4d7f073491
Throw when inputs aren't the expected size.
575 lines
24 KiB
C++
575 lines
24 KiB
C++
// Copyright (c) 2016, Monero Research Labs
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//
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// Author: Shen Noether <shen.noether@gmx.com>
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "misc_log_ex.h"
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#include "rctSigs.h"
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using namespace crypto;
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using namespace std;
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namespace rct {
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//Schnorr Non-linkable
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//Gen Gives a signature (L1, s1, s2) proving that the sender knows "x" such that xG = one of P1 or P2
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//Ver Verifies that signer knows an "x" such that xG = one of P1 or P2
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//These are called in the below ASNL sig generation
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void GenSchnorrNonLinkable(key & L1, key & s1, key & s2, const key & x, const key & P1, const key & P2, int index) {
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key c1, c2, L2;
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key a = skGen();
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if (index == 0) {
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scalarmultBase(L1, a);
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hash_to_scalar(c2, L1);
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skGen(s2);
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addKeys2(L2, s2, c2, P2);
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hash_to_scalar(c1, L2);
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sc_mulsub(s1.bytes, x.bytes, c1.bytes, a.bytes);
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}
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else if (index == 1) {
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scalarmultBase(L2, a);
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skGen(s1);
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hash_to_scalar(c1, L2);
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addKeys2(L1, s1, c1, P1);
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hash_to_scalar(c2, L1);
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sc_mulsub(s2.bytes, x.bytes, c2.bytes, a.bytes);
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}
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else {
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throw std::runtime_error("GenSchnorrNonLinkable: invalid index (should be 0 or 1)");
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}
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}
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//Schnorr Non-linkable
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//Gen Gives a signature (L1, s1, s2) proving that the sender knows "x" such that xG = one of P1 or P2
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//Ver Verifies that signer knows an "x" such that xG = one of P1 or P2
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//These are called in the below ASNL sig generation
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bool VerSchnorrNonLinkable(const key & P1, const key & P2, const key & L1, const key & s1, const key & s2) {
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key c2, L2, c1, L1p;
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hash_to_scalar(c2, L1);
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addKeys2(L2, s2, c2, P2);
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hash_to_scalar(c1, L2);
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addKeys2(L1p, s1, c1, P1);
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return equalKeys(L1, L1p);
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}
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//Aggregate Schnorr Non-linkable Ring Signature (ASNL)
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// c.f. http://eprint.iacr.org/2015/1098 section 5.
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// These are used in range proofs (alternatively Borromean could be used)
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// Gen gives a signature which proves the signer knows, for each i,
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// an x[i] such that x[i]G = one of P1[i] or P2[i]
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// Ver Verifies the signer knows a key for one of P1[i], P2[i] at each i
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asnlSig GenASNL(key64 x, key64 P1, key64 P2, bits indices) {
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DP("Generating Aggregate Schnorr Non-linkable Ring Signature\n");
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key64 s1;
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int j = 0;
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asnlSig rv;
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rv.s = zero();
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for (j = 0; j < ATOMS; j++) {
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//void GenSchnorrNonLinkable(Bytes L1, Bytes s1, Bytes s2, const Bytes x, const Bytes P1,const Bytes P2, int index) {
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GenSchnorrNonLinkable(rv.L1[j], s1[j], rv.s2[j], x[j], P1[j], P2[j], (int)indices[j]);
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sc_add(rv.s.bytes, rv.s.bytes, s1[j].bytes);
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}
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return rv;
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}
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//Aggregate Schnorr Non-linkable Ring Signature (ASNL)
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// c.f. http://eprint.iacr.org/2015/1098 section 5.
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// These are used in range proofs (alternatively Borromean could be used)
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// Gen gives a signature which proves the signer knows, for each i,
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// an x[i] such that x[i]G = one of P1[i] or P2[i]
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// Ver Verifies the signer knows a key for one of P1[i], P2[i] at each i
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bool VerASNL(const key64 P1, const key64 P2, const asnlSig &as) {
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DP("Verifying Aggregate Schnorr Non-linkable Ring Signature\n");
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key LHS = identity();
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key RHS = scalarmultBase(as.s);
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key c2, L2, c1;
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int j = 0;
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for (j = 0; j < ATOMS; j++) {
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hash_to_scalar(c2, as.L1[j]);
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addKeys2(L2, as.s2[j], c2, P2[j]);
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addKeys(LHS, LHS, as.L1[j]);
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hash_to_scalar(c1, L2);
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addKeys(RHS, RHS, scalarmultKey(P1[j], c1));
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}
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key cc;
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sc_sub(cc.bytes, LHS.bytes, RHS.bytes);
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DP(cc);
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return sc_isnonzero(cc.bytes) == 0;
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}
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//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
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//These are aka MG signatutes in earlier drafts of the ring ct paper
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// c.f. http://eprint.iacr.org/2015/1098 section 2.
