diff options
Diffstat (limited to 'src/ringct/rctOps.cpp')
| -rw-r--r-- | src/ringct/rctOps.cpp | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/src/ringct/rctOps.cpp b/src/ringct/rctOps.cpp index 50693bad7..6c3c4500e 100644 --- a/src/ringct/rctOps.cpp +++ b/src/ringct/rctOps.cpp @@ -60,6 +60,17 @@ namespace rct { //Various key generation functions + bool toPointCheckOrder(ge_p3 *P, const unsigned char *data) + { + if (ge_frombytes_vartime(P, data)) + return false; + ge_p2 R; + ge_scalarmult(&R, curveOrder().bytes, P); + key tmp; + ge_tobytes(tmp.bytes, &R); + return tmp == identity(); + } + //generates a random scalar which can be used as a secret key or mask void skGen(key &sk) { random32_unbiased(sk.bytes); @@ -193,15 +204,33 @@ namespace rct { //Computes aH where H= toPoint(cn_fast_hash(G)), G the basepoint key scalarmultH(const key & a) { - ge_p3 A; ge_p2 R; - CHECK_AND_ASSERT_THROW_MES_L1(ge_frombytes_vartime(&A, H.bytes) == 0, "ge_frombytes_vartime failed at "+boost::lexical_cast<std::string>(__LINE__)); - ge_scalarmult(&R, a.bytes, &A); + ge_scalarmult(&R, a.bytes, &ge_p3_H); key aP; ge_tobytes(aP.bytes, &R); return aP; } + //Computes 8P + key scalarmult8(const key & P) { + ge_p3 p3; + CHECK_AND_ASSERT_THROW_MES_L1(ge_frombytes_vartime(&p3, P.bytes) == 0, "ge_frombytes_vartime failed at "+boost::lexical_cast<std::string>(__LINE__)); + ge_p2 p2; + ge_p3_to_p2(&p2, &p3); + ge_p1p1 p1; + ge_mul8(&p1, &p2); + ge_p1p1_to_p2(&p2, &p1); + rct::key res; + ge_tobytes(res.bytes, &p2); + return res; + } + + //Computes aL where L is the curve order + bool isInMainSubgroup(const key & a) { + ge_p3 p3; + return toPointCheckOrder(&p3, a.bytes); + } + //Curve addition / subtractions //for curve points: AB = A + B |