Systematic approach to the composition of control functions in the information security systems

The paper highlights the procedure of forming the composition of management functions in the information security systems, which is based on a systematic approach. The stages of the life cycle of the threat and the realization pattern of the function have been chosen as indicators of the classification of information security functions — a priori (before the threat was manifested, i.e. responses to threats are taken on a scheduled basis), or a posteriori (after the threat had been realized, i.e. responses to threats are taken in real time). Two classes of functions are distinguished: functions ensuring the information security and functions controlling mechanisms for ensuring the information security. The research of all the dedicated functions resulted in forming a set of 22 functions. For the information security functions there were built two diagrams of possible outcomes, such as successful protection of information, breaking the security system, or its damage in the course of the function realization. The procedure of finding probabilities for the outcomes using the diagrams has been described. The efficient realization of the functions offered is more dependent on the way the functions are used and organized in the framework of an integral technology of providing information security and on the amount of the resource and financial support of these functions. Building the diagram of the outcomes helps to formalize and solve the tasks of distribution of the resources needed for increasing the level of information security. As an example there have been presented two statements of the distribution problem for improving the efficiency of realization of each of the above functions.