Access control systems are used to control access to a computer, network or other resource.
Unauthorized can occur even if the user is authorized to access that computer or network but is not authorized for that particular activity.
This include possessed knowledge access systems that use password or other types of possessed knowledge; possessed object access systems that use physical objects and biometric access system.
For employees of some companies, checking personal e-mail at work might be classified as unauthorized use.
The unauthorized use, access, modification and destruction of hardware, software, data or network resource is defined as computer crime by the Association of Information Technology Professionals.
Unauthorized use of computer system
