function _subWord($word) { static $sbox; if (empty($sbox)) { list(, , , , $sbox) = $this->_getTables(); } return $sbox[$word & 0xff] | $sbox[$word >> 8 & 0xff] << 8 | $sbox[$word >> 16 & 0xff] << 16 | $sbox[$word >> 24 & 0xff] << 24; }