Mandatory access control (MAC)
Access control where access rights cannot be changed by the users.
Data about data – that is, data describing the structure, content or use of some other data.
The ability of a computer system to process information with different security levels, to permit access by users with different security clearances, and to prevent users from obtaining access to information for which they do not have authorised access
Data representing documents, audio (sound), still images (pictures) and moving images (video).