Access control
Access control is the combination of policies and mechanisms that determines which subjects may perform which actions on particular resources.
Access control list: A resource-associated list specifying which subjects or groups may perform particular operations. It stores permissions alongside each resource, making it a direct implementation of access control.
Subject (computer security): An active entity, such as a user or process, that requests access to a resource. Every access decision starts with the identity or attributes of a requesting subject.
Authorization: The process of deciding which actions an authenticated or otherwise identified subject may perform. It is the decision-making stage that access-control policies govern.
Authentication: The process of verifying a claimed identity or the origin of a request. Authentication verifies identity; access control determines which actions are allowed.
Role-based access control: An access-control model that assigns permissions to roles and roles to users. It simplifies administration by grouping permissions around organizational roles.
Object (computer security): A passive resource, such as a file or database record, that a subject may access. Policies specify permissions in relation to the particular resource being requested.
Computer file permissions: Operating-system rules specifying which users or groups can read, write, or execute files. File permissions are a familiar, concrete form of resource-level access control.
Encryption: The transformation of information into ciphertext using an algorithm and key. Encryption protects content from disclosure, while access control governs authorized operations.
Attribute-based access control: An access-control model that evaluates subject, resource, action, and environmental attributes against policies. It enables decisions based on context beyond a user’s identity or role.
Privilege (computing): An authorized ability to perform an operation on a system or resource. Access rules distinguish not only who can enter, but which operations are permitted.