题目编号:GFSJ1202
附件下载后是一个python文件:
1. 分析代码,已添加详细注释
from Crypto.Cipher import AES # 导入AES对称加密算法模块
from Crypto.Util.strxor import strxor as xor # 导入按位异或函数,并重命名为xor
from Crypto.Util.Padding import pad # 导入填充函数,用于将数据填充到指定块大小
from random import * # 导入随机数生成模块的所有函数
from base64 import * # 导入Base64编码解码模块的所有函数
from copy import copy # 导入copy模块,用于复制对象
from secret import data # 从名为secret的模块中导入变量data(明文数据)
# 生成一个随机的16字节初始向量(IV)
iv = bytes([randint(0, 2**8 - 1) for i in range(16)])
iva = copy(iv) # 复制一份IV,可能在后续中备用
# 生成一个随机的16字节AES密钥
key = bytes([randint(0, 2**8 - 1) for i in range(16)])
# 使用生成的密钥创建一个AES ECB模式的密码对象
cipher = AES.new(key, mode=AES.MODE_ECB)
# 对明文数据进行填充,使其长度为16的倍数(AES的块大小)
data = pad(data, 16)
c = b"" # 初始化密文为一个空的字节串
# 对明文数据进行分块处理,每次处理16字节(一个块)
for i in range(0, len(data), 16):
# 取出当前的16字节块,如果不足16字节,用换行符补齐(虽然已经填充过了,这里是双重确保)
s = data[i:i+16].ljust(16, b"\n")
# 将当前的明文块s与IV进行按位异或,结果作为AES加密的输入
# 这一步引入了前一个块的加密结果,形成某种类似于反馈的模式
c += cipher.encrypt(xor(s, iv))
# 更新IV为当前的明文块s与刚刚生成的密文块c[-16:](最新的16字节密文)之间的异或结果
# 这样下一个块的加密会受到当前块的影响,增加了密文的复杂性
iv = xor(s, c[-16:])
# 将密钥进行Base64编码,便于以文本形式输出或存储
key = b64encode(key)
# 将密文进行Base64编码,同样是为了便于输出或存储
c = b64encode(c)
# 输出Base64编码后的密钥和密文
print(key)
print(c)
'''
key_b64 = b'+0zkhmid1PFjVdxSP09zSw=='
c_b64=b'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