diff --git a/core/vm/common.go b/core/vm/common.go
index c9d2ba65cd70..a2f30fdb7a78 100644
--- a/core/vm/common.go
+++ b/core/vm/common.go
@@ -103,12 +103,3 @@ func toWordSize(size uint64) uint64 {
 
 	return (size + 31) / 32
 }
-
-func allZero(b []byte) bool {
-	for _, byte := range b {
-		if byte != 0 {
-			return false
-		}
-	}
-	return true
-}
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 3d10174d1e63..6b0bb94b945c 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -25,6 +25,7 @@ import (
 	"math/big"
 
 	"github.com/XinFinOrg/XDPoSChain/common"
+	"github.com/XinFinOrg/XDPoSChain/common/bitutil"
 	"github.com/XinFinOrg/XDPoSChain/core/tracing"
 	"github.com/XinFinOrg/XDPoSChain/core/vm/privacy"
 	"github.com/XinFinOrg/XDPoSChain/crypto"
@@ -249,7 +250,7 @@ func (c *ecrecover) Run(input []byte) ([]byte, error) {
 	v := input[63] - 27
 
 	// tighter sig s values input homestead only apply to tx sigs
-	if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
+	if bitutil.TestBytes(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
 		return nil, nil
 	}
 	// We must make sure not to modify the 'input', so placing the 'v' along with