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add Straus multiexp
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@moneromooo-monero
moneromooo-monero committed Sep 11, 2018
1 parent 9ff6e6a commit 939bc22
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Showing 6 changed files with 279 additions and 150 deletions.
190 changes: 47 additions & 143 deletions src/ringct/bulletproofs.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,14 @@ static const rct::keyV twoN = vector_powers(TWO, maxN);
static const rct::key ip12 = inner_product(oneN, twoN);
static boost::mutex init_mutex;

static inline rct::key multiexp(const std::vector<MultiexpData> &data, bool HiGi)
{
if (HiGi || data.size() < 1000)
return straus(data, HiGi);
else
return bos_coster_heap_conv_robust(data);
}

//addKeys3acc_p3
//aAbB += a*A + b*B where a, b are scalars, A, B are curve points
//A and B must be input after applying "precomp"
Expand Down Expand Up @@ -126,35 +134,15 @@ static rct::key vector_exponent(const rct::keyV &a, const rct::keyV &b)
{
CHECK_AND_ASSERT_THROW_MES(a.size() == b.size(), "Incompatible sizes of a and b");
CHECK_AND_ASSERT_THROW_MES(a.size() <= maxN*maxM, "Incompatible sizes of a and maxN");
#if 1

std::vector<MultiexpData> multiexp_data;
multiexp_data.reserve(a.size()*2);
for (size_t i = 0; i < a.size(); ++i)
{
if (!(a[i] == rct::zero()))
{
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = a[i];
multiexp_data.back().point = Gi_p3[i];
}
if (!(b[i] == rct::zero()))
{
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = b[i];
multiexp_data.back().point = Hi_p3[i];
}
multiexp_data.emplace_back(a[i], Gi_p3[i]);
multiexp_data.emplace_back(b[i], Hi_p3[i]);
}
return bos_coster_heap_conv_robust(multiexp_data);
#else
ge_p3 res_p3 = ge_p3_identity;
for (size_t i = 0; i < a.size(); ++i)
{
rct::addKeys3acc_p3(&res_p3, a[i], Gprecomp[i], b[i], Hprecomp[i]);
}
rct::key res;
ge_p3_tobytes(res.bytes, &res_p3);
return res;
#endif
return multiexp(multiexp_data, true);
}

/* Compute a custom vector-scalar commitment */
Expand All @@ -164,63 +152,19 @@ static rct::key vector_exponent_custom(const rct::keyV &A, const rct::keyV &B, c
CHECK_AND_ASSERT_THROW_MES(a.size() == b.size(), "Incompatible sizes of a and b");
CHECK_AND_ASSERT_THROW_MES(a.size() == A.size(), "Incompatible sizes of a and A");
CHECK_AND_ASSERT_THROW_MES(a.size() <= maxN*maxM, "Incompatible sizes of a and maxN");
#if 1

