Software watermarking via assembly code transformation

[theCaller]

Hi wizards,
surfing around the net seeking for the ida 4.6sp1 full version that is unfindable ... damn I need that debugger ... I found this interesting thesis about SW watermarking that I'm pleased to share with the community ... I started reading it and I think it could be somehow useful ...

hope it helps, regards
theCaller

It sounds like she's just a tad idealistic about the security and benefits of her particular scheme But it does illustrate a method that is used as part of more complex schemes.

I disagree with her that the code ought to be able to check its own watermark. While that sounds like a good idea in principle, I think it would backfire in practice. If the code reads its own watermark, you've just given the reverser all the information they need to both find and decipher your watermarks. The whole idea of this kind of watermark is to remain completely undetected. So I would think that your watermarked code should avoid interacting with the watermark entirely.

Here is a good (but much more difficult to understand) thesis on actual code watermarking techniques:
http://www.julienstern.org/files/codemark/
The bibliography gives a lot of good reading material, too. You might find it useful to peruse his site in general - there's a lot of good reading there.

I get the feeling that it might help to read "A secure, robust watermark for multimedia" from Lecture Notes In Computer Science, Vol. 1174 before reading Stern's thesis, but I'm having difficulty locating the actual text.

Ok, I did finally find it, but it's terrible quality. Many of the equations are nearly unreadable, unfortunately:
http://www.cs.bgu.ac.il/~ns041/cox_et_al.pdf

Here's what looks like a later revision of the paper, but it's also in a really bad state:
http://www.assuredigit.com/tech_doc/more/IP97.pdf

[EDIT:JMI Please notice the "Edit" button was designed to make additions to a post. A "new" one is not necessary.]

Hi,

well there are some nice ideas for watermarks. If you are bored try analysing IDA itself. Its well know for its watermarks. However this sheme is build on the basis thats its compiled for each customer. So it depends on the number of customers. Some techniques used in IDA seems to be the order of the functions, or encrypting/decrypting a database with the key of the user. Using parts of the key to create a valid disassembling or it will just produce garbage. There are lots of ways to protect and watermark an application. It only depends on ideas in my opinion. If you create a tool only for a few customers and can compile the program for each customer you have a freedom to do nearly everything you want. The problem of watermarking a program which is designed for lots of customers is another topic. But here it only depends on time. You have the possiblity to compare different versions to find and remove the watermarks.