core: move crypto to core/crypto (#140)

- Move key-holder to authenticator

   Make core.keyHolder public as core.Authenticator, it
   is not required to make this part an interface.

- Make private when there is no need to go public.
- Fix data race

42 files changed, 112 insertions, 135 deletions

diff --git a/core/agreement-state_test.go b/core/agreement-state_test.go
index 0142724..2aa50ac 100644
--- a/core/agreement-state_test.go
+++ b/core/agreement-state_test.go
@@ -24,9 +24,9 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 type AgreementStateTestSuite struct {
diff --git a/core/agreement.go b/core/agreement.go
index ffc4ba8..1b1cbde 100644
--- a/core/agreement.go
+++ b/core/agreement.go
@@ -24,8 +24,8 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Errors for agreement module.
diff --git a/core/agreement_test.go b/core/agreement_test.go
index 681d7b6..4f8a3ac 100644
--- a/core/agreement_test.go
+++ b/core/agreement_test.go
@@ -21,9 +21,9 @@ import (
 	"testing"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
diff --git a/core/key-holder.go b/core/authenticator.go
index 355c823..480d6cc 100644
--- a/core/key-holder.go
+++ b/core/authenticator.go
@@ -19,55 +19,57 @@ package core
 
 import (
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
-type keyHolder struct {
+// Authenticator verify data owner.
+type Authenticator struct {
 	prvKey   crypto.PrivateKey
 	pubKey   crypto.PublicKey
 	sigToPub SigToPubFn
 }
 
-func newKeyHolder(prvKey crypto.PrivateKey, sigToPub SigToPubFn) *keyHolder {
-	return &keyHolder{
+// NewAuthenticator constructs an Authenticator instance.
+func NewAuthenticator(prvKey crypto.PrivateKey, sigToPub SigToPubFn) *Authenticator {
+	return &Authenticator{
 		prvKey:   prvKey,
 		pubKey:   prvKey.PublicKey(),
 		sigToPub: sigToPub,
 	}
 }
 
-// SignBlock implements core.Signer.
-func (h *keyHolder) SignBlock(b *types.Block) (err error) {
-	b.ProposerID = types.NewNodeID(h.pubKey)
+// SignBlock signs a types.Block.
+func (au *Authenticator) SignBlock(b *types.Block) (err error) {
+	b.ProposerID = types.NewNodeID(au.pubKey)
 	if b.Hash, err = hashBlock(b); err != nil {
 		return
 	}
-	if b.Signature, err = h.prvKey.Sign(b.Hash); err != nil {
+	if b.Signature, err = au.prvKey.Sign(b.Hash); err != nil {
 		return
 	}
 	return
 }
 
-// SignVote implements core.Signer.
-func (h *keyHolder) SignVote(v *types.Vote) (err error) {
-	v.ProposerID = types.NewNodeID(h.pubKey)
-	v.Signature, err = h.prvKey.Sign(hashVote(v))
+// SignVote signs a types.Vote.
+func (au *Authenticator) SignVote(v *types.Vote) (err error) {
+	v.ProposerID = types.NewNodeID(au.pubKey)
+	v.Signature, err = au.prvKey.Sign(hashVote(v))
 	return
 }
 
-// SignCRS implements core.Signer
-func (h *keyHolder) SignCRS(b *types.Block, crs common.Hash) (err error) {
-	if b.ProposerID != types.NewNodeID(h.pubKey) {
+// SignCRS signs CRS signature of types.Block.
+func (au *Authenticator) SignCRS(b *types.Block, crs common.Hash) (err error) {
+	if b.ProposerID != types.NewNodeID(au.pubKey) {
 		err = ErrInvalidProposerID
 		return
 	}
-	b.CRSSignature, err = h.prvKey.Sign(hashCRS(b, crs))
+	b.CRSSignature, err = au.prvKey.Sign(hashCRS(b, crs))
 	return
 }
 
