Execution Domains in Architecture

A.

In computer science, hierarchical protection domains, often called protection rings, are a mechanism to protect data and functionality from faults (fault tolerance) and malicious behavior (computer security)

This approach is diametrically opposite to that of capability-based security.

Computer operating systems provide different levels of access to resources.

A protection ring is one of two or more hierarchical levels or layers of privilege within the architecture of a computer system.

This is generally hardware-enforced by some CPU architectures that provide different CPU modes at the hardware or microcode level.

Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with the highest ring number)

On most operating systems, Ring 0 is the level with the most privileges and interacts most directly with the physical hardware such as the CPU and memory.

Special gates between rings are provided to allow an outer ring to access an inner ring's resources in a predefined manner, as opposed to allowing arbitrary usage.

Correctly gating access between rings can improve security by preventing programs from one ring or privilege level from misusing resources intended for programs in another.

For example, spyware running as a user program in Ring 3 should be prevented from turning on a web camera without informing the user, since hardware access should be a Ring 1 function reserved for device drivers.

Programs such as web browsers running in higher numbered rings must request access to the network, a resource restricted to a lower numbered ring.

Ring Architecture -

All of the other answers are incorrect because they are detractors.

References: OIG CBK Security Architecture and Models (page 311) and https://en.wikipedia.org/wiki/Ring_%28computer_security%29

The correct answer to the question is A. Ring Architecture.

In computer systems, a privilege level is a mechanism for restricting access to certain resources or functionality based on the level of permissions granted to a user or process. Privilege levels are often implemented through an architecture known as the ring architecture, which divides the system's resources into hierarchical rings or levels.

Each ring represents a different level of privilege, with higher levels having greater access to system resources and functionality than lower levels. In a ring architecture, the system's resources are organized into concentric rings, with the innermost ring being the most privileged and the outermost ring being the least privileged.

The ring architecture was first introduced in the early 1970s with the development of the Multics operating system, and it has since been used in many other operating systems, including Unix and Windows.

Ring architecture typically uses at least two rings, one for user mode and another for kernel mode. However, some architectures may use more than two rings, with each additional ring representing a higher level of privilege.

Ring layering, on the other hand, refers to the organization of software components or modules into layers, where each layer provides a specific level of abstraction or functionality. This is a different concept from ring architecture, although the two are related in that they both involve the organization of resources into hierarchical layers.

Network environment and security models are broader concepts that encompass various aspects of computer security, and are not directly related to the specific architecture used to implement privilege levels.