Abstract: Methods and techniques allowing to calculate quantitative estimates of level of protection from unauthorized physical intrusion for different informatization objects using various means and protection systems are currently being intensively developed. Generally the quantitative evaluation of protection is represented by a set of probability characteristics, the predominant of which is some integral indicator. Therefore, developing mathematical and simulation models for calculating an estimate of informatization object protection from unauthorized physical access is an urgent task. This model then is used as a part of a complex system of information security. To solve this problem the article presented uses methods of information protection, graph theory and probability theory. The results shown in the article were calculated using Maple system of computer algebra. Scientific novelty of the work is: – in creating a mathematical model for calculation the probability of detecting of unauthorized physical access to information by an alarm system;
– in bulding of a simulation model for evaluation of level of protection of informatization object from unauthorized physical access;
– in developing of a technique of evaluation of full protection from unauthorized physical access for object of informatization

Abstract: The paper deals with the algorithm of Chenxi Wang’s, shows are the main disadvantages of this algorithm. The authors suggest the ways of modification to improve it. The algorithm of Chenxi Wang's is one of the most famous. The input data for the algorithm is the usual procedure, written in high level language. The authors describe the three stages of obfuscation of any such procedure. In the classic version of Chenxi Wang's the algorithm has poor stability. The authors suggest ways to improve stability of the algorithm, present modified version of the algorithm and reviews results of its implementation. The authors compare the source code and the resulting code and conclude that it is almost impossible to establish their functional identity and the logic of the program code is very difficult to understand using obfuscated source. Sometimes this can be done using the examples run of the resulting source code. This implies that after eliminating the shortcomings the algorithm is quite effective.

Abstract: Modern computer technology makes it a variety of tasks relevant to the field of information security. For example, for the protection of copyright in the images methods of steganography are used. To solve the problem of proving authorship (or vice versa) code obfuscation techniques are used. Obfuscation (from Lat. Obfuscare - obscure, obfuscate, and English. Obfuscate - make non-obvious, confusing, confusing) or obfuscated code - is the process of bringing the source code or executable program code to the form, that keeps its functionality, but complicates the analysis, understanding algorithms and modification during decompilation. Currently, there are special programs called obfuscators that performes obfuscation to solve the task in different ways. The article discusses the techniques of obfuscation from the most basic to sophisticated polymorphic generators obfuscators performing the mathematical transformation of the code, as well as the relationship of obfuscation and efficiency of program code execution and reduce the size of the program. The authors describe further development of obfuscation techniques.