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February 24, 2014 01:41
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<?php | |
/* | |
* Password Hashing With PBKDF2 (http://crackstation.net/hashing-security.htm). | |
* Copyright (c) 2013, Taylor Hornby | |
* All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without | |
* modification, are permitted provided that the following conditions are met: | |
* | |
* 1. Redistributions of source code must retain the above copyright notice, | |
* this list of conditions and the following disclaimer. | |
* | |
* 2. Redistributions in binary form must reproduce the above copyright notice, | |
* this list of conditions and the following disclaimer in the documentation | |
* and/or other materials provided with the distribution. | |
* | |
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | |
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
* POSSIBILITY OF SUCH DAMAGE. | |
*/ | |
// These constants may be changed without breaking existing hashes. | |
define("PBKDF2_HASH_ALGORITHM", "sha256"); | |
define("PBKDF2_ITERATIONS", 1000); | |
define("PBKDF2_SALT_BYTE_SIZE", 24); | |
define("PBKDF2_HASH_BYTE_SIZE", 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_BYTE_SIZE, MCRYPT_DEV_URANDOM)); | |
return PBKDF2_HASH_ALGORITHM . ":" . PBKDF2_ITERATIONS . ":" . $salt . ":" . | |
base64_encode(pbkdf2( | |
PBKDF2_HASH_ALGORITHM, | |
$password, | |
$salt, | |
PBKDF2_ITERATIONS, | |
PBKDF2_HASH_BYTE_SIZE, | |
true | |
)); | |
} | |
function validate_password($password, $correct_hash) | |
{ | |
$params = explode(":", $correct_hash); | |
if(count($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($algorithm, hash_algos(), true)) | |
trigger_error('PBKDF2 ERROR: Invalid hash algorithm.', E_USER_ERROR); | |
if($count <= 0 || $key_length <= 0) | |
trigger_error('PBKDF2 ERROR: Invalid parameters.', E_USER_ERROR); | |
if (function_exists("hash_pbkdf2")) { | |
// The output length is in NIBBLES (4-bits) if $raw_output is false! | |
if (!$raw_output) { | |
$key_length = $key_length * 2; | |
} | |
return hash_pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output); | |
} | |
$hash_length = strlen(hash($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)); | |
} | |
?> |
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