std::vector<MultiexpData> multiexp_data;
multiexp_data.reserve(a.size()*2);
for (size_t i = 0; i < a.size(); ++i)
{
if (!(a[i] == rct::zero()))
{
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = a[i];
CHECK_AND_ASSERT_THROW_MES(ge_frombytes_vartime(&multiexp_data.back().point, A[i].bytes) == 0, "ge_frombytes_vartime failed");
}
if (!(b[i] == rct::zero()))
{
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = b[i];
CHECK_AND_ASSERT_THROW_MES(ge_frombytes_vartime(&multiexp_data.back().point, B[i].bytes) == 0, "ge_frombytes_vartime failed");
}
}
return bos_coster_heap_conv_robust(multiexp_data);
#else
ge_p3 res_p3 = ge_p3_identity;
for (size_t i = 0; i < a.size(); ++i)
{
#if 0
rct::key term;
// we happen to know where A and B might fall, so don't bother checking the rest
ge_dsmp *Acache = NULL, *Bcache = NULL;
ge_dsmp Acache_custom[1], Bcache_custom[1];
if (Gi[i] == A[i])
Acache = Gprecomp + i;
else if (i<32 && Gi[i+32] == A[i])
Acache = Gprecomp + i + 32;
else
{
rct::precomp(Acache_custom[0], A[i]);
Acache = Acache_custom;
}
if (i == 0 && B[i] == Hi[0])
Bcache = Hprecomp;
else
{
rct::precomp(Bcache_custom[0], B[i]);
Bcache = Bcache_custom;
}
rct::addKeys3(term, a[i], *Acache, b[i], *Bcache);
rct::addKeys(res, res, term);
#else
ge_dsmp Acache, Bcache;
rct::precomp(Bcache, B[i]);
rct::precomp(Acache, A[i]);
addKeys3acc_p3(&res_p3, a[i], Acache, b[i], Bcache);
#endif
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = a[i];
CHECK_AND_ASSERT_THROW_MES(ge_frombytes_vartime(&multiexp_data.back().point, A[i].bytes) == 0, "ge_frombytes_vartime failed");
multiexp_data.resize(multiexp_data.size() + 1);
multiexp_data.back().scalar = b[i];
CHECK_AND_ASSERT_THROW_MES(ge_frombytes_vartime(&multiexp_data.back().point, B[i].bytes) == 0, "ge_frombytes_vartime failed");
}
rct::key res;
ge_p3_tobytes(res.bytes, &res_p3);
return res;
#endif
return multiexp(multiexp_data, false);
}

/* Given a scalar, construct a vector of powers */
Expand Down Expand Up @@ -986,26 +930,23 @@ bool bulletproof_VERIFY(const Bulletproof &proof)
}
PERF_TIMER_STOP(VERIFY_line_61);

// multiexp is slower for small numbers of calcs
if (M >= 16)
// bos coster is slower for small numbers of calcs, straus seems not
if (1)
{
PERF_TIMER_START_BP(VERIFY_line_61rl_new);
sc_muladd(tmp.bytes, z.bytes, ip1y.bytes, k.bytes);
std::vector<MultiexpData> multiexp_data;
multiexp_data.reserve(3+M);
multiexp_data.push_back({tmp, rct::H});
for (size_t j = 0; j < M; j++)
multiexp_data.reserve(3+proof.V.size());
multiexp_data.emplace_back(tmp, rct::H);
for (size_t j = 0; j < proof.V.size(); j++)
{
if (!(zpow[j+2] == rct::zero()))
multiexp_data.push_back({zpow[j+2], j < proof.V.size() ? proof.V[j] : rct::identity()});
multiexp_data.emplace_back(zpow[j+2], proof.V[j]);
}
if (!(x == rct::zero()))
multiexp_data.push_back({x, proof.T1});
multiexp_data.emplace_back(x, proof.T1);
rct::key xsq;
sc_mul(xsq.bytes, x.bytes, x.bytes);
if (!(xsq == rct::zero()))
multiexp_data.push_back({xsq, proof.T2});
L61Right = bos_coster_heap_conv_robust(multiexp_data);
multiexp_data.emplace_back(xsq, proof.T2);
L61Right = multiexp(multiexp_data, false);
PERF_TIMER_STOP(VERIFY_line_61rl_new);
}
else
Expand Down Expand Up @@ -1114,10 +1055,8 @@ bool bulletproof_VERIFY(const Bulletproof &proof)
sc_muladd(tmp.bytes, z.bytes, ypow.bytes, tmp.bytes);
sc_mulsub(h_scalar.bytes, tmp.bytes, yinvpow.bytes, h_scalar.bytes);

if (!(g_scalar == rct::zero()))
multiexp_data.push_back({g_scalar, Gi_p3[i]});
if (!(h_scalar == rct::zero()))
multiexp_data.push_back({h_scalar, Hi_p3[i]});
multiexp_data.emplace_back(g_scalar, Gi_p3[i]);
multiexp_data.emplace_back(h_scalar, Hi_p3[i]);

if (i != MN-1)
{
Expand All @@ -1126,63 +1065,28 @@ bool bulletproof_VERIFY(const Bulletproof &proof)
}
}

rct::key inner_prod = bos_coster_heap_conv_robust(multiexp_data);
rct::key inner_prod = multiexp(multiexp_data, true);
PERF_TIMER_STOP(VERIFY_line_24_25);