-// VerifyBlock implements core.CryptoVerifier.
-func (h *keyHolder) VerifyBlock(b *types.Block) (err error) {
+// VerifyBlock verifies the signature of types.Block.
+func (au *Authenticator) VerifyBlock(b *types.Block) (err error) {
 	hash, err := hashBlock(b)
 	if err != nil {
 		return
@@ -76,7 +78,7 @@ func (h *keyHolder) VerifyBlock(b *types.Block) (err error) {
 		err = ErrIncorrectHash
 		return
 	}
-	pubKey, err := h.sigToPub(b.Hash, b.Signature)
+	pubKey, err := au.sigToPub(b.Hash, b.Signature)
 	if err != nil {
 		return
 	}
@@ -87,12 +89,12 @@ func (h *keyHolder) VerifyBlock(b *types.Block) (err error) {
 	return
 }
 
-// VerifyVote implements core.CryptoVerifier.
-func (h *keyHolder) VerifyVote(v *types.Vote) (bool, error) {
-	return verifyVoteSignature(v, h.sigToPub)
+// VerifyVote verifies the signature of types.Vote.
+func (au *Authenticator) VerifyVote(v *types.Vote) (bool, error) {
+	return verifyVoteSignature(v, au.sigToPub)
 }
 
-// VerifyWitness implements core.CryptoVerifier.
-func (h *keyHolder) VerifyCRS(b *types.Block, crs common.Hash) (bool, error) {
-	return verifyCRSSignature(b, crs, h.sigToPub)
+// VerifyCRS verifies the CRS signature of types.Block.
+func (au *Authenticator) VerifyCRS(b *types.Block, crs common.Hash) (bool, error) {
+	return verifyCRSSignature(b, crs, au.sigToPub)
 }
diff --git a/core/key-holder_test.go b/core/authenticator_test.go
index cb5fda7..40b5e0c 100644
--- a/core/key-holder_test.go
+++ b/core/authenticator_test.go
@@ -22,23 +22,23 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
-type KeyHolderTestSuite struct {
+type AuthenticatorTestSuite struct {
 	suite.Suite
 }
 
-func (s *KeyHolderTestSuite) setupKeyHolder() *keyHolder {
+func (s *AuthenticatorTestSuite) setupAuthenticator() *Authenticator {
 	k, err := eth.NewPrivateKey()
 	s.NoError(err)
-	return newKeyHolder(k, eth.SigToPub)
+	return NewAuthenticator(k, eth.SigToPub)
 }
 
-func (s *KeyHolderTestSuite) TestBlock() {
-	k := s.setupKeyHolder()
+func (s *AuthenticatorTestSuite) TestBlock() {
+	k := s.setupAuthenticator()
 	b := &types.Block{
 		ParentHash: common.NewRandomHash(),
 		Position: types.Position{
@@ -52,8 +52,8 @@ func (s *KeyHolderTestSuite) TestBlock() {
 	s.NoError(k.VerifyBlock(b))
 }
 
-func (s *KeyHolderTestSuite) TestVote() {
-	k := s.setupKeyHolder()
+func (s *AuthenticatorTestSuite) TestVote() {
+	k := s.setupAuthenticator()
 	v := &types.Vote{
 		ProposerID: types.NodeID{Hash: common.NewRandomHash()},
 		Type:       types.VoteConfirm,
@@ -70,8 +70,8 @@ func (s *KeyHolderTestSuite) TestVote() {
 	s.NoError(err)
 }
 
-func (s *KeyHolderTestSuite) TestCRS() {
-	k := s.setupKeyHolder()
+func (s *AuthenticatorTestSuite) TestCRS() {
+	k := s.setupAuthenticator()
 	b := &types.Block{
 		ParentHash: common.NewRandomHash(),
 		Position: types.Position{
@@ -91,6 +91,6 @@ func (s *KeyHolderTestSuite) TestCRS() {
 	s.NoError(err)
 }
 
