From 641b08c920f9c68d957e13147cf9c3e329cf83f1 Mon Sep 17 00:00:00 2001 From: Sarang Noether <32460187+SarangNoether@users.noreply.github.com> Date: Tue, 10 Mar 2020 18:46:37 -0400 Subject: CLSAG optimizations --- src/ringct/rctSigs.cpp | 264 +++++++++++++++++++++++++------------------------ src/ringct/rctSigs.h | 7 +- 2 files changed, 139 insertions(+), 132 deletions(-) (limited to 'src/ringct') diff --git a/src/ringct/rctSigs.cpp b/src/ringct/rctSigs.cpp index 074812156..2e56dad58 100644 --- a/src/ringct/rctSigs.cpp +++ b/src/ringct/rctSigs.cpp @@ -168,12 +168,17 @@ namespace rct { // Generate a CLSAG signature // See paper by Goodell et al. (https://eprint.iacr.org/2019/654) - clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const unsigned int l, const multisig_kLRki *kLRki, key *mscout, key *mspout) { + // + // The keys are set as follows: + // P[l] == p*G + // C[l] == z*G + // C[i] == C_nonzero[i] - C_offset (for hashing purposes) for all i + clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const keyV & C_nonzero, const key & C_offset, const unsigned int l, const multisig_kLRki *kLRki, key *mscout, key *mspout) { clsag sig; size_t n = P.size(); // ring size CHECK_AND_ASSERT_THROW_MES(n == C.size(), "Signing and commitment key vector sizes must match!"); + CHECK_AND_ASSERT_THROW_MES(n == C_nonzero.size(), "Signing and commitment key vector sizes must match!"); CHECK_AND_ASSERT_THROW_MES(l < n, "Signing index out of range!"); - CHECK_AND_ASSERT_THROW_MES(scalarmultBase(z) == C[l], "C does not match z!"); CHECK_AND_ASSERT_THROW_MES((kLRki && mscout) || (!kLRki && !mscout), "Only one of kLRki/mscout is present"); CHECK_AND_ASSERT_THROW_MES((mscout && mspout) || !kLRki, "Multisig pointers are not all present"); @@ -212,8 +217,8 @@ namespace rct { scalarmultKey(aH,H,a); // Aggregation hashes - keyV mu_P_to_hash(2*n+3); // domain, I, D, P, C - keyV mu_C_to_hash(2*n+3); // domain, I, D, P, C + keyV mu_P_to_hash(2*n+4); // domain, I, D, P, C, C_offset + keyV mu_C_to_hash(2*n+4); // domain, I, D, P, C, C_offset sc_0(mu_P_to_hash[0].bytes); memcpy(mu_P_to_hash[0].bytes,config::HASH_KEY_CLSAG_AGG_0,sizeof(config::HASH_KEY_CLSAG_AGG_0)-1); sc_0(mu_C_to_hash[0].bytes); @@ -223,40 +228,43 @@ namespace rct { mu_C_to_hash[i] = P[i-1]; } for (size_t i = n+1; i < 2*n+1; ++i) { - mu_P_to_hash[i] = C[i-n-1]; - mu_C_to_hash[i] = C[i-n-1]; + mu_P_to_hash[i] = C_nonzero[i-n-1]; + mu_C_to_hash[i] = C_nonzero[i-n-1]; } mu_P_to_hash[2*n+1] = sig.I; mu_P_to_hash[2*n+2] = sig.D; + mu_P_to_hash[2*n+3] = C_offset; mu_C_to_hash[2*n+1] = sig.I; mu_C_to_hash[2*n+2] = sig.D; + mu_C_to_hash[2*n+3] = C_offset; key mu_P, mu_C; mu_P = hash_to_scalar(mu_P_to_hash); mu_C = hash_to_scalar(mu_C_to_hash); // Initial commitment - keyV