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 versions 4 and 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 Crypt_AES extends 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 'Crypt/AES.php';
27 *
28 *    $aes = new Crypt_AES();
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 * LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
43 * of this software and associated documentation files (the "Software"), to deal
44 * in the Software without restriction, including without limitation the rights
45 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
46 * copies of the Software, and to permit persons to whom the Software is
47 * furnished to do so, subject to the following conditions:
48 *
49 * The above copyright notice and this permission notice shall be included in
50 * all copies or substantial portions of the Software.
51 *
52 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
53 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
54 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
55 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
56 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
57 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
58 * THE SOFTWARE.
59 *
60 * @category  Crypt
61 * @package   Crypt_AES
62 * @author    Jim Wigginton <terrafrost@php.net>
63 * @copyright 2008 Jim Wigginton
64 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
65 * @link      http://phpseclib.sourceforge.net
66 */
67
68/**
69 * Include Crypt_Rijndael
70 */
71if (!class_exists('Crypt_Rijndael')) {
72    include_once 'Rijndael.php';
73}
74
75/**#@+
76 * @access public
77 * @see self::encrypt()
78 * @see self::decrypt()
79 */
80/**
81 * Encrypt / decrypt using the Counter mode.
82 *
83 * Set to -1 since that's what Crypt/Random.php uses to index the CTR mode.
84 *
85 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Counter_.28CTR.29
86 */
87define('CRYPT_AES_MODE_CTR', CRYPT_MODE_CTR);
88/**
89 * Encrypt / decrypt using the Electronic Code Book mode.
90 *
91 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29
92 */
93define('CRYPT_AES_MODE_ECB', CRYPT_MODE_ECB);
94/**
95 * Encrypt / decrypt using the Code Book Chaining mode.
96 *
97 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29
98 */
99define('CRYPT_AES_MODE_CBC', CRYPT_MODE_CBC);
100/**
101 * Encrypt / decrypt using the Cipher Feedback mode.
102 *
103 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher_feedback_.28CFB.29
104 */
105define('CRYPT_AES_MODE_CFB', CRYPT_MODE_CFB);
106/**
107 * Encrypt / decrypt using the Cipher Feedback mode.
108 *
109 * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Output_feedback_.28OFB.29
110 */
111define('CRYPT_AES_MODE_OFB', CRYPT_MODE_OFB);
112/**#@-*/
113
114/**
115 * Pure-PHP implementation of AES.
116 *
117 * @package Crypt_AES
118 * @author  Jim Wigginton <terrafrost@php.net>
119 * @access  public
120 */
121class Crypt_AES extends Crypt_Rijndael
122{
123    /**
124     * The namespace used by the cipher for its constants.
125     *
126     * @see Crypt_Base::const_namespace
127     * @var string
128     * @access private
129     */
130    var $const_namespace = 'AES';
131
132    /**
133     * Dummy function
134     *
135     * Since Crypt_AES extends Crypt_Rijndael, this function is, technically, available, but it doesn't do anything.
136     *
137     * @see Crypt_Rijndael::setBlockLength()
138     * @access public
139     * @param int $length
140     */
141    function setBlockLength($length)
142    {
143        return;
144    }
145
146    /**
147     * Sets the key length
148     *
149     * Valid key lengths are 128, 192, and 256.  If the length is less than 128, it will be rounded up to
150     * 128.  If the length is greater than 128 and invalid, it will be rounded down to the closest valid amount.
151     *
152     * @see Crypt_Rijndael:setKeyLength()
153     * @access public
154     * @param int $length
155     */
156    function setKeyLength($length)
157    {
158        switch ($length) {
159            case 160:
160                $length = 192;
161                break;
162            case 224:
163                $length = 256;
164        }
165        parent::setKeyLength($length);
166    }
167
168    /**
169     * Sets the key.
170     *
171     * Rijndael supports five different key lengths, AES only supports three.
172     *
173     * @see Crypt_Rijndael:setKey()
174     * @see setKeyLength()
175     * @access public
176     * @param string $key
177     */
178    function setKey($key)
179    {
180        parent::setKey($key);
181
182        if (!$this->explicit_key_length) {
183            $length = strlen($key);
184            switch (true) {
185                case $length <= 16:
186                    $this->key_length = 16;
187                    break;
188                case $length <= 24:
189                    $this->key_length = 24;
190                    break;
191                default:
192                    $this->key_length = 32;
193            }
194            $this->_setEngine();
195        }
196    }
197}
198