-func TestKeyHolder(t *testing.T) {
-	suite.Run(t, new(KeyHolderTestSuite))
+func TestAuthenticator(t *testing.T) {
+	suite.Run(t, new(AuthenticatorTestSuite))
 }
diff --git a/core/compaction-chain.go b/core/compaction-chain.go
index 4405bbc..4bb3ffb 100644
--- a/core/compaction-chain.go
+++ b/core/compaction-chain.go
@@ -26,8 +26,8 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Errors for compaction chain.
diff --git a/core/compaction-chain_test.go b/core/compaction-chain_test.go
index 3603fb6..ed02b78 100644
--- a/core/compaction-chain_test.go
+++ b/core/compaction-chain_test.go
@@ -23,8 +23,8 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
diff --git a/core/configuration-chain.go b/core/configuration-chain.go
index a6c0f39..46f02cc 100644
--- a/core/configuration-chain.go
+++ b/core/configuration-chain.go
@@ -23,8 +23,8 @@ import (
 	"sync"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Errors for configuration chain..
diff --git a/core/configuration-chain_test.go b/core/configuration-chain_test.go
index ae82e42..fc3f48e 100644
--- a/core/configuration-chain_test.go
+++ b/core/configuration-chain_test.go
@@ -25,11 +25,11 @@ import (
 
 	"github.com/stretchr/testify/suite"
 
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/dkg"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/dkg"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 type ConfigurationChainTestSuite struct {
@@ -113,7 +113,12 @@ func (r *testCCReceiver) ProposeDKGAntiNackComplaint(
 		prv.Signature, err = prvKey.Sign(hashDKGPrivateShare(prv))
 		r.s.Require().NoError(err)
 		for _, cc := range r.nodes {
-			err = cc.processPrivateShare(prv)
+			// Use Marshal/Unmarshal to do deep copy.
+			data, err := json.Marshal(prv)
+			r.s.Require().NoError(err)
+			prvCopy := &types.DKGPrivateShare{}
+			r.s.Require().NoError(json.Unmarshal(data, prvCopy))
+			err = cc.processPrivateShare(prvCopy)
 			r.s.Require().NoError(err)
 		}
 	}()
diff --git a/core/consensus.go b/core/consensus.go
index c7eea32..b8c8f77 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -27,8 +27,8 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // SigToPubFn is a function to recover public key from signature.
diff --git a/core/consensus_test.go b/core/consensus_test.go
index a58d3e8..799698e 100644
--- a/core/consensus_test.go
+++ b/core/consensus_test.go
@@ -24,9 +24,9 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
diff --git a/core/crypto.go b/core/crypto.go
index 26e44f9..2a1e3c5 100644
--- a/core/crypto.go
+++ b/core/crypto.go
@@ -21,8 +21,8 @@ import (
 	"encoding/binary"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 func hashWitness(block *types.Block) (common.Hash, error) {
diff --git a/crypto/dkg/constant.go b/core/crypto/dkg/constant.go
index 119613b..119613b 100644
--- a/crypto/dkg/constant.go
+++ b/core/crypto/dkg/constant.go
diff --git a/crypto/dkg/dkg.go b/core/crypto/dkg/dkg.go
index f2a2f3a..fe05e96 100644
--- a/crypto/dkg/dkg.go
+++ b/core/crypto/dkg/dkg.go
@@ -24,7 +24,7 @@ import (
 	"github.com/Spiderpowa/bls/ffi/go/bls"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 var (
diff --git a/crypto/dkg/dkg_test.go b/core/crypto/dkg/dkg_test.go
index badb0ce..9488dcc 100644
--- a/crypto/dkg/dkg_test.go
+++ b/core/crypto/dkg/dkg_test.go
@@ -27,7 +27,7 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 type DKGTestSuite struct {
diff --git a/crypto/dkg/utils.go b/core/crypto/dkg/utils.go
index 3684964..967973d 100644
--- a/crypto/dkg/utils.go
+++ b/core/crypto/dkg/utils.go
@@ -22,7 +22,7 @@ import (
 
 	"github.com/Spiderpowa/bls/ffi/go/bls"
 
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 // PartialSignature is a partial signature in DKG+TSIG protocol.
diff --git a/crypto/eth/eth.go b/core/crypto/eth/eth.go
index c3c5a7c..e82ac29 100644
--- a/crypto/eth/eth.go
+++ b/core/crypto/eth/eth.go
@@ -23,19 +23,19 @@ import (
 	ethcrypto "github.com/ethereum/go-ethereum/crypto"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 // PrivateKey represents a private key structure used in geth and implments
 // Crypto.PrivateKey interface.
 type PrivateKey struct {
 	privateKey ecdsa.PrivateKey
-	publicKey  PublicKey
+	publicKey  publicKey
 }
 