c_to_hash(2*n+4); // domain, P, C, message, aG, aH + keyV c_to_hash(2*n+5); // domain, P, C, C_offset, message, aG, aH key c; sc_0(c_to_hash[0].bytes); memcpy(c_to_hash[0].bytes,config::HASH_KEY_CLSAG_ROUND,sizeof(config::HASH_KEY_CLSAG_ROUND)-1); for (size_t i = 1; i < n+1; ++i) { c_to_hash[i] = P[i-1]; - c_to_hash[i+n] = C[i-1]; + c_to_hash[i+n] = C_nonzero[i-1]; } - c_to_hash[2*n+1] = message; + c_to_hash[2*n+1] = C_offset; + c_to_hash[2*n+2] = message; // Multisig data is present if (kLRki) { a = kLRki->k; - c_to_hash[2*n+2] = kLRki->L; - c_to_hash[2*n+3] = kLRki->R; + c_to_hash[2*n+3] = kLRki->L; + c_to_hash[2*n+4] = kLRki->R; } else { - c_to_hash[2*n+2] = aG; - c_to_hash[2*n+3] = aH; + c_to_hash[2*n+3] = aG; + c_to_hash[2*n+4] = aH; } c = hash_to_scalar(c_to_hash); @@ -295,8 +303,8 @@ namespace rct { ge_dsm_precomp(H_precomp.k, &Hi_p3); addKeys_aAbBcC(R,sig.s[i],H_precomp.k,c_p,I_precomp.k,c_c,D_precomp.k); - c_to_hash[2*n+2] = L; - c_to_hash[2*n+3] = R; + c_to_hash[2*n+3] = L; + c_to_hash[2*n+4] = R; c_new = hash_to_scalar(c_to_hash); copy(c,c_new); @@ -320,99 +328,8 @@ namespace rct { return sig; } - clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const unsigned int l) { - return CLSAG_Gen(message, P, p, C, z, l, NULL, NULL, NULL); - } - - // Verify a CLSAG signature - // See paper by Goodell et al. (https://eprint.iacr.org/2019/654) - bool CLSAG_Ver(const key &message, const keyV & P, const keyV & C, const clsag & sig) - { - size_t n = P.size(); // ring size - CHECK_AND_ASSERT_MES(n == C.size(), false, "Signing and commitment key vector sizes must match!"); - CHECK_AND_ASSERT_MES(n == sig.s.size(), false, "Signature scalar vector is the wrong size!"); - for (size_t i = 0; i < n; ++i) - CHECK_AND_ASSERT_MES(sc_check(sig.s[i].bytes) == 0, false, "Bad signature scalar!"); - CHECK_AND_ASSERT_MES(sc_check(sig.c1.bytes) == 0, false, "Bad signature commitment!"); - - key c = copy(sig.c1); - key D_8 = scalarmult8(sig.D); - geDsmp I_precomp; - geDsmp D_precomp; - precomp(I_precomp.k,sig.I); - precomp(D_precomp.k,D_8); - - // Aggregation hashes - keyV mu_P_to_hash(2*n+3); // domain, I, D, P, C - keyV mu_C_to_hash(2*n+3); // domain, I, D, P, C - sc_0(mu_P_to_hash[0].bytes); - memcpy(mu_P_to_hash[0].bytes,config::HASH_KEY_CLSAG_AGG_0,sizeof(config::HASH_KEY_CLSAG_AGG_0)-1); - sc_0(mu_C_to_hash[0].bytes); - memcpy(mu_C_to_hash[0].bytes,config::HASH_KEY_CLSAG_AGG_1,sizeof(config::HASH_KEY_CLSAG_AGG_1)-1); - for (size_t i = 1; i < n+1; ++i) { - mu_P_to_hash[i] = P[i-1]; - mu_C_to_hash[i] = P[i-1]; - } - for (size_t i = n+1; i < 2*n+1; ++i) { - mu_P_to_hash[i] = C[i-n-1]; - mu_C_to_hash[i] = C[i-n-1]; - } - mu_P_to_hash[2*n+1] = sig.I; - mu_P_to_hash[2*n+2] = sig.D; - mu_C_to_hash[2*n+1] = sig.I; - mu_C_to_hash[2*n+2] = sig.D; - key