Obfuscating C-based binaries to avoid decompilation

Question

Is there some way to obfuscate C-based executables or libraries to prevent decompilation?

Answer 1

The easy way: Buy a packer/cryptor/obfuscator product. Some are expensive and used in games, some are not. Google for them by buzzwords like "copy protection", etc.

The fast way: pack with UPX and then mangle the header somewhere so it will still be loaded in memory and run fine, but the upx utility will fail with an error (try the version field). 95% will give up if the upx utility fails.

The hard way: Write your own packer.

oh, I forgot:

The real easy way: Just ship it as it is. No really - whatever you do people can still reverse engineer your code. The amount of effort you put it in just restricts how many can reverse it.