【编程】Python3 使用自定义编码字符表解密Base64数据

前言

Python提供了“base64”模块用于编码、解码Base64数据。
但是并不是所有的Base64数据都会使用默认的字符表进行编码，所以这里对Python下实现自定义编码字符表解密Base64数据做一个简要记录。（关于Base64内部实现等相关内容可以参考这篇文章）

Python2.7

 1 # -*- coding: utf-8
 2 import base64
 3 import string
 4
 5 STANDARD_ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
 6 CUSTOM_ALPHABET = 'JXaYOjSNTet1dDrHsVlc0m5EknG7Ko6qibhFBuyzQUwxWCp4ZLf23gAvMR8PI9+/'
 7 ENCODE_TRANS = string.maketrans(STANDARD_ALPHABET, CUSTOM_ALPHABET)
 8 DECODE_TRANS = string.maketrans(CUSTOM_ALPHABET, STANDARD_ALPHABET)
 9
10 def encode(input):
11     return base64.b64encode(input).translate(ENCODE_TRANS)
12
13 def decode(input):
14     return base64.b64decode(input.translate(DECODE_TRANS))
15
16 enstr = encode("123")
17 print enstr #dcT2
18
19 destr = decode(enstr)
20 print destr #123

Python3.8

 1 # -*- coding: utf-8
 2 import base64
 3
 4 STANDARD_ALPHABET = b'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
 5 CUSTOM_ALPHABET = b'JXaYOjSNTet1dDrHsVlc0m5EknG7Ko6qibhFBuyzQUwxWCp4ZLf23gAvMR8PI9+/'
 6 ENCODE_TRANS = bytes.maketrans(STANDARD_ALPHABET, CUSTOM_ALPHABET)
 7 DECODE_TRANS = bytes.maketrans(CUSTOM_ALPHABET, STANDARD_ALPHABET)
 8
 9 def encode(input):
10   return base64.b64encode(input).translate(ENCODE_TRANS)
11
12 def decode(input):
13   return base64.b64decode(input.translate(DECODE_TRANS))
14
15 enstr = encode("123".encode())
16 print(enstr.decode()) #dcT2
17
18 destr = decode(enstr)
19 print(destr.decode()) #123

参考链接：

https://bbs.khcloud.net/?thread-285.htm