使用PBKDF2在MySQL数据库中存储密码和salt

我一直在尝试使用pbkdf2使我的用户密码真正安全。

密码散列可以很好地进入数据库，但salt则不然。

salt似乎包含mysql列不喜欢的外来字符。

我的"users"表中的所有列都是UTF8_unicode_ci。

这是我的密码散列：

$size = mcrypt_get_iv_size(MCRYPT_CAST_256, MCRYPT_MODE_CFB);
$salt = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);
$passHash = pbkdf2('SHA512', $pass, $salt, 8192, 256) ;
include("dbconnect.php") ;
$result = $dbh->prepare("INSERT INTO users (name, email, qq, password, salt)VALUES(?, ?, ?, ?, ?)") ;
    $result->bindParam(1, $name, PDO::PARAM_STR) ;
    $result->bindParam(2, $email, PDO::PARAM_STR) ;
    $result->bindParam(3, $qq, PDO::PARAM_STR) ;
    $result->bindParam(4, $passHash, PDO::PARAM_STR) ;
    $result->bindParam(5, $salt, PDO::PARAM_STR) ;
$result->execute() ;

和pbkdf2:

/*
 * PBKDF2 key derivation function as defined by RSA's PKCS #5: https://www.ietf.org/rfc/rfc2898.txt
 * $algorithm - The hash algorithm to use. Recommended: SHA256
 * $password - The password.
 * $salt - A salt that is unique to the password.
* $count - Iteration count. Higher is better, but slower. Recommended: At least 1000.
* $key_length - The length of the derived key in bytes.
* $raw_output - If true, the key is returned in raw binary format. Hex encoded otherwise.
* Returns: A $key_length-byte key derived from the password and salt.
*
* Test vectors can be found here: https://www.ietf.org/rfc/rfc6070.txt
*
* This implementation of PBKDF2 was originally created by https://defuse.ca
* With improvements by http://www.variations-of-shadow.com
*/
function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false){
$algorithm = strtolower($algorithm);
if(!in_array($algorithm, hash_algos(), true))
    die('PBKDF2 ERROR: Invalid hash algorithm.');
if($count <= 0 || $key_length <= 0)
    die('PBKDF2 ERROR: Invalid parameters.');
$hash_length = strlen(hash($algorithm, "", true));
$block_count = ceil($key_length / $hash_length);
$output = "";
for($i = 1; $i <= $block_count; $i++) {
    // $i encoded as 4 bytes, big endian.
    $last = $salt . pack("N", $i);
    // first iteration
    $last = $xorsum = hash_hmac($algorithm, $last, $password, true);
    // perform the other $count - 1 iterations
    for ($j = 1; $j < $count; $j++) {
        $xorsum ^= ($last = hash_hmac($algorithm, $last, $password, true));
    }
    $output .= $xorsum;
}
if($raw_output)
    return substr($output, 0, $key_length);
else
    return bin2hex(substr($output, 0, $key_length));
}

此外，我刚刚注意到，它为相同的密码存储了完全不同的哈希。

我这样做对吗？