ringct_tests.cpp

// Copyright (c) 2017-2023 The Particl Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <test/util/setup_common.h>
#include <test/util/random.h>
#include <test/data/ringct.json.h>

#include <crypto/sha256.h>
#include <key/stealth.h>
#include <util/strencodings.h>

#include <secp256k1.h>
#include <secp256k1_rangeproof.h>
#include <secp256k1_mlsag.h>
#include <stdint.h>
#include <univalue.h>

#include <boost/test/unit_test.hpp>

extern UniValue read_json(const std::string& jsondata);

BOOST_FIXTURE_TEST_SUITE(ringct_tests, BasicTestingSetup)


class CTxOutValueTest
{
public:
    CPubKey pk;
    secp256k1_pedersen_commitment commitment;
    std::vector<unsigned char> vchRangeproof;
    std::vector<unsigned char> vchNonceCommitment;
};

struct S32Bytes {
  uint8_t d[32];
};

static int memncmp(uint8_t *p, uint8_t c, size_t len)
{
    for (size_t k = 0; k < len; ++k, ++p) {
        if (*p < c) {
            return -1;
        }
        if (*p > c) {
            return 1;
        }
    }
    return 0;
}

static int testCommitmentSum(secp256k1_context *ctx, CAmount nValueIn,
    std::vector<CAmount> &amountsOut, CAmount nValueOutPlain, size_t nCols,
    bool fPass, bool fUnblindedOutputs=false, bool fUnblindedInputs=false)
{
    SeedInsecureRand();
    int rv;
    std::vector<CTxOutValueTest> txins(1);

    std::vector<CKey> kto_outs(amountsOut.size());
    std::vector<CPubKey> pkto_outs(amountsOut.size());
    std::vector<CTxOutValueTest> txouts(amountsOut.size());
    std::vector<S32Bytes> blind(txouts.size());

    std::vector<CKey> k_ins(1);
    InsecureNewKey(k_ins[0], true);

    txins[0].pk = k_ins[0].GetPubKey();
    std::vector<const uint8_t*> pBlinds;
    uint8_t blindsin[1][32];

    if (fUnblindedInputs) {
        memset(&blindsin[0][0], 0, 32);
    } else {
        InsecureRandBytes(&blindsin[0][0], 32);
    }

    pBlinds.push_back(&blindsin[0][0]);

    BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txins[0].commitment, &blindsin[0][0], (uint64_t)nValueIn, &secp256k1_generator_const_h, &secp256k1_generator_const_g));

    size_t nBlinded = 0;
    for (size_t k = 0; k < txouts.size(); ++k) {
        InsecureNewKey(kto_outs[k], true);
        pkto_outs[k] = kto_outs[k].GetPubKey();

        CTxOutValueTest &txout = txouts[k];

        if (fUnblindedOutputs) {
            memset(&blind[nBlinded].d[0], 0, 32);
        } else {
            InsecureRandBytes(&blind[nBlinded].d[0], 32);
        }
        pBlinds.push_back(&blind[nBlinded++].d[0]);

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txout.commitment, (uint8_t*)pBlinds.back(), (uint64_t)amountsOut[k], &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        // Generate ephemeral key for ECDH nonce generation
        CKey ephemeral_key;
        InsecureNewKey(ephemeral_key, true);
        CPubKey ephemeral_pubkey = ephemeral_key.GetPubKey();
        txout.vchNonceCommitment.resize(33);
        memcpy(&txout.vchNonceCommitment[0], &ephemeral_pubkey[0], 33);

        // Generate nonce
        uint256 nonce = ephemeral_key.ECDH(pkto_outs[k]);
        CSHA256().Write(nonce.begin(), 32).Finalize(nonce.begin());
        // Create range proof
        size_t nRangeProofLen = 5134;

        // TODO: smarter min_value selection

        txout.vchRangeproof.resize(nRangeProofLen);

        uint64_t min_value = 0;
        int ct_exponent = 2;
        int ct_bits = 32;

