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-rw-r--r--src/ringct/rctSigs.cpp264
-rw-r--r--src/ringct/rctSigs.h7
2 files changed, 139 insertions, 132 deletions
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
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