1<?php
2
3/**
4 * Pure-PHP implementation of AES.
5 *
6 * Uses mcrypt, if available/possible, and an internal implementation, otherwise.
7 *
8 * PHP version 5
9 *
10 * NOTE: Since AES.php is (for compatibility and phpseclib-historical reasons) virtually
11 * just a wrapper to Rijndael.php you may consider using Rijndael.php instead of
12 * to save one include_once().
13 *
14 * If {@link self::setKeyLength() setKeyLength()} isn't called, it'll be calculated from
15 * {@link self::setKey() setKey()}.  ie. if the key is 128-bits, the key length will be 128-bits.  If it's 136-bits
16 * it'll be null-padded to 192-bits and 192 bits will be the key length until {@link self::setKey() setKey()}
17 * is called, again, at which point, it'll be recalculated.
18 *
19 * Since \phpseclib3\Crypt\AES extends \phpseclib3\Crypt\Rijndael, some functions are available to be called that, in the context of AES, don't
20 * make a whole lot of sense.  {@link self::setBlockLength() setBlockLength()}, for instance.  Calling that function,
21 * however possible, won't do anything (AES has a fixed block length whereas Rijndael has a variable one).
22 *
23 * Here's a short example of how to use this library:
24 * <code>
25 * <?php
26 *    include 'vendor/autoload.php';
27 *
28 *    $aes = new \phpseclib3\Crypt\AES('ctr');
29 *
30 *    $aes->setKey('abcdefghijklmnop');
31 *
32 *    $size = 10 * 1024;
33 *    $plaintext = '';
34 *    for ($i = 0; $i < $size; $i++) {
35 *        $plaintext.= 'a';
36 *    }
37 *
38 *    echo $aes->decrypt($aes->encrypt($plaintext));
39 * ?>
40 * </code>
41 *
42 * @author    Jim Wigginton <terrafrost@php.net>
43 * @copyright 2008 Jim Wigginton
44 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
45 * @link      http://phpseclib.sourceforge.net
46 */
47
48namespace phpseclib3\Crypt;
49
50/**
51 * Pure-PHP implementation of AES.
52 *
53 * @author  Jim Wigginton <terrafrost@php.net>
54 */
55class AES extends Rijndael
56{
57    /**
58     * Dummy function
59     *
60     * Since \phpseclib3\Crypt\AES extends \phpseclib3\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
61     *
62     * @see \phpseclib3\Crypt\Rijndael::setBlockLength()
63     * @param int $length
64     * @throws \BadMethodCallException anytime it's called
65     */
66    public function setBlockLength($length)
67    {
68        throw new \BadMethodCallException('The block length cannot be set for AES.');
69    }
70
71    /**
72     * Sets the key length
73     *
74     * Valid key lengths are 128, 192, and 256.  Set the link to bool(false) to disable a fixed key length
75     *
76     * @see \phpseclib3\Crypt\Rijndael:setKeyLength()
77     * @param int $length
78     * @throws \LengthException if the key length isn't supported
79     */
80    public function setKeyLength($length)
81    {
82        switch ($length) {
83            case 128:
84            case 192:
85            case 256:
86                break;
87            default:
88                throw new \LengthException('Key of size ' . $length . ' not supported by this algorithm. Only keys of sizes 128, 192 or 256 supported');
89        }
90        parent::setKeyLength($length);
91    }
92
93    /**
94     * Sets the key.
95     *
96     * Rijndael supports five different key lengths, AES only supports three.
97     *
98     * @see \phpseclib3\Crypt\Rijndael:setKey()
99     * @see setKeyLength()
100     * @param string $key
101     * @throws \LengthException if the key length isn't supported
102     */
103    public function setKey($key)
104    {
105        switch (strlen($key)) {
106            case 16:
107            case 24:
108            case 32:
109                break;
110            default:
111                throw new \LengthException('Key of size ' . strlen($key) . ' not supported by this algorithm. Only keys of sizes 16, 24 or 32 supported');
112        }
113
114        parent::setKey($key);
115    }
116}
117