How the Crack Works

Before I delve into any code, here's how the crack works in theory:

1. A legitimate user purchases your digitally signed and encrypted application using a jailbroken iPhone.
   
2. The legitimate user will ssh into their iPhone from their desktop.
3. The legitimate user will navigate to your application's bundle and load it into a debugger like gdb.
4. Your application is executed and decrypted by the iPhone because the user purchased it.
5. The decrypted application that is in memory is then dumped to file by gdb.
6. Your application bundle's Info.plist is modified so that the iPhone thinks it belongs to Apple!
7. Your encrypted executable is replaced by the new decrypted copy.
8. Your application bundle is re-packaged and distributed on BitTorrent

The process is a bit more detailed than that but that's how it works.

This should be enough to get any intrepid and enterprising App Store developer started on detecting a compromised application bundle.

Actual code coming up!