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// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
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// Gen creates a signature which proves that for some column in the keymatrix "pk"
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// the signer knows a secret key for each row in that column
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// Ver verifies that the MG sig was created correctly
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keyV keyImageV(const keyV &xx) {
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keyV II(xx.size());
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size_t i = 0;
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for (i = 0; i < xx.size(); i++) {
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II[i] = scalarmultKey(hashToPoint(scalarmultBase(xx[i])), xx[i]);
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}
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return II;
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}
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//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
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//This is a just slghtly more efficient version than the ones described below
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//(will be explained in more detail in Ring Multisig paper
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//These are aka MG signatutes in earlier drafts of the ring ct paper
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// c.f. http://eprint.iacr.org/2015/1098 section 2.
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// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
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// Gen creates a signature which proves that for some column in the keymatrix "pk"
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// the signer knows a secret key for each row in that column
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// Ver verifies that the MG sig was created correctly
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mgSig MLSAG_Gen(key message, const keyM & pk, const keyV & xx, const unsigned int index) {
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mgSig rv;
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size_t cols = pk.size();
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CHECK_AND_ASSERT_THROW_MES(cols >= 2, "Error! What is c if cols = 1!");
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CHECK_AND_ASSERT_THROW_MES(index < cols, "Index out of range");
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size_t rows = pk[0].size();
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CHECK_AND_ASSERT_THROW_MES(rows >= 1, "Empty pk");
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for (size_t i = 1; i < cols; ++i) {
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CHECK_AND_ASSERT_THROW_MES(pk[i].size() == rows, "pk is not rectangular");
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}
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CHECK_AND_ASSERT_THROW_MES(xx.size() == rows, "Bad xx size");
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size_t i = 0, j = 0;
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key c, c_old, L, R, Hi;
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sc_0(c_old.bytes);
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vector<geDsmp> Ip(rows);
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rv.II = keyV(rows);
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rv.ss = keyM(cols, rv.II);
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keyV alpha(rows);
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keyV aG(rows);
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keyV aHP(rows);
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key m2hash;
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unsigned char m2[128];
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memcpy(m2, message.bytes, 32);
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DP("here1");
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for (i = 0; i < rows; i++) {
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skpkGen(alpha[i], aG[i]); //need to save alphas for later..
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Hi = hashToPoint(pk[index][i]);
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aHP[i] = scalarmultKey(Hi, alpha[i]);
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memcpy(m2+32, pk[index][i].bytes, 32);
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memcpy(m2 + 64, aG[i].bytes, 32);
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memcpy(m2 + 96, aHP[i].bytes, 32);
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rv.II[i] = scalarmultKey(Hi, xx[i]);
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precomp(Ip[i].k, rv.II[i]);
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m2hash = hash_to_scalar128(m2);
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sc_add(c_old.bytes, c_old.bytes, m2hash.bytes);
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}
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i = (index + 1) % cols;
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if (i == 0) {
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copy(rv.cc, c_old);
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}
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while (i != index) {
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rv.ss[i] = skvGen(rows);
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sc_0(c.bytes);
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for (j = 0; j < rows; j++) {
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addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
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hashToPoint(Hi, pk[i][j]);
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addKeys3(R, rv.ss[i][j], Hi, c_old, Ip[j].k);
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memcpy(m2+32, pk[i][j].bytes, 32);
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memcpy(m2 + 64, L.bytes, 32);
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memcpy(m2 + 96, R.bytes, 32);
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m2hash = hash_to_scalar128(m2);
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sc_add(c.bytes, c.bytes, m2hash.bytes);
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}
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copy(c_old, c);
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i = (i + 1) % cols;
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if (i == 0) {
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copy(rv.cc, c_old);
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}
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}
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for (j = 0; j < rows; j++) {
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sc_mulsub(rv.ss[index][j].bytes, c.bytes, xx[j].bytes, alpha[j].bytes);
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}
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return rv;
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}
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//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
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//This is a just slghtly more efficient version than the ones described below
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//(will be explained in more detail in Ring Multisig paper
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//These are aka MG signatutes in earlier drafts of the ring ct paper
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// c.f. http://eprint.iacr.org/2015/1098 section 2.
