What principle ensures that access to an object is denied unless it has been explicitly granted?

The principle that ensures access to an object is denied unless it has been explicitly granted is known as Implicit Deny. This principle is a foundational concept in security and access control models, indicating that by default, any access request is denied until an explicit permission is granted. The rationale behind this approach is that it minimizes the risk of unauthorized access by ensuring that all permissions must be defined and assigned deliberately.

In practice, this means that when users or systems attempt to access resources, the security system evaluates their permissions. If there are no existing explicit grants for that access, the action will be denied. This is a key part of establishing a secure policy for managing user rights and permissions.

Other options like the Access Control Matrix, Capability Tables, and Identity-based Access Control refer to different methods or frameworks for managing permissions and defining access controls, but they do not inherently embody the principle of denying access unless explicitly granted, which is central to the Implicit Deny principle.