I am making an adventure game in Python. Asking about Saving/loading - currency + other basic commands

I am making an adventure game in Python. Asking about Saving/loading -
currency + other basic commands

First of all I just want to apologize for my bad English; it's not my
native tongue.
I am currently making a game in Python, using only the console (MUD, only
singleplayer.)
I want this game to be huge, with a lot of levels. Currently, the game
consists of 2777 lines of code, and that's just part of level 1.
Because of this, I will make it possible for the user to save the game.
The user can only save the game at certain points.
I can most of the basic Python, and I actually think I could make a really
basic version of this.
I could make a code that saved the current location (def) to a .txt-file,
but then it is very simple for the user to manipulate it, and get to
levels or rooms the user are not allowed into.
I want a code or script that make a encrypted folder or file, where the
location of the user is placed. I also want there to be 3 savefiles. I
will either have three different encrypted files, or all the save files
located in one encrypted file. I really hope you understand what I mean. I
am terrible at explaining things in English.
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Another thing I want to have in my game, is currency. After the user have
completed a quest, I want the currency to