mu_P, mu_C; - mu_P = hash_to_scalar(mu_P_to_hash); - mu_C = hash_to_scalar(mu_C_to_hash); - - keyV c_to_hash(2*n+4); // domain, P, C, message, L, R - sc_0(c_to_hash[0].bytes); - memcpy(c_to_hash[0].bytes,config::HASH_KEY_CLSAG_ROUND,sizeof(config::HASH_KEY_CLSAG_ROUND)-1); - for (size_t i = 1; i < n+1; ++i) - { - c_to_hash[i] = P[i-1]; - c_to_hash[i+n] = C[i-1]; - } - c_to_hash[2*n+1] = message; - key c_p; // = c[i]*mu_P - key c_c; // = c[i]*mu_C - key c_new; - key L; - key R; - geDsmp P_precomp; - geDsmp C_precomp; - geDsmp H_precomp; - size_t i = 0; - ge_p3 hash8_p3; - geDsmp hash_precomp; - - while (i < n) { - sc_0(c_new.bytes); - sc_mul(c_p.bytes,mu_P.bytes,c.bytes); - sc_mul(c_c.bytes,mu_C.bytes,c.bytes); - - // Precompute points - precomp(P_precomp.k,P[i]); - precomp(C_precomp.k,C[i]); - - // Compute L - addKeys_aGbBcC(L,sig.s[i],c_p,P_precomp.k,c_c,C_precomp.k); - - // Compute R - hash_to_p3(hash8_p3,P[i]); - ge_dsm_precomp(hash_precomp.k, &hash8_p3); - addKeys_aAbBcC(R,sig.s[i],hash_precomp.k,c_p,I_precomp.k,c_c,D_precomp.k); - - c_to_hash[2*n+2] = L; - c_to_hash[2*n+3] = R; - c_new = hash_to_scalar(c_to_hash); - CHECK_AND_ASSERT_MES(!(c_new == rct::zero()), false, "Bad signature hash"); - copy(c,c_new); - - i = i + 1; - } - sc_sub(c_new.bytes,c.bytes,sig.c1.bytes); - return sc_isnonzero(c_new.bytes) == 0; + clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const keyV & C_nonzero, const key & C_offset, const unsigned int l) { + return CLSAG_Gen(message, P, p, C, z, C_nonzero, C_offset, l, NULL, NULL, NULL); } // MLSAG signatures @@ -816,12 +733,14 @@ namespace rct { size_t i; keyM M(cols, tmp); - keyV P, C; + keyV P, C, C_nonzero; P.reserve(pubs.size()); C.reserve(pubs.size()); + C_nonzero.reserve(pubs.size()); for (const ctkey &k: pubs) { P.push_back(k.dest); + C_nonzero.push_back(k.mask); rct::key tmp; subKeys(tmp, k.mask, Cout); C.push_back(tmp); @@ -829,7 +748,7 @@ namespace rct { sk[0] = copy(inSk.dest); sc_sub(sk[1].bytes, inSk.mask.bytes, a.bytes); - clsag result = CLSAG_Gen(message, P, sk[0], C, sk[1], index, kLRki, mscout, mspout); + clsag result = CLSAG_Gen(message, P, sk[0], C, sk[1], C_nonzero, Cout, index, kLRki, mscout, mspout); memwipe(sk.data(), sk.size() * sizeof(key)); return result; } @@ -913,29 +832,116 @@ namespace rct { catch (...) { return false; } } - bool verRctCLSAGSimple(const key &message, const clsag &clsag, const ctkeyV & pubs, const key & C) { + bool verRctCLSAGSimple(const key &message, const clsag &sig, const ctkeyV & pubs, const key & C_offset) { try { PERF_TIMER(verRctCLSAGSimple); - //setup vars - const size_t cols = pubs.size(); - CHECK_AND_ASSERT_MES(cols >= 1, false, "Empty pubs"); - keyV Pi(cols), Ci(cols); - ge_p3 Cp3; - CHECK_AND_ASSERT_MES_L1(ge_frombytes_vartime(&Cp3, C.bytes) == 