diff options
Diffstat (limited to 'src/ringct/rctSigs.cpp')
-rw-r--r-- | src/ringct/rctSigs.cpp | 421 |
1 files changed, 404 insertions, 17 deletions
diff --git a/src/ringct/rctSigs.cpp b/src/ringct/rctSigs.cpp index 2e3e7007e..5fd7ac06d 100644 --- a/src/ringct/rctSigs.cpp +++ b/src/ringct/rctSigs.cpp @@ -36,6 +36,7 @@ #include "rctSigs.h" #include "bulletproofs.h" #include "cryptonote_basic/cryptonote_format_utils.h" +#include "cryptonote_config.h" using namespace crypto; using namespace std; @@ -165,6 +166,167 @@ namespace rct { return verifyBorromean(bb, P1_p3, P2_p3); } + // Generate a CLSAG signature + // See paper by Goodell et al. (https://eprint.iacr.org/2019/654) + // + // 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, hw::device &hwdev) { + 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((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"); + + // Key images + ge_p3 H_p3; + hash_to_p3(H_p3,P[l]); + key H; + ge_p3_tobytes(H.bytes,&H_p3); + + key D; + + // Initial values + key a; + key aG; + key aH; + + // Multisig + if (kLRki) + { + sig.I = kLRki->ki; + scalarmultKey(D,H,z); + } + else + { + hwdev.clsag_prepare(p,z,sig.I,D,H,a,aG,aH); + } + + geDsmp I_precomp; + geDsmp D_precomp; + precomp(I_precomp.k,sig.I); + precomp(D_precomp.k,D); + + // Offset key image + scalarmultKey(sig.D,D,INV_EIGHT); + + // 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] = 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_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+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_nonzero[i-1]; + } + 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+3] = kLRki->L; + c_to_hash[2*n+4] = kLRki->R; + } + else + { + c_to_hash[2*n+3] = aG; + c_to_hash[2*n+4] = aH; + } + hwdev.clsag_hash(c_to_hash,c); + + size_t i; + i = (l + 1) % n; + if (i == 0) + copy(sig.c1, c); + + // Decoy indices + sig.s = keyV(n); + key c_new; + key L; + key R; + key c_p; // = c[i]*mu_P + key c_c; // = c[i]*mu_C + geDsmp P_precomp; + geDsmp C_precomp; + geDsmp H_precomp; + ge_p3 Hi_p3; + + while (i != l) { + sig.s[i] = skGen(); + 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(Hi_p3,P[i]); + 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+3] = L; + c_to_hash[2*n+4] = R; + hwdev.clsag_hash(c_to_hash,c_new); + copy(c,c_new); + + i = (i + 1) % n; + if (i == 0) + copy(sig.c1,c); + } + + // Compute final scalar + hwdev.clsag_sign(c,a,p,z,mu_P,mu_C,sig.s[l]); + memwipe(&a, sizeof(key)); + + if (mscout) + *mscout = c; + if (mspout) + *mspout = mu_P; + + return sig; + } + + 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, hw::get_device("default")); + } + // MLSAG signatures // See paper by Noether (https://eprint.iacr.org/2015/1098) // This generalization allows for some dimensions not to require linkability; @@ -427,7 +589,7 @@ namespace rct { hashes.push_back(hash2rct(h)); keyV kv; - if (rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2) + if (rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG) { kv.reserve((6*2+9) * rv.p.bulletproofs.size()); for (const auto &p: rv.p.bulletproofs) @@ -555,6 +717,37 @@ namespace rct { return result; } + clsag proveRctCLSAGSimple(const key &message, const ctkeyV &pubs, const ctkey &inSk, const key &a, const key &Cout, const multisig_kLRki *kLRki, key *mscout, key *mspout, unsigned int index, hw::device &hwdev) { + //setup vars + size_t rows = 1; + size_t cols = pubs.size(); + CHECK_AND_ASSERT_THROW_MES(cols >= 1, "Empty pubs"); + CHECK_AND_ASSERT_THROW_MES((kLRki && mscout) || (!kLRki && !mscout), "Only one of kLRki/mscout is present"); + keyV tmp(rows + 1); + keyV sk(rows + 1); + size_t i; + keyM M(cols, tmp); + + 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); + } + + 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], C_nonzero, Cout, index, kLRki, mscout, mspout, hwdev); + memwipe(sk.data(), sk.size() * sizeof(key)); + return result; + } + //Ring-ct MG sigs //Prove: @@ -634,6 +827,120 @@ namespace rct { catch (...) { return false; } } + bool verRctCLSAGSimple(const key &message, const clsag &sig, const ctkeyV & pubs, const key & C_offset) { + try + { + PERF_TIMER(verRctCLSAGSimple); + 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; + } + sc_sub(c_new.bytes,c.bytes,sig.c1.bytes); + return sc_isnonzero(c_new.bytes) == 0; + } + catch (...) { return false; } + } + //These functions get keys from blockchain //replace these when connecting blockchain @@ -726,7 +1033,7 @@ namespace rct { //mask amount and mask rv.ecdhInfo[i].mask = copy(outSk[i].mask); rv.ecdhInfo[i].amount = d2h(amounts[i]); - hwdev.ecdhEncode(rv.ecdhInfo[i], amount_keys[i], rv.type == RCTTypeBulletproof2); + hwdev.ecdhEncode(rv.ecdhInfo[i], amount_keys[i], rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG); } //set txn fee @@ -774,7 +1081,27 @@ namespace rct { } rctSig rv; - rv.type = bulletproof ? (rct_config.bp_version == 0 || rct_config.bp_version >= 2 ? RCTTypeBulletproof2 : RCTTypeBulletproof) : RCTTypeSimple; + if (bulletproof) + { + switch (rct_config.bp_version) + { + case 0: + case 3: + rv.type = RCTTypeCLSAG; + break; + case 2: + rv.type = RCTTypeBulletproof2; + break; + case 1: + rv.type = RCTTypeBulletproof; + break; + default: + ASSERT_MES_AND_THROW("Unsupported BP version: " << rct_config.bp_version); + } + } + else + rv.type = RCTTypeSimple; + rv.message = message; rv.outPk.resize(destinations.size()); if (!bulletproof) @@ -864,7 +1191,7 @@ namespace rct { //mask amount and mask rv.ecdhInfo[i].mask = copy(outSk[i].mask); rv.ecdhInfo[i].amount = d2h(outamounts[i]); - hwdev.ecdhEncode(rv.ecdhInfo[i], amount_keys[i], rv.type == RCTTypeBulletproof2); + hwdev.ecdhEncode(rv.ecdhInfo[i], amount_keys[i], rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG); } //set txn fee @@ -874,7 +1201,10 @@ namespace rct { rv.mixRing = mixRing; keyV &pseudoOuts = bulletproof ? rv.p.pseudoOuts : rv.pseudoOuts; pseudoOuts.resize(inamounts.size()); - rv.p.MGs.resize(inamounts.size()); + if (rv.type == RCTTypeCLSAG) + rv.p.CLSAGs.resize(inamounts.size()); + else + rv.p.MGs.resize(inamounts.size()); key sumpouts = zero(); //sum pseudoOut masks keyV a(inamounts.size()); for (i = 0 ; i < inamounts.size() - 1; i++) { @@ -888,9 +1218,20 @@ namespace rct { key full_message = get_pre_mlsag_hash(rv,hwdev); if (msout) - msout->c.resize(inamounts.size()); - for (i = 0 ; i < inamounts.size(); i++) { - rv.p.MGs[i] = proveRctMGSimple(full_message, rv.mixRing[i], inSk[i], a[i], pseudoOuts[i], kLRki ? &(*kLRki)[i]: NULL, msout ? &msout->c[i] : NULL, index[i], hwdev); + { + msout->c.resize(inamounts.size()); + msout->mu_p.resize(rv.type == RCTTypeCLSAG ? inamounts.size() : 0); + } + for (i = 0 ; i < inamounts.size(); i++) + { + if (rv.type == RCTTypeCLSAG) + { + rv.p.CLSAGs[i] = proveRctCLSAGSimple(full_message, rv.mixRing[i], inSk[i], a[i], pseudoOuts[i], kLRki ? &(*kLRki)[i]: NULL, msout ? &msout->c[i] : NULL, msout ? &msout->mu_p[i] : NULL, index[i], hwdev); + } + else + { + rv.p.MGs[i] = proveRctMGSimple(full_message, rv.mixRing[i], inSk[i], a[i], pseudoOuts[i], kLRki ? &(*kLRki)[i]: NULL, msout ? &msout->c[i] : NULL, index[i], hwdev); + } } return rv; } @@ -995,13 +1336,22 @@ namespace rct { { CHECK_AND_ASSERT_MES(rvp, false, "rctSig pointer is NULL"); const rctSig &rv = *rvp; - CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2, + CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG, false, "verRctSemanticsSimple called on non simple rctSig"); const bool bulletproof = is_rct_bulletproof(rv.type); if (bulletproof) { CHECK_AND_ASSERT_MES(rv.outPk.size() == n_bulletproof_amounts(rv.p.bulletproofs), false, "Mismatched sizes of outPk and bulletproofs"); - CHECK_AND_ASSERT_MES(rv.p.pseudoOuts.size() == rv.p.MGs.size(), false, "Mismatched sizes of rv.p.pseudoOuts and rv.p.MGs"); + if (rv.type == RCTTypeCLSAG) + { + CHECK_AND_ASSERT_MES(rv.p.MGs.empty(), false, "MGs are not empty for CLSAG"); + CHECK_AND_ASSERT_MES(rv.p.pseudoOuts.size() == rv.p.CLSAGs.size(), false, "Mismatched sizes of rv.p.pseudoOuts and rv.p.CLSAGs"); + } + else + { + CHECK_AND_ASSERT_MES(rv.p.CLSAGs.empty(), false, "CLSAGs are not empty for MLSAG"); + CHECK_AND_ASSERT_MES(rv.p.pseudoOuts.size() == rv.p.MGs.size(), false, "Mismatched sizes of rv.p.pseudoOuts and rv.p.MGs"); + } CHECK_AND_ASSERT_MES(rv.pseudoOuts.empty(), false, "rv.pseudoOuts is not empty"); } else @@ -1095,7 +1445,7 @@ namespace rct { { PERF_TIMER(verRctNonSemanticsSimple); - CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2, + CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG, false, "verRctNonSemanticsSimple called on non simple rctSig"); const bool bulletproof = is_rct_bulletproof(rv.type); // semantics check is early, and mixRing/MGs aren't resolved yet @@ -1118,14 +1468,19 @@ namespace rct { results.resize(rv.mixRing.size()); for (size_t i = 0 ; i < rv.mixRing.size() ; i++) { tpool.submit(&waiter, [&, i] { - results[i] = verRctMGSimple(message, rv.p.MGs[i], rv.mixRing[i], pseudoOuts[i]); + if (rv.type == RCTTypeCLSAG) + { + results[i] = verRctCLSAGSimple(message, rv.p.CLSAGs[i], rv.mixRing[i], pseudoOuts[i]); + } + else + results[i] = verRctMGSimple(message, rv.p.MGs[i], rv.mixRing[i], pseudoOuts[i]); }); } waiter.wait(&tpool); for (size_t i = 0; i < results.size(); ++i) { if (!results[i]) { - LOG_PRINT_L1("verRctMGSimple failed for input " << i); + LOG_PRINT_L1("verRctMGSimple/verRctCLSAGSimple failed for input " << i); return false; } } @@ -1162,7 +1517,7 @@ namespace rct { //mask amount and mask ecdhTuple ecdh_info = rv.ecdhInfo[i]; - hwdev.ecdhDecode(ecdh_info, sk, rv.type == RCTTypeBulletproof2); + hwdev.ecdhDecode(ecdh_info, sk, rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG); mask = ecdh_info.mask; key amount = ecdh_info.amount; key C = rv.outPk[i].mask; @@ -1186,13 +1541,13 @@ namespace rct { } xmr_amount decodeRctSimple(const rctSig & rv, const key & sk, unsigned int i, key &mask, hw::device &hwdev) { - CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2, false, "decodeRct called on non simple rctSig"); + CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG, false, "decodeRct called on non simple rctSig"); CHECK_AND_ASSERT_THROW_MES(i < rv.ecdhInfo.size(), "Bad index"); CHECK_AND_ASSERT_THROW_MES(rv.outPk.size() == rv.ecdhInfo.size(), "Mismatched