diff --git a/src/abstract/utils.ts b/src/abstract/utils.ts
index 2682f2f..50ebfda 100644
--- a/src/abstract/utils.ts
+++ b/src/abstract/utils.ts
@@ -44,7 +44,8 @@ export function hexToNumber(hex: string): bigint {
   return BigInt(hex === '' ? '0' : `0x${hex}`);
 }
 
-const enum HexCharCode {
+// We use very optimized technique to convert hex string to byte array
+const enum HexC {
   ZERO = 48, // 0
   NINE = 57, // 9
   A_UP = 65, // A
@@ -54,15 +55,10 @@ const enum HexCharCode {
 }
 
 function charCodeToBase16(char: number) {
-  if (char >= HexCharCode.ZERO && char <= HexCharCode.NINE) {
-    return char - HexCharCode.ZERO;
-  } else if (char >= HexCharCode.A_UP && char <= HexCharCode.F_UP) {
-    return char - (HexCharCode.A_UP - 10);
-  } else if (char >= HexCharCode.A_LO && char <= HexCharCode.F_LO) {
-    return char - (HexCharCode.A_LO - 10);
-  }
-
-  throw new Error('Invalid byte sequence.');
+  if (char >= HexC.ZERO && char <= HexC.NINE) return char - HexC.ZERO;
+  else if (char >= HexC.A_UP && char <= HexC.F_UP) return char - (HexC.A_UP - 10);
+  else if (char >= HexC.A_LO && char <= HexC.F_LO) return char - (HexC.A_LO - 10);
+  throw new Error('Invalid byte sequence');
 }
 
 /**
@@ -72,8 +68,9 @@ export function hexToBytes(hex: string): Uint8Array {
   if (typeof hex !== 'string') throw new Error('hex string expected, got ' + typeof hex);
   const len = hex.length;
   if (len % 2) throw new Error('padded hex string expected, got unpadded hex of length ' + len);
-  const array = new Uint8Array(len / 2);
-  for (let i = 0, j = 0, l = array.length; i < l; i++) {
+  const al = len / 2;
+  const array = new Uint8Array(al);
+  for (let i = 0, j = 0; i < al; i++) {
     const n1 = charCodeToBase16(hex.charCodeAt(j++));
     const n2 = charCodeToBase16(hex.charCodeAt(j++));
     array[i] = n1 * 16 + n2;