iphone app binary file to source code

Question

Hi, I just have a question about binary file in iPhone app.

When an iPhone developer wants to submit their app to testers or App store they build the binary file of their appliction. My question is it possible to edit your app's binary to get the source code, or just simply edit the binary for someones purpose.

If it is posible how can I prevent it to happen.

Thanks.

Answer 1

In general, getting source from compiled code is technically possible, but not to the extent you fear. Decompiling isn't usually done for a few reasons.

• One of the things a compiler is optimize a lot of different things in your application, e.g. unrolling some loops or inlining some functions. That would make a decompiled code very different from the source and harder to modify.
• Symbols are generally lost when compiling. I don't know the process for every compiler (Especially not for iPhone apps), but I know Visual Studio keeps a separate database for debugging. Without that database, var UserPreferences would turn to _a or something along those lines.

All that said, you can't completely keep someone from decompiling your code, but there's pretty much nothing you need to do to make it hard for them to get something useful.

Answer 2

As Alex said you cannot prevent someone from decompiling your binary if they really want to do so however unless you have some secret code or something they can't get any other way it is usually less work to write a clone of your app then decompile it and use the result.

If you do have a secret code or something you need to hide from people (usually as part of a DRM or DRM-like system) one way to made it harder to get to would be to not directly put the code in your app. Use a state machine or something to build the code so it is harder to figure out what is going on. That might buy you a week, anyway.