The Research On Software Rights Protection Based On Dynamic Graph

A traditional technology to protect software copyright is software eneryption,which give user authority to use the software.Software watermark is a noveltechnology for software copyright protection, when property theft has occurred,allows us to prove ownership and find the thief.CT algorithm is a software watermark algorithm based on dynamic graph, whichis stored in the execution state of a program. It would be diffcult to statically analyzecode that builds graph structures, and such watermarks are immunity tosemantics-preserving transformations. On the Java platform, CT algorithm isimplemented in SandMark, which bring a framework for our work.Asmuth-Bloom scheme is a threshold scheme which is originally used to sharingsecret, so there is no restriction on sub-key`s length. With that scheme, we candivides the watermark into n pieces with a redundance number y, only n-y of the npieces are needed while retrieving the watermark, which increases resilience.However, Asmuth-Bloom scheme isn`t design to divide watermark, so watermark`length is expanded, and the software`s performance will be affected.With a expanded Asmuth-Bloom threshold scheme, sub-key`s length can bereduced. Expanded AB algorithm, A new algorithm based on expanded threshold andCT algorithm is proposed. Moreover, a new watermarking system which namedJamrk is implemented on the Java platform by using dynamic graph, the dynamicgraph is constructed by LinkedList which is a data structure from the Java standardlibrary. With the Jamrk, watermarks can be embed into a Class file immediately.Experimental results show that Expanded AB algorithm can reduce the dataexpansion, and make the recovery process easier. The conditions above mentionedare suitable for information hiding. With that, we propose a new copyright protectionsystem which hide the eneryption system`s safe-source in dynamic graph watermark.