From 0f5c6c5e2daa9fbf3a0bb753debd8989a872823c Mon Sep 17 00:00:00 2001
From: obscuren <geffobscura@gmail.com>
Date: Wed, 10 Dec 2014 14:17:10 +0100
Subject: Changed new methods to use ecdsa package for pub prv keys

---
 crypto/crypto.go               | 55 ++++++++++++++++++++++++------------------
 crypto/encrypt_decrypt_test.go |  6 ++---
 2 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/crypto/crypto.go b/crypto/crypto.go
index 87dd72dc7..d70a5a4db 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -18,19 +18,6 @@ func init() {
 	ecies.AddParamsForCurve(S256(), ecies.ECIES_AES128_SHA256)
 }
 
-func ToECDSA(prv []byte) *ecdsa.PrivateKey {
-	priv := new(ecdsa.PrivateKey)
-	priv.PublicKey.Curve = S256()
-	priv.D = ethutil.BigD(prv)
-	priv.PublicKey.X, priv.PublicKey.Y = S256().ScalarBaseMult(prv)
-	return priv
-}
-
-func FromECDSA(prv *ecdsa.PrivateKey) []byte {
-	return prv.D.Bytes()
-}
-
-// TODO refactor, remove (bin)
 func Sha3(data []byte) []byte {
 	d := sha3.NewKeccak256()
 	d.Write(data)
@@ -67,23 +54,45 @@ func Ecrecover(data []byte) []byte {
 	return r
 }
 
-func SigToPub(hash, sig []byte) []byte {
-	return Ecrecover(append(hash, sig...))
+// New methods using proper ecdsa keys from the stdlib
+func ToECDSA(prv []byte) *ecdsa.PrivateKey {
+	priv := new(ecdsa.PrivateKey)
+	priv.PublicKey.Curve = S256()
+	priv.D = ethutil.BigD(prv)
+	priv.PublicKey.X, priv.PublicKey.Y = S256().ScalarBaseMult(prv)
+	return priv
 }
 
-func Sign(hash, prv []byte) (sig []byte, err error) {
-	sig, err = secp256k1.Sign(hash, prv)
-	return
+func FromECDSA(prv *ecdsa.PrivateKey) []byte {
+	return prv.D.Bytes()
 }
 
-func Encrypt(pub, message []byte) ([]byte, error) {
+func PubToECDSA(pub []byte) *ecdsa.PublicKey {
 	x, y := elliptic.Unmarshal(S256(), pub)
-	epub := &ecdsa.PublicKey{S256(), x, y}
+	return &ecdsa.PublicKey{S256(), x, y}
+}
+
+func GenerateKey() (*ecdsa.PrivateKey, error) {
+	return ecdsa.GenerateKey(S256(), rand.Reader)
+}
+
+func SigToPub(hash, sig []byte) *ecdsa.PublicKey {
+	s := Ecrecover(append(hash, sig...))
+	x, y := elliptic.Unmarshal(S256(), s)
+
+	return &ecdsa.PublicKey{S256(), x, y}
+}
+
+func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
+	sig, err = secp256k1.Sign(hash, prv.D.Bytes())
+	return
+}
 
-	return ecies.Encrypt(rand.Reader, ecies.ImportECDSAPublic(epub), message, nil, nil)
+func Encrypt(pub *ecdsa.PublicKey, message []byte) ([]byte, error) {
+	return ecies.Encrypt(rand.Reader, ecies.ImportECDSAPublic(pub), message, nil, nil)
 }
 
-func Decrypt(prv, ct []byte) ([]byte, error) {
-	key := ecies.ImportECDSA(ToECDSA(prv))
+func Decrypt(prv *ecdsa.PrivateKey, ct []byte) ([]byte, error) {
+	key := ecies.ImportECDSA(prv)
 	return key.Decrypt(rand.Reader, ct, nil, nil)
 }
diff --git a/crypto/encrypt_decrypt_test.go b/crypto/encrypt_decrypt_test.go
index 44bb26f47..850fa94e4 100644
--- a/crypto/encrypt_decrypt_test.go
+++ b/crypto/encrypt_decrypt_test.go
@@ -9,9 +9,9 @@ import (
 )
 
 func TestBox(t *testing.T) {
-	prv1 := ethutil.Hex2Bytes("4b50fa71f5c3eeb8fdc452224b2395af2fcc3d125e06c32c82e048c0559db03f")
-	prv2 := ethutil.Hex2Bytes("d0b043b4c5d657670778242d82d68a29d25d7d711127d17b8e299f156dad361a")
-	pub2 := ethutil.Hex2Bytes("04bd27a63c91fe3233c5777e6d3d7b39204d398c8f92655947eb5a373d46e1688f022a1632d264725cbc7dc43ee1cfebde42fa0a86d08b55d2acfbb5e9b3b48dc5")
+	prv1 := ToECDSA(ethutil.Hex2Bytes("4b50fa71f5c3eeb8fdc452224b2395af2fcc3d125e06c32c82e048c0559db03f"))
+	prv2 := ToECDSA(ethutil.Hex2Bytes("d0b043b4c5d657670778242d82d68a29d25d7d711127d17b8e299f156dad361a"))
+	pub2 := PubToECDSA(ethutil.Hex2Bytes("04bd27a63c91fe3233c5777e6d3d7b39204d398c8f92655947eb5a373d46e1688f022a1632d264725cbc7dc43ee1cfebde42fa0a86d08b55d2acfbb5e9b3b48dc5"))
 
 	message := []byte("Hello, world.")
 	ct, err := Encrypt(pub2, message)
-- 
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