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// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
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// Gen creates a signature which proves that for some column in the keymatrix "pk"
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// the signer knows a secret key for each row in that column
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// Ver verifies that the MG sig was created correctly
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bool MLSAG_Ver(key message, const keyM & pk, const mgSig & rv) {
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size_t cols = pk.size();
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CHECK_AND_ASSERT_THROW_MES(cols >= 2, "Error! What is c if cols = 1!");
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size_t rows = pk[0].size();
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CHECK_AND_ASSERT_THROW_MES(rows >= 1, "Empty pk");
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for (size_t i = 1; i < cols; ++i) {
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CHECK_AND_ASSERT_THROW_MES(pk[i].size() == rows, "pk is not rectangular");
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}
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CHECK_AND_ASSERT_THROW_MES(rv.II.size() == rows, "Bad rv.II size");
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CHECK_AND_ASSERT_THROW_MES(rv.ss.size() == cols, "Bad rv.ss size");
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for (size_t i = 0; i < cols; ++i) {
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CHECK_AND_ASSERT_THROW_MES(rv.ss[i].size() == rows, "rv.ss is not rectangular");
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}
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size_t i = 0, j = 0;
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key c, L, R, Hi;
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key c_old = copy(rv.cc);
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vector<geDsmp> Ip(rows);
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for (i= 0 ; i< rows ; i++) {
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precomp(Ip[i].k, rv.II[i]);
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}
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unsigned char m2[128];
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memcpy(m2, message.bytes, 32);
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key m2hash;
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i = 0;
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while (i < cols) {
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sc_0(c.bytes);
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for (j = 0; j < rows; j++) {
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addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
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hashToPoint(Hi, pk[i][j]);
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addKeys3(R, rv.ss[i][j], Hi, c_old, Ip[j].k);
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memcpy(m2 + 32, pk[i][j].bytes, 32);
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memcpy(m2 + 64, L.bytes, 32);
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memcpy(m2 + 96, R.bytes, 32);
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m2hash = hash_to_scalar128(m2);
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sc_add(c.bytes, c.bytes, m2hash.bytes);
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}
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copy(c_old, c);
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i = (i + 1);
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}
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DP("c0");
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DP(rv.cc);
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DP("c_old");
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DP(c_old);
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sc_sub(c.bytes, c_old.bytes, rv.cc.bytes);
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return sc_isnonzero(c.bytes) == 0;
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}
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//proveRange and verRange
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//proveRange gives C, and mask such that \sumCi = C
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// c.f. http://eprint.iacr.org/2015/1098 section 5.1
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// and Ci is a commitment to either 0 or 2^i, i=0,...,63
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// thus this proves that "amount" is in [0, 2^64]
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// mask is a such that C = aG + bH, and b = amount
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//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
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rangeSig proveRange(key & C, key & mask, const xmr_amount & amount) {
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sc_0(mask.bytes);
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identity(C);
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bits b;
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d2b(b, amount);
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rangeSig sig;
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key64 ai;
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key64 CiH;
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int i = 0;
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for (i = 0; i < ATOMS; i++) {
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sc_0(ai[i].bytes);
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if (b[i] == 0) {
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scalarmultBase(sig.Ci[i], ai[i]);
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}
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if (b[i] == 1) {
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addKeys1(sig.Ci[i], ai[i], H2[i]);
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}
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subKeys(CiH[i], sig.Ci[i], H2[i]);
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sc_add(mask.bytes, mask.bytes, ai[i].bytes);
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addKeys(C, C, sig.Ci[i]);
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}
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sig.asig = GenASNL(ai, sig.Ci, CiH, b);
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return sig;
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}
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//proveRange and verRange
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//proveRange gives C, and mask such that \sumCi = C
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// c.f. http://eprint.iacr.org/2015/1098 section 5.1
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// and Ci is a commitment to either 0 or 2^i, i=0,...,63
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// thus this proves that "amount" is in [0, 2^64]
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// mask is a such that C = aG + bH, and b = amount
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//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
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bool verRange(const key & C, const rangeSig & as) {
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key64 CiH;
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int i = 0;
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key Ctmp = identity();
