my lite-c file packer script also offers encryption. the used XTEA algorithm is very secure but of course it depends a bit on how well the key and the decryption process are hidden in the exe. it also would be easy to add some wizard functionality to my script.

...but no matter how secure your encryption system is, your data will end up in ram/graphics ram unencrypted anyway and there you can grab it with various tools quite easily. so i think this whole packing thing is quite overrated by most people. most AAA games also seem to only use some kind of unprotected zip files.