code: public static byte[] rjust(byte[] bytes, int width) {
      if (bytes.length >= width) {
        return Arrays.copyOfRange(bytes, bytes.length - width, bytes.length);
      } else {
        byte[] rjustied = new byte[width];
        System.arraycopy(bytes, 0, rjustied, width - bytes.length, bytes.length);
        return rjustied;
      }
    }
docs: Modifies the length of a byte array by padding zero bytes to the left.
  
  @param bytes
  a byte array
  @param width
  of the new byte array
  @return new byte array