php基于mcrypt_encrypt和mcrypt_decrypt实现字符串加密解密的方法

$key = "miyao";//密钥$string="jiami"//需要加密的字符//自带的加密函数$crypttext = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, md5(md5($key))));$encrypted =trim($this->safe_b64encode($crypttext));//对特殊字符进行处理$key="miyao"$crypttexttb=safe_b64decode($encrypted)//对特殊字符解析$decryptedtb = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($crypttexttb), MCRYPT_MODE_CBC, md5(md5($key))), "/0")//解密函数//处理特殊字符public function safe_b64encode($string) {    $data = base64_encode($string);    $data = str_replace(array('+','/','='),array('-','_',''),$data);    return $data;}//解析特殊字符public function safe_b64decode($string) {    $data = str_replace(array('-','_'),array('+','/'),$string);    $mod4 = strlen($data) % 4;    if ($mod4) {      $data .= substr('====', $mod4);    }    return base64_decode($data);}