-// PublicKey represents a public key structure used in geth and implements
+// publicKey represents a public key structure used in geth and implements
 // Crypto.PublicKey interface.
-type PublicKey struct {
+type publicKey struct {
 	publicKey []byte
 }
 
@@ -52,16 +52,16 @@ func NewPrivateKey() (*PrivateKey, error) {
 }
 
 // newPublicKey creates a new PublicKey structure.
-func newPublicKey(prvKey *ecdsa.PrivateKey) *PublicKey {
-	return &PublicKey{
+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) {
+// decompressPubkey parses a public key in the 33-byte compressed format.
+func decompressPubkey(pubkey []byte) (publicKey, error) {
 	_, err := ethcrypto.DecompressPubkey(pubkey)
-	return PublicKey{
+	return publicKey{
 		publicKey: pubkey,
 	}, err
 }
@@ -90,7 +90,7 @@ func (prv *PrivateKey) Sign(hash common.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(
+func (pub publicKey) VerifySignature(
 	hash common.Hash, signature crypto.Signature) bool {
 	if len(signature) == 65 {
 		// The last byte is for ecrecover.
@@ -100,12 +100,12 @@ func (pub PublicKey) VerifySignature(
 }
 
 // Compress encodes a public key to the 33-byte compressed format.
-func (pub PublicKey) Compress() []byte {
+func (pub publicKey) Compress() []byte {
 	return pub.publicKey
 }
 
 // Bytes returns the []byte representation of public key.
-func (pub PublicKey) Bytes() []byte {
+func (pub publicKey) Bytes() []byte {
 	return pub.Compress()
 }
 
@@ -114,7 +114,7 @@ func SigToPub(
 	hash common.Hash, signature crypto.Signature) (crypto.PublicKey, error) {
 	key, err := ethcrypto.SigToPub(hash[:], signature[:])
 	if err != nil {
-		return PublicKey{}, err
+		return publicKey{}, err
 	}
-	return PublicKey{publicKey: ethcrypto.CompressPubkey(key)}, nil
+	return publicKey{publicKey: ethcrypto.CompressPubkey(key)}, nil
 }
diff --git a/crypto/eth/eth_test.go b/core/crypto/eth/eth_test.go
index f6f48cb..acda1a8 100644
--- a/crypto/eth/eth_test.go
+++ b/core/crypto/eth/eth_test.go
@@ -21,7 +21,7 @@ import (
 	"testing"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/stretchr/testify/suite"
 )
 
@@ -55,7 +55,7 @@ func (s *ETHCryptoTestSuite) TestSignature() {
 	s.NotEqual(sig11, sig12)
 
 	// Test VerifySignature with correct public key.
-	pub1, ok := prv1.PublicKey().(PublicKey)
+	pub1, ok := prv1.PublicKey().(publicKey)
 	s.Require().True(ok)
 	s.True(pub1.VerifySignature(hash1, sig11))
 
@@ -69,7 +69,7 @@ func (s *ETHCryptoTestSuite) TestSignature() {
 
 	// Test compress and decompress of public key.
 	compressPub1 := pub1.Compress()
-	decompressPub1, err := DecompressPubkey(compressPub1)
+	decompressPub1, err := decompressPubkey(compressPub1)
 	s.Require().Nil(err)
 	s.Equal(pub1, decompressPub1)
 	s.True(decompressPub1.VerifySignature(hash1, sig11))
diff --git a/crypto/interfaces.go b/core/crypto/interfaces.go
index 280082e..ac2754d 100644
--- a/crypto/interfaces.go
+++ b/core/crypto/interfaces.go
@@ -31,7 +31,7 @@ type PrivateKey interface {
 	PublicKey() PublicKey
 
 	// Sign calculates a signature.
-	Sign(hash common.Hash) (sig Signature, err error)
+	Sign(hash common.Hash) (Signature, error)
 }
 
