diff --git a/common/bitutil/bitutil.go b/common/bitutil/bitutil.go
index a18a6d18eed..86482bb0c77 100644
--- a/common/bitutil/bitutil.go
+++ b/common/bitutil/bitutil.go
@@ -27,20 +27,29 @@ func XORBytes(dst, a, b []byte) int {
 // fastXORBytes xors in bulk. It only works on architectures that support
 // unaligned read/writes.
 func fastXORBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
+	n := min(len(a), len(b), len(dst))
+	if n == 0 {
+		return 0
 	}
-	w := n / wordSize
+	wordSize := int(unsafe.Sizeof(uintptr(0)))
+
+	i := 0
+	for ; i < n && uintptr(unsafe.Pointer(&a[i]))%uintptr(wordSize) != 0; i++ {
+		dst[i] = a[i] ^ b[i]
+	}
+
+	w := (n - i) / wordSize
 	if w > 0 {
-		dw := *(*[]uintptr)(unsafe.Pointer(&dst))
-		aw := *(*[]uintptr)(unsafe.Pointer(&a))
-		bw := *(*[]uintptr)(unsafe.Pointer(&b))
-		for i := 0; i < w; i++ {
-			dw[i] = aw[i] ^ bw[i]
+		ad := unsafe.Slice((*uintptr)(unsafe.Pointer(&a[i])), w)
+		bd := unsafe.Slice((*uintptr)(unsafe.Pointer(&b[i])), w)
+		dd := unsafe.Slice((*uintptr)(unsafe.Pointer(&dst[i])), w)
+		for j := 0; j < w; j++ {
+			dd[j] = ad[j] ^ bd[j]
 		}
+		i += w * wordSize
 	}
-	for i := n - n%wordSize; i < n; i++ {
+
+	for ; i < n; i++ {
 		dst[i] = a[i] ^ b[i]
 	}
 	return n
@@ -49,11 +58,8 @@ func fastXORBytes(dst, a, b []byte) int {
 // safeXORBytes xors one by one. It works on all architectures, independent if
 // it supports unaligned read/writes or not.
 func safeXORBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
-	}
-	for i := 0; i < n; i++ {
+	n := min(len(b), len(a))
+	for i := range n {
 		dst[i] = a[i] ^ b[i]
 	}
 	return n
@@ -71,20 +77,29 @@ func ANDBytes(dst, a, b []byte) int {
 // fastANDBytes ands in bulk. It only works on architectures that support
 // unaligned read/writes.
 func fastANDBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
+	n := min(len(a), len(b), len(dst))
+	if n == 0 {
+		return 0
 	}
-	w := n / wordSize
+	wordSize := int(unsafe.Sizeof(uintptr(0)))
+
+	i := 0
+	for ; i < n && uintptr(unsafe.Pointer(&a[i]))%uintptr(wordSize) != 0; i++ {
+		dst[i] = a[i] & b[i]
+	}
+
+	w := (n - i) / wordSize
 	if w > 0 {
-		dw := *(*[]uintptr)(unsafe.Pointer(&dst))
-		aw := *(*[]uintptr)(unsafe.Pointer(&a))
-		bw := *(*[]uintptr)(unsafe.Pointer(&b))
-		for i := 0; i < w; i++ {
-			dw[i] = aw[i] & bw[i]
+		ad := unsafe.Slice((*uintptr)(unsafe.Pointer(&a[i])), w)
+		bd := unsafe.Slice((*uintptr)(unsafe.Pointer(&b[i])), w)
+		dd := unsafe.Slice((*uintptr)(unsafe.Pointer(&dst[i])), w)
+		for j := 0; j < w; j++ {
+			dd[j] = ad[j] & bd[j]
 		}
+		i += w * wordSize
 	}
-	for i := n - n%wordSize; i < n; i++ {
+
+	for ; i < n; i++ {
 		dst[i] = a[i] & b[i]
 	}
 	return n
@@ -93,11 +108,8 @@ func fastANDBytes(dst, a, b []byte) int {
 // safeANDBytes ands one by one. It works on all architectures, independent if
 // it supports unaligned read/writes or not.
 func safeANDBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
-	}
-	for i := 0; i < n; i++ {
+	n := min(len(b), len(a))
+	for i := range n {
 		dst[i] = a[i] & b[i]
 	}
 	return n
@@ -115,20 +127,29 @@ func ORBytes(dst, a, b []byte) int {
 // fastORBytes ors in bulk. It only works on architectures that support
 // unaligned read/writes.
 func fastORBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
+	n := min(len(a), len(b), len(dst))
+	if n == 0 {
+		return 0
 	}
-	w := n / wordSize
+	wordSize := int(unsafe.Sizeof(uintptr(0)))
+
+	i := 0
+	for ; i < n && uintptr(unsafe.Pointer(&a[i]))%uintptr(wordSize) != 0; i++ {
+		dst[i] = a[i] | b[i]
+	}
+
+	w := (n - i) / wordSize
 	if w > 0 {
-		dw := *(*[]uintptr)(unsafe.Pointer(&dst))
-		aw := *(*[]uintptr)(unsafe.Pointer(&a))
-		bw := *(*[]uintptr)(unsafe.Pointer(&b))
-		for i := 0; i < w; i++ {
-			dw[i] = aw[i] | bw[i]
+		ad := unsafe.Slice((*uintptr)(unsafe.Pointer(&a[i])), w)
+		bd := unsafe.Slice((*uintptr)(unsafe.Pointer(&b[i])), w)
+		dd := unsafe.Slice((*uintptr)(unsafe.Pointer(&dst[i])), w)
+		for j := 0; j < w; j++ {
+			dd[j] = ad[j] | bd[j]
 		}
+		i += w * wordSize
 	}
-	for i := n - n%wordSize; i < n; i++ {
+
+	for ; i < n; i++ {
 		dst[i] = a[i] | b[i]
 	}
 	return n
@@ -137,10 +158,7 @@ func fastORBytes(dst, a, b []byte) int {
 // safeORBytes ors one by one. It works on all architectures, independent if
 // it supports unaligned read/writes or not.
 func safeORBytes(dst, a, b []byte) int {
-	n := len(a)
-	if len(b) < n {
-		n = len(b)
-	}
+	n := min(len(b), len(a))
 	for i := 0; i < n; i++ {
 		dst[i] = a[i] | b[i]
 	}
@@ -179,7 +197,7 @@ func fastTestBytes(p []byte) bool {
 // safeTestBytes tests for set bits one byte at a time. It works on all
 // architectures, independent if it supports unaligned read/writes or not.
 func safeTestBytes(p []byte) bool {
-	for i := 0; i < len(p); i++ {
+	for i := range p {
 		if p[i] != 0 {
 			return true
 		}
diff --git a/common/bytes.go b/common/bytes.go
index d1f5c6c9958..b3438c177d2 100644
--- a/common/bytes.go
+++ b/common/bytes.go
@@ -52,22 +52,13 @@ 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.