        BOOST_REQUIRE(secp256k1_rangeproof_sign(ctx,
            &txout.vchRangeproof[0], &nRangeProofLen,
            min_value, &txout.commitment,
            pBlinds.back(), nonce.begin(),
            ct_exponent, ct_bits,
            (uint64_t)amountsOut[k],
            nullptr, 0,
            nullptr, 0,
            secp256k1_generator_h));

        txout.vchRangeproof.resize(nRangeProofLen);
    }

    size_t nRows = txins.size() + 1; // last row sums commitments
    size_t index = rand() % nCols;

    uint8_t *m = (uint8_t*) calloc(nCols * nRows, 33); // m[(col+(cols*row))*33]
    BOOST_REQUIRE(m);

    size_t haveFee = (nValueOutPlain != 0) ? 1 : 0;
    std::vector<const uint8_t*> pcm_in(nCols * txins.size()); // pcm_in[col+(cols*row)]
    std::vector<const uint8_t*> pcm_out(txouts.size() + haveFee);

    std::vector<CTxOutValueTest> tx_mixin(txins.size() * (nCols-1));

    size_t iMix = 0;
    for (size_t k = 0; k < nRows-1; ++k)
    for (size_t i = 0; i < nCols; ++i) {
        if (i == index) {
            memcpy(&m[(i+k*nCols)*33], txins[k].pk.begin(), 33);
            pcm_in[i+k*nCols] = txins[k].commitment.data;
            continue;
        }

        // Make fake input
        CKey key;
        InsecureNewKey(key, true);

        CTxOutValueTest &mixin = tx_mixin[iMix++];
        mixin.pk = key.GetPubKey();
        CAmount nValue = rand() % (5000 * COIN);
        uint8_t blind[32];
        //GetStrongRandBytes(&blind[0], 32);
        InsecureRandBytes(&blind[0], 32);
        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &mixin.commitment, blind, (uint64_t)nValue, &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        memcpy(&m[(i+k*nCols)*33], mixin.pk.begin(), 33);
        pcm_in[i+k*nCols] = mixin.commitment.data;
    }

    uint8_t blindSum[32];
    memset(blindSum, 0, 32);

    for (size_t k = 0; k < txouts.size(); ++k) {
        pcm_out[k] = txouts[k].commitment.data;
    }

    secp256k1_pedersen_commitment feeCommitment;
    if (nValueOutPlain != 0) {
        uint8_t zeroBlind[32];
        memset(zeroBlind, 0, 32);

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &feeCommitment, &zeroBlind[0], (uint64_t)nValueOutPlain, &secp256k1_generator_const_h, &secp256k1_generator_const_g));
        pcm_out[txouts.size()] = feeCommitment.data;
    }

    rv = secp256k1_prepare_mlsag(m, blindSum,
        txouts.size()+haveFee, txouts.size(), nCols, nRows,
        &pcm_in[0], &pcm_out[0], &pBlinds[0]);
    BOOST_REQUIRE(0 == rv);


    if (memncmp(blindSum, 0, 32) == 0) {
        BOOST_REQUIRE(fPass == (0 == memncmp(&m[(index+(nRows-1)*nCols)*33], 0, 33))); // point at infinity encoded as 0*33
        free(m);
        return 0;
    }

    CKey kTest;
    kTest.Set(blindSum, blindSum+32, true);
    BOOST_REQUIRE(kTest.IsValid());

    CPubKey pkTestFromCommitmentSum;
    pkTestFromCommitmentSum.Set(&m[(index+(nRows-1)*nCols)*33], &m[(index+(nRows-1)*nCols)*33]+33);
    BOOST_REQUIRE(pkTestFromCommitmentSum.IsValid());

    CPubKey pkTestFromBlindKey;
    pkTestFromBlindKey = kTest.GetPubKey();
    BOOST_REQUIRE(pkTestFromBlindKey.IsValid());

    BOOST_REQUIRE(fPass == (pkTestFromCommitmentSum == pkTestFromBlindKey));

    free(m);

    return 0;
};

