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14d4f286 S |
1 | <?php |
2 | /** | |
3 | * An implementation of the RFC 2898 PBKDF2 Standard key derivation function | |
4 | * | |
5 | * PHP version 5.3 | |
6 | * | |
7 | * @see http://www.ietf.org/rfc/rfc2898.txt | |
8 | * @category PHPCryptLib | |
9 | * @package Key | |
10 | * @subpackage Derivation | |
11 | * @author Anthony Ferrara <ircmaxell@ircmaxell.com> | |
12 | * @copyright 2011 The Authors | |
13 | * @license http://www.opensource.org/licenses/mit-license.html MIT License | |
14 | * @version Build @@version@@ | |
15 | */ | |
16 | ||
17 | namespace CryptLib\Key\Derivation\PBKDF; | |
18 | ||
19 | use CryptLib\Hash\Hash; | |
20 | ||
21 | /** | |
22 | * An implementation of the RFC 2898 PBKDF2 Standard key derivation function | |
23 | * | |
24 | * @see http://www.ietf.org/rfc/rfc2898.txt | |
25 | * @category PHPCryptLib | |
26 | * @package Key | |
27 | * @subpackage Derivation | |
28 | * @author Anthony Ferrara <ircmaxell@ircmaxell.com> | |
29 | */ | |
30 | class PBKDF2 | |
31 | extends \CryptLib\Key\Derivation\AbstractDerivation | |
32 | implements \CryptLib\Key\Derivation\PBKDF | |
33 | { | |
34 | ||
35 | /** | |
36 | * Derive a key from the supplied arguments | |
37 | * | |
38 | * @param string $password The password to derive from | |
39 | * @param string $salt The salt string to use | |
40 | * @param int $iterations The number of iterations to use | |
41 | * @param int $length The size of the string to generate | |
42 | * | |
43 | * @return string The derived key | |
44 | */ | |
45 | public function derive($password, $salt, $iterations, $length) { | |
46 | $size = Hash::getHashSize($this->hash); | |
47 | $len = ceil($length / $size); | |
48 | $result = ''; | |
49 | for ($i = 1; $i <= $len; $i++) { | |
50 | $tmp = hash_hmac( | |
51 | $this->hash, | |
52 | $salt . pack('N', $i), | |
53 | $password, | |
54 | true | |
55 | ); | |
56 | $res = $tmp; | |
57 | for ($j = 1; $j < $iterations; $j++) { | |
58 | $tmp = hash_hmac($this->hash, $tmp, $password, true); | |
59 | $res ^= $tmp; | |
60 | } | |
61 | $result .= $res; | |
62 | } | |
63 | return substr($result, 0, $length); | |
64 | } | |
65 | ||
66 | /** | |
67 | * Get the signature for this implementation | |
68 | * | |
69 | * This should include all information needed to build the same isntance | |
70 | * later. | |
71 | * | |
72 | * @return string The signature for this instance | |
73 | */ | |
74 | public function getSignature() { | |
75 | return 'pbkdf2-' . $this->hash; | |
76 | } | |
77 | ||
78 | } | |
79 |