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oxen-core/src/ringct/rctSigs.cpp

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// Copyright (c) 2016, Monero Research Labs
//
// Author: Shen Noether <shen.noether@gmx.com>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "misc_log_ex.h"
#include "common/perf_timer.h"
#include "common/task_region.h"
#include "common/thread_group.h"
#include "common/util.h"
#include "rctSigs.h"
#include "cryptonote_basic/cryptonote_format_utils.h"
using namespace crypto;
using namespace std;
#undef MONERO_DEFAULT_LOG_CATEGORY
#define MONERO_DEFAULT_LOG_CATEGORY "ringct"
namespace rct {
//Borromean (c.f. gmax/andytoshi's paper)
boroSig genBorromean(const key64 x, const key64 P1, const key64 P2, const bits indices) {
key64 L[2], alpha;
key c;
int naught = 0, prime = 0, ii = 0, jj=0;
boroSig bb;
for (ii = 0 ; ii < 64 ; ii++) {
naught = indices[ii]; prime = (indices[ii] + 1) % 2;
skGen(alpha[ii]);
scalarmultBase(L[naught][ii], alpha[ii]);
if (naught == 0) {
skGen(bb.s1[ii]);
c = hash_to_scalar(L[naught][ii]);
addKeys2(L[prime][ii], bb.s1[ii], c, P2[ii]);
}
}
bb.ee = hash_to_scalar(L[1]); //or L[1]..
key LL, cc;
for (jj = 0 ; jj < 64 ; jj++) {
if (!indices[jj]) {
sc_mulsub(bb.s0[jj].bytes, x[jj].bytes, bb.ee.bytes, alpha[jj].bytes);
} else {
skGen(bb.s0[jj]);
addKeys2(LL, bb.s0[jj], bb.ee, P1[jj]); //different L0
cc = hash_to_scalar(LL);
sc_mulsub(bb.s1[jj].bytes, x[jj].bytes, cc.bytes, alpha[jj].bytes);
}
}
return bb;
}
//see above.
bool verifyBorromean(const boroSig &bb, const key64 P1, const key64 P2) {
key64 Lv1; key chash, LL;
int ii = 0;
for (ii = 0 ; ii < 64 ; ii++) {
addKeys2(LL, bb.s0[ii], bb.ee, P1[ii]);
chash = hash_to_scalar(LL);
addKeys2(Lv1[ii], bb.s1[ii], chash, P2[ii]);
}
key eeComputed = hash_to_scalar(Lv1); //hash function fine
return equalKeys(eeComputed, bb.ee);
}
//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
//These are aka MG signatutes in earlier drafts of the ring ct paper
// c.f. http://eprint.iacr.org/2015/1098 section 2.
// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
// Gen creates a signature which proves that for some column in the keymatrix "pk"
// the signer knows a secret key for each row in that column
// Ver verifies that the MG sig was created correctly
keyV keyImageV(const keyV &xx) {
keyV II(xx.size());
size_t i = 0;
for (i = 0; i < xx.size(); i++) {
II[i] = scalarmultKey(hashToPoint(scalarmultBase(xx[i])), xx[i]);
}
return II;
}
//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
//This is a just slghtly more efficient version than the ones described below
//(will be explained in more detail in Ring Multisig paper
//These are aka MG signatutes in earlier drafts of the ring ct paper
// c.f. http://eprint.iacr.org/2015/1098 section 2.
// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
// Gen creates a signature which proves that for some column in the keymatrix "pk"
// the signer knows a secret key for each row in that column
// Ver verifies that the MG sig was created correctly
mgSig MLSAG_Gen(const key &message, const keyM & pk, const keyV & xx, const unsigned int index, size_t dsRows) {
mgSig rv;
size_t cols = pk.size();
CHECK_AND_ASSERT_THROW_MES(cols >= 2, "Error! What is c if cols = 1!");
CHECK_AND_ASSERT_THROW_MES(index < cols, "Index out of range");
size_t rows = pk[0].size();
CHECK_AND_ASSERT_THROW_MES(rows >= 1, "Empty pk");
for (size_t i = 1; i < cols; ++i) {
CHECK_AND_ASSERT_THROW_MES(pk[i].size() == rows, "pk is not rectangular");
}
CHECK_AND_ASSERT_THROW_MES(xx.size() == rows, "Bad xx size");
CHECK_AND_ASSERT_THROW_MES(dsRows <= rows, "Bad dsRows size");
size_t i = 0, j = 0, ii = 0;
key c, c_old, L, R, Hi;
sc_0(c_old.bytes);
vector<geDsmp> Ip(dsRows);
rv.II = keyV(dsRows);
keyV alpha(rows);
keyV aG(rows);
rv.ss = keyM(cols, aG);
keyV aHP(dsRows);
keyV toHash(1 + 3 * dsRows + 2 * (rows - dsRows));
toHash[0] = message;
DP("here1");
for (i = 0; i < dsRows; i++) {
skpkGen(alpha[i], aG[i]); //need to save alphas for later..