BOOST_AUTO_TEST_CASE(ringct_test_commitment_sums)
{
    secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);

    std::vector<CAmount> amountsOut(2);
    amountsOut[0] = 30 * COIN;
    amountsOut[1] = -10 * COIN;
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 0, 3, false);

    amountsOut[0] = 10 * COIN;
    amountsOut[1] = 10 * COIN;
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 0, 3, true);

    amountsOut[0] = 10 * COIN;
    amountsOut[1] = 8 * COIN;
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 3, true);
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 3 * COIN, 3, false);

    amountsOut[0] = 10 * COIN;
    amountsOut[1] = 8 * COIN;
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 3, true, true);

    amountsOut.resize(3);
    amountsOut[0] = 5 * COIN;
    amountsOut[1] = 8 * COIN;
    amountsOut[2] = 5 * COIN;
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 5, true, true);
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 5, true, true, true);
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 5, true, false, true);
    testCommitmentSum(ctx, 20 * COIN, amountsOut, 2 * COIN, 5, true);

    testCommitmentSum(ctx, 20 * COIN, amountsOut, 1 * COIN, 5, false, true, true);

    secp256k1_context_destroy(ctx);
}

BOOST_AUTO_TEST_CASE(ringct_test)
{
    secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);

    SeedInsecureRand();
    uint32_t rseed = InsecureRand32();
    //GetStrongRandBytes((uint8_t*)&rseed, 4);
    srand(rseed);

    std::vector<CTxOutValueTest> txins(1);

    std::vector<CKey> k_ins(1);
    InsecureNewKey(k_ins[0], true);

    txins[0].pk = k_ins[0].GetPubKey();
    std::vector<const uint8_t*> pBlinds;
    uint8_t blindsin[1][32];

    //GetStrongRandBytes(&blindsin[0][0], 32);
    InsecureRandBytes(&blindsin[0][0], 32);
    pBlinds.push_back(&blindsin[0][0]);

    CAmount nValueIn = 45.69 * COIN;
    BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txins[0].commitment, &blindsin[0][0], (uint64_t)nValueIn, &secp256k1_generator_const_h, &secp256k1_generator_const_g));


    std::vector<CStealthAddress> txout_addrs(2);
    std::vector<CTxOutValueTest> txouts(2);

    std::vector<CAmount> amount_outs(2);
    amount_outs[0] = 5.69 * COIN;
    amount_outs[1] = 40 * COIN;

    std::vector<CKey> kto_outs(2);
    std::vector<CPubKey> pkto_outs(2);
    std::vector<S32Bytes> blind(txouts.size());

    size_t nBlinded = 0;
    for (size_t k = 0; k < txouts.size(); ++k) {
        InsecureNewKey(kto_outs[k], true);
        pkto_outs[k] = kto_outs[k].GetPubKey();

        CTxOutValueTest &txout = txouts[k];

        //GetStrongRandBytes(&blind[nBlinded].d[0], 32);
        InsecureRandBytes(&blind[nBlinded].d[0], 32);
        pBlinds.push_back(&blind[nBlinded++].d[0]);

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txout.commitment, (uint8_t*)pBlinds.back(), (uint64_t)amount_outs[k], &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        // Generate ephemeral key for ECDH nonce generation
        CKey ephemeral_key;
        InsecureNewKey(ephemeral_key, true);
        CPubKey ephemeral_pubkey = ephemeral_key.GetPubKey();
        txout.vchNonceCommitment.resize(33);
        memcpy(&txout.vchNonceCommitment[0], &ephemeral_pubkey[0], 33);

        // Generate nonce
        uint256 nonce = ephemeral_key.ECDH(pkto_outs[k]);
        CSHA256().Write(nonce.begin(), 32).Finalize(nonce.begin());
        // Create range proof
        size_t nRangeProofLen = 5134;

        // TODO: smarter min_value selection

        txout.vchRangeproof.resize(nRangeProofLen);

        uint64_t min_value = 0;
        int ct_exponent = 2;
        int ct_bits = 32;

        BOOST_CHECK(secp256k1_rangeproof_sign(ctx,
            &txout.vchRangeproof[0], &nRangeProofLen,
            min_value, &txout.commitment,
            pBlinds.back(), nonce.begin(),
            ct_exponent, ct_bits,
            (uint64_t)amount_outs[k],
            nullptr, 0,
            nullptr, 0,
            secp256k1_generator_h));

        txout.vchRangeproof.resize(nRangeProofLen);
    }

    size_t nRows = txins.size() + 1; // last row sums commitments
    size_t nCols = 1 + (rand() % 32); // ring size

    size_t index = rand() % nCols;

    uint8_t *m = (uint8_t*) calloc(nCols * nRows, 33); // m[(col+(cols*row))*33]
    BOOST_REQUIRE(m);

