PHPaes algorithm-PHP source code

Php code of PHPaes algorithm

function aes128cbcEncrypt($key, $text){    /**     * Open the cipher     */    $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');    if (! $td)    {        throw new GeneralSecurityException('Invalid mcrypt cipher, check your libmcrypt library and php-mcrypt extention');    }     // replaced MCRYPT_DEV_RANDOM with MCRYPT_RAND since windows doesn't have /dev/rand :)    srand((double)microtime() * 1000000);    $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);    /**     * Intialize encryption     */    mcrypt_generic_init($td, $key, $iv);    /**     * Encrypt data     */    $encrypted = mcrypt_generic($td, $text);    /**     * Terminate encryption handler     */    mcrypt_generic_deinit($td);    /**     * AES-128-CBC encryption.  The IV is returned as the first 16 bytes       * of the cipher text.     */    return $iv . $encrypted;} function aes128cbcDecrypt($key, $encrypted_text){    /**     * Open the cipher     */    $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');    if (is_callable('mb_substr'))    {        $iv = mb_substr($encrypted_text, 0, Crypto_CIPHER_BLOCK_SIZE, 'latin1');    }     else    {        $iv = substr($encrypted_text, 0, Crypto_CIPHER_BLOCK_SIZE);    }     /**     * Initialize encryption module for decryption     */    mcrypt_generic_init($td, $key, $iv);    /**     * Decrypt encrypted string     */    if (is_callable('mb_substr'))    {        $encrypted = mb_substr($encrypted_text, Crypto_CIPHER_BLOCK_SIZE, mb_strlen($encrypted_text, 'latin1'), 'latin1');    }     else    {        $encrypted = substr($encrypted_text, Crypto_CIPHER_BLOCK_SIZE);    }     $decrypted = mdecrypt_generic($td, $encrypted);    /**     * Terminate decryption handle and close module     */    mcrypt_generic_deinit($td);    mcrypt_module_close($td);    /**     * Show string     */    return trim($decrypted);} define('Crypto_CIPHER_BLOCK_SIZE', 16);$a = aes128cbcEncrypt('pass', 'this is text');echo base64_encode($a) . "/r/n";$b = aes128cbcDecrypt('pass', $a);echo $b . "/r/n";$c = aes128cbcDecrypt('pass', base64_decode(base64_encode($a)));echo $c . "/r/n";?>