python實現AES對稱加解密

python實現AES對稱加解密

關於aes對稱加密的概念網上很多，在此不在贅述，直接上代碼。

import base64
from Crypto.Cipher import AES

"""
AES加密解密工具類
數據塊128位
key 爲16位
iv 爲16位
AES加密模式爲cbc
填充 pkcs7padding
"""


class MyRes(object):
    def __init__(self, key):
        self.key = key

    @staticmethod
    def pkcs7padding(text):
        bs = AES.block_size
        length = len(text)
        bytes_length = len(bytes(text, encoding='utf-8'))
        padding_size = length if(bytes_length == length) else bytes_length
        padding = bs - padding_size % bs
        # chr(padding)看與其它語言的約定，有的會使用'\0'
        padding_text = chr(padding) * padding
        return text + padding_text

    @staticmethod
    def pkcs7unpadding(text):
        length = len(text)
        unpadding = ord(text[length-1])
        return text[0:length-unpadding]

    def encrypt(self, content):
        key_bytes = bytes(self.key, encoding='utf-8')
        iv = key_bytes
        cipher = AES.new(key_bytes, AES.MODE_CBC, iv)

        content_padding = self.pkcs7padding(content)

        encrypt_bytes = cipher.encrypt(bytes(content_padding, encoding='utf-8'))

        result = str(base64.b64encode(encrypt_bytes), encoding='utf-8')
        return result

    def decrypt(self, content):
        key_bytes = bytes(self.key, encoding='utf-8')
        iv = key_bytes
        cipher = AES.new(key_bytes, AES.MODE_CBC, iv)

        encrypt_bytes = base64.b64decode(content)

        decrypt_bytes = cipher.decrypt(encrypt_bytes)

        result = str(decrypt_bytes, encoding='utf-8')

        result = self.pkcs7unpadding(result)

        return result


if __name__ == '__main__':
    text = "hello world"
    myrsa = MyRes("1234567890abcdef")
    encrypt_text = myrsa.encrypt(text)
    print("加密後：", encrypt_text)
    decrypt_text = myrsa.decrypt(encrypt_text)
    print("解密後：", decrypt_text)