Explanation
The policy engine (PE) is the component in a ZTA that is responsible for deciding whether to grant access to a resource. The PE evaluates the policies and the contextual data collected from various sources, such as the user identity, the device posture, the network location, the resource attributes, and the environmental factors, and then generates an access decision. The PE communicates the access decision to the policy enforcement point (PEP), which enforces the decision on the resource.
References =
Certificate of Competence in Zero Trust (CCZT) prepkit, page 14, section 2.2.2 What Is Zero Trust Architecture (ZTA)? - F5, section "Policy Engine" What is Zero Trust Architecture (ZTA)? | NextLabs, section "Core Components"
[SP 800-207, Zero Trust Architecture], page 11, section 3.3.1

Explanation
ZTA is based on the principle of never trusting any user or device by default, regardless of their location or ownership. ZTA policies can use various methods to verify the identity and context of third-party users and devices, such as tokens, certificates, multifactor authentication, device posture assessment, etc. ZTA policies can also enforce granular and dynamic access policies that grant the minimum necessary privileges to third-party users and devices for accessing specific resources, while hiding all other assets from their view.
This reduces the attack surface and prevents unauthorized access and lateral movement within the network.

Explanation
Optimal compliance posture is mainly achieved through two key ZT features: never trusting and reducing the attack surface. Never trusting means that no entity or resource is assumed to be trustworthy or