Aes CBC加密

 1 <?php
 2 namespace app\components;
 3 use yii;
 4 class Aes
 5 {
 6     /**
 7      * This was AES-128 / CBC / PKCS5Padding
 8      * return base64_encode string
 9      * @param string $plaintext
10      * @param string $key
11      * @return string
12      */
13     public static function AesEncrypt($plaintext,$key = null)
14     {
15         $plaintext = trim($plaintext);
16         if ($plaintext == '') return '';
17         $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
18 
19         //PKCS5Padding
20         $padding = $size - strlen($plaintext) % $size;
21         // 添加Padding
22         $plaintext .= str_repeat(chr($padding), $padding);
23 
24 
25         $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
26         $key=self::substr($key, 0, mcrypt_enc_get_key_size($module));
27         $iv = $key;
28         // str_repeat($key, $size);
29         /* Intialize encryption */
30         mcrypt_generic_init($module, $key, $iv);
31 
32 
33         /* Encrypt data */
34         $encrypted = mcrypt_generic($module, $plaintext);
35         /* Terminate encryption handler */
36         mcrypt_generic_deinit($module);
37         mcrypt_module_close($module);
38         return base64_encode($encrypted);
39     }
40     /**
41      * Returns the length of the given string.
42      * If available uses the multibyte string function mb_strlen.
43      * @param string $string the string being measured for length
44      * @return integer the length of the string
45      */
46     private static function strlen($string)
47     {
48         return extension_loaded('mbstring') ? mb_strlen($string,'8bit') : strlen($string);
49     }
50 
51 
52     /**
53      * Returns the portion of string specified by the start and length parameters.
54      * If available uses the multibyte string function mb_substr
55      * @param string $string the input string. Must be one character or longer.
56      * @param integer $start the starting position
57      * @param integer $length the desired portion length
58      * @return string the extracted part of string, or FALSE on failure or an empty string.
59      */
60     private static function substr($string,$start,$length)
61     {
62         return extension_loaded('mbstring') ? mb_substr($string,$start,$length,'8bit') : substr($string,$start,$length);
63     }
64     /**
65      * This was AES-128 / CBC / PKCS5Padding
66      * @param string $encrypted     base64_encode encrypted string
67      * @param string $key
68      * @throws CException
69      * @return string
70      */
71     public static function AesDecrypt($encrypted, $key = null)
72     {
73         if ($encrypted == '') return '';
74         $ciphertext_dec = base64_decode($encrypted);
75         $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
76         $key=self::substr($key, 0, mcrypt_enc_get_key_size($module));
77         $iv = $key;
78         // str_repeat($key, 16);    //解密的初始化向量要和加密时一样。
79         /* Initialize encryption module for decryption */
80         mcrypt_generic_init($module, $key, $iv);
81 
82 
83         /* Decrypt encrypted string */
84         $decrypted = mdecrypt_generic($module, $ciphertext_dec);
85 
86         /* Terminate decryption handle and close module */
87         mcrypt_generic_deinit($module);
88         mcrypt_module_close($module);
89         // echo $decrypted;die;
90         //$a = rtrim($decrypted,"\0");
91         return rtrim($decrypted,"\0");
92     }
93 }