Simple compressor source

[luis]

Hi Jeremy, I'm asking you because with your background you probably can give me some very useful starting points.

I would like to do some experiment with exe compression, maybe create a very silly exe packer on my own, not for real world use probably, just to learn something new. I have some experience in assembly but I would prefer use a high level language since I've not constraints about size or efficiency.

I found documentation on how the PE header is structured and how a program is loaded and started by the OS. Can you give me some pointers on what I should look now ? There is some very simple exe packer source I can examine ? UPX is way too much complex for me at the moment.
Or maybe there is some book around treating about this argument ?

Any suggestion is welcome.

Luis

[Jeremy Collake]

Executable compression is actually surprisingly complex, but there are simpler examples of it. There are some packers from years ago that were released in the cracking scene, and included free source code. One example may be Yoda Crypt. You can search for them. Look for simple packers authored by individuals.