Computer security is often divided into three distinct master categories, commonly referred to as controls:
Physical
Technical
Administrative
These three broad categories define the main objectives of proper security implementation. Within these controls are sub-categories that further detail the controls and how to implement them.
Physical control is the implementation of security measures in a defined structure used to deter or prevent unauthorized access to sensitive material. Examples of physical controls are:
Closed-circuit surveillance cameras
Motion or thermal alarm systems
Security guards
Picture IDs
Locked and dead-bolted steel doors
Biometrics (includes fingerprint, voice, face, iris, handwriting, and other automated methods used to recognize individuals)
Technical controls use technology as a basis for controlling the access and usage of sensitive data throughout a physical structure and over a network. Technical controls are far-reaching in scope and encompass such technologies as:
Encryption
Smart cards
Network authentication
Access control lists (ACLs)
File integrity auditing software
Administrative controls define the human factors of security. It involves all levels of personnel within an organization and determines which users have access to what resources and information by such means as:
Training and awareness
Disaster preparedness and recovery plans
Personnel recruitment and separation strategies
Personnel registration and accounting