Käyttöoikeuslistat

Käyttöoikeuslistat, or access control lists (ACLs), are mechanisms used in computing to manage access to resources. They specify which users or system processes are granted permissions to access specific objects, such as files, directories, or network resources. Each entry in an ACL, often called an access control entry (ACE), defines a security principal (like a user or group) and the set of permissions (such as read, write, execute, or delete) that are granted or denied to that principal for the associated resource.

The primary purpose of an ACL is to enforce security policies by determining whether an attempted access operation should be allowed or denied. When a user or process tries to access a resource, the system checks the ACL associated with that resource. It then compares the identity of the requester with the entries in the ACL. If a matching entry is found that grants the necessary permission, the access is allowed. If no matching entry is found, or if an entry explicitly denies the permission, the access is denied.

ACLs are a fundamental component of access control systems in many operating systems, including Windows, Linux, and macOS, as well as in network devices and applications. They provide a granular way to control permissions, allowing administrators to define precise rules for resource access. This helps in protecting sensitive data and ensuring that only authorized individuals or processes can perform specific actions. The implementation and syntax of ACLs can vary between different systems, but the core concept of associating permissions with identities remains consistent.