python aes_cbc加密

from Crypto.Cipher import AES

    # aes加密解密
    def pkcs7padding(self,text):
        """
        明文使用PKCS7填充
        最终调用AES加密方法时，传入的是一个byte数组，要求是16的整数倍，因此需要对明文进行处理
        :param text: 待加密内容(明文)
        :return:
        """
        bs = AES.block_size  # 16
        length = len(text)
        bytes_length = len(bytes(text, encoding='utf-8'))
        # tips：utf-8编码时，英文占1个byte，而中文占3个byte
        padding_size = length if (bytes_length == length) else bytes_length
        padding = bs - padding_size % bs
        # tips：chr(padding)看与其它语言的约定，有的会使用'\0'
        padding_text = chr(padding) * padding
        return text + padding_text

    def pkcs7unpadding(self,text):
        """
        处理使用PKCS7填充过的数据
        :param text: 解密后的字符串
        :return:
        """
        length = len(text)
        unpadding = ord(text[length - 1])
        return text[0:length - unpadding]
    def aescode(self, type_, str_):
        thirdpass_key = b'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'
        thirdpass_iv = b'aaaaaaaaaaaaaaaa'

        key = thirdpass_key  # 32bytes
        iv = thirdpass_iv
        # 还需要使用iv一个向量.
        # 使用key和iv初始化AES对象, 使用MODE_CFB模式.
        try:
            aesobj = AES.new(key, AES.MODE_CBC, iv)
        except Exception as e:
            return (False, 'aes初始化失败')

        try:
            if type_ == 'encode':
                # 处理明文
                content_padding = self.pkcs7padding(str_)
                data_str = content_padding.encode("utf-8")
                aesencode = base64.b64encode(aesobj.encrypt(data_str)).decode()
                return (True, aesencode)
            elif type_ == 'decode':
                # 处理明文
                data_str = str_.encode("utf-8")
                aesdecode = aesobj.decrypt(base64.b64decode(data_str)).decode()
                aesdecode = self.pkcs7unpadding(aesdecode)
                return (True, aesdecode)
            else:
                return (False, 'type_ is encode/decode')
        except Exception as e:
            return (False, 'aes方法报错')

[True, 'CCAVPBaD6gptwAeGwtC0Rw==']
(True, '{"k": "a"}'