N.A. Baranov, I.V. Vasiliev

We consider the model of the system functioning in hazardous external influences. It is assumed that counteraction to threats is only for their timely identification. The efficiency of counteraction and the probability of timely the threat identification are determined by costs of creating counteraction-subsystem and the identification-subsystem. It is assumed that the system is unrecoverable. Security effectiveness is estimated by ratio of profits to losses caused by external threats. The risk estimation assumes that there are two types of losses. The first type of loss associated with the cost of a counteraction of the external threats. The second type of loss associated with the damage being done to the system in case of threat realization. The paper takes into account changes in profits and cost of losses over time due to inflation. All economic indicators are discounted at the beginning of system operation. Using the developed model, we analyze the impact of the security cost on efficiency