Development of protecting a software product mathematical model from unlicensed copying based on the GERT method

The subject of the research is methods and algorithms for developing GERT networks that provide a hidden transition along branches control logic graph ability to encode digital watermarks in context existing threats licensing security software systems. aim work develop system product licensed based on carry properties watermarks. article solves following goal: development model developed using networks. Methods mathematical modeling, numerical experiment, complexity theory cryptography are used. results were obtained: basis analysis models ensuring security, main requirements synthesized within framework model, as well machine implementation algorithm, identified. Based investigation watermark systems, attack them, put forward algorithm was formed system. Conclusions: first time, safe GERT-networks developed, which used product. This implemented depending identification or serial number; has been not only empirical, but also theoretical substantiation resistance attacks by an intruder.