Hi = hashToPoint(pk[index][i]);
aHP[i] = scalarmultKey(Hi, alpha[i]);
toHash[3 * i + 1] = pk[index][i];
toHash[3 * i + 2] = aG[i];
toHash[3 * i + 3] = aHP[i];
rv.II[i] = scalarmultKey(Hi, xx[i]);
precomp(Ip[i].k, rv.II[i]);
}
size_t ndsRows = 3 * dsRows; //non Double Spendable Rows (see identity chains paper)
for (i = dsRows, ii = 0 ; i < rows ; i++, ii++) {
skpkGen(alpha[i], aG[i]); //need to save alphas for later..
toHash[ndsRows + 2 * ii + 1] = pk[index][i];
toHash[ndsRows + 2 * ii + 2] = aG[i];
}
c_old = hash_to_scalar(toHash);
i = (index + 1) % cols;
if (i == 0) {
copy(rv.cc, c_old);
}
while (i != index) {
rv.ss[i] = skvGen(rows);
sc_0(c.bytes);
for (j = 0; j < dsRows; j++) {
addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
hashToPoint(Hi, pk[i][j]);
addKeys3(R, rv.ss[i][j], Hi, c_old, Ip[j].k);
toHash[3 * j + 1] = pk[i][j];
toHash[3 * j + 2] = L;
toHash[3 * j + 3] = R;
}
for (j = dsRows, ii = 0; j < rows; j++, ii++) {
addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
toHash[ndsRows + 2 * ii + 1] = pk[i][j];
toHash[ndsRows + 2 * ii + 2] = L;
}
c = hash_to_scalar(toHash);
copy(c_old, c);
i = (i + 1) % cols;
if (i == 0) {
copy(rv.cc, c_old);
}
}
for (j = 0; j < rows; j++) {
sc_mulsub(rv.ss[index][j].bytes, c.bytes, xx[j].bytes, alpha[j].bytes);
}
return rv;
}
//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
//This is a just slghtly more efficient version than the ones described below
//(will be explained in more detail in Ring Multisig paper
//These are aka MG signatutes in earlier drafts of the ring ct paper
// c.f. http://eprint.iacr.org/2015/1098 section 2.
// keyImageV just does I[i] = xx[i] * Hash(xx[i] * G) for each i
// Gen creates a signature which proves that for some column in the keymatrix "pk"
// the signer knows a secret key for each row in that column
// Ver verifies that the MG sig was created correctly
bool MLSAG_Ver(const key &message, const keyM & pk, const mgSig & rv, size_t dsRows) {
size_t cols = pk.size();
CHECK_AND_ASSERT_MES(cols >= 2, false, "Error! What is c if cols = 1!");
size_t rows = pk[0].size();
CHECK_AND_ASSERT_MES(rows >= 1, false, "Empty pk");
for (size_t i = 1; i < cols; ++i) {
CHECK_AND_ASSERT_MES(pk[i].size() == rows, false, "pk is not rectangular");
}
CHECK_AND_ASSERT_MES(rv.II.size() == dsRows, false, "Bad II size");
CHECK_AND_ASSERT_MES(rv.ss.size() == cols, false, "Bad rv.ss size");
for (size_t i = 0; i < cols; ++i) {
CHECK_AND_ASSERT_MES(rv.ss[i].size() == rows, false, "rv.ss is not rectangular");
}
CHECK_AND_ASSERT_MES(dsRows <= rows, false, "Bad dsRows value");
for (size_t i = 0; i < rv.ss.size(); ++i)
for (size_t j = 0; j < rv.ss[i].size(); ++j)
CHECK_AND_ASSERT_MES(sc_check(rv.ss[i][j].bytes) == 0, false, "Bad ss slot");