    std::vector<const uint8_t*> pcm_in(nCols * txins.size()); // pcm_in[col+(cols*row)]
    std::vector<const uint8_t*> pcm_out(txouts.size());

    std::vector<CTxOutValueTest> tx_mixin(txins.size() * (nCols-1));

    size_t iMix = 0;
    for (size_t k = 0; k < nRows-1; ++k)
    for (size_t i = 0; i < nCols; ++i) {
        if (i == index) {
            memcpy(&m[(i+k*nCols)*33], txins[k].pk.begin(), 33);
            pcm_in[i+k*nCols] = txins[k].commitment.data;
            continue;
        }

        // Make fake input
        CKey key;
        InsecureNewKey(key, true);

        CTxOutValueTest &mixin = tx_mixin[iMix++];
        mixin.pk = key.GetPubKey();
        CAmount nValue = rand() % (5000 * COIN);
        uint8_t blind[32];
        //GetStrongRandBytes(&blind[0], 32);
        InsecureRandBytes(&blind[0], 32);
        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &mixin.commitment, blind, (uint64_t)nValue, &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        memcpy(&m[(i+k*nCols)*33], mixin.pk.begin(), 33);
        pcm_in[i+k*nCols] = mixin.commitment.data;
    }

    std::vector<const uint8_t*> sk(nRows); // pass in pointer to secret keys to keep them in secured memory

    for (size_t k = 0; k < txins.size(); ++k) {
        sk[k] = UCharCast(k_ins[k].begin());
    }
    uint8_t blindSum[32];
    memset(blindSum, 0, 32);
    sk[nRows-1] = blindSum;


    for (size_t k = 0; k < txouts.size(); ++k) {
        pcm_out[k] = txouts[k].commitment.data;
    }
    BOOST_CHECK(0 == secp256k1_prepare_mlsag(m, blindSum,
        txouts.size(), txouts.size(), nCols, nRows,
        &pcm_in[0], &pcm_out[0], &pBlinds[0]));
    uint8_t randSeed[32];
    InsecureRandBytes(randSeed, 32);
    //GetStrongRandBytes(randSeed, 32);
    uint8_t preimage[32];
    InsecureRandBytes(preimage, 32);
    //GetStrongRandBytes(preimage, 32);

    uint8_t pc[32];
    std::vector<uint8_t> ki(33 * txins.size());
    std::vector<uint8_t> ss(nCols * nRows * 32);


    BOOST_CHECK(0 == secp256k1_generate_mlsag(ctx, &ki[0], pc, &ss[0],
        randSeed, preimage, nCols, nRows, index,
        &sk[0], m));
    BOOST_CHECK(0 == secp256k1_verify_mlsag(
        preimage, nCols, nRows,
        m, &ki[0], pc, &ss[0]));

    free(m);

    for (size_t k = 0; k < txouts.size(); ++k) {
        CTxOutValueTest &txout = txouts[k];

        int rexp;
        int rmantissa;
        uint64_t min_value;
        uint64_t max_value;

        BOOST_CHECK(secp256k1_rangeproof_info(ctx,
            &rexp, &rmantissa,
            &min_value, &max_value,
            &txout.vchRangeproof[0], txout.vchRangeproof.size()) == 1);

        min_value = 0;
        max_value = 0;
        BOOST_CHECK(1 == secp256k1_rangeproof_verify(ctx, &min_value, &max_value,
            &txout.commitment, txout.vchRangeproof.data(), txout.vchRangeproof.size(),
            nullptr, 0,
            secp256k1_generator_h));

        CPubKey ephemeral_key(txout.vchNonceCommitment);
        BOOST_CHECK(ephemeral_key.IsValid());
        uint256 nonce = kto_outs[k].ECDH(ephemeral_key);
        CSHA256().Write(nonce.begin(), 32).Finalize(nonce.begin());

        uint8_t blindOut[32];
        unsigned char msg[4096];
        size_t msg_size = sizeof(msg);
        uint64_t amountOut;
        BOOST_CHECK(secp256k1_rangeproof_rewind(ctx,
            blindOut, &amountOut, msg, &msg_size, nonce.begin(),
            &min_value, &max_value,
            &txout.commitment, txout.vchRangeproof.data(), txout.vchRangeproof.size(),
            nullptr, 0,
            secp256k1_generator_h));
    }

