class CryptHelper {

    /**

     * 加密

     * @param unknown $password

     * @param unknown $salt

     * @return string

     */

    public static function crypt($password,$salt){

        // $saltPrefix .= '$2y$'; // Blowfish 算法

        // $saltPrefix .= '13'; // 两位 cost 参数

        // $saltPrefix .= '$'; // 一个 $

        // $saltSuffix .= 'LGsF2ctmKKHE1yr2Py.vtu';

        return crypt($password, $salt);

    }

    /**

     * 字符比较

     * @param unknown $expected

     * @param unknown $actual

     * @return boolean

     */

    public static function compareString($expected, $actual)

    {

        $expected .= "\0";

        $actual .= "\0";

        $expectedLength = mb_strlen($expected, '8bit');

        $actualLength = mb_strlen($actual, '8bit');

        $diff = $expectedLength - $actualLength;

        for ($i = 0; $i < $actualLength; $i++) {

            $diff |= (ord($actual[$i]) ^ ord($expected[$i % $expectedLength]));

        }

        return $diff === 0;

    }

    /**

     * 校验密码

     * @param unknown $password

     * @param unknown $hash

     * @return boolean

     */

    public static function validatePassword($password, $hash)

    {

        if (!is_string($password) || $password === '') {

            return false;

        }

        if (!preg_match('/^\$2[axy]\$(\d\d)\$[\.\/0-9A-Za-z]{22}/', $hash, $matches)

            || $matches[1] < 4

            || $matches[1] > 30

        ) {

            return false;

        }

        $test = self::crypt($password, $hash);

        $n = strlen($test);

        if ($n !== 60) {

            return false;

        }

        return self::compareString($test, $hash);

    }

}

// --------- 测试 --------

// 加密

$salt = '$2y$13$LGsF2ctmKKHE1yr2Py.vtu'; // 7 + 22 == 29

$password = '123456';

echo CryptHelper::crypt($password,$salt);

echo PHP_EOL;

// 校验

$hash = '$2y$13$LGsF2ctmKKHE1yr2Py.vtuiUR/A0C6tARkCxMO.LUlsiRISu7u53m';

echo CryptHelper::crypt($password,$hash);

echo PHP_EOL;

echo strlen($hash);

echo PHP_EOL;

echo CryptHelper::validatePassword($password, $hash);