CHECK_AND_ASSERT_MES(sc_check(rv.cc.bytes) == 0, false, "Bad cc");
size_t i = 0, j = 0, ii = 0;
key c, L, R, Hi;
key c_old = copy(rv.cc);
vector<geDsmp> Ip(dsRows);
for (i = 0 ; i < dsRows ; i++) {
precomp(Ip[i].k, rv.II[i]);
}
size_t ndsRows = 3 * dsRows; //non Double Spendable Rows (see identity chains paper
keyV toHash(1 + 3 * dsRows + 2 * (rows - dsRows));
toHash[0] = message;
i = 0;
while (i < cols) {
sc_0(c.bytes);
for (j = 0; j < dsRows; j++) {
addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
hashToPoint(Hi, pk[i][j]);
addKeys3(R, rv.ss[i][j], Hi, c_old, Ip[j].k);
toHash[3 * j + 1] = pk[i][j];
toHash[3 * j + 2] = L;
toHash[3 * j + 3] = R;
}
for (j = dsRows, ii = 0 ; j < rows ; j++, ii++) {
addKeys2(L, rv.ss[i][j], c_old, pk[i][j]);
toHash[ndsRows + 2 * ii + 1] = pk[i][j];
toHash[ndsRows + 2 * ii + 2] = L;
}
c = hash_to_scalar(toHash);
copy(c_old, c);
i = (i + 1);
}
sc_sub(c.bytes, c_old.bytes, rv.cc.bytes);
return sc_isnonzero(c.bytes) == 0;
}
//proveRange and verRange
//proveRange gives C, and mask such that \sumCi = C
// c.f. http://eprint.iacr.org/2015/1098 section 5.1
// and Ci is a commitment to either 0 or 2^i, i=0,...,63
// thus this proves that "amount" is in [0, 2^64]
// mask is a such that C = aG + bH, and b = amount
//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
rangeSig proveRange(key & C, key & mask, const xmr_amount & amount) {
sc_0(mask.bytes);
identity(C);
bits b;
d2b(b, amount);
rangeSig sig;
key64 ai;
key64 CiH;
int i = 0;
for (i = 0; i < ATOMS; i++) {
skGen(ai[i]);
if (b[i] == 0) {
scalarmultBase(sig.Ci[i], ai[i]);
}
if (b[i] == 1) {
addKeys1(sig.Ci[i], ai[i], H2[i]);
}
subKeys(CiH[i], sig.Ci[i], H2[i]);
sc_add(mask.bytes, mask.bytes, ai[i].bytes);
addKeys(C, C, sig.Ci[i]);
}
sig.asig = genBorromean(ai, sig.Ci, CiH, b);
return sig;
}
//proveRange and verRange
//proveRange gives C, and mask such that \sumCi = C
// c.f. http://eprint.iacr.org/2015/1098 section 5.1
// and Ci is a commitment to either 0 or 2^i, i=0,...,63
// thus this proves that "amount" is in [0, 2^64]
// mask is a such that C = aG + bH, and b = amount
//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
bool verRange(const key & C, const rangeSig & as) {
try
{
PERF_TIMER(verRange);
key64 CiH;
int i = 0;
key Ctmp = identity();
for (i = 0; i < 64; i++) {
subKeys(CiH[i], as.Ci[i], H2[i]);
addKeys(Ctmp, Ctmp, as.Ci[i]);
}
if (!equalKeys(C, Ctmp))
return false;
if (!verifyBorromean(as.asig, as.Ci, CiH))
return false;
return true;
}
// we can get deep throws from ge_frombytes_vartime if input isn't valid
catch (...) { return false; }
}
key get_pre_mlsag_hash(const rctSig &rv)
{
keyV hashes;
hashes.reserve(3);
hashes.push_back(rv.message);
crypto::hash h;
std::stringstream ss;