    secp256k1_context_destroy(ctx);
}



static int GetDeterministicBytes(uint8_t *p, size_t len)
{
    for (size_t k = 0; k < len; ++k) {
        *(p+k) = rand() % 256;
    }
    return 0;
}

static int GetBytes(uint8_t *p, size_t len, bool fDeterministic)
{
    if (fDeterministic) {
        GetDeterministicBytes(p, len);
    } else {
        GetStrongRandBytes2(p, len);
    }
    return 0;
}

int doTest(secp256k1_context *ctx, size_t nInputs, size_t nOutputs, CAmount nFee, bool fDeterministic)
{
    uint8_t tmp[64];
    std::vector<const uint8_t*> pBlinds;
    std::vector<CTxOutValueTest> txins(nInputs);
    std::vector<CKey> kIns(nInputs);

    std::vector<S32Bytes> blindsIn(nInputs);

    // Make inputs
    CAmount nInputSum = 0;
    for (size_t k = 0; k < nInputs; ++k) {
        CAmount nValueIn = rand() % 4 == 0 ? 0 : nFee * (rand() % 20000);

        // Can't use MakeNewKey if fDeterministic
        GetBytes(tmp, 32, fDeterministic);
        kIns[k].Set(tmp, true);
        txins[k].pk = kIns[k].GetPubKey();

        GetBytes(&blindsIn[k].d[0], 32, fDeterministic);
        pBlinds.push_back(&blindsIn[k].d[0]);

        // Make sure there's always enough coin
        if (k == nInputs-1
            && nInputSum < nFee * 2) {
            nValueIn = nFee * 2 + nFee * (rand() % 20000);
        }
        nInputSum += nValueIn;

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txins[k].commitment, &blindsIn[k].d[0], (uint64_t)nValueIn, &secp256k1_generator_const_h, &secp256k1_generator_const_g));
    }

    std::vector<CStealthAddress> txoutAddrs(nOutputs);
    std::vector<CTxOutValueTest> txouts(nOutputs);

    std::vector<CAmount> amountsOut(nOutputs);
    CAmount nOutputLeft = nInputSum - nFee;
    for (size_t k = 0; k < nOutputs-1; ++k) {
        amountsOut[k] = rand() % 4 == 0 ? 0 : (rand() % nOutputLeft);
        nOutputLeft -= amountsOut[k];
    }
    amountsOut[nOutputs-1] = nOutputLeft;

    std::vector<CKey> kto_outs(nOutputs);
    std::vector<CPubKey> pkto_outs(nOutputs);
    std::vector<S32Bytes> blind(txouts.size());

    for (size_t k = 0; k < txouts.size(); ++k) {
        GetBytes(tmp, 32, fDeterministic);
        kto_outs[k].Set(tmp, true);
        pkto_outs[k] = kto_outs[k].GetPubKey();

        CTxOutValueTest &txout = txouts[k];

        GetBytes(&blind[k].d[0], 32, fDeterministic);
        pBlinds.push_back(&blind[k].d[0]);

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &txout.commitment, (uint8_t*)pBlinds.back(), amountsOut[k], &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        // Generate ephemeral key for ECDH nonce generation
        CKey ephemeral_key;
        GetBytes(tmp, 32, fDeterministic);
        ephemeral_key.Set(tmp, true);
        CPubKey ephemeral_pubkey = ephemeral_key.GetPubKey();
        txout.vchNonceCommitment.resize(33);
        memcpy(&txout.vchNonceCommitment[0], &ephemeral_pubkey[0], 33);

        // Generate nonce
        uint256 nonce = ephemeral_key.ECDH(pkto_outs[k]);
        CSHA256().Write(nonce.begin(), 32).Finalize(nonce.begin());
        // Create range proof
        size_t nRangeProofLen = 5134;

        // TODO: smarter min_value selection

        txout.vchRangeproof.resize(nRangeProofLen);

        uint64_t min_value = 0;
        int ct_exponent = 2;
        int ct_bits = 32;

