}
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bool ml2s_rsum(size_t n, const std::vector<point_t>& X_array, const std::vector<scalar_t>& c1_array,
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const std::vector<scalar_t>& c3_array, point_t& result)
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{
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size_t N = (size_t)1 << n;
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CHECK_AND_ASSERT_MES(n != 0, false, "n == 0");
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CHECK_AND_ASSERT_MES(N == X_array.size(), false, "|X_array| != N, " << X_array.size() << ", " << N);
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CHECK_AND_ASSERT_MES(c1_array.size() == n, false, "|c1_array| != n, " << c1_array.size() << ", " << n);
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CHECK_AND_ASSERT_MES(c3_array.size() == n - 1, false, "|c3_array| != n - 1, " << c3_array.size() << ", " << n - 1);
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result = ml2s_rsum_impl(n, N, X_array.begin(), c1_array, c3_array, c1_array[n - 1]);
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return true;
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}
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struct ml2s_signature_element
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{
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point_t Z0;
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point_t T0;
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scalar_t t0;
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point_t Z;
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std::vector<scalar_t> r_array;
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std::vector<point_t> H_array;
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point_t T;
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scalar_t t;
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};
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struct ml2s_signature
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{
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scalar_t z;
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std::vector<ml2s_signature_element> elements;
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};
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/* WIP
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// reference: mL2SLnkSig_Verif()
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bool ml2s_lnk_sig_verif(const scalar_t& m, const std::vector<point_t>& B_array, const ml2s_signature& signature, uint8_t* p_err = nullptr)
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{
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#define CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(cond, err_code) \
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if (!(cond)) { LOG_PRINT_RED("ml2s_lnk_sig_verif: \"" << #cond << "\" is false at " << LOCATION_SS, LOG_LEVEL_3); if (p_err) *p_err = err_code; return false; }
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auto hash_point_lambda = [&signature](const point_t& point) { return point + signature.z * hash_helper_t::hp(point); };
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size_t L = signature.elements.size();
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(L > 0, 0);
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size_t n = signature.elements[0].r_array.size();
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(n < 32, 4);
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size_t N = (size_t)1 << n;
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(B_array.size() == N / 2, 5);
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std::vector<point_t> I_array(L);
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std::vector<point_t> A_array(L);
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for (size_t i = 0; i < L; ++i)
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{
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I_array[i] = (signature.elements[i].Z0 - c_point_G) / signature.z;
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A_array[i] = signature.elements[i].Z0;
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(signature.elements[i].r_array.size() == n, 1);
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(signature.elements[i].H_array.size() == n, 2);
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}
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scalar_t z_ = hash_helper_t::hs(m, B_array, I_array);
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(z_ == signature.z, 3);
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scalar_t e = hash_helper_t::hs(signature.z);
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// ref: mL2SHPoM_Verif()
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// ref: X = mL2SHPoM_GetDecoySet(N, A, hash_point_cb, preimage_set_gen_cb)
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std::vector<point_t> P_array(B_array.size());
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for (size_t i = 0; i < B_array.size(); ++i)
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P_array[i] = hash_point_lambda(B_array[i]);
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point_t Q_shift = hash_helper_t::hs(A_array, P_array) * c_point_G;
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CHECK_AND_FAIL_WITH_ERROR_IF_FALSE(P_array.size() * 2 == N, 6);
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std::vector<point_t> X_array(N);
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// X_array = { P_array[0], Q_array[0], P_array[1], Q_array[1], etc.
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for (size_t i = 0; i < N; ++i)
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{
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if (i % 2 == 0)
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X_array[i] = P_array[i / 2];
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else
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X_array[i] = hash_point_lambda(Q_shift + B_array[i / 2]);
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}
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return false;
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#undef CHECK_AND_FAIL_WITH_ERROR_IF_FALSE
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}
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*/
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