binary_archive<true> ba(ss);
const size_t inputs = rv.pseudoOuts.size();
const size_t outputs = rv.ecdhInfo.size();
CHECK_AND_ASSERT_THROW_MES(const_cast<rctSig&>(rv).serialize_rctsig_base(ba, inputs, outputs),
"Failed to serialize rctSigBase");
cryptonote::get_blob_hash(ss.str(), h);
hashes.push_back(hash2rct(h));
keyV kv;
kv.reserve((64*3+1) * rv.p.rangeSigs.size());
for (auto r: rv.p.rangeSigs)
{
for (size_t n = 0; n < 64; ++n)
kv.push_back(r.asig.s0[n]);
for (size_t n = 0; n < 64; ++n)
kv.push_back(r.asig.s1[n]);
kv.push_back(r.asig.ee);
for (size_t n = 0; n < 64; ++n)
kv.push_back(r.Ci[n]);
}
hashes.push_back(cn_fast_hash(kv));
return cn_fast_hash(hashes);
}
//Ring-ct MG sigs
//Prove:
// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
// This does the MG sig on the "dest" part of the given key matrix, and
// the last row is the sum of input commitments from that column - sum output commitments
// this shows that sum inputs = sum outputs
//Ver:
// verifies the above sig is created corretly
mgSig proveRctMG(const key &message, const ctkeyM & pubs, const ctkeyV & inSk, const ctkeyV &outSk, const ctkeyV & outPk, unsigned int index, key txnFeeKey) {
mgSig mg;
//setup vars
size_t cols = pubs.size();
CHECK_AND_ASSERT_THROW_MES(cols >= 1, "Empty pubs");
size_t rows = pubs[0].size();
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");
}
CHECK_AND_ASSERT_THROW_MES(inSk.size() == rows, "Bad inSk size");
CHECK_AND_ASSERT_THROW_MES(outSk.size() == outPk.size(), "Bad outSk/outPk size");
keyV sk(rows + 1);
keyV tmp(rows + 1);
size_t i = 0, j = 0;
for (i = 0; i < rows + 1; i++) {
sc_0(sk[i].bytes);
identity(tmp[i]);
}
keyM M(cols, tmp);
//create the matrix to mg sig
for (i = 0; i < cols; i++) {
M[i][rows] = identity();
for (j = 0; j < rows; j++) {
M[i][j] = pubs[i][j].dest;
addKeys(M[i][rows], M[i][rows], pubs[i][j].mask); //add input commitments in last row
}
}
sc_0(sk[rows].bytes);
for (j = 0; j < rows; j++) {
sk[j] = copy(inSk[j].dest);
sc_add(sk[rows].bytes, sk[rows].bytes, inSk[j].mask.bytes); //add masks in last row
}
for (i = 0; i < cols; i++) {
for (size_t j = 0; j < outPk.size(); j++) {
subKeys(M[i][rows], M[i][rows], outPk[j].mask); //subtract output Ci's in last row
}
//subtract txn fee output in last row
subKeys(M[i][rows], M[i][rows], txnFeeKey);
}
for (size_t j = 0; j < outPk.size(); j++) {
sc_sub(sk[rows].bytes, sk[rows].bytes, outSk[j].mask.bytes); //subtract output masks in last row..
}
return MLSAG_Gen(message, M, sk, index, rows);
}
//Ring-ct MG sigs Simple
// Simple version for when we assume only
// post rct inputs
// here pubs is a vector of (P, C) length mixin
// inSk is x, a_in corresponding to signing index
// a_out, Cout is for the output commitment
// index is the signing index..