 // PublicKey describes the asymmetric cryptography interface that interacts
diff --git a/crypto/utils.go b/core/crypto/utils.go
index 07a8b2b..07a8b2b 100644
--- a/crypto/utils.go
+++ b/core/crypto/utils.go
diff --git a/crypto/utils_test.go b/core/crypto/utils_test.go
index 977027a..977027a 100644
--- a/crypto/utils_test.go
+++ b/core/crypto/utils_test.go
diff --git a/core/crypto_test.go b/core/crypto_test.go
index 6c807da..4ff4606 100644
--- a/core/crypto_test.go
+++ b/core/crypto_test.go
@@ -22,10 +22,10 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/dkg"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/dkg"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
diff --git a/core/dkg-tsig-protocol.go b/core/dkg-tsig-protocol.go
index 0f5cb0b..a69cdd2 100644
--- a/core/dkg-tsig-protocol.go
+++ b/core/dkg-tsig-protocol.go
@@ -21,9 +21,9 @@ import (
 	"fmt"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/dkg"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/dkg"
 )
 
 // Errors for dkg module.
diff --git a/core/dkg-tsig-protocol_test.go b/core/dkg-tsig-protocol_test.go
index 0c938f7..97d9d34 100644
--- a/core/dkg-tsig-protocol_test.go
+++ b/core/dkg-tsig-protocol_test.go
@@ -23,11 +23,11 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/dkg"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/dkg"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 type DKGTSIGProtocolTestSuite struct {
diff --git a/core/interfaces.go b/core/interfaces.go
index 7f6ff2b..eebf8ff 100644
--- a/core/interfaces.go
+++ b/core/interfaces.go
@@ -21,8 +21,8 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Application describes the application interface that interacts with DEXON
@@ -56,7 +56,7 @@ type Debug interface {
 
 	// TotalOrderingDelivered is called when the total ordering algorithm deliver
 	// a set of block.
-	TotalOrderingDelivered(blockHashes common.Hashes, early bool)
+	TotalOrderingDelivered(common.Hashes, bool)
 }
 
 // Network describs the network interface that interacts with DEXON consensus
@@ -101,7 +101,7 @@ type Governance interface {
 	ProposeThresholdSignature(round uint64, signature crypto.Signature)
 
 	// Get a ThresholdSignature of round.
-	GetThresholdSignature(round uint64) (sig crypto.Signature, exist bool)
+	GetThresholdSignature(round uint64) (crypto.Signature, bool)
 
 	//// DKG-related methods.
 
@@ -126,33 +126,3 @@ type Ticker interface {
 	// Stop the ticker.
 	Stop()
 }
-
-// Signer defines a role to sign data.
-type Signer interface {
-	// SignBlock signs a block.
-	SignBlock(b *types.Block) error
-
-	// SignVote signs a vote.
-	SignVote(v *types.Vote) error
-
-	// SignCRS sign a block's CRS signature.
-	SignCRS(b *types.Block, crs common.Hash) error
-}
-
-// CryptoVerifier defines a role to verify data in crypto's way.
-type CryptoVerifier interface {
-	// VerifyBlock verifies if a block is properly signed or not.
-	VerifyBlock(b *types.Block) (ok bool, err error)
-
-	// VerifyVote verfies if a vote is properly signed or not.
-	VerifyVote(v *types.Vote) (ok bool, err error)
-
-	// VerifyCRS verifies if a CRS signature of one block is valid or not.
-	VerifyCRS(b *types.Block, crs common.Hash) (ok bool, err error)
-}
-
-// Authenticator verify/sign who own the data.
-type Authenticator interface {
-	Signer
-	CryptoVerifier
-}
diff --git a/core/leader-selector.go b/core/leader-selector.go
index ce5134a..8a20055 100644
--- a/core/leader-selector.go
+++ b/core/leader-selector.go
@@ -22,8 +22,8 @@ import (
 	"math/big"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Errors for leader module.
diff --git a/core/leader-selector_test.go b/core/leader-selector_test.go
index 211680d..02562ba 100644
--- a/core/leader-selector_test.go
+++ b/core/leader-selector_test.go
@@ -23,8 +23,8 @@ import (
 	"github.com/stretchr/testify/suite"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 type LeaderSelectorTestSuite struct {
diff --git a/core/shard.go b/core/shard.go
index 270b070..28b64f1 100644
--- a/core/shard.go
+++ b/core/shard.go
@@ -23,8 +23,8 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // Shard represents a unit to produce a global ordering from multiple chains.
diff --git a/core/shard_test.go b/core/shard_test.go
index 42c8d7b..2a9016b 100644
--- a/core/shard_test.go
+++ b/core/shard_test.go
@@ -23,9 +23,9 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 	"github.com/stretchr/testify/suite"
 )
 
