core: change CRSSignature with bls (#563)

4 files changed, 45 insertions, 18 deletions

diff --git a/core/utils/crypto.go b/core/utils/crypto.go
index 7fd3a77..496944d 100644
--- a/core/utils/crypto.go
+++ b/core/utils/crypto.go
@@ -18,6 +18,7 @@
 package utils
 
 import (
+	"bytes"
 	"encoding/binary"
 
 	"github.com/dexon-foundation/dexon-consensus/common"
@@ -122,21 +123,27 @@ func VerifyVoteSignature(vote *types.Vote) (bool, error) {
 
 func hashCRS(block *types.Block, crs common.Hash) common.Hash {
 	hashPos := HashPosition(block.Position)
+	if block.Position.Round < dkgDelayRound {
+		return crypto.Keccak256Hash(crs[:], hashPos[:], block.ProposerID.Hash[:])
+	}
 	return crypto.Keccak256Hash(crs[:], hashPos[:])
 }
 
 // VerifyCRSSignature verifies the CRS signature of types.Block.
-func VerifyCRSSignature(block *types.Block, crs common.Hash) (
-	bool, error) {
+func VerifyCRSSignature(
+	block *types.Block, crs common.Hash, npks *typesDKG.NodePublicKeys) bool {
 	hash := hashCRS(block, crs)
-	pubKey, err := crypto.SigToPub(hash, block.CRSSignature)
-	if err != nil {
-		return false, err
+	if block.Position.Round < dkgDelayRound {
+		return bytes.Compare(block.CRSSignature.Signature[:], hash[:]) == 0
 	}
-	if block.ProposerID != types.NewNodeID(pubKey) {
-		return false, nil
+	if npks == nil {
+		return false
 	}
-	return true, nil
+	pubKey, exist := npks.PublicKeys[block.ProposerID]
+	if !exist {
+		return false
+	}
+	return pubKey.VerifySignature(hash, block.CRSSignature)
 }
 
 // HashPosition generates hash of a types.Position.
diff --git a/core/utils/crypto_test.go b/core/utils/crypto_test.go
index 5dfd82b..24ea68e 100644
--- a/core/utils/crypto_test.go
+++ b/core/utils/crypto_test.go
@@ -127,6 +127,7 @@ func (s *CryptoTestSuite) TestVoteSignature() {
 }
 
 func (s *CryptoTestSuite) TestCRSSignature() {
+	dkgDelayRound = 1
 	crs := common.NewRandomHash()
 	prv, err := ecdsa.NewPrivateKey()
 	s.Require().NoError(err)
@@ -135,14 +136,12 @@ func (s *CryptoTestSuite) TestCRSSignature() {
 	block := &types.Block{
 		ProposerID: nID,
 	}
-	block.CRSSignature, err = prv.Sign(hashCRS(block, crs))
-	s.Require().NoError(err)
-	ok, err := VerifyCRSSignature(block, crs)
-	s.Require().NoError(err)
+	hash := hashCRS(block, crs)
+	block.CRSSignature.Signature = hash[:]
+	ok := VerifyCRSSignature(block, crs, nil)
 	s.True(ok)
 	block.Position.Height++
-	ok, err = VerifyCRSSignature(block, crs)
-	s.Require().NoError(err)
+	ok = VerifyCRSSignature(block, crs, nil)
 	s.False(ok)
 }
 
diff --git a/core/utils/signer.go b/core/utils/signer.go
index 7694dab..9904410 100644
--- a/core/utils/signer.go
+++ b/core/utils/signer.go
@@ -31,13 +31,17 @@ var (
 	ErrInvalidProposerID  = errors.New("invalid proposer id")
 	ErrIncorrectHash      = errors.New("hash of block is incorrect")
 	ErrIncorrectSignature = errors.New("signature of block is incorrect")
+	ErrNoBLSSigner        = errors.New("bls signer not set")
 )
 
+type blsSigner func(round uint64, hash common.Hash) (crypto.Signature, error)
+
 // Signer signs a segment of data.
 type Signer struct {
 	prvKey     crypto.PrivateKey
 	pubKey     crypto.PublicKey
 	proposerID types.NodeID
+	blsSign    blsSigner
 }
 
 // NewSigner constructs an Signer instance.
@@ -50,6 +54,11 @@ func NewSigner(prvKey crypto.PrivateKey) (s *Signer) {
 	return
 }
 
+// SetBLSSigner for signing CRSSignature
+func (s *Signer) SetBLSSigner(signer blsSigner) {
+	s.blsSign = signer
+}
+
 // SignBlock signs a types.Block.
 func (s *Signer) SignBlock(b *types.Block) (err error) {
 	b.ProposerID = s.proposerID
@@ -76,7 +85,19 @@ func (s *Signer) SignCRS(b *types.Block, crs common.Hash) (err error) {
 		err = ErrInvalidProposerID
 		return
 	}
-	b.CRSSignature, err = s.prvKey.Sign(hashCRS(b, crs))
+	if b.Position.Round < dkgDelayRound {
+		hash := hashCRS(b, crs)
+		b.CRSSignature = crypto.Signature{
+			Type:      "bls",
+			Signature: hash[:],
+		}
+		return
+	}
+	if s.blsSign == nil {
+		err = ErrNoBLSSigner
+		return
+	}
+	b.CRSSignature, err = s.blsSign(b.Position.Round, hashCRS(b, crs))
 	return
 }
 
diff --git a/core/utils/signer_test.go b/core/utils/signer_test.go
index 3905352..0ee1c30 100644
--- a/core/utils/signer_test.go
+++ b/core/utils/signer_test.go
@@ -66,11 +66,12 @@ func (s *SignerTestSuite) TestVote() {
 }
 
 func (s *SignerTestSuite) TestCRS() {
+	dkgDelayRound = 1
 	k := s.setupSigner()
 	b := &types.Block{
 		ParentHash: common.NewRandomHash(),
 		Position: types.Position{
-			Round:  8,
+			Round:  0,
 			Height: 9,
 		},
 		Timestamp: time.Now().UTC(),
@@ -80,9 +81,8 @@ func (s *SignerTestSuite) TestCRS() {
 	// Hash block before hash CRS.
 	s.NoError(k.SignBlock(b))
 	s.NoError(k.SignCRS(b, crs))
-	ok, err := VerifyCRSSignature(b, crs)
+	ok := VerifyCRSSignature(b, crs, nil)
 	s.True(ok)
-	s.NoError(err)
 }
 
 func TestSigner(t *testing.T) {