code: public boolean isInAlphabet(final byte[] arrayOctet, final boolean allowWSPad) {
          for (int i = 0; i < arrayOctet.length; i++) {
              if (!isInAlphabet(arrayOctet[i]) &&
                      (!allowWSPad || (arrayOctet[i] != PAD) && !isWhiteSpace(arrayOctet[i]))) {
                  return false;
              }
          }
          return true;
      }
docs: Tests a given byte array to see if it contains only valid characters within the alphabet.
  The method optionally treats whitespace and pad as valid.
  
  @param arrayOctet byte array to test
  @param allowWSPad if {@code true}, then whitespace and PAD are also allowed
  
  @return {@code true} if all bytes are valid characters in the alphabet or if the byte array is empty;
  {@code false}, otherwise