1 files changed, 80 insertions, 0 deletions
diff --git a/vendor/github.com/byzantine-lab/dexon-consensus/core/crypto/utils.go b/vendor/github.com/byzantine-lab/dexon-consensus/core/crypto/utils.go
new file mode 100644
index 000000000..744be3e5f
--- /dev/null
+++ b/vendor/github.com/byzantine-lab/dexon-consensus/core/crypto/utils.go
@@ -0,0 +1,80 @@
+// Copyright 2018 The dexon-consensus Authors
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus 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 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 library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package crypto
+
+import (
+	"encoding/hex"
+	"fmt"
+
+	"github.com/byzantine-lab/go-tangerine/crypto"
+
+	"github.com/byzantine-lab/dexon-consensus/common"
+)
+
+var (
+	// ErrSigToPubTypeNotFound is reported if the type is already used.
+	ErrSigToPubTypeNotFound = fmt.Errorf("type of sigToPub is not found")
+
+	// ErrSigToPubTypeAlreadyExist is reported if the type is already used.
+	ErrSigToPubTypeAlreadyExist = fmt.Errorf("type of sigToPub is already exist")
+)
+
+// SigToPubFn is a function to recover public key from signature.
+type SigToPubFn func(hash common.Hash, signature Signature) (PublicKey, error)
+
+var sigToPubCB map[string]SigToPubFn
+
+func init() {
+	sigToPubCB = make(map[string]SigToPubFn)
+}
+
+// Keccak256Hash calculates and returns the Keccak256 hash of the input data,
+// converting it to an internal Hash data structure.
+func Keccak256Hash(data ...[]byte) (h common.Hash) {
+	return common.Hash(crypto.Keccak256Hash(data...))
+}
+
+// Clone returns a deep copy of a signature.
+func (sig Signature) Clone() Signature {
+	return Signature{
+		Type:      sig.Type,
+		Signature: sig.Signature[:],
+	}
+}
+
+func (sig Signature) String() string {
+	return hex.EncodeToString([]byte(sig.Signature[:]))
+}
+
+// RegisterSigToPub registers a sigToPub function of type.
+func RegisterSigToPub(sigType string, sigToPub SigToPubFn) error {
+	if _, exist := sigToPubCB[sigType]; exist {
+		return ErrSigToPubTypeAlreadyExist
+	}
+	sigToPubCB[sigType] = sigToPub
+	return nil
+}
+
+// SigToPub recovers public key from signature.
+func SigToPub(hash common.Hash, signature Signature) (PublicKey, error) {
+	sigToPub, exist := sigToPubCB[signature.Type]
+	if !exist {
+		return nil, ErrSigToPubTypeNotFound
+	}
+	return sigToPub(hash, signature)
+}