EN
The paper presents issues concerning the development of IT system security, ensuring the confidentiality, integrity and availability of information in modern communication systems on the strategic level. The discussion includes implications of the malfunctioning of critical infrastructure and the wide use of modern cyber weapons, which can be observed not only on the military battlefield but also in many contemporary activities. The author analyses and classifies threats in cyberspace including electronic crimes and terrorist acts, and finally shows developments in improving cybersecurity of a modern country.