mgSig proveRctMGSimple(const key &message, const ctkeyV & pubs, const ctkey & inSk, const key &a , const key &Cout, unsigned int index) {
mgSig mg;
//setup vars
size_t rows = 1;
size_t cols = pubs.size();
CHECK_AND_ASSERT_THROW_MES(cols >= 1, "Empty pubs");
keyV tmp(rows + 1);
keyV sk(rows + 1);
size_t i;
keyM M(cols, tmp);
for (i = 0; i < cols; i++) {
M[i][0] = pubs[i].dest;
subKeys(M[i][1], pubs[i].mask, Cout);
sk[0] = copy(inSk.dest);
sc_sub(sk[1].bytes, inSk.mask.bytes, a.bytes);
}
return MLSAG_Gen(message, M, sk, index, rows);
}
//Ring-ct MG sigs
//Prove:
// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
// This does the MG sig on the "dest" part of the given key matrix, and
// the last row is the sum of input commitments from that column - sum output commitments
// this shows that sum inputs = sum outputs
//Ver:
// verifies the above sig is created corretly
bool verRctMG(const mgSig &mg, const ctkeyM & pubs, const ctkeyV & outPk, key txnFeeKey, const key &message) {
PERF_TIMER(verRctMG);
//setup vars
size_t cols = pubs.size();
CHECK_AND_ASSERT_MES(cols >= 1, false, "Empty pubs");
size_t rows = pubs[0].size();
CHECK_AND_ASSERT_MES(rows >= 1, false, "Empty pubs");
for (size_t i = 1; i < cols; ++i) {
CHECK_AND_ASSERT_MES(pubs[i].size() == rows, false, "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); //add Ci in last row
}
}
for (i = 0; i < cols; i++) {
for (j = 0; j < outPk.size(); j++) {
subKeys(M[i][rows], M[i][rows], outPk[j].mask); //subtract output Ci's in last row
}
//subtract txn fee output in last row
subKeys(M[i][rows], M[i][rows], txnFeeKey);
}
return MLSAG_Ver(message, M, mg, rows);
}
//Ring-ct Simple MG sigs
//Ver:
//This does a simplified version, assuming only post Rct
//inputs
bool verRctMGSimple(const key &message, const mgSig &mg, const ctkeyV & pubs, const key & C) {
try
{
PERF_TIMER(verRctMGSimple);
//setup vars
size_t rows = 1;
size_t cols = pubs.size();
CHECK_AND_ASSERT_MES(cols >= 1, false, "Empty pubs");
keyV tmp(rows + 1);
size_t i;
keyM M(cols, tmp);
//create the matrix to mg sig
for (i = 0; i < cols; i++) {
M[i][0] = pubs[i].dest;
subKeys(M[i][1], pubs[i].mask, C);
}
//DP(C);
return MLSAG_Ver(message, M, mg, rows);
}
catch (...) { return false; }
}
//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" + 1 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 + 1, 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);
}
//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).
xmr_amount populateFromBlockchainSimple(ctkeyV & mixRing, const ctkey & inPk, int mixin) {
int index = randXmrAmount(mixin);
int i = 0;
for (i = 0; i <= mixin; i++) {
if (i != index) {
getKeyFromBlockchain(mixRing[i], (size_t)randXmrAmount(1000));
} else {
mixRing[i] = inPk;
}
}
return 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
// Note: For txn fees, the last index in the amounts vector should contain that
// Thus the amounts vector will be "one" longer than the destinations vectort
rctSig genRct(const key &message, const ctkeyV & inSk, const keyV & destinations, const vector<xmr_amount> & amounts, const ctkeyM &mixRing, const keyV &amount_keys, unsigned int index, ctkeyV &outSk) {
CHECK_AND_ASSERT_THROW_MES(amounts.size() == destinations.size() || amounts.size() == destinations.size() + 1, "Different number of amounts/destinations");
CHECK_AND_ASSERT_THROW_MES(amount_keys.size() == destinations.size(), "Different number of amount_keys/destinations");
CHECK_AND_ASSERT_THROW_MES(index < mixRing.size(), "Bad index into mixRing");
for (size_t n = 0; n < mixRing.size(); ++n) {
CHECK_AND_ASSERT_THROW_MES(mixRing[n].size() == inSk.size(), "Bad mixRing size");
}
rctSig rv;
rv.type = RCTTypeFull;
rv.message = message;
rv.outPk.resize(destinations.size());
rv.p.rangeSigs.resize(destinations.size());
rv.ecdhInfo.resize(destinations.size());
size_t i = 0;
keyV masks(destinations.size()); //sk mask..
