Split headers/code

ecdsa.cpp

@@ -0,0 +1,82 @@
+#include "num.h"
+#include "field.h"
+#include "group.h"
+#include "ecmult.h"
+#include "ecdsa.h"
+
+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();
+}
+
+bool Signature::Parse(const unsigned char *sig, int size) {
+    if (sig[0] != 0x30) return false;
+    int lenr = sig[3];
+    if (5+lenr >= size) return false;
+    int lens = sig[lenr+5];
+    if (sig[1] != lenr+lens+4) return false;
+    if (lenr+lens+6 > size) return false;
+    if (sig[2] != 0x02) return false;
+    if (lenr == 0) return false;
+    if (sig[lenr+4] != 0x02) return false;
+    if (lens == 0) return false;
+    r.SetBytes(sig+4, lenr);
+    s.SetBytes(sig+6+lenr, lens);
+    return true;
+}
+
+bool Signature::RecomputeR(Number &r2, 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;
+
+    Number sn, u1, u2;
+    sn.SetModInverse(s, c.order);
+    u1.SetModMul(sn, message, c.order);
+    u2.SetModMul(sn, r, c.order);
+    GroupElemJac pr; ECMult(pr, pubkey, u2, u1);
+    if (pr.IsInfinity())
+        return false;
+    FieldElem xr; pr.GetX(xr);
+    unsigned char xrb[32]; xr.GetBytes(xrb);
+    r2.SetBytes(xrb,32); r2.SetMod(r2,c.order);
+    return true;
+}
+
+bool Signature::Verify(const GroupElemJac &pubkey, const Number &message) {
+    Number r2;
+    if (!RecomputeR(r2, pubkey, message))
+        return false;
+    return r2.Compare(r) == 0;
+}
+
+void Signature::SetRS(const Number &rin, const Number &sin) {
+    r = rin;
+    s = sin;
+}
+
+std::string Signature::ToString() const {
+    return "(" + r.ToString() + "," + s.ToString() + ")";
+}
+
+}