encrypting python modules

[Paul Sijben]

Hello,

this question has come by repeatedly in several guises over the past
years but has never been solved in this forum as far as I have been able
to Google.

However since so many people are asking the question, I hope someone has
made a solution and is willing to share it.

The problem: I have a client-server app written in python. I want to
make sure that the client is not:
1) destabilized by users accidentally or on purpose dropping python
files in the path (after which calling the helpdesk will not be useful)
2) extended with "new features" without me knowing about it (again
resulting in calls to my helpdesk...)
3) trivially decompiled.

Added issue, I want the client to be able to update itself when I have
fixed bugs or created new functionality.

I know that I can not stop a dedicated hacker deconstructing my code.
Since all clients need to go through the server I am not afraid of
"freeloaders".

I am now considering overriding import with some code that will only
import modules signed and crypted by me.

However I can not imagine that I would be the first one planning to do this.
So is there a solution like this available somewhere?

Paul Sijben