        BOOST_CHECK(secp256k1_rangeproof_sign(ctx,
            &txout.vchRangeproof[0], &nRangeProofLen,
            min_value, &txout.commitment,
            pBlinds.back(), nonce.begin(),
            ct_exponent, ct_bits,
            (uint64_t)amountsOut[k],
            nullptr, 0,
            nullptr, 0,
            secp256k1_generator_h));

        txout.vchRangeproof.resize(nRangeProofLen);
    }

    size_t nRows = txins.size() + 1; // last row sums commitments
    size_t nCols = 1 + (rand() % 128); // ring size
    size_t index = rand() % nCols;

    uint8_t *m = (uint8_t*) calloc(nCols * nRows, 33); // m[(col+(cols*row))*33]
    BOOST_REQUIRE(m);

    size_t haveFee = (nFee != 0) ? 1 : 0;
    std::vector<const uint8_t*> pcm_in(nCols * txins.size()); // pcm_in[col+(cols*row)]
    std::vector<const uint8_t*> pcm_out(txouts.size() + haveFee);

    std::vector<CTxOutValueTest> tx_mixin(txins.size() * (nCols-1));

    size_t iMix = 0;
    for (size_t k = 0; k < nRows-1; ++k)
    for (size_t i = 0; i < nCols; ++i) {
        if (i == index) {
            memcpy(&m[(i+k*nCols)*33], txins[k].pk.begin(), 33);
            pcm_in[i+k*nCols] = txins[k].commitment.data;
            continue;
        }

        // Make fake input
        CKey key;
        GetBytes(tmp, 32, fDeterministic);
        key.Set(tmp, true);

        CTxOutValueTest &mixin = tx_mixin[iMix++];
        mixin.pk = key.GetPubKey();
        CAmount nValue = rand() % (5000 * COIN);

        uint8_t blind[32];
        GetBytes(&blind[0], 32, fDeterministic);
        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &mixin.commitment, blind, nValue, &secp256k1_generator_const_h, &secp256k1_generator_const_g));

        memcpy(&m[(i+k*nCols)*33], mixin.pk.begin(), 33);
        pcm_in[i+k*nCols] = mixin.commitment.data;
    }

    std::vector<const uint8_t*> sk(nRows); // pass in pointer to secret keys to keep them in secured memory

    for (size_t k = 0; k < txins.size(); ++k) {
        sk[k] = UCharCast(kIns[k].begin());
    }
    uint8_t blindSum[32]; // memory for last key (sum of blinding factors)
    memset(blindSum, 0, 32);
    sk[nRows-1] = blindSum;

    for (size_t k = 0; k < txouts.size(); ++k) {
        pcm_out[k] = txouts[k].commitment.data;
    }

    // Add commitment for fee
    secp256k1_pedersen_commitment feeCommitment;
    if (haveFee) {
        uint8_t zeroBlind[32];
        memset(zeroBlind, 0, 32);

        BOOST_CHECK(secp256k1_pedersen_commit(ctx, &feeCommitment, &zeroBlind[0], nFee, &secp256k1_generator_const_h, &secp256k1_generator_const_g));
        pcm_out[txouts.size()] = feeCommitment.data;
    }

    BOOST_CHECK(0 == secp256k1_prepare_mlsag(m, blindSum,
        txouts.size()+haveFee, txouts.size(), nCols, nRows,
        &pcm_in[0], &pcm_out[0], &pBlinds[0]));


    uint8_t randSeed[32], preimage[32], pc[32];
    std::vector<uint8_t> ki(33 * txins.size());
    std::vector<uint8_t> ss(nCols * nRows * 32);

    GetBytes(randSeed, 32, fDeterministic);
    GetBytes(preimage, 32, fDeterministic);

    BOOST_CHECK(0 == secp256k1_generate_mlsag(ctx, &ki[0], pc, &ss[0],
        randSeed, preimage, nCols, nRows, index,
        &sk[0], m));

    BOOST_CHECK(0 == secp256k1_verify_mlsag(
        preimage, nCols, nRows,
        m, &ki[0], pc, &ss[0]));

    free(m);

    for (size_t k = 0; k < txouts.size(); ++k) {
        CTxOutValueTest &txout = txouts[k];

        int rexp;
        int rmantissa;
        uint64_t min_value;
        uint64_t max_value;

