Prevent from reverse engineering C++ binary

Question

I have read several articles on the topic as this one and implemented most of the described techniques. But I also want to add some extra un-referenced/never-used code to the binary. Ideally I want to be able to add this code to the built binary through a tool. Is there such a tool? Any ideas on how to build such a tool? Or how to generate and add to my C++ program some never-used code? Where should I put it?

In an analysis of Skype internals I read that they mess the code as much as possible. One way of achieving it is to compute each call dynamically:

if ( sin(a) == 42 ) {
   do_dummy_stuff () ;
}

Should I enter into the dummy function? Or is the dummy function the never-used code?

Update: the reason I want to add never-used code to the binary is because we ship many e-books. I want the binaries of each to be little different so if one is compromised, the others not to be (at least not right away).

I don't imagine it would be difficult for someone to find out which code in your program is actually called, if they were interested. Further, your compiler will likely need to be told not to optimize this away. — Anthony Burleigh, Sep 12 '12 at 06:12
A clever compiler would perhaps notice that `sin` never gets quite as big as 42 and eliminate the entire p.o.c. — Kerrek SB, Sep 12 '12 at 06:12

score 4 · Accepted Answer · edited May 23 '17 at 11:55

4

If I got you right, you are talking about obfuscation.

This question on Stackoverflow covers the topic. There is a lot of software that obfuscates C++ code, quick googling shows a lot of such apps, e.g. this or this.

edited May 23 '17 at 11:55

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answered Sep 12 '12 at 06:12

SingerOfTheFall

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Obfuscation is one part of the story. I want to add some never-used code to the binary. – Martin Dimitrov Sep 12 '12 at 06:26
Actually we don't ship the source code, so I don't think obfuscation would do us any good. – Martin Dimitrov Sep 12 '12 at 06:30

score 3 · Answer 2 · edited May 23 '17 at 11:49

3

Is there such a tool?

Yes, there is. It is called compiler with proper parameters, and to add to it a linker. Add to this combination strip, and you'll get a proper library.

On a serious note, there are no ways to prevent reverse engineering. You can only make it harder (or better annoying) for the cracker. You can take a look in this article (where developers of spyro tried all sorts of piracy protection)

edited May 23 '17 at 11:49

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answered Sep 12 '12 at 06:12

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That is what I try to do, make it harder to reverse-engineer the code. – Martin Dimitrov Sep 12 '12 at 06:25

Prevent from reverse engineering C++ binary

2 Answers2