Measures and controls that ensure confidentiality, integrity, and availability of information-system (IS) assets including hardware, software, firmware, and information being processed, stored, and communicated. Synonym automated information systems security. 2. The application of hardware, firmware and software security features to a computer system in order to protect against, or prevent, the unauthorized disclosure, manipulation, deletion of information or denial of service. 3. The protection resulting from all measures to deny unauthorized access and exploitation of friendly computer systems.