outSk.resize(destinations.size());
for (i = 0; i < destinations.size(); i++) {
//add destination to sig
rv.outPk[i].dest = copy(destinations[i]);
//compute range proof
rv.p.rangeSigs[i] = proveRange(rv.outPk[i].mask, outSk[i].mask, amounts[i]);
#ifdef DBG
CHECK_AND_ASSERT_THROW_MES(verRange(rv.outPk[i].mask, rv.p.rangeSigs[i]), "verRange failed on newly created proof");
#endif
//mask amount and mask
rv.ecdhInfo[i].mask = copy(outSk[i].mask);
rv.ecdhInfo[i].amount = d2h(amounts[i]);
ecdhEncode(rv.ecdhInfo[i], amount_keys[i]);
}
//set txn fee
if (amounts.size() > destinations.size())
{
rv.txnFee = amounts[destinations.size()];
}
else
{
rv.txnFee = 0;
}
key txnFeeKey = scalarmultH(d2h(rv.txnFee));
rv.mixRing = mixRing;
rv.p.MGs.push_back(proveRctMG(get_pre_mlsag_hash(rv), rv.mixRing, inSk, outSk, rv.outPk, index, txnFeeKey));
return rv;
}
rctSig genRct(const key &message, const ctkeyV & inSk, const ctkeyV & inPk, const keyV & destinations, const vector<xmr_amount> & amounts, const keyV &amount_keys, const int mixin) {
unsigned int index;
ctkeyM mixRing;
ctkeyV outSk;
tie(mixRing, index) = populateFromBlockchain(inPk, mixin);
return genRct(message, inSk, destinations, amounts, mixRing, amount_keys, index, outSk);
}
//RCT simple
//for post-rct only
rctSig genRctSimple(const key &message, const ctkeyV & inSk, const keyV & destinations, const vector<xmr_amount> &inamounts, const vector<xmr_amount> &outamounts, xmr_amount txnFee, const ctkeyM & mixRing, const keyV &amount_keys, const std::vector<unsigned int> & index, ctkeyV &outSk) {
CHECK_AND_ASSERT_THROW_MES(inamounts.size() > 0, "Empty inamounts");
CHECK_AND_ASSERT_THROW_MES(inamounts.size() == inSk.size(), "Different number of inamounts/inSk");
CHECK_AND_ASSERT_THROW_MES(outamounts.size() == destinations.size(), "Different number of amounts/destinations");
CHECK_AND_ASSERT_THROW_MES(amount_keys.size() == destinations.size(), "Different number of amount_keys/destinations");
CHECK_AND_ASSERT_THROW_MES(index.size() == inSk.size(), "Different number of index/inSk");
CHECK_AND_ASSERT_THROW_MES(mixRing.size() == inSk.size(), "Different number of mixRing/inSk");
for (size_t n = 0; n < mixRing.size(); ++n) {
CHECK_AND_ASSERT_THROW_MES(index[n] < mixRing[n].size(), "Bad index into mixRing");
}
rctSig rv;
rv.type = RCTTypeSimple;
rv.message = message;
rv.outPk.resize(destinations.size());
rv.p.rangeSigs.resize(destinations.size());
rv.ecdhInfo.resize(destinations.size());
size_t i;
keyV masks(destinations.size()); //sk mask..
outSk.resize(destinations.size());
key sumout = zero();
for (i = 0; i < destinations.size(); i++) {
//add destination to sig
rv.outPk[i].dest = copy(destinations[i]);
//compute range proof
rv.p.rangeSigs[i] = proveRange(rv.outPk[i].mask, outSk[i].mask, outamounts[i]);
#ifdef DBG
verRange(rv.outPk[i].mask, rv.p.rangeSigs[i]);
#endif
sc_add(sumout.bytes, outSk[i].mask.bytes, sumout.bytes);
//mask amount and mask
rv.ecdhInfo[i].mask = copy(outSk[i].mask);
rv.ecdhInfo[i].amount = d2h(outamounts[i]);
ecdhEncode(rv.ecdhInfo[i], amount_keys[i]);
}
//set txn fee
rv.txnFee = txnFee;
// TODO: unused ??
