code: public static String encodeHex(byte[] bytes) {
  		char[] result = new char[bytes.length * 2];
  		for (int i = 0; i < bytes.length; i++) {
  			result[i * 2] = hexa[(bytes[i] & 0xF0) >> 4];
  			result[i * 2 + 1] = hexa[bytes[i] & 0x0F];
  		}
  		return new String(result);
  	}
docs: Encode bytes[] to lowercase hex string
  @param bytes
  @return lowcased hex value