sizes of rv.outPk and rv.ecdhInfo"); //mask amount and mask ecdhTuple ecdh_info = rv.ecdhInfo[i]; - hwdev.ecdhDecode(ecdh_info, sk, rv.type == RCTTypeBulletproof2); + hwdev.ecdhDecode(ecdh_info, sk, rv.type == RCTTypeBulletproof2 || rv.type == RCTTypeCLSAG); mask = ecdh_info.mask; key amount = ecdh_info.amount; key C = rv.outPk[i].mask; @@ -1215,12 +1570,13 @@ namespace rct { return decodeRctSimple(rv, sk, i, mask, hwdev); } - bool signMultisig(rctSig &rv, const std::vector<unsigned int> &indices, const keyV &k, const multisig_out &msout, const key &secret_key) { + bool signMultisigMLSAG(rctSig &rv, const std::vector<unsigned int> &indices, const keyV &k, const multisig_out &msout, const key &secret_key) { CHECK_AND_ASSERT_MES(rv.type == RCTTypeFull || rv.type == RCTTypeSimple || rv.type == RCTTypeBulletproof || rv.type == RCTTypeBulletproof2, false, "unsupported rct type"); CHECK_AND_ASSERT_MES(indices.size() == k.size(), false, "Mismatched k/indices sizes"); CHECK_AND_ASSERT_MES(k.size() == rv.p.MGs.size(), false, "Mismatched k/MGs size"); CHECK_AND_ASSERT_MES(k.size() == msout.c.size(), false, "Mismatched k/msout.c size"); + CHECK_AND_ASSERT_MES(rv.p.CLSAGs.empty(), false, "CLSAGs not empty for MLSAGs"); if (rv.type == RCTTypeFull) { CHECK_AND_ASSERT_MES(rv.p.MGs.size() == 1, false, "MGs not a single element"); @@ -1230,6 +1586,8 @@ namespace rct { CHECK_AND_ASSERT_MES(!rv.p.MGs[n].ss[indices[n]].empty(), false, "empty ss line"); } + // MLSAG: each player contributes a share to the secret-index ss: k - cc*secret_key_share + // cc: msout.c[n], secret_key_share: secret_key for (size_t n = 0; n < indices.size(); ++n) { rct::key diff; sc_mulsub(diff.bytes, msout.c[n].bytes, secret_key.bytes, k[n].bytes); @@ -1237,4 +1595,33 @@ namespace rct { } return true; } + + bool signMultisigCLSAG(rctSig &rv, const std::vector<unsigned int> &indices, const keyV &k, const multisig_out &msout, const key &secret_key) { + CHECK_AND_ASSERT_MES(rv.type == RCTTypeCLSAG, false, "unsupported rct type"); + CHECK_AND_ASSERT_MES(indices.size() == k.size(), false, "Mismatched k/indices sizes"); + CHECK_AND_ASSERT_MES(k.size() == rv.p.CLSAGs.size(), false, "Mismatched k/CLSAGs size"); + CHECK_AND_ASSERT_MES(k.size() == msout.c.size(), false, "Mismatched k/msout.c size"); + CHECK_AND_ASSERT_MES(rv.p.MGs.empty(), false, "MGs not empty for CLSAGs"); + CHECK_AND_ASSERT_MES(msout.c.size() == msout.mu_p.size(), false, "Bad mu_p size"); + for (size_t n = 0; n < indices.size(); ++n) { + CHECK_AND_ASSERT_MES(indices[n] < rv.p.CLSAGs[n].s.size(), false, "Index out of range"); + } + + // CLSAG: each player contributes a share to the secret-index ss: k - cc*mu_p*secret_key_share + // cc: msout.c[n], mu_p, msout.mu_p[n], secret_key_share: secret_key + for (size_t n = 0; n < indices.size(); ++n) { + rct::key diff, sk; + sc_mul(sk.bytes, msout.mu_p[n].bytes, secret_key.bytes); + sc_mulsub(diff.bytes, msout.c[n].bytes, sk.bytes, k[n].bytes); + sc_add(rv.p.CLSAGs[n].s[indices[n]].bytes, rv.p.CLSAGs[n].s[indices[n]].bytes, diff.bytes); + } + return true; + } + + bool signMultisig(rctSig &rv, const std::vector<unsigned int> &indices, const keyV &k, const multisig_out &msout, const key &secret_key) { + if (rv.type == RCTTypeCLSAG) + return signMultisigCLSAG(rv, indices, k, msout, secret_key); + else + return signMultisigMLSAG(rv, indices, k, msout, secret_key); + } } |