0, false, "point conv failed"); - ge_cached Ccached; - ge_p3_to_cached(&Ccached, &Cp3); - ge_p1p1 p1; - //create the matrix to mg sig - for (size_t i = 0; i < cols; i++) { - Pi[i] = pubs[i].dest; - ge_p3 p3; - CHECK_AND_ASSERT_MES_L1(ge_frombytes_vartime(&p3, pubs[i].mask.bytes) == 0, false, "point conv failed"); - ge_sub(&p1, &p3, &Ccached); - ge_p1p1_to_p3(&p3, &p1); - ge_p3_tobytes(Ci[i].bytes, &p3); + const size_t n = pubs.size(); + + // Check data + CHECK_AND_ASSERT_MES(n >= 1, false, "Empty pubs"); + CHECK_AND_ASSERT_MES(n == sig.s.size(), false, "Signature scalar vector is the wrong size!"); + for (size_t i = 0; i < n; ++i) + CHECK_AND_ASSERT_MES(sc_check(sig.s[i].bytes) == 0, false, "Bad signature scalar!"); + CHECK_AND_ASSERT_MES(sc_check(sig.c1.bytes) == 0, false, "Bad signature commitment!"); + CHECK_AND_ASSERT_MES(!(sig.I == rct::identity()), false, "Bad key image!"); + + // Cache commitment offset for efficient subtraction later + ge_p3 C_offset_p3; + CHECK_AND_ASSERT_MES(ge_frombytes_vartime(&C_offset_p3, C_offset.bytes) == 0, false, "point conv failed"); + ge_cached C_offset_cached; + ge_p3_to_cached(&C_offset_cached, &C_offset_p3); + + // Prepare key images + key c = copy(sig.c1); + key D_8 = scalarmult8(sig.D); + CHECK_AND_ASSERT_MES(!(D_8 == rct::identity()), false, "Bad auxiliary key image!"); + geDsmp I_precomp; + geDsmp D_precomp; + precomp(I_precomp.k,sig.I); + precomp(D_precomp.k,D_8); + + // Aggregation hashes + keyV mu_P_to_hash(2*n+4); // domain, I, D, P, C, C_offset + keyV mu_C_to_hash(2*n+4); // domain, I, D, P, C, C_offset + sc_0(mu_P_to_hash[0].bytes); + memcpy(mu_P_to_hash[0].bytes,config::HASH_KEY_CLSAG_AGG_0,sizeof(config::HASH_KEY_CLSAG_AGG_0)-1); + sc_0(mu_C_to_hash[0].bytes); + memcpy(mu_C_to_hash[0].bytes,config::HASH_KEY_CLSAG_AGG_1,sizeof(config::HASH_KEY_CLSAG_AGG_1)-1); + for (size_t i = 1; i < n+1; ++i) { + mu_P_to_hash[i] = pubs[i-1].dest; + mu_C_to_hash[i] = pubs[i-1].dest; + } + for (size_t i = n+1; i < 2*n+1; ++i) { + mu_P_to_hash[i] = pubs[i-n-1].mask; + mu_C_to_hash[i] = pubs[i-n-1].mask; + } + mu_P_to_hash[2*n+1] = sig.I; + mu_P_to_hash[2*n+2] = sig.D; + mu_P_to_hash[2*n+3] = C_offset; + mu_C_to_hash[2*n+1] = sig.I; + mu_C_to_hash[2*n+2] = sig.D; + mu_C_to_hash[2*n+3] = C_offset; + key mu_P, mu_C; + mu_P = hash_to_scalar(mu_P_to_hash); + mu_C = hash_to_scalar(mu_C_to_hash); + + // Set up round hash + keyV c_to_hash(2*n+5); // domain, P, C, C_offset, message, L, R + sc_0(c_to_hash[0].bytes); + memcpy(c_to_hash[0].bytes,config::HASH_KEY_CLSAG_ROUND,sizeof(config::HASH_KEY_CLSAG_ROUND)-1); + for (size_t i = 1; i < n+1; ++i) + { + c_to_hash[i] = pubs[i-1].dest; + c_to_hash[i+n] = pubs[i-1].mask; + } + c_to_hash[2*n+1] = C_offset; + c_to_hash[2*n+2] = message; + key