// key txnFeeKey = scalarmultH(d2h(rv.txnFee));
rv.mixRing = mixRing;
rv.pseudoOuts.resize(inamounts.size());
rv.p.MGs.resize(inamounts.size());
key sumpouts = zero(); //sum pseudoOut masks
keyV a(inamounts.size());
for (i = 0 ; i < inamounts.size() - 1; i++) {
skGen(a[i]);
sc_add(sumpouts.bytes, a[i].bytes, sumpouts.bytes);
genC(rv.pseudoOuts[i], a[i], inamounts[i]);
}
rv.mixRing = mixRing;
sc_sub(a[i].bytes, sumout.bytes, sumpouts.bytes);
genC(rv.pseudoOuts[i], a[i], inamounts[i]);
DP(rv.pseudoOuts[i]);
key full_message = get_pre_mlsag_hash(rv);
for (i = 0 ; i < inamounts.size(); i++) {
rv.p.MGs[i] = proveRctMGSimple(full_message, rv.mixRing[i], inSk[i], a[i], rv.pseudoOuts[i], index[i]);
}
return rv;
}
rctSig genRctSimple(const key &message, const ctkeyV & inSk, const ctkeyV & inPk, const keyV & destinations, const vector<xmr_amount> &inamounts, const vector<xmr_amount> &outamounts, const keyV &amount_keys, xmr_amount txnFee, unsigned int mixin) {
std::vector<unsigned int> index;
index.resize(inPk.size());
ctkeyM mixRing;
ctkeyV outSk;
mixRing.resize(inPk.size());
for (size_t i = 0; i < inPk.size(); ++i) {
mixRing[i].resize(mixin+1);
index[i] = populateFromBlockchainSimple(mixRing[i], inPk[i], mixin);
}
return genRctSimple(message, inSk, destinations, inamounts, outamounts, txnFee, mixRing, amount_keys, index, outSk);
}
//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(const rctSig & rv, bool semantics) {
PERF_TIMER(verRct);
CHECK_AND_ASSERT_MES(rv.type == RCTTypeFull, false, "verRct called on non-full rctSig");
if (semantics)
{
CHECK_AND_ASSERT_MES(rv.outPk.size() == rv.p.rangeSigs.size(), false, "Mismatched sizes of outPk and rv.p.rangeSigs");
CHECK_AND_ASSERT_MES(rv.outPk.size() == rv.ecdhInfo.size(), false, "Mismatched sizes of outPk and rv.ecdhInfo");
CHECK_AND_ASSERT_MES(rv.p.MGs.size() == 1, false, "full rctSig has not one MG");
}
else
{
// semantics check is early, we don't have the MGs resolved yet
}
// some rct ops can throw
try
{
if (semantics) {
std::deque<bool> results(rv.outPk.size(), false);
tools::thread_group threadpool(tools::thread_group::optimal_with_max(rv.outPk.size()));
tools::task_region(threadpool, [&] (tools::task_region_handle& region) {
DP("range proofs verified?");
for (size_t i = 0; i < rv.outPk.size(); i++) {
region.run([&, i] {
results[i] = verRange(rv.outPk[i].mask, rv.p.rangeSigs[i]);
});
}
});
for (size_t i = 0; i < rv.outPk.size(); ++i) {
if (!results[i]) {
LOG_PRINT_L1("Range proof verified failed for output " << i);
return false;
}
}
}
if (!semantics) {
//compute txn fee
key txnFeeKey = scalarmultH(d2h(rv.txnFee));
bool mgVerd = verRctMG(rv.p.MGs[0], rv.mixRing, rv.outPk, txnFeeKey, get_pre_mlsag_hash(rv));
DP("mg sig verified?");
DP(mgVerd);
if (!mgVerd) {
LOG_PRINT_L1("MG signature verification failed");
return false;
}
}
return true;
}
catch(...)
{
return false;
}
}
//ver RingCT simple
//assumes only post-rct style inputs (at least for max anonymity)
bool verRctSimple(const rctSig & rv, bool semantics) {
try
{
PERF_TIMER(verRctSimple);
CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple, false, "verRctSimple called on non simple rctSig");
if (semantics)
{
CHECK_AND_ASSERT_MES(rv.outPk.size() == rv.p.rangeSigs.size(), false, "Mismatched sizes of outPk and rv.p.rangeSigs");
CHECK_AND_ASSERT_MES(rv.outPk.size() == rv.ecdhInfo.size(), false, "Mismatched sizes of outPk and rv.ecdhInfo");
CHECK_AND_ASSERT_MES(rv.pseudoOuts.size() == rv.p.MGs.size(), false, "Mismatched sizes of rv.pseudoOuts and rv.p.MGs");
}
else
{
// semantics check is early, and mixRing/MGs aren't resolved yet
CHECK_AND_ASSERT_MES(rv.pseudoOuts.size() == rv.mixRing.size(), false, "Mismatched sizes of rv.pseudoOuts and mixRing");
}
const size_t threads = std::max(rv.outPk.size(), rv.mixRing.size());
std::deque<bool> results(threads);
tools::thread_group threadpool(tools::thread_group::optimal_with_max(threads));
if (semantics) {
key sumOutpks = identity();
for (size_t i = 0; i < rv.outPk.size(); i++) {
addKeys(sumOutpks, sumOutpks, rv.outPk[i].mask);
}
DP(sumOutpks);
key txnFeeKey = scalarmultH(d2h(rv.txnFee));
addKeys(sumOutpks, txnFeeKey, sumOutpks);
key sumPseudoOuts = identity();
for (size_t i = 0 ; i < rv.pseudoOuts.size() ; i++) {
addKeys(sumPseudoOuts, sumPseudoOuts, rv.pseudoOuts[i]);
}
DP(sumPseudoOuts);
//check pseudoOuts vs Outs..
