aboutsummaryrefslogtreecommitdiff
path: root/src/ringct/rctSigs.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'src/ringct/rctSigs.cpp')
-rw-r--r--src/ringct/rctSigs.cpp163
1 files changed, 77 insertions, 86 deletions
diff --git a/src/ringct/rctSigs.cpp b/src/ringct/rctSigs.cpp
index b773be1e5..b7efe3ae7 100644
--- a/src/ringct/rctSigs.cpp
+++ b/src/ringct/rctSigs.cpp
@@ -40,94 +40,66 @@ using namespace crypto;
using namespace std;
namespace rct {
- //Schnorr Non-linkable
- //Gen Gives a signature (L1, s1, s2) proving that the sender knows "x" such that xG = one of P1 or P2
- //Ver Verifies that signer knows an "x" such that xG = one of P1 or P2
- //These are called in the below ASNL sig generation
-
- void GenSchnorrNonLinkable(key & L1, key & s1, key & s2, const key & x, const key & P1, const key & P2, unsigned int index) {
- key c1, c2, L2;
- key a = skGen();
- if (index == 0) {
- scalarmultBase(L1, a);
- hash_to_scalar(c2, L1);
- skGen(s2);
- addKeys2(L2, s2, c2, P2);
- hash_to_scalar(c1, L2);
- //s1 = a - x * c1
- sc_mulsub(s1.bytes, x.bytes, c1.bytes, a.bytes);
- }
- else if (index == 1) {
- scalarmultBase(L2, a);
- hash_to_scalar(c1, L2);
- skGen(s1);
- addKeys2(L1, s1, c1, P1);
- hash_to_scalar(c2, L1);
- sc_mulsub(s2.bytes, x.bytes, c2.bytes, a.bytes);
- }
- else {
- throw std::runtime_error("GenSchnorrNonLinkable: invalid index (should be 0 or 1)");
+ namespace {
+ struct verRangeWrapper_ {
+ void operator()(const key & C, const rangeSig & as, bool &result) const {
+ result = verRange(C, as);
}
- }
+ };
+ constexpr const verRangeWrapper_ verRangeWrapper{};
- //Schnorr Non-linkable
- //Gen Gives a signature (L1, s1, s2) proving that the sender knows "x" such that xG = one of P1 or P2
- //Ver Verifies that signer knows an "x" such that xG = one of P1 or P2
- //These are called in the below ASNL sig generation
- bool VerSchnorrNonLinkable(const key & P1, const key & P2, const key & L1, const key & s1, const key & s2) {
- key c2, L2, c1, L1p;
- hash_to_scalar(c2, L1);
- addKeys2(L2, s2, c2, P2);
- hash_to_scalar(c1, L2);
- addKeys2(L1p, s1, c1, P1);
-
- return equalKeys(L1, L1p);
+ struct verRctMGSimpleWrapper_ {
+ void operator()(const key &message, const mgSig &mg, const ctkeyV & pubs, const key & C, bool &result) const {
+ result = verRctMGSimple(message, mg, pubs, C);
+ }
+ };
+ constexpr const verRctMGSimpleWrapper_ verRctMGSimpleWrapper{};
}
- //Aggregate Schnorr Non-linkable Ring Signature (ASNL)
- // c.f. http://eprint.iacr.org/2015/1098 section 5.
- // These are used in range proofs (alternatively Borromean could be used)
- // Gen gives a signature which proves the signer knows, for each i,
- // an x[i] such that x[i]G = one of P1[i] or P2[i]
- // Ver Verifies the signer knows a key for one of P1[i], P2[i] at each i
- asnlSig GenASNL(key64 x, key64 P1, key64 P2, bits indices) {
- DP("Generating Aggregate Schnorr Non-linkable Ring Signature\n");
- key64 s1;
- int j = 0;
- asnlSig rv;
- rv.s = zero();
- for (j = 0; j < ATOMS; j++) {
- GenSchnorrNonLinkable(rv.L1[j], s1[j], rv.s2[j], x[j], P1[j], P2[j], indices[j]);
- sc_add(rv.s.bytes, rv.s.bytes, s1[j].bytes);
+ //Borromean (c.f. gmax/andytoshi's paper)
+ boroSig genBorromean(const key64 x, const key64 P1, const key64 P2, const bits indices) {
+ key64 L[2], alpha;
+ key c;
+ int naught = 0, prime = 0, ii = 0, jj=0;
+ boroSig bb;
+ for (ii = 0 ; ii < 64 ; ii++) {
+ naught = indices[ii]; prime = (indices[ii] + 1) % 2;
+ skGen(alpha[ii]);
+ scalarmultBase(L[naught][ii], alpha[ii]);
+ if (naught == 0) {
+ skGen(bb.s1[ii]);
+ c = hash_to_scalar(L[naught][ii]);
+ addKeys2(L[prime][ii], bb.s1[ii], c, P2[ii]);
+ }
}
- return rv;
- }
-
- //Aggregate Schnorr Non-linkable Ring Signature (ASNL)
- // c.f. http://eprint.iacr.org/2015/1098 section 5.
- // These are used in range proofs (alternatively Borromean could be used)
- // Gen gives a signature which proves the signer knows, for each i,
- // an x[i] such that x[i]G = one of P1[i] or P2[i]
- // Ver Verifies the signer knows a key for one of P1[i], P2[i] at each i
- bool VerASNL(const key64 P1, const key64 P2, const asnlSig &as) {
- PERF_TIMER(VerASNL);
- DP("Verifying Aggregate Schnorr Non-linkable Ring Signature\n");
- key LHS = identity();
- key RHS = scalarmultBase(as.s);
- key c2, L2, c1;
- int j = 0;
- for (j = 0; j < ATOMS; j++) {
- hash_to_scalar(c2, as.L1[j]);
- addKeys2(L2, as.s2[j], c2, P2[j]);
- addKeys(LHS, LHS, as.L1[j]);
- hash_to_scalar(c1, L2);
- addKeys(RHS, RHS, scalarmultKey(P1[j], c1));
- }
- key cc;
- sc_sub(cc.bytes, LHS.bytes, RHS.bytes);
- return sc_isnonzero(cc.bytes) == 0;
+ bb.ee = hash_to_scalar(L[1]); //or L[1]..
