Hello all!

Yesterday I decided making a file encrypter would be fun, and so off I went!

What I want it to do:

-Take an .exe
-Encrypt that .exe
-Add to it the decryption process, so that when the file is run, it will automatically decrypt and continue running the original program.

What I've got so far:
I began writing this, but found a pretty good example source code which works, and has much of what I was aiming for, but it doesnt add the decryption routine to the file (I believe this is referred to as a 'loader')
( http://www.planet-source-code.com/vb...tp%2FA75078212 )

So I'm wondering
How hard is it to modify this code to add in what I'm looking for, or would it be easier to start from scratch?
For some reason I'm thinking that this last part requires about another thousand lines of code, but hopefully I'm wrong there :P

I also assumed there would already have been a tutorial (or two!) written about this, but I wasn't able to find one, so if anybody knows of one that would be great too!

looking forward to all replies Thanks!