private function _binaryXor($left, $round)
    {
        $xOr = gmp_xor(
            gmp_init($left, 2),
            gmp_init($round, 2)
        );

        $bin = gmp_strval($xOr, 2);

        return str_pad($bin, $this->sideSize, '0', STR_PAD_LEFT);
    }
private function _binaryXor($left, $round)
    {
        $xOr = gmp_xor(
            gmp_init($left, 2),
            gmp_init($round, 2)
        );

        $bin = gmp_strval($xOr, 2);

        return str_pad($bin, $this->sideSize, '0', STR_PAD_LEFT);
    }
private function _binaryXor ( $ left , $ round ) { $ xOr = gmp_xor ( gmp_init ( $ left , 2 ) , gmp_init ( $ round , 2 ) ) ; $ bin = gmp_strval ( $ xOr , 2 ) ; return str_pad ( $ bin , $ this -> sideSize , '0' , STR_PAD_LEFT ) ; }
Binary xor helper.

@param string $left
@param string $round

@return string Binary string.
Binary xor helper .