secp256k1: use compressed pubkey, bitcoin-style address

priv_key.go

@@ -160,9 +160,9 @@ func (privKey PrivKeySecp256k1) Sign(msg []byte) Signature {
 
 func (privKey PrivKeySecp256k1) PubKey() PubKey {
 	_, pub__ := secp256k1.PrivKeyFromBytes(secp256k1.S256(), privKey[:])
-	pub := [64]byte{}
-	copy(pub[:], pub__.SerializeUncompressed()[1:])
-	return PubKeySecp256k1(pub)
+	var pub PubKeySecp256k1
+	copy(pub[:], pub__.SerializeCompressed())
+	return pub
 }
 
 func (privKey PrivKeySecp256k1) Equals(other PrivKey) bool {

pub_key.go

@@ -2,6 +2,7 @@ package crypto
 
 import (
 	"bytes"
+	"crypto/sha256"
 
 	secp256k1 "github.com/btcsuite/btcd/btcec"
 	"github.com/tendermint/ed25519"
@@ -135,20 +136,20 @@ func (pubKey PubKeyEd25519) Equals(other PubKey) bool {
 
 //-------------------------------------
 
-// Implements PubKey
-type PubKeySecp256k1 [64]byte
+// Implements PubKey.
+// Compressed pubkey (just the x-cord),
+// prefixed with 0x02 or 0x03, depending on the y-cord.
+type PubKeySecp256k1 [33]byte
 
+// Implements Bitcoin style addresses: RIPEMD160(SHA256(pubkey))
 func (pubKey PubKeySecp256k1) Address() []byte {
-	w, n, err := new(bytes.Buffer), new(int), new(error)
-	wire.WriteBinary(pubKey[:], w, n, err)
-	if *err != nil {
-		PanicCrisis(*err)
-	}
-	// append type byte
-	encodedPubkey := append([]byte{TypeSecp256k1}, w.Bytes()...)
-	hasher := ripemd160.New()
-	hasher.Write(encodedPubkey) // does not error
-	return hasher.Sum(nil)
+	hasherSHA256 := sha256.New()
+	hasherSHA256.Write(pubKey[:]) // does not error
+	sha := hasherSHA256.Sum(nil)
+
+	hasherRIPEMD160 := ripemd160.New()
+	hasherRIPEMD160.Write(sha) // does not error
+	return hasherRIPEMD160.Sum(nil)
 }
 
 func (pubKey PubKeySecp256k1) Bytes() []byte {
@@ -166,7 +167,7 @@ func (pubKey PubKeySecp256k1) VerifyBytes(msg []byte, sig_ Signature) bool {
 		return false
 	}
 
-	pub__, err := secp256k1.ParsePubKey(append([]byte{0x04}, pubKey[:]...), secp256k1.S256())
+	pub__, err := secp256k1.ParsePubKey(pubKey[:], secp256k1.S256())
 	if err != nil {
 		return false
 	}

pub_key_test.go

@@ -0,0 +1,41 @@
+package crypto
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/btcsuite/btcutil/base58"
+	"github.com/stretchr/testify/assert"
+)
+
+type keyData struct {
+	priv string
+	pub  string
+	addr string
+}
+
+var secpDataTable = []keyData{
+	{
+		priv: "a96e62ed3955e65be32703f12d87b6b5cf26039ecfa948dc5107a495418e5330",
+		pub:  "02950e1cdfcb133d6024109fd489f734eeb4502418e538c28481f22bce276f248c",
+		addr: "1CKZ9Nx4zgds8tU7nJHotKSDr4a9bYJCa3",
+	},
+}
+
+func TestPubKeySecp256k1Address(t *testing.T) {
+	for _, d := range secpDataTable {
+		privB, _ := hex.DecodeString(d.priv)
+		pubB, _ := hex.DecodeString(d.pub)
+		addrB, _, _ := base58.CheckDecode(d.addr)
+
+		var priv PrivKeySecp256k1
+		copy(priv[:], privB)
+
+		pubT := priv.PubKey().(PubKeySecp256k1)
+		pub := pubT[:]
+		addr := priv.PubKey().Address()
+
+		assert.Equal(t, pub, pubB, "Expected pub keys to match")
+		assert.Equal(t, addr, addrB, "Expected addresses to match")
+	}
+}