如何在python3中解码base64

How to decode base64 in python3

提问by Tspm1eca

I have a base64 encrypt code, and I can't decode in python3.5

我有一个base64加密代码，在python3.5中无法解码

import base64
code = "YWRtaW46MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA" # Unencrypt is 202cb962ac59075b964b07152d234b70
base64.b64decode(code)

Result:

结果：

binascii.Error: Incorrect padding

But same website(base64decode) can decode it,

但是同一个网站（base64decode）可以解码它，

Please anybody can tell me why, and how to use python3.5 decode it?

请谁能告诉我为什么，以及如何使用python3.5解码它？

Thanks

谢谢

回答by Daniel

Base64 needs a string with length multiple of 4. If the string is short, it is padded with 1 to 3 =.

Base64 需要长度为 4 倍的字符串。如果字符串很短，则用 1 到 3 填充=。

import base64
code = "YWRtaW46MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA="
base64.b64decode(code)
# b'admin:202cb962ac59075b964b07152d234b70'

回答by Saurav Gupta

According to this answer, you can just add the required padding.

根据此答案，您只需添加所需的填充即可。

code = "YWRtaW46MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA"
b64_string = code
b64_string += "=" * ((4 - len(b64_string) % 4) % 4)
base64.b64decode(b64_string) #'admin:202cb962ac59075b964b07152d234b70'

回答by user2853437

I tried the other way around. If you know what the unencrypted value is:

我尝试了相反的方法。如果您知道未加密的值是什么：

>>> import base64
>>> unencoded = b'202cb962ac59075b964b07152d234b70'
>>> encoded = base64.b64encode(unencoded)
>>> print(encoded)
b'MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA='
>>> decoded = base64.b64decode(encoded)
>>> print(decoded)
b'202cb962ac59075b964b07152d234b70'

Now you see the correct padding. b'MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA=

现在您可以看到正确的填充。 b'MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA=

回答by janbrohl

It actually seems to just be that codeis incorrectly padded(codeis incomplete)

实际上似乎只是填充不code正确（不完整）code

import base64
code = "YWRtaW46MjAyY2I5NjJhYzU5MDc1Yjk2NGIwNzE1MmQyMzRiNzA"
base64.b64decode(code+"=")

returns b'admin:202cb962ac59075b964b07152d234b70'

返回 b'admin:202cb962ac59075b964b07152d234b70'