Definition
Discretionary access control (DAC) is a security model where the owner of a resource determines who can access it and what permissions they have. This means the owner can grant or revoke access rights to files, folders, or other objects at their discretion. In practice, DAC is implemented through access control lists (ACLs) associated with each resource, specifying user or group permissions. Understanding DAC is crucial for managing data privacy and preventing unauthorized access in various IT environments. For example, a user might grant read-only access to a document to a colleague while keeping full editing rights for themselves. Unlike mandatory access control (MAC), where access is determined by security labels and system wide policies, DAC offers more flexibility to individual users. This concept is frequently tested on certifications like CompTIA Security+ and CISSP.