core: rename crypto/eth to crypto/ecdsa (#144)

2 files changed, 223 insertions, 0 deletions

diff --git a/core/crypto/ecdsa/ecdsa.go b/core/crypto/ecdsa/ecdsa.go
new file mode 100644
index 0000000..5f98395
--- /dev/null
+++ b/core/crypto/ecdsa/ecdsa.go
@@ -0,0 +1,130 @@
+// Copyright 2018 The dexon-consensus-core Authors
+// This file is part of the dexon-consensus-core library.
+//
+// The dexon-consensus-core library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus-core library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus-core library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package ecdsa
+
+import (
+	"crypto/ecdsa"
+
+	ethcrypto "github.com/dexon-foundation/dexon/crypto"
+
+	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+)
+
+const cryptoType = "ecdsa"
+
+func init() {
+	crypto.RegisterSigToPub(cryptoType, SigToPub)
+}
+
+// PrivateKey represents a private key structure used in geth and implments
+// Crypto.PrivateKey interface.
+type PrivateKey struct {
+	privateKey ecdsa.PrivateKey
+	publicKey  publicKey
+}
+
+// publicKey represents a public key structure used in geth and implements
+// Crypto.PublicKey interface.
+type publicKey struct {
+	publicKey []byte
+}
+
+// NewPrivateKey creates a new PrivateKey structure.
+func NewPrivateKey() (*PrivateKey, error) {
+	key, err := ethcrypto.GenerateKey()
+	if err != nil {
+		return nil, err
+	}
+	return &PrivateKey{
+		privateKey: *key,
+		publicKey:  *newPublicKey(key),
+	}, nil
+}
+
+// newPublicKey creates a new PublicKey structure.
+func newPublicKey(prvKey *ecdsa.PrivateKey) *publicKey {
+	return &publicKey{
+		publicKey: ethcrypto.CompressPubkey(&prvKey.PublicKey),
+	}
+}
+
+// decompressPubkey parses a public key in the 33-byte compressed format.
+func decompressPubkey(pubkey []byte) (publicKey, error) {
+	_, err := ethcrypto.DecompressPubkey(pubkey)
+	return publicKey{
+		publicKey: pubkey,
+	}, err
+}
+
+// PublicKey returns the public key associate this private key.
+func (prv *PrivateKey) PublicKey() crypto.PublicKey {
+	return prv.publicKey
+}
+
+// Sign calculates an ECDSA signature.
+//
+// This function is susceptible to chosen plaintext attacks that can leak
+// information about the private key that is used for signing. Callers must
+// be aware that the given hash cannot be chosen by an adversery. Common
+// solution is to hash any input before calculating the signature.
+//
+// The produced signature is in the [R || S || V] format where V is 0 or 1.
+func (prv *PrivateKey) Sign(hash common.Hash) (
+	sig crypto.Signature, err error) {
+	s, err := ethcrypto.Sign(hash[:], &prv.privateKey)
+	sig = crypto.Signature{
+		Type:      cryptoType,
+		Signature: s,
+	}
+	return
+}
+
+// VerifySignature checks that the given public key created signature over hash.
+// The public key should be in compressed (33 bytes) or uncompressed (65 bytes)
+// format.
+// The signature should have the 64 byte [R || S] format.
+func (pub publicKey) VerifySignature(
+	hash common.Hash, signature crypto.Signature) bool {
+	sig := signature.Signature
+	if len(sig) == 65 {
+		// The last byte is for ecrecover.
+		sig = sig[:64]
+	}
+	return ethcrypto.VerifySignature(pub.publicKey, hash[:], sig)
+}
+
+// Compress encodes a public key to the 33-byte compressed format.
+func (pub publicKey) Compress() []byte {
+	return pub.publicKey
+}
+
+// Bytes returns the []byte representation of public key.
+func (pub publicKey) Bytes() []byte {
+	return pub.Compress()
+}
+
+// SigToPub returns the PublicKey that created the given signature.
+func SigToPub(
+	hash common.Hash, signature crypto.Signature) (crypto.PublicKey, error) {
+	key, err := ethcrypto.SigToPub(hash[:], signature.Signature[:])
+	if err != nil {
+		return publicKey{}, err
+	}
+	return publicKey{publicKey: ethcrypto.CompressPubkey(key)}, nil
+}
diff --git a/core/crypto/ecdsa/ecdsa_test.go b/core/crypto/ecdsa/ecdsa_test.go
new file mode 100644
index 0000000..3543b04
--- /dev/null
+++ b/core/crypto/ecdsa/ecdsa_test.go
@@ -0,0 +1,93 @@
+// Copyright 2018 The dexon-consensus-core Authors
+// This file is part of the dexon-consensus-core library.
+//
+// The dexon-consensus-core library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus-core library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus-core library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package ecdsa
+
+import (
+	"testing"
+
+	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/stretchr/testify/suite"
+)
+
+type ETHCryptoTestSuite struct {
+	suite.Suite
+}
+
+func (s *ETHCryptoTestSuite) TestSignature() {
+	prv1, err := NewPrivateKey()
+	s.Require().Nil(err)
+	hash1 := common.NewRandomHash()
+	hash2 := common.NewRandomHash()
+
+	// Test that same private key should produce same signature.
+	sig11, err := prv1.Sign(hash1)
+	s.Require().Nil(err)
+	sig112, err := prv1.Sign(hash1)
+	s.Require().Nil(err)
+	s.Equal(sig11, sig112)
+
+	// Test that different private key should produce different signature.
+	prv2, err := NewPrivateKey()
+	s.Require().Nil(err)
+	sig21, err := prv2.Sign(hash1)
+	s.Require().Nil(err)
+	s.NotEqual(sig11, sig21)
+
+	// Test that different hash should produce different signature.
+	sig12, err := prv1.Sign(hash2)
+	s.Require().Nil(err)
+	s.NotEqual(sig11, sig12)
+
+	// Test VerifySignature with correct public key.
+	pub1, ok := prv1.PublicKey().(publicKey)
+	s.Require().True(ok)
+	s.True(pub1.VerifySignature(hash1, sig11))
+
+	// Test VerifySignature with wrong hash.
+	s.False(pub1.VerifySignature(hash2, sig11))
+	// Test VerifySignature with wrong signature.
+	s.False(pub1.VerifySignature(hash1, sig21))
+	// Test VerifySignature with wrong public key.
+	pub2 := prv2.PublicKey()
+	s.False(pub2.VerifySignature(hash1, sig11))
+
+	// Test compress and decompress of public key.
+	compressPub1 := pub1.Compress()
+	decompressPub1, err := decompressPubkey(compressPub1)
+	s.Require().Nil(err)
+	s.Equal(pub1, decompressPub1)
+	s.True(decompressPub1.VerifySignature(hash1, sig11))
+}
+
+func (s *ETHCryptoTestSuite) TestSigToPub() {
+	prv, err := NewPrivateKey()
+	s.Require().Nil(err)
+	data := "DEXON is infinitely scalable and low-latency."
+	hash := crypto.Keccak256Hash([]byte(data))
+	sigmsg, err := prv.Sign(hash)
+	s.Require().Nil(err)
+
+	pubkey, err := SigToPub(hash, sigmsg)
+	s.Require().Nil(err)
+	s.Equal(pubkey, prv.PublicKey())
+}
+
+func TestCrypto(t *testing.T) {
+	suite.Run(t, new(ETHCryptoTestSuite))
+}