From d312d472988a87761a6c852d51c411fff1b760ea Mon Sep 17 00:00:00 2001
From: Jimmy Song <jaejoon@gmail.com>
Date: Sat, 27 Sep 2014 13:33:45 -0500
Subject: [PATCH] RecoverCompact and SignCompact now use the btcec.PrivateKey
 and btcec.PublicKey types.

btcwallet/rpcserver.go needs a corresponding change or else that will break.

This closes #6
---
 signature.go      | 12 +++++-------
 signature_test.go |  3 ++-
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/signature.go b/signature.go
index 2c0e17af..9bd9fa6a 100644
--- a/signature.go
+++ b/signature.go
@@ -7,7 +7,6 @@ package btcec
 import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
-	"crypto/rand"
 	"errors"
 	"fmt"
 	"math/big"
@@ -263,7 +262,7 @@ func hashToInt(hash []byte, c elliptic.Curve) *big.Int {
 // case in step 1.6. This counter is used in the bitcoin compressed signature
 // format and thus we match bitcoind's behaviour here.
 func recoverKeyFromSignature(curve *KoblitzCurve, sig *Signature, msg []byte,
-	iter int, doChecks bool) (*ecdsa.PublicKey, error) {
+	iter int, doChecks bool) (*PublicKey, error) {
 	// 1.1 x = (n * i) + r
 	Rx := new(big.Int).Mul(curve.Params().N,
 		new(big.Int).SetInt64(int64(iter/2)))
@@ -314,7 +313,7 @@ func recoverKeyFromSignature(curve *KoblitzCurve, sig *Signature, msg []byte,
 	// step to prevent the jacobian conversion back and forth.
 	Qx, Qy := curve.Add(sRx, sRy, minuseGx, minuseGy)
 
-	return &ecdsa.PublicKey{
+	return &PublicKey{
 		Curve: curve,
 		X:     Qx,
 		Y:     Qy,
@@ -328,14 +327,13 @@ func recoverKeyFromSignature(curve *KoblitzCurve, sig *Signature, msg []byte,
 // returned in the format:
 // <(byte of 27+public key solution)+4 if compressed >< padded bytes for signature R><padded bytes for signature S>
 // where the R and S parameters are padde up to the bitlengh of the curve.
-func SignCompact(curve *KoblitzCurve, key *ecdsa.PrivateKey,
+func SignCompact(curve *KoblitzCurve, key *PrivateKey,
 	hash []byte, isCompressedKey bool) ([]byte, error) {
-	r, s, err := ecdsa.Sign(rand.Reader, key, hash)
+	sig, err := key.Sign(hash)
 	if err != nil {
 		return nil, err
 	}
 
-	sig := &Signature{R: r, S: s}
 	// bitcoind checks the bit length of R and S here. The ecdsa signature
 	// algorithm returns R and S mod N therefore they will be the bitsize of
 	// the curve, and thus correctly sized.
@@ -377,7 +375,7 @@ func SignCompact(curve *KoblitzCurve, key *ecdsa.PrivateKey,
 // key will be returned as well as a boolen if the original key was compressed
 // or not, else an error will be returned.
 func RecoverCompact(curve *KoblitzCurve, signature,
-	hash []byte) (*ecdsa.PublicKey, bool, error) {
+	hash []byte) (*PublicKey, bool, error) {
 	bitlen := (curve.BitSize + 7) / 8
 	if len(signature) != 1+bitlen*2 {
 		return nil, false, errors.New("invalid compact signature size")
diff --git a/signature_test.go b/signature_test.go
index 8ea3b11a..087f329e 100644
--- a/signature_test.go
+++ b/signature_test.go
@@ -427,7 +427,8 @@ func TestSignatureSerialize(t *testing.T) {
 
 func testSignCompact(t *testing.T, tag string, curve *btcec.KoblitzCurve,
 	data []byte, isCompressed bool) {
-	priv, _ := ecdsa.GenerateKey(curve, rand.Reader)
+	tmp, _ := ecdsa.GenerateKey(curve, rand.Reader)
+	priv := (*btcec.PrivateKey)(tmp)
 
 	hashed := []byte("testing")
 	sig, err := btcec.SignCompact(curve, priv, hashed, isCompressed)