aes/cbc/pkcs5padding/128加解密

    //******aes/cbc/pkcs5padding/128加解密******
    private function aesEncrypt($data,$iv=''){
        $enc_key = 'KlW';//随机生成16为由大小写字符和数字组成的字符串
        $enc_iv = self::aesRandom(16,'1234567890abcdefghijklmnopqrstuvwxyz');//随机生成16位iv
        if($iv){
            $enc_iv=$iv;
        }
        $method = MCRYPT_RIJNDAEL_128;
        $mode = MCRYPT_MODE_CBC;
        //优化
        $block = mcrypt_get_block_size($method, $mode);
        $pad = $block - (strlen($data)%$block);
        $pad = $data.str_repeat(chr($pad), $pad);

        $td = mcrypt_module_open($method, '', $mode, '');
        mcrypt_generic_init($td , $enc_key , $enc_iv);
        $encrypt = mcrypt_generic($td, $pad);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return base64_encode($enc_iv.$encrypt);//iv拼密串之后base64
    }

    private function aesDecrypt($data){
        $dec_key = 'lW';//随机生成16为由大小写字符和数字组成的字符串
        $data = base64_decode($data) ;//base64
        $dec_iv = substr($data, 0, 16);//前16位为iv
        if(strlen($dec_iv)<16){
            return false;
        }
        $data = substr($data,16);       //16位后未密串

        $method = MCRYPT_RIJNDAEL_128;
        $mode = MCRYPT_MODE_CBC;
        $td = mcrypt_module_open($method, '', $mode, '');
        mcrypt_generic_init($td , $dec_key , $dec_iv);
        $decrypt = mdecrypt_generic($td, $data);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        //Remove the padding
        $pad = ord($decrypt[($len = strlen($decrypt))-1]);
        //优化
        $beforePad = strlen($decrypt) - $pad;
        $decrypt = substr($decrypt, $beforePad) == str_repeat(substr($decrypt, -1), $pad) ? substr($decrypt, 0, $len - $pad) : $decrypt;
        return $decrypt;
    }

    private function aesRandom($length, $chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789')
    {
        $hash = '';
        $max = strlen($chars) - 1;
        for($i = 0; $i < $length; $i++)
        {
            $hash .= $chars[mt_rand(0, $max)];
        }
        return $hash;
    }
    private function checkOpenid($openid){
        if(!$openid){
            $json = json_encode(array('success'=>false,'msg'=>'参数非法'));
            return $json;
        }
//        $openid = str_replace(' ', '+', urldecode($openid));
        return $this->aesDecrypt(urldecode($openid));
    }