An access control list (ACL) is a list of permissions that are associated with a specific file or resource on a computer system or network. The purpose of an ACL is to define which users or systems are allowed to access a particular resource, and what actions they are allowed to perform on that resource. An ACL can be implemented in a variety of ways, such as through file system permissions, through access control mechanisms in network protocols, or through access control lists in software applications.
ACLs can be used to enforce a wide range of access control policies, depending on the needs of the system or organization. For example, an ACL might be used to allow certain users to read a file, but not modify it, while other users are allowed to both read and modify the file. An ACL might also be used to allow certain users or systems to access a network resource, such as a server or database, while denying access to other users or systems.
ACLs can be used in a variety of different contexts, including on individual computers, on networks, and in cloud-based systems. They are a crucial component of many security systems, and are often used in conjunction with other security measures, such as firewalls and intrusion detection systems, to provide a comprehensive security solution.