PHP - hash_pbkdf2函数

Question

我正在尝试使用这个php函数来执行函数来散列密码：http://be.php.net/manual/en/function.hash-pbkdf2.php。

这是代码：

$hash_algo = "sha256";
$password = "password";
$salt = "salt";
$iterations = 1;
$length = 1;
$raw_output = false;

$hash = hash_pbkdf2($hash_algo, $password, $salt, $iterations ,$length ,$raw_output);

echo $hash;

我收到此错误：致命错误：调用未定义的函数hash_pbkdf2（）。

如何定义函数？

PS：我的变量的所有值都是为测试函数而设置的。显然盐不会是“盐”等。

Answer 1

编辑：从PHP 5.5.0开始，此功能现已捆绑到核心库中。

---

这个功能（但无论如何）在核心PHP中都不可用。它不是很久以前提出的，到目前为止你只能把它作为patch。

您可以使用crypt或hash代替。 crypt实际上是在hash_pbkdf2 documentation建议的：

警告 PBKDF2方法可用于存储的散列密码（NIST已批准用于此用途）。但是，应该注意CRYPT_BLOWFISH更适合密码存储，应该通过crypt()使用。

Answer 2

如果您自己包含该功能，可以使用PBKDF2。只需将this website上的代码粘贴到您的应用程序中，就不会那么容易了。代码是公共领域（如该网站所述）。

这是完整的代码：

<?php
/*
 * Password hashing with PBKDF2.
 * Author: havoc AT defuse.ca
 * www: https://defuse.ca/php-pbkdf2.htm
 */

// These constants may be changed without breaking existing hashes.
define("PBKDF2_HASH_ALGORITHM", "sha256");
define("PBKDF2_ITERATIONS", 1000);
define("PBKDF2_SALT_BYTES", 24);
define("PBKDF2_HASH_BYTES", 24);

define("HASH_SECTIONS", 4);
define("HASH_ALGORITHM_INDEX", 0);
define("HASH_ITERATION_INDEX", 1);
define("HASH_SALT_INDEX", 2);
define("HASH_PBKDF2_INDEX", 3);

function create_hash($password)
{
    // format: algorithm:iterations:salt:hash
    $salt = base64_encode(mcrypt_create_iv(PBKDF2_SALT_BYTES, MCRYPT_DEV_URANDOM));
    return PBKDF2_HASH_ALGORITHM . ":" . PBKDF2_ITERATIONS . ":" .  $salt . ":" . 
        base64_encode(pbkdf2(
            PBKDF2_HASH_ALGORITHM,
            $password,
            $salt,
            PBKDF2_ITERATIONS,
            PBKDF2_HASH_BYTES,
            true
        ));
}

function validate_password($password, $good_hash)
{
    $params = explode(":", $good_hash);
    if(count($params) < HASH_SECTIONS)
       return false; 
    $pbkdf2 = base64_decode($params[HASH_PBKDF2_INDEX]);
    return slow_equals(
        $pbkdf2,
        pbkdf2(
            $params[HASH_ALGORITHM_INDEX],
            $password,
            $params[HASH_SALT_INDEX],
            (int)$params[HASH_ITERATION_INDEX],
            strlen($pbkdf2),
            true
        )
    );
}

// Compares two strings $a and $b in length-constant time.
function slow_equals($a, $b)
{
    $diff = strlen($a) ^ strlen($b);
    for($i = 0; $i < strlen($a) && $i < strlen($b); $i++)
    {
        $diff |= ord($a[$i]) ^ ord($b[$i]);
    }
    return $diff === 0; 
}

/*
 * 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));
}
?>

如果您需要了解有关散列，盐，迭代以及所有其他内容的任何信息，this website可以提供所有正确答案。

Answer 3

您可以在手册中找到它。

（没有可用的版本信息，可能只在SVN中）

这意味着此功能不可用。

Answer 4

更新

现在hash_pbkdf2可用于（PHP 5> = 5.5.0，PHP 7）。 Doc：http://be.php.net/manual/en/function.hash-pbkdf2.php