        BOOST_CHECK(1 == secp256k1_rangeproof_info(ctx,
            &rexp, &rmantissa,
            &min_value, &max_value,
            &txout.vchRangeproof[0], txout.vchRangeproof.size()));


        BOOST_CHECK(1 == secp256k1_rangeproof_verify(ctx, &min_value, &max_value,
            &txout.commitment, txout.vchRangeproof.data(), txout.vchRangeproof.size(),
            nullptr, 0,
            secp256k1_generator_h));

        CPubKey ephemeral_key(txout.vchNonceCommitment);
        BOOST_CHECK(ephemeral_key.IsValid());
        uint256 nonce = kto_outs[k].ECDH(ephemeral_key);
        CSHA256().Write(nonce.begin(), 32).Finalize(nonce.begin());

        uint8_t blindOut[32];
        unsigned char msg[4096];
        size_t mlen = sizeof(msg); // input is size of buffer, output is data written
        uint64_t amountOut;
        BOOST_CHECK(secp256k1_rangeproof_rewind(ctx,
            blindOut, &amountOut, msg, &mlen, nonce.begin(),
            &min_value, &max_value,
            &txout.commitment, txout.vchRangeproof.data(), txout.vchRangeproof.size(),
            nullptr, 0,
            secp256k1_generator_h));

        BOOST_CHECK(amountsOut[k] == (CAmount) amountOut);
    }

    return 0;
}

BOOST_AUTO_TEST_CASE(ringct_test_2in_fee)
{
    secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);

    uint32_t rseed = 1;
    srand(rseed);

    doTest(ctx, 2, 3, 0.001 * COIN, true);

    rseed = InsecureRand32();
    srand(rseed);
    for (size_t k = 0; k < 10; ++k) {
        //doTest(ctx, 1 + (rand() % 15), 1 + (rand() % 15), 0.001 * COIN, false);
        doTest(ctx, 1 + (rand() % 15), 1 + (rand() % 15), 0.001 * COIN, true); // use less entropy
    }

    secp256k1_context_destroy(ctx);
}

BOOST_AUTO_TEST_CASE(ringct_test_set_have)
{
    std::set<int64_t> setHaveI;

    BOOST_CHECK(setHaveI.insert(1).second == true);
    BOOST_CHECK(setHaveI.insert(1).second == false);
    BOOST_CHECK(setHaveI.insert(2).second == true);
}


BOOST_AUTO_TEST_CASE(ringct_test_deterministic)
{
    // See github.com/tecnovert/particl_debug_scripts/mlsag_deterministic.py
    secp256k1_context *ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);

    UniValue tests_vectors = read_json(json_tests::ringct);

    for (unsigned int idx = 0; idx < tests_vectors.size(); idx++) {
        const UniValue &test = tests_vectors[idx];
        size_t rows = test[0].getInt<int>();
        size_t cols = test[1].getInt<int>();
        size_t real_column = test[2].getInt<int>();

        std::vector<uint8_t> nonce = ParseHex(test[3].get_str());
        std::vector<uint8_t> preimage = ParseHex(test[4].get_str());
        std::vector<uint8_t> secret_keys = ParseHex(test[5].get_str());
        std::vector<uint8_t> pubkey_matrix = ParseHex(test[6].get_str());
        std::vector<uint8_t> expect_hash = ParseHex(test[7].get_str());

        std::vector<uint8_t> ki(33 * (rows - 1));
        uint8_t sigc[32], result_hash[32];
        std::vector<uint8_t> sigs(cols * rows * 32);

        std::vector<const uint8_t*> sk(rows);
        for (size_t k = 0; k < rows; ++k) {
            sk[k] = &secret_keys[k * 32];
        }

        BOOST_CHECK(0 == secp256k1_generate_mlsag(ctx, ki.data(), sigc, sigs.data(),
            nonce.data(), preimage.data(), cols, rows, real_column,
            &sk[0], pubkey_matrix.data()));


        CSHA256().Write(ki.data(), ki.size())
                 .Write(sigc, 32)
                 .Write(sigs.data(), sigs.size())
                 .Finalize(result_hash);

        BOOST_CHECK(memcmp(expect_hash.data(), result_hash, 32) == 0);
    }

    secp256k1_context_destroy(ctx);
}

BOOST_AUTO_TEST_SUITE_END()