Access control refers to the selective restriction of access to physical locations, digital systems, data, and other critical resources. It is a fundamental component of security frameworks designed to ensure that only authorized individuals or systems can access specific assets. In physical environments, access control systems regulate entry to buildings, rooms, or restricted zones using mechanisms such as keycards, biometric scanners, PIN codes, and security personnel. In digital environments, access control governs who can log in to systems, view data, modify records, or execute specific applications. By verifying identity and enforcing permissions, access control helps protect sensitive information, prevent unauthorized activities, and maintain operational integrity across organizations of all sizes.
At its core, access control operates on three essential elements: identification, authentication, and authorization. Identification involves claiming an identity, such as entering a username or presenting an ID card. Authentication verifies that identity through credentials like passwords, biometric data, smart cards, or multi-factor authentication methods. Authorization then determines what level of access the authenticated user is permitted, based on predefined policies. These policies are typically structured using models such as role-based access control (RBAC), attribute-based access control (ABAC), or discretionary access control (DAC). Each model defines permissions differently, but all share the goal of limiting exposure to sensitive assets and reducing the risk of misuse or compromise.