Минаев В.А.

Dedicated to model studies of fiber-optic communication channels (FOCC) in quantum cryptographic systems (QCS). Th ere are two main problems with the use of QCS related to the reliability of information transfer. The analysis of the energy loss factors in the classical fiber-optic channel has been carried out and the additive loss formula in it is discussed in detail. The fiber-optic channel of quantum information transmission using integrated optical devices is considered. The additive formula of optical losses in such a channel is discussed. The features of losses in integrated optical devices are shown, in particular light att enuation in optical fiber, losses on bends and micro-bends, technological, dispersion and transition losses. The features of quantum cryptographic system of information transmission are characterized. For example, when constructing a model of a photo detector, three main parameters are taken into account: quantum effi ciency, speed, noise level. As a result, the model of FOCC QCS taking into account energy losses is proposed, which allows competently in theoretical terms and visualize the passage of information through modern quantum cryptographically secure telecommunications while providing control in government structures.

We consider a common type of computer attacks – DDoS-attacks on automated information systems (AIS), leading to denial of service. Th e aim of the article is to assess the probability of failure-free operation of an automated system. Simulated protection system AIS from DDoS-att acks, which has a main protected channel for data transmission and two reserved channels. The problem of the flow allocation in the system of multi-channel service with different channel capacity is presented. The problem connected with its formal description by diff erential equations. The full set of hypotheses about the order of channels selection at receipt of applications for processing in the system is considered. Formulas for calculating the maximum probability of system failure in the steady-state processing of incoming applications are derived. The full probability of failure of the AIS to service the flow of applications is found. Flow parameters are evaluated for simple cases when there is a need to use additional secure channels. It is concluded that in order to avoid failures in the service flow of applications during the implementation of DDoS-attacks on AIS, it is necessary to adapt the overall bandwidth of automated systems. In addition, in case of difficulties in the analytical representation of failure probabilities, it is possible to build a simulation model of the AIS protection system.