What should I do first? Decrypt or Decompress? Python

问题

I'm trying to decrypt Bloomberg data files that I know are DES encrypted.

FileName = 'comdty_option_namr.out.gz.enc'

What is the right order to do things: Open the file and decompress and then decrypt or vice-versa?

回答1:

Well, it all depends on the way the file was transformed, and there are two possible ways (in your case is #1):

1. first create the zip, then encrypt the zip
2. first encrypt the file, then zip it

The extension of the file tells you the order of operations, by reading them from left to right:

1. comdty_option_namr.out is the name of the file
2. the file got gzipped, thus getting to comdty_option_namr.out.gz
3. after which the gzip archive to encrypted, resulting the file comdty_option_namr.out.gz.enc

来源：https://stackoverflow.com/questions/29741887/what-should-i-do-first-decrypt-or-decompress-python