if (!equalKeys(sumPseudoOuts, sumOutpks)) {
LOG_PRINT_L1("Sum check failed");
return false;
}
results.clear();
results.resize(rv.outPk.size());
tools::task_region(threadpool, [&] (tools::task_region_handle& region) {
for (size_t i = 0; i < rv.outPk.size(); i++) {
region.run([&, i] {
results[i] = verRange(rv.outPk[i].mask, rv.p.rangeSigs[i]);
});
}
});
for (size_t i = 0; i < results.size(); ++i) {
if (!results[i]) {
LOG_PRINT_L1("Range proof verified failed for output " << i);
return false;
}
}
}
else {
const key message = get_pre_mlsag_hash(rv);
results.clear();
results.resize(rv.mixRing.size());
tools::task_region(threadpool, [&] (tools::task_region_handle& region) {
for (size_t i = 0 ; i < rv.mixRing.size() ; i++) {
region.run([&, i] {
results[i] = verRctMGSimple(message, rv.p.MGs[i], rv.mixRing[i], rv.pseudoOuts[i]);
});
}
});
for (size_t i = 0; i < results.size(); ++i) {
if (!results[i]) {
LOG_PRINT_L1("verRctMGSimple failed for input " << i);
return false;
}
}
}
return true;
}
// we can get deep throws from ge_frombytes_vartime if input isn't valid
catch (...) { return false; }
}
//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(const rctSig & rv, const key & sk, unsigned int i, key & mask) {
CHECK_AND_ASSERT_MES(rv.type == RCTTypeFull, false, "decodeRct called on non-full rctSig");
CHECK_AND_ASSERT_THROW_MES(rv.p.rangeSigs.size() > 0, "Empty rv.p.rangeSigs");
CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.p.rangeSigs.size(), "Mismatched sizes of rv.outPk and rv.p.rangeSigs");
CHECK_AND_ASSERT_THROW_MES(i < rv.ecdhInfo.size(), "Bad index");
//mask amount and mask
ecdhTuple ecdh_info = rv.ecdhInfo[i];
ecdhDecode(ecdh_info, sk);
mask = ecdh_info.mask;
key amount = ecdh_info.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) {
CHECK_AND_ASSERT_THROW_MES(false, "warning, amount decoded incorrectly, will be unable to spend");
}
return h2d(amount);
}
xmr_amount decodeRct(const rctSig & rv, const key & sk, unsigned int i) {
key mask;
return decodeRct(rv, sk, i, mask);
}
xmr_amount decodeRctSimple(const rctSig & rv, const key & sk, unsigned int i, key &mask) {
CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple, false, "decodeRct called on non simple rctSig");
CHECK_AND_ASSERT_THROW_MES(rv.p.rangeSigs.size() > 0, "Empty rv.p.rangeSigs");
CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.p.rangeSigs.size(), "Mismatched sizes of rv.outPk and rv.p.rangeSigs");
CHECK_AND_ASSERT_THROW_MES(i < rv.ecdhInfo.size(), "Bad index");
//mask amount and mask
ecdhTuple ecdh_info = rv.ecdhInfo[i];
ecdhDecode(ecdh_info, sk);
mask = ecdh_info.mask;
key amount = ecdh_info.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) {
CHECK_AND_ASSERT_THROW_MES(false, "warning, amount decoded incorrectly, will be unable to spend");
}
return h2d(amount);
}
xmr_amount decodeRctSimple(const rctSig & rv, const key & sk, unsigned int i) {
key mask;
return decodeRctSimple(rv, sk, i, mask);
}
}
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