+ key LL, cc;
+ for (jj = 0 ; jj < 64 ; jj++) {
+ if (!indices[jj]) {
+ sc_mulsub(bb.s0[jj].bytes, x[jj].bytes, bb.ee.bytes, alpha[jj].bytes);
+ } else {
+ skGen(bb.s0[jj]);
+ addKeys2(LL, bb.s0[jj], bb.ee, P1[jj]); //different L0
+ cc = hash_to_scalar(LL);
+ sc_mulsub(bb.s1[jj].bytes, x[jj].bytes, cc.bytes, alpha[jj].bytes);
+ }
+ }
+ return bb;
}
+ //see above.
+ bool verifyBorromean(const boroSig &bb, const key64 P1, const key64 P2) {
+ key64 Lv1; key chash, LL;
+ int ii = 0;
+ for (ii = 0 ; ii < 64 ; ii++) {
+ addKeys2(LL, bb.s0[ii], bb.ee, P1[ii]);
+ chash = hash_to_scalar(LL);
+ addKeys2(Lv1[ii], bb.s1[ii], chash, P2[ii]);
+ }
+ key eeComputed = hash_to_scalar(Lv1); //hash function fine
+ return equalKeys(eeComputed, bb.ee);
+ }
+
//Multilayered Spontaneous Anonymous Group Signatures (MLSAG signatures)
//These are aka MG signatutes in earlier drafts of the ring ct paper
// c.f. http://eprint.iacr.org/2015/1098 section 2.
@@ -259,6 +231,11 @@ namespace rct {
}
CHECK_AND_ASSERT_MES(dsRows <= rows, false, "Bad dsRows value");
+ for (size_t i = 0; i < rv.ss.size(); ++i)
+ for (size_t j = 0; j < rv.ss[i].size(); ++j)
+ CHECK_AND_ASSERT_MES(sc_check(rv.ss[i][j].bytes) == 0, false, "Bad ss slot");
+ CHECK_AND_ASSERT_MES(sc_check(rv.cc.bytes) == 0, false, "Bad cc");
+
size_t i = 0, j = 0, ii = 0;
key c, L, R, Hi;
key c_old = copy(rv.cc);
@@ -323,7 +300,7 @@ namespace rct {
sc_add(mask.bytes, mask.bytes, ai[i].bytes);
addKeys(C, C, sig.Ci[i]);
}
- sig.asig = GenASNL(ai, sig.Ci, CiH, b);
+ sig.asig = genBorromean(ai, sig.Ci, CiH, b);
return sig;
}
@@ -335,6 +312,8 @@ namespace rct {
// mask is a such that C = aG + bH, and b = amount
//verRange verifies that \sum Ci = C and that each Ci is a commitment to 0 or 2^i
bool verRange(const key & C, const rangeSig & as) {
+ try
+ {
PERF_TIMER(verRange);
key64 CiH;
int i = 0;
@@ -345,9 +324,12 @@ namespace rct {
}
if (!equalKeys(C, Ctmp))
return false;
- if (!VerASNL(as.Ci, CiH, as.asig))
+ if (!verifyBorromean(as.asig, as.Ci, CiH))
return false;
return true;
+ }
+ // we can get deep throws from ge_frombytes_vartime if input isn't valid
+ catch (...) { return false; }
}
key get_pre_mlsag_hash(const rctSig &rv)
@@ -371,10 +353,10 @@ namespace rct {
for (auto r: rv.p.rangeSigs)
{
for (size_t n = 0; n < 64; ++n)
- kv.push_back(r.asig.L1[n]);
+ kv.push_back(r.asig.s0[n]);
for (size_t n = 0; n < 64; ++n)
- kv.push_back(r.asig.s2[n]);
- kv.push_back(r.asig.s);
+ kv.push_back(r.asig.s1[n]);
+ kv.push_back(r.asig.ee);
for (size_t n = 0; n < 64; ++n)
kv.push_back(r.Ci[n]);
}
@@ -513,6 +495,8 @@ namespace rct {
//This does a simplified version, assuming only post Rct
//inputs
bool verRctMGSimple(const key &message, const mgSig &mg, const ctkeyV & pubs, const key & C) {
+ try
+ {
PERF_TIMER(verRctMGSimple);
//setup vars
size_t rows = 1;
@@ -528,6 +512,8 @@ namespace rct {
}
//DP(C);
return MLSAG_Ver(message, M, mg, rows);
+ }
+ catch (...) { return false; }
}
@@ -790,6 +776,8 @@ namespace rct {
//ver RingCT simple
//assumes only post-rct style inputs (at least for max anonymity)
bool verRctSimple(const rctSig & rv) {
+ try
+ {
PERF_TIMER(verRctSimple);
CHECK_AND_ASSERT_MES(rv.type == RCTTypeSimple, false, "verRctSimple called on non simple rctSig");
@@ -860,6 +848,9 @@ namespace rct {
}
return true;
+ }
+ // we can get deep throws from ge_frombytes_vartime if input isn't valid
+ catch (...) { return false; }
}
//RingCT protocol
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-03 03:09:14 +0000