#ifndef _SECP256K1_ECDSA_ #define _SECP256K1_ECDSA_ namespace secp256k1 { bool ParsePubkey(GroupElemJac &elem, const unsigned char *pub, int size) { if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) { FieldElem x; x.SetBytes(pub+1); elem.SetCompressed(x, pub[0] == 0x03); } else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) { FieldElem x,y; x.SetBytes(pub+1); y.SetBytes(pub+33); elem = GroupElem(x,y); if ((pub[0] == 0x06 || pub[0] == 0x07) && y.IsOdd() != (pub[0] == 0x07)) return false; } else { return false; } return elem.IsValid(); } class Signature { private: Number r,s; public: bool Verify(Context &ctx, const GroupElemJac &pubkey, const Number &message) { const GroupConstants &c = GetGroupConst(); if (r.IsNeg() || s.IsNeg()) return false; if (r.IsZero() || s.IsZero()) return false; if (r.Compare(c.order) >= 0 || s.Compare(c.order) >= 0) return false; Context ct(ctx); Number sn(ct); sn.SetModInverse(ct, s, c.order); Number u1(ct); u1.SetModMul(ct, sn, message, c.order); Number u2(ct); u2.SetModMul(ct, sn, r, c.order); GroupElemJac pr; ECMult(ct, pr, pubkey, u2, u1); if (pr.IsInfinity()) return false; FieldElem xr; pr.GetX(xr); unsigned char xrb[32]; xr.GetBytes(xrb); Number xrn(ct); xrn.SetBytes(xrb,32); xrn.SetMod(ct,xrn,c.order); return xrn.Compare(r) == 0; } }; } #endif