diff --git a/common/bytes.go b/common/bytes.go
index d1f5c6c995..2dd86f3d76 100644
--- a/common/bytes.go
+++ b/common/bytes.go
@@ -20,6 +20,7 @@ package common
 import (
 	"encoding/hex"
 	"errors"
+	"strings"
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
 )
@@ -27,10 +28,10 @@ import (
 // FromHex returns the bytes represented by the hexadecimal string s.
 // s may be prefixed with "0x".
 func FromHex(s string) []byte {
-	if has0xPrefix(s) {
+	if len(s) >= 2 && strings.HasPrefix(strings.ToLower(s), "0x") {
 		s = s[2:]
 	}
-	if len(s)%2 == 1 {
+	if len(s)&1 == 1 {
 		s = "0" + s
 	}
 	return Hex2Bytes(s)
@@ -47,27 +48,13 @@ func CopyBytes(b []byte) (copiedBytes []byte) {
 	return
 }
 
-// has0xPrefix validates str begins with '0x' or '0X'.
-func has0xPrefix(str string) bool {
-	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
-}
-
-// isHexCharacter returns bool of c being a valid hexadecimal.
-func isHexCharacter(c byte) bool {
-	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
-}
-
 // isHex validates whether each byte is valid hexadecimal string.
 func isHex(str string) bool {
 	if len(str)%2 != 0 {
 		return false
 	}
-	for _, c := range []byte(str) {
-		if !isHexCharacter(c) {
-			return false
-		}
-	}
-	return true
+	_, err := hex.DecodeString(str)
+	return err == nil
 }
 
 // Bytes2Hex returns the hexadecimal encoding of d.
diff --git a/common/types.go b/common/types.go
index db4de8bcbd..13dc65d8a3 100644
--- a/common/types.go
+++ b/common/types.go
@@ -231,7 +231,7 @@ func HexToAddress(s string) Address { return BytesToAddress(FromHex(s)) }
 // IsHexAddress verifies whether a string can represent a valid hex-encoded
 // Ethereum address or not.
 func IsHexAddress(s string) bool {
-	if has0xPrefix(s) {
+	if len(s) >= 2 && strings.HasPrefix(strings.ToLower(s), "0x") {
 		s = s[2:]
 	}
 	return len(s) == 2*AddressLength && isHex(s)