The improved performance of binary decompilers and the popularity of
bytecode languages like Java has meant that the intellectual property
that exists in software programs is susceptible to loss by reverse
engineering and piracy. One approach to discourage such piracy is to
use a software watermark to serve as proof of authorship or ownership,
and a means of tracing the source of an illegal distribution. In this
talk, we describe a novel technique for embedding identifiers robustly
in a program using dynamic software watermarks based on
multi-threading and thread-contention. In addition to embedding an
identifier, thread-based watermarks increase the complexity of
software making it harder for an attacker to analyze and destroy our
watermark. In building this technique, we pay special attention to
preventing pattern-matching attacks which many implementations of
dynamic watermarking techniques are susceptible to.
