Cryptography Reference
In-Depth Information
This techniquemay bemore useful as a watermarking tool than
as an obfuscator. Small changes in the code can mark individ-
ual copies of the software.
Still, there are simple techniques that can be used to strip away
some of the watermarking tools. Decompiling the binary soft-
ware and then recompiling it is one simple solution that will
remove many of the effects described here. Or simply adding
another watermark on top of the software can remove the old
one.
How to Use It?
There are a number of packages that will do simple
obfuscation. See Section 18.4. Most of these will only perform
basic obfuscation by renaming variables and doing some ba-
sic reordering. More sophisticated commercial tools are also
widely available.
Further Reading
•
There are a number of code obfuscation tools on the mar-
ket, but they are not designed to hide information while
obfuscating the code. RetroGuard from
retrologic.com
and CodeShield from
codingart.com
work with Java code.
•
Christian S. Collberg and Clark Thomborson survey many
of the techniques for obfuscation and watermarking, in-
cluding dynamic watermarking that morphs as the pro-
gram executes, making it harder to identify the watermark.
[CT02]
•
Bertrand Anckaert, Matias Madou and Koen De Bosschere
offer a general way to think about self-modifying code,
something that makes it much simpler to build dynamic
watermarks.
