Read encrypted file

[ByLost 139]

Helo!

I am studying a little about file encryption.
I would like to clarify some doubts.

1º I encrypted the intrologin.py file
So when running the game, I get this error: compile() expected string without null bytes

That is a system.py warning error.
The question is, how do I do the responsible files, then read this encrypted file?

How does this "start" of system.py work

Thanks