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for (i = 0; i < 64; i++) {
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subKeys(CiH[i], as.Ci[i], H2[i]);
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addKeys(Ctmp, Ctmp, as.Ci[i]);
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}
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bool reb = equalKeys(C, Ctmp);
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DP("is sum Ci = C:");
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DP(reb);
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bool rab = VerASNL(as.Ci, CiH, as.asig);
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DP("Is in range?");
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DP(rab);
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return (reb && rab);
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}
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//Ring-ct MG sigs
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//Prove:
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// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
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// This does the MG sig on the "dest" part of the given key matrix, and
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// the last row is the sum of input commitments from that column - sum output commitments
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// this shows that sum inputs = sum outputs
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//Ver:
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// verifies the above sig is created corretly
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mgSig proveRctMG(const ctkeyM & pubs, const ctkeyV & inSk, const ctkeyV &outSk, const ctkeyV & outPk, unsigned int index) {
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mgSig mg;
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//setup vars
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size_t cols = pubs.size();
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CHECK_AND_ASSERT_THROW_MES(cols >= 1, "Empty pubs");
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size_t rows = pubs[0].size();
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CHECK_AND_ASSERT_THROW_MES(rows >= 1, "Empty pubs");
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for (size_t i = 1; i < cols; ++i) {
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CHECK_AND_ASSERT_THROW_MES(pubs[i].size() == rows, "pubs is not rectangular");
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}
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CHECK_AND_ASSERT_THROW_MES(inSk.size() == rows, "Bad inSk size");
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CHECK_AND_ASSERT_THROW_MES(outSk.size() == outPk.size(), "Bad outSk/outPk size");
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keyV sk(rows + 1);
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keyV tmp(rows + 1);
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size_t i = 0, j = 0;
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for (i = 0; i < rows + 1; i++) {
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sc_0(sk[i].bytes);
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identity(tmp[i]);
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}
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keyM M(cols, tmp);
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//create the matrix to mg sig
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for (i = 0; i < cols; i++) {
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M[i][rows] = identity();
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for (j = 0; j < rows; j++) {
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M[i][j] = pubs[i][j].dest;
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addKeys(M[i][rows], M[i][rows], pubs[i][j].mask);
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}
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}
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sc_0(sk[rows].bytes);
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for (j = 0; j < rows; j++) {
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sk[j] = copy(inSk[j].dest);
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sc_add(sk[rows].bytes, sk[rows].bytes, inSk[j].mask.bytes);
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}
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for (i = 0; i < cols; i++) {
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for (size_t j = 0; j < outPk.size(); j++) {
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subKeys(M[i][rows], M[i][rows], outPk[j].mask);
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}
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}
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for (size_t j = 0; j < outPk.size(); j++) {
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sc_sub(sk[rows].bytes, sk[rows].bytes, outSk[j].mask.bytes);
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}
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key message = cn_fast_hash(outPk);
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return MLSAG_Gen(message, M, sk, index);
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}
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//Ring-ct MG sigs
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//Prove:
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// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
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// This does the MG sig on the "dest" part of the given key matrix, and
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// the last row is the sum of input commitments from that column - sum output commitments
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// this shows that sum inputs = sum outputs
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//Ver:
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// verifies the above sig is created corretly
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bool verRctMG(mgSig mg, const ctkeyM & pubs, const ctkeyV & outPk) {
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//setup vars
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size_t cols = pubs.size();
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CHECK_AND_ASSERT_THROW_MES(cols >= 1, "Empty pubs");
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size_t rows = pubs[0].size();
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CHECK_AND_ASSERT_THROW_MES(rows >= 1, "Empty pubs");
|
|
for (size_t i = 1; i < cols; ++i) {
|
|
CHECK_AND_ASSERT_THROW_MES(pubs[i].size() == rows, "pubs is not rectangular");
|
|
}
|
|
|
|
keyV tmp(rows + 1);
|
|
size_t i = 0, j = 0;
|
|
for (i = 0; i < rows + 1; i++) {
|
|
identity(tmp[i]);
|
|
}
|
|
keyM M(cols, tmp);
|
|
|
|
//create the matrix to mg sig
|
|
for (j = 0; j < rows; j++) {
|
|
for (i = 0; i < cols; i++) {
|
|
M[i][j] = pubs[i][j].dest;
|
|
addKeys(M[i][rows], M[i][rows], pubs[i][j].mask);
|
|
}
|
|
}
|
|
for (size_t j = 0; j < outPk.size(); j++) {
|
|
for (i = 0; i < cols; i++) {
|
|
subKeys(M[i][rows], M[i][rows], outPk[j].mask);
|
|
}
|
|
|
|
}
|
|
key message = cn_fast_hash(outPk);
|
|
DP("message:");
|
|
DP(message);
|
|
return MLSAG_Ver(message, M, mg);
|
|
|
|
}
|
|
|
|
//These functions get keys from blockchain
|
|
//replace these when connecting blockchain
|
|
//getKeyFromBlockchain grabs a key from the blockchain at "reference_index" to mix with
|
|
//populateFromBlockchain creates a keymatrix with "mixin" columns and one of the columns is inPk
|
|
// the return value are the key matrix, and the index where inPk was put (random).
