CryptoJS中的AES-CTR是否与PyCrypto兼容？ [英] Is AES-CTR in CryptoJS compatible with PyCrypto?
问题描述
我试图使用PyCrypto库解密一些AES-CTR-256数据。密文是由Cryptocat多方聊天Javascript代码生成的，它依赖于CryptoJS库。 IV方案如Cryptocat 多方协议规范中所述： p>
I'm trying to decrypt some AES-CTR-256 data using the PyCrypto library. The ciphertext was produced by the Cryptocat multiparty chat Javascript code, which relies on the CryptoJS library. The IV scheme is as described in the Cryptocat Multiparty Protocol Specification:
初始化向量（IV）由16个字节组成：12个字节，
随机生成，4个字节用作计数器，每个块增加
一次。
The Initialization Vector (IV) is composed of 16 bytes: 12 bytes that are randomly generated and 4 bytes acting as the counter, incremented once per block.
（这12个随机字节在4个计数器字节之前。）
(The 12 random bytes come before the 4 counter bytes.)
这是我的Python代码：
Here's my Python code:
import struct
import base64
import Crypto.Cipher.AES
def bytestring_to_int(s):
r = 0
for b in s:
r = r * 256 + ord(b)
return r
class IVCounter(object):
def __init__(self, prefix="", iv="\x00\x00\x00\x00"):
self.prefix = prefix
self.initial_value = iv
def increment(self, b):
if b == "\xff\xff\xff\xff":
raise ValueError("Reached the counter limit")
return struct.pack(">I", bytestring_to_int(b)+1)
def __call__(self):
self.initial_value = self.increment(self.initial_value)
n = base64.b64decode(self.prefix) + self.initial_value
return n
def decrypt_msg(key, msg, iv):
k = base64.b16decode(key.upper())
ctr = IVCounter(prefix=iv)
aes = Crypto.Cipher.AES.new(k, Crypto.Cipher.AES.MODE_CTR, counter=ctr)
plaintext = aes.decrypt(msg)
return plaintext
if __name__ == "__main__":
key = 'b1df40bc2e4a1d4e31c50574735e1c909aa3c8fda58eca09bf2681ce4d117e11'
msg = 'LwFUZbKzuarvPR6pmXM2AiYVD2iL0/Ww2gs/9OpcMy+MWasvvzA2UEmRM8dq4loB\ndfPaYOe65JqGQMWoLOTWo1TreBd9vmPUZt72nFs='
iv = 'gpG388l8rT02vBH4'
plaintext = decrypt_msg(key, msg, iv)
print plaintext
这是如何做同样的事情Javascript：
And this is how to do the same thing in Javascript:
- 安装CryptoCat扩充功能
- 执行CryptoCat
- 启动开发者控制台（Chrome / Firefox中的F12）
- 运行以下代码行
- Install the CryptoCat extension
- Run CryptoCat
- Fire up the developer console (F12 in Chrome/Firefox)
- Run these lines of code
key = 'b1df40bc2e4a1d4e31c50574735e1c909aa3c8fda58eca09bf2681ce4d117e11';
msg = 'LwFUZbKzuarvPR6pmXM2AiYVD2iL0/Ww2gs/9OpcMy+MWasvvzA2UEmRM8dq4loB\ndfPaYOe65JqGQMWoLOTWo1TreBd9vmPUZt72nFs=';
iv = 'gpG388l8rT02vBH4';
opts = {mode: CryptoJS.mode.CTR, iv: CryptoJS.enc.Base64.parse(iv), padding: CryptoJS.pad.NoPadding};
CryptoJS.AES.decrypt(msg, CryptoJS.enc.Hex.parse(key), opts).toString(CryptoJS.enc.Utf8);
预期输出：Hello，world！ImiAq7aVLlmZDM9RfhDQgPp0CrAyZE0lyzJ6HDq4VoUmIiKUg7i2xpTSPs28USU8。正如预期的，这适用于Javascript。
Expected output: "Hello, world!ImiAq7aVLlmZDM9RfhDQgPp0CrAyZE0lyzJ6HDq4VoUmIiKUg7i2xpTSPs28USU8". As expected, this works on Javascript.
但是，Python代码输出乱码。 repr（明文）给出：
However, the Python code outputs gibberish. repr(plaintext) gives:
'\x91I\xbd\n\xd5\x11\x0fkE\xaa\x04\x81V\xc9\x16;.\xe3\xd3#\x92\x85\xd2\x99\xaf;\xc5\xafI\xac\xb6\xbdT\xf4{l\x17\xa1`\x85\x13\xf2\x8e\x844\xac1OS\xad\x9eZ<\xea\xbb6\x9dS\xd5\xbc\xfd\xc4\r\xf94Y~\xaf\xf3\xe0I\xad\xa6.\xfa\x7f\xf8U\x16\x0e\x85\x82\x8c\x8e\x04\xcb,X\x8b\xf7\xef\xb2\xc2\xe3~\xf1\x80\x08L\x8b \x9f\xaf\x0e\x0b'
我不知道为什么正在发生。我很确定我的IVCounter实现匹配的方案，JS代码使用。可能是没有Python等价的CryptoJS NoPadding选项？
I'm not sure why this is happening. I'm pretty sure my IVCounter implementation matches the scheme that the JS code uses. Could it be that there is no Python equivalent of the CryptoJS NoPadding option? I'm stumped.
推荐答案
我递增计数器的方式有一些问题。显然，正确的计数器值应用于错误的位置。以下是解决问题的后续问题。 使用Python和JavaScript的AES点击模式的奇怪问题< a>
There's something wrong with the way I'm incrementing the counter. Apparently the right counter values are applied to the wrong places. Here's a follow-up question that addresses the issue. Strange issue with AES CTR mode with Python and Javascript
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