Advanced system security deals with understanding cyber-attacks and defence strategies. Understanding underlying principles of access control mechanisms. Exploring software vulnerabilities, attacks and protection mechanisms of wireless networks and protocols, mobile devices and web applications. Understanding and exploring techniques used in digital forensics. Digital forensics (sometimes known as digital forensic science) is a branch of forensic science encompassing the recovery and investigation of material found in digital devices, often in relation to computer crime. The term digital forensics was originally used as a synonym for computer forensics but has expanded to cover investigation of all devices capable of storing digital data. With roots in the personal computing revolution of the late 1970s and early 1980s, the discipline evolved in a haphazard manner during the 1990s, and it was not until the early 21st century that national policies emerged.