Zero Trust Networks, 2nd Edition

Chapter 4. Making Authorization Decisions

Authorization is arguably the most important process occurring within a zero trust network, and as such, making an authorization decision should not be taken lightly. Every flow and/or request will ultimately require that a decision be made.

The databases and supporting systems we will discuss here are the key systems that come together to make and affect those decisions. Together, they are authoritative for access control and thus need to be rigorously isolated from each other. Careful distinction should be made between these responsibilities, particularly when deciding whether to collapse them into a single system, which should generally be avoided if possible.

Taking reality into account, this chapter will focus on the high-level architectural arrangement of the components required to make zero trust authorization decisions, as well as how they fit together and enforce said decisions.

Authorization Architecture

The zero trust authorization architecture comprises four main components, as shown in Figure 4-1:

• Enforcement

• Policy engine

• Trust engine

• Data stores

These four components are distinct in their responsibilities, and as a result, we treat them as separate systems. From a security standpoint, it is highly desirable that these components be isolated from each other. These systems represent the practical crown jewels of the zero trust security model, so special care should be taken in their maintenance and security posture. It ...