|
|
void getKeyFromBlockchain(ctkey & a, size_t reference_index) {
|
|
a.mask = pkGen();
|
|
a.dest = pkGen();
|
|
}
|
|
|
|
//These functions get keys from blockchain
|
|
//replace these when connecting blockchain
|
|
//getKeyFromBlockchain grabs a key from the blockchain at "reference_index" to mix with
|
|
//populateFromBlockchain creates a keymatrix with "mixin" columns and one of the columns is inPk
|
|
// the return value are the key matrix, and the index where inPk was put (random).
|
|
tuple<ctkeyM, xmr_amount> populateFromBlockchain(ctkeyV inPk, int mixin) {
|
|
int rows = inPk.size();
|
|
ctkeyM rv(mixin, inPk);
|
|
int index = randXmrAmount(mixin);
|
|
int i = 0, j = 0;
|
|
for (i = 0; i < mixin; i++) {
|
|
if (i != index) {
|
|
for (j = 0; j < rows; j++) {
|
|
getKeyFromBlockchain(rv[i][j], (size_t)randXmrAmount);
|
|
}
|
|
}
|
|
}
|
|
return make_tuple(rv, index);
|
|
}
|
|
|
|
//RingCT protocol
|
|
//genRct:
|
|
// creates an rctSig with all data necessary to verify the rangeProofs and that the signer owns one of the
|
|
// columns that are claimed as inputs, and that the sum of inputs = sum of outputs.
|
|
// Also contains masked "amount" and "mask" so the receiver can see how much they received
|
|
//verRct:
|
|
// verifies that all signatures (rangeProogs, MG sig, sum inputs = outputs) are correct
|
|
//decodeRct: (c.f. http://eprint.iacr.org/2015/1098 section 5.1.1)
|
|
// uses the attached ecdh info to find the amounts represented by each output commitment
|
|
// must know the destination private key to find the correct amount, else will return a random number
|
|
rctSig genRct(ctkeyV & inSk, ctkeyV & inPk, const keyV & destinations, const vector<xmr_amount> amounts, const int mixin) {
|
|
CHECK_AND_ASSERT_THROW_MES(mixin >= 0, "Mixin must be positive");
|
|
CHECK_AND_ASSERT_THROW_MES(amounts.size() > 0, "Amounts must not be empty");
|
|
CHECK_AND_ASSERT_THROW_MES(inSk.size() == inPk.size(), "Different number of public/private keys");
|
|
|
|
rctSig rv;
|
|
rv.outPk.resize(destinations.size());
|
|
rv.rangeSigs.resize(destinations.size());
|
|
rv.ecdhInfo.resize(destinations.size());
|
|
|
|
size_t i = 0;
|
|
keyV masks(destinations.size()); //sk mask..
