In this paper, the authors consider such an area of information security as logical encryption. Logical encryption is one of the most important methods of hardware protection, which introduces additional key inputs into a given combinational scheme to protect functionality from unauthorized use. The authors conducted a research of the relevance and problems of the studied area, conducted experimental tests and identified the main characteristics of the processes. In addition, the authors proposed a new method of applying PRNG based on the logical encryption. This topic is important for controlling the production of integrated circuits, preventing Trojans and many other programs in the field of hardware security.