diff --git a/core/test/blocks-generator.go b/core/test/blocks-generator.go
index 4038450..eacc436 100644
--- a/core/test/blocks-generator.go
+++ b/core/test/blocks-generator.go
@@ -25,9 +25,9 @@ import (
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 // TODO(mission): blocks generator should generate blocks based on chain,
diff --git a/core/test/governance.go b/core/test/governance.go
index 137662f..81b71e5 100644
--- a/core/test/governance.go
+++ b/core/test/governance.go
@@ -22,9 +22,9 @@ import (
 	"sync"
 	"time"
 
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 var (
diff --git a/core/types/block.go b/core/types/block.go
index ddd0abd..e4b4466 100644
--- a/core/types/block.go
+++ b/core/types/block.go
@@ -27,7 +27,7 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 var (
diff --git a/core/types/dkg.go b/core/types/dkg.go
index a21c983..16737c6 100644
--- a/core/types/dkg.go
+++ b/core/types/dkg.go
@@ -20,8 +20,8 @@ package types
 import (
 	"fmt"
 
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/dkg"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/dkg"
 )
 
 // DKGPrivateShare describe a secret share in DKG protocol.
diff --git a/core/types/node.go b/core/types/node.go
index 8a856de..177e407 100644
--- a/core/types/node.go
+++ b/core/types/node.go
@@ -21,7 +21,7 @@ import (
 	"bytes"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 // NodeID is the ID type for nodes.
diff --git a/core/types/vote.go b/core/types/vote.go
index e92aa67..294bc74 100644
--- a/core/types/vote.go
+++ b/core/types/vote.go
@@ -21,7 +21,7 @@ import (
 	"fmt"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 // VoteType is the type of vote.
diff --git a/core/types/witness.go b/core/types/witness.go
index 46aa1cc..3c455d8 100644
--- a/core/types/witness.go
+++ b/core/types/witness.go
@@ -23,7 +23,7 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 )
 
 // WitnessAck represents the acking to the compaction chain.
diff --git a/core/utils.go b/core/utils.go
index 30456ef..3c1d211 100644
--- a/core/utils.go
+++ b/core/utils.go
@@ -25,8 +25,8 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 var (
diff --git a/integration_test/node.go b/integration_test/node.go
index 118a38f..4fdd746 100644
--- a/integration_test/node.go
+++ b/integration_test/node.go
@@ -26,10 +26,10 @@ import (
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
 )
 
 type consensusEventType int
diff --git a/integration_test/utils.go b/integration_test/utils.go
index 6a94a17..5b414c5 100644
--- a/integration_test/utils.go
+++ b/integration_test/utils.go
@@ -4,9 +4,9 @@ import (
 	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 )
 
 // PrepareNodes setups nodes for testing.
diff --git a/simulation/governance.go b/simulation/governance.go
index 133276c..a48e221 100644
--- a/simulation/governance.go
+++ b/simulation/governance.go
@@ -22,8 +22,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/simulation/config"
 )
 
diff --git a/simulation/node.go b/simulation/node.go
index 8b282c7..2d5c7a4 100644
--- a/simulation/node.go
+++ b/simulation/node.go
@@ -24,8 +24,8 @@ import (
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core"
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
-	"github.com/dexon-foundation/dexon-consensus-core/crypto"
 	"github.com/dexon-foundation/dexon-consensus-core/simulation/config"
 )
 
diff --git a/simulation/simulation.go b/simulation/simulation.go
index 61e09c7..c14c953 100644
--- a/simulation/simulation.go
+++ b/simulation/simulation.go
@@ -20,7 +20,7 @@ package simulation
 import (
 	"sync"
 
-	"github.com/dexon-foundation/dexon-consensus-core/crypto/eth"
+	"github.com/dexon-foundation/dexon-consensus-core/core/crypto/eth"
 	"github.com/dexon-foundation/dexon-consensus-core/simulation/config"
 )