|
|
ctkeyV outSk(destinations.size());
|
|
for (i = 0; i < destinations.size(); i++) {
|
|
//add destination to sig
|
|
rv.outPk[i].dest = copy(destinations[i]);
|
|
//compute range proof
|
|
rv.rangeSigs[i] = proveRange(rv.outPk[i].mask, outSk[i].mask, amounts[i]);
|
|
#ifdef DBG
|
|
verRange(rv.outPk[i].mask, rv.rangeSigs[i]);
|
|
#endif
|
|
|
|
//mask amount and mask
|
|
rv.ecdhInfo[i].mask = copy(outSk[i].mask);
|
|
rv.ecdhInfo[i].amount = d2h(amounts[i]);
|
|
ecdhEncode(rv.ecdhInfo[i], destinations[i]);
|
|
|
|
}
|
|
|
|
unsigned int index;
|
|
tie(rv.mixRing, index) = populateFromBlockchain(inPk, mixin);
|
|
rv.MG = proveRctMG(rv.mixRing, inSk, outSk, rv.outPk, index);
|
|
return rv;
|
|
}
|
|
|
|
//RingCT protocol
|
|
//genRct:
|
|
// creates an rctSig with all data necessary to verify the rangeProofs and that the signer owns one of the
|
|
// columns that are claimed as inputs, and that the sum of inputs = sum of outputs.
|
|
// Also contains masked "amount" and "mask" so the receiver can see how much they received
|
|
//verRct:
|
|
// verifies that all signatures (rangeProogs, MG sig, sum inputs = outputs) are correct
|
|
//decodeRct: (c.f. http://eprint.iacr.org/2015/1098 section 5.1.1)
|
|
// uses the attached ecdh info to find the amounts represented by each output commitment
|
|
// must know the destination private key to find the correct amount, else will return a random number
|
|
bool verRct(rctSig & rv) {
|
|
CHECK_AND_ASSERT_THROW_MES(rv.rangeSigs.size() > 0, "Empty rv.rangeSigs");
|
|
CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.rangeSigs.size(), "Mismatched sizes of rv.outPk and rv.rangeSigs");
|
|
|
|
size_t i = 0;
|
|
bool rvb = true;
|
|
bool tmp;
|
|
DP("range proofs verified?");
|
|
for (i = 0; i < rv.outPk.size(); i++) {
|
|
tmp = verRange(rv.outPk[i].mask, rv.rangeSigs[i]);
|
|
DP(tmp);
|
|
rvb = (rvb && tmp);
|
|
}
|
|
bool mgVerd = verRctMG(rv.MG, rv.mixRing, rv.outPk);
|
|
DP("mg sig verified?");
|
|
DP(mgVerd);
|
|
|
|
return (rvb && mgVerd);
|
|
}
|
|
|
|
//RingCT protocol
|
|
//genRct:
|
|
// creates an rctSig with all data necessary to verify the rangeProofs and that the signer owns one of the
|
|
// columns that are claimed as inputs, and that the sum of inputs = sum of outputs.
|
|
// Also contains masked "amount" and "mask" so the receiver can see how much they received
|
|
//verRct:
|
|
// verifies that all signatures (rangeProogs, MG sig, sum inputs = outputs) are correct
|
|
//decodeRct: (c.f. http://eprint.iacr.org/2015/1098 section 5.1.1)
|
|
// uses the attached ecdh info to find the amounts represented by each output commitment
|
|
// must know the destination private key to find the correct amount, else will return a random number
|
|
xmr_amount decodeRct(rctSig & rv, key & sk, unsigned int i) {
|
|
CHECK_AND_ASSERT_THROW_MES(rv.rangeSigs.size() > 0, "Empty rv.rangeSigs");
|
|
CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.rangeSigs.size(), "Mismatched sizes of rv.outPk and rv.rangeSigs");
|
|
CHECK_AND_ASSERT_THROW_MES(i < rv.ecdhInfo.size(), "Bad index");
|
|
|
|
//mask amount and mask
|
|
ecdhDecode(rv.ecdhInfo[i], sk);
|
|
key mask = rv.ecdhInfo[i].mask;
|
|
key amount = rv.ecdhInfo[i].amount;
|
|
key C = rv.outPk[i].mask;
|
|
DP("C");
|
|
DP(C);
|
|
key Ctmp;
|
|
addKeys2(Ctmp, mask, amount, H);
|
|
DP("Ctmp");
|
|
DP(Ctmp);
|
|
if (equalKeys(C, Ctmp) == false) {
|
|
printf("warning, amount decoded incorrectly, will be unable to spend");
|
|
}
|
|
return h2d(amount);
|
|
}
|
|
|
|
}
|