Graph watermarking techniques encode a watermark in a graph structure which is embedded in a program either statically, or dynamically. Static watermarks can be encoded in a control flow graph while dynamic graphs are encoded in a data structure built at runtime. Like other static watermarking algorithms, static graph watermarking is susceptible to semantics-preserving transformation attacks. Collberg and Thomborson proposed the first dynamic graph based watermarking scheme, CT, to overcome problems with static watermarking schemes.