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 * @category  Crypt
43 * @package   AES
44 * @author    Jim Wigginton <terrafrost@php.net>
45 * @copyright 2008 Jim Wigginton
46 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
47 * @link      http://phpseclib.sourceforge.net
48 */
49
50namespace phpseclib3\Crypt;
51
52/**
53 * Pure-PHP implementation of AES.
54 *
55 * @package AES
56 * @author  Jim Wigginton <terrafrost@php.net>
57 * @access  public
58 */
59class AES extends Rijndael
60{
61    /**
62     * Dummy function
63     *
64     * Since \phpseclib3\Crypt\AES extends \phpseclib3\Crypt\Rijndael, this function is, technically, available, but it doesn't do anything.
65     *
66     * @see \phpseclib3\Crypt\Rijndael::setBlockLength()
67     * @access public
68     * @param int $length
69     * @throws \BadMethodCallException anytime it's called
70     */
71    public function setBlockLength($length)
72    {
73        throw new \BadMethodCallException('The block length cannot be set for AES.');
74    }
75
76    /**
77     * Sets the key length
78     *
79     * Valid key lengths are 128, 192, and 256.  Set the link to bool(false) to disable a fixed key length
80     *
81     * @see \phpseclib3\Crypt\Rijndael:setKeyLength()
82     * @access public
83     * @param int $length
84     * @throws \LengthException if the key length isn't supported
85     */
86    public function setKeyLength($length)
87    {
88        switch ($length) {
89            case 128:
90            case 192:
91            case 256:
92                break;
93            default:
94                throw new \LengthException('Key of size ' . $length . ' not supported by this algorithm. Only keys of sizes 128, 192 or 256 supported');
95        }
96        parent::setKeyLength($length);
97    }
98
99    /**
100     * Sets the key.
101     *
102     * Rijndael supports five different key lengths, AES only supports three.
103     *
104     * @see \phpseclib3\Crypt\Rijndael:setKey()
105     * @see setKeyLength()
106     * @access public
107     * @param string $key
108     * @throws \LengthException if the key length isn't supported
109     */
110    public function setKey($key)
111    {
112        switch (strlen($key)) {
113            case 16:
114            case 24:
115            case 32:
116                break;
117            default:
118                throw new \LengthException('Key of size ' . strlen($key) . ' not supported by this algorithm. Only keys of sizes 16, 24 or 32 supported');
119        }
120
121        parent::setKey($key);
122    }
123}
124