// PAPER LINE 26
rct::key pprime;
// multiexp does not seem to give any speedup here
if(0)
{
PERF_TIMER_START_BP(VERIFY_line_26_new);
// PAPER LINE 26
std::vector<MultiexpData> multiexp_data;
multiexp_data.reserve(1+2*rounds);

sc_sub(tmp.bytes, rct::zero().bytes, proof.mu.bytes);
rct::addKeys(pprime, P, rct::scalarmultBase(tmp));
for (size_t i = 0; i < rounds; ++i)
{
sc_mul(tmp.bytes, w[i].bytes, w[i].bytes);
sc_mul(tmp2.bytes, winv[i].bytes, winv[i].bytes);
if (!(tmp == rct::zero()))
multiexp_data.push_back({tmp, proof.L[i]});
if (!(tmp2 == rct::zero()))
multiexp_data.push_back({tmp2, proof.R[i]});
}
sc_mul(tmp.bytes, proof.t.bytes, x_ip.bytes);
if (!(tmp == rct::zero()))
multiexp_data.push_back({tmp, rct::H});
addKeys(pprime, pprime, bos_coster_heap_conv_robust(multiexp_data));
PERF_TIMER_STOP(VERIFY_line_26_new);
}
PERF_TIMER_START_BP(VERIFY_line_26_new);
multiexp_data.clear();
multiexp_data.reserve(1+2*rounds);

sc_sub(tmp.bytes, rct::zero().bytes, proof.mu.bytes);
rct::addKeys(pprime, P, rct::scalarmultBase(tmp));
for (size_t i = 0; i < rounds; ++i)
{
PERF_TIMER_START_BP(VERIFY_line_26_old);
// PAPER LINE 26
sc_sub(tmp.bytes, rct::zero().bytes, proof.mu.bytes);
rct::addKeys(pprime, P, rct::scalarmultBase(tmp));
ge_p3 pprime_p3;
CHECK_AND_ASSERT_MES(ge_frombytes_vartime(&pprime_p3, pprime.bytes) == 0, false, "ge_frombytes_vartime failed");

for (size_t i = 0; i < rounds; ++i)
{
sc_mul(tmp.bytes, w[i].bytes, w[i].bytes);
sc_mul(tmp2.bytes, winv[i].bytes, winv[i].bytes);
#if 1
ge_dsmp cacheL, cacheR;
rct::precomp(cacheL, proof.L[i]);
rct::precomp(cacheR, proof.R[i]);
addKeys3acc_p3(&pprime_p3, tmp, cacheL, tmp2, cacheR);
#else
rct::addKeys(pprime, pprime, rct::scalarmultKey(proof.L[i], tmp));
rct::addKeys(pprime, pprime, rct::scalarmultKey(proof.R[i], tmp2));
#endif
}
sc_mul(tmp.bytes, proof.t.bytes, x_ip.bytes);
addKeys_acc_p3(&pprime_p3, tmp, rct::H);
ge_p3_tobytes(pprime.bytes, &pprime_p3);
PERF_TIMER_STOP(VERIFY_line_26_old);
sc_mul(tmp.bytes, w[i].bytes, w[i].bytes);
sc_mul(tmp2.bytes, winv[i].bytes, winv[i].bytes);
multiexp_data.emplace_back(tmp, proof.L[i]);
multiexp_data.emplace_back(tmp2, proof.R[i]);
}
sc_mul(tmp.bytes, proof.t.bytes, x_ip.bytes);
multiexp_data.emplace_back(tmp, rct::H);
addKeys(pprime, pprime, multiexp(multiexp_data, false));
PERF_TIMER_STOP(VERIFY_line_26_new);

PERF_TIMER_START_BP(VERIFY_step2_check);
sc_mul(tmp.bytes, proof.a.bytes, proof.b.bytes);
Expand Down
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