PHP - hash_pbkdf2 function

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I'm trying to do a function to hash passwords with this php function: http://be.php.net/manual/en/function.hash-pbkdf2.php.

Here is the code:

$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;

I got this error: Fatal error: Call to undefined function hash_pbkdf2().

How can the function be undefined???

PS: All the values of my variables are set just for testing the function. Obviously the salt will not be "salt", etc.

EDIT: As of PHP 5.5.0 this function is now bundled into the core library.


This function is not (yet anyway) available in core PHP. It was proposed not that long ago and so far you can only get it as a patch.

You can use crypt or hash instead. crypt is actually suggested in hash_pbkdf2 documentation:

Caution The PBKDF2 method can be used for hashing passwords for storage (it is NIST approved for that use). However, it should be noted that CRYPT_BLOWFISH is better suited for password storage and should be used instead via crypt().

hash_pbkdf2 - Manual, Parameters �. algo. Name of selected hashing algorithm (i.e. md5, sha256, haval160,4, etc..) See hash_algos() for a list of supported algorithms. password. PHP | hash_pbkdf2() Function The hash_pbkdf2() function is an inbuilt function in PHP which is used to generate a PBKDF2 key derivation of a supplied password. Syntax:

You CAN use PBKDF2 if you include the function yourself. Just paste the code on this website into your application, it couldn't be easier. The code is public domain (as stated on that site).

Here is the code in full:

<?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));
}
?>

If you need to know anything about hashing, salts, iterations, and all that other stuff, this website has all the right answers.

hash-pbkdf2 function, hash_pbkdf2. (PHP 5 >= 5.5.0). hash_pbkdf2 — Generate a PBKDF2 key derivation of a supplied password� The PBKDF2 method can be used for hashing passwords for storage (it is NIST approved for that use). However, it should be noted that CRYPT_BLOWFISH is better suited for password storage and should be used instead via crypt ().

You could find this in the manual.

(No version information available, might only be in SVN)

It means this function is not available.

PHP - hash_pbkdf2 function, EDIT: As of PHP 5.5.0 this function is now bundled into the core library. This function is not (yet anyway) available in core PHP. It was proposed� PHP hash_pbkdf2 - 30 examples found. These are the top rated real world PHP examples of hash_pbkdf2 extracted from open source projects. You can rate examples to help us improve the quality of examples.

Update

Now hash_pbkdf2 is available for (PHP 5 >= 5.5.0, PHP 7). Doc : http://be.php.net/manual/en/function.hash-pbkdf2.php

Proposal and Patch. The proposal is to add a hash_pbkdf2 () function to the hash extension in core. The proposed function has a signature: string hash_pbkdf2 (string algo, string password, string salt, int iterations [, int length = 0, bool raw_output = false]) The patch is available as a pull request to trunk.

openssl_pbkdf2() computes PBKDF2 (Password-Based Key Derivation Function 2), a key derivation function defined in PKCS5 v2.

hash_pbkdf2 — Generate a PBKDF2 key derivation of a supplied password hash_update_file — Pump data into an active hashing context from a file hash_update_stream — Pump data into an active hashing context from an open stream

I made a PHP script that will let you sort all the available hashes on your system by generation time or by the length of the hash. It shows a general correlation on my system (longer hashes take longer to calculate) but some are faster than others, for example, sha512 makes the (joint) longest hash, but is actually only ninth slowest (from 43

Comments
  • Probably your version of php doesn't support it. "No version information available, might only be in SVN"