c_p; // = c[i]*mu_P + key c_c; // = c[i]*mu_C + key c_new; + key L; + key R; + geDsmp P_precomp; + geDsmp C_precomp; + geDsmp H_precomp; + size_t i = 0; + ge_p3 hash8_p3; + geDsmp hash_precomp; + ge_p3 temp_p3; + ge_p1p1 temp_p1; + + while (i < n) { + sc_0(c_new.bytes); + sc_mul(c_p.bytes,mu_P.bytes,c.bytes); + sc_mul(c_c.bytes,mu_C.bytes,c.bytes); + + // Precompute points for L/R + precomp(P_precomp.k,pubs[i].dest); + + CHECK_AND_ASSERT_MES(ge_frombytes_vartime(&temp_p3, pubs[i].mask.bytes) == 0, false, "point conv failed"); + ge_sub(&temp_p1,&temp_p3,&C_offset_cached); + ge_p1p1_to_p3(&temp_p3,&temp_p1); + ge_dsm_precomp(C_precomp.k,&temp_p3); + + // Compute L + addKeys_aGbBcC(L,sig.s[i],c_p,P_precomp.k,c_c,C_precomp.k); + + // Compute R + hash_to_p3(hash8_p3,pubs[i].dest); + ge_dsm_precomp(hash_precomp.k, &hash8_p3); + addKeys_aAbBcC(R,sig.s[i],hash_precomp.k,c_p,I_precomp.k,c_c,D_precomp.k); + + c_to_hash[2*n+3] = L; + c_to_hash[2*n+4] = R; + c_new = hash_to_scalar(c_to_hash); + CHECK_AND_ASSERT_MES(!(c_new == rct::zero()), false, "Bad signature hash"); + copy(c,c_new); + + i = i + 1; } - return CLSAG_Ver(message, Pi, Ci, clsag); + sc_sub(c_new.bytes,c.bytes,sig.c1.bytes); + return sc_isnonzero(c_new.bytes) == 0; } catch (...) { return false; } } diff --git a/src/ringct/rctSigs.h b/src/ringct/rctSigs.h index ed82f6bc5..199ad9aef 100644 --- a/src/ringct/rctSigs.h +++ b/src/ringct/rctSigs.h @@ -77,9 +77,10 @@ namespace rct { mgSig MLSAG_Gen(const key &message, const keyM & pk, const keyV & xx, const multisig_kLRki *kLRki, key *mscout, const unsigned int index, size_t dsRows, hw::device &hwdev); bool MLSAG_Ver(const key &message, const keyM &pk, const mgSig &sig, size_t dsRows); - clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const unsigned int l, const multisig_kLRki *kLRki, key *mscout, key *mspout); - clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const key & z, const unsigned int l); - bool CLSAG_Ver(const key &message, const keyV & P, const keyV & C, const clsag & sig); + clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const keyV & C_nonzero, const key & C_offset, const key & z, const unsigned int l, const multisig_kLRki *kLRki, key *mscout, key *mspout); + clsag CLSAG_Gen(const key &message, const keyV & P, const key & p, const keyV & C, const keyV & C_nonzero, const key & C_offset, const key & z, const unsigned int l); + clsag proveRctCLSAGSimple(const key &, const ctkeyV &, const ctkey &, const key &, const key &, const multisig_kLRki *, key *, key *, unsigned int, hw::device &); + bool verRctCLSAGSimple(const key &, const clsag &, const ctkeyV &, const key &); //proveRange and verRange //proveRange gives C, and mask such that \sumCi = C -- cgit v1.2.3