Introduction to Computer Security

Information and computer technologies (ICT), or simply IT technologies, are everywhere, in all fields of activities (business, commerce, transportation systems, health, leisure, education, administration, national security, army, etc.). This chapter aims at providing an introduction to the main issues and notions of security in computer-based systems. It aims only to present the notions of IT security, in particular the security services that can be supported by cryptographic algorithms.

The three basic security services are referred to as the CIA triad. CIA stands for Confidentiality-Integrity-Availability. Sometimes, CIA are called basic properties of security.

In addition to CIA, authentication, authorization, and non-repudiation are services often required in the cyberspace. The chapter also provides an overview of defense actions, commonly called countermeasures.