EVALUATION OF THE CRYPTOGRAPHIC QUALITIES OF A DATA SOURCE AUTHENTICATION MODEL BASED ON A STREAM CIPHER

The article considers the problems and actual tasks of applying the methodology for constructing a high-speed imitation-resistant multi-alphabet substitution cipher based on a bit stream of pseudorandom data with simultaneous generation of a MAC authentication code. The issues of assessing the adequacy of the security level of its application in cases of realization of threats of the main types of cryptanalytic attacks by an attacker are studied. In particular, the cryptographic resistance to frequency analysis, linear and differential analysis, as well as to the “meeting in the middle” attack is analyzed. The question is provably answered positively. Investigating the cryptographic properties of the proposed model, it is noted that the most suitable for building a cipher overlay node are substitution substitutions that have certain structural characteristics. On the basis of the proposed cryptographic model, a secure protocol for implementing the friend-or-foe (IFF) identification procedure for mobile objects, including robotic systems, is built. The protocol takes into account the potential threat of man-in-the-middle (MIM) cryptanalytic attacks, for which purpose geolocation data is used as an additional factor in verifying the authenticity of identification information. The relevance of the proposed solution is constantly growing, due to the widespread use of robotic systems in wartime and the possibility of the presence of “friendly” UAVs performing various technical functions in the areas where critical infrastructure facilities are located. A separate direction for further research in terms of improving the proposed cryptographic model is to solve the problem of estimating the distribution of structural characteristics of random substitutions.