[HELP] How to write a simple Loader in ASM on MSDOS

[stoney81]

Hi guys!

I´m having trouble protecting a DOS Exe (with Overlay) and none of the tools in the otherwise excellent DOSEXE Collection seems to work, so I thought why not try to learn something along the way.

I would need a simple Loader (best would be ASM Code I could compile with nasm) that would load a XORed or otherwise encrypted game.bin File. The idea is to encrypt the Overlay EXE and use the Loader to load the file. This way no one can just snoop around in the EXE.

Protection doesn´t have to be bullet proof, it should just fend off newbies who try to hexedit or check for changes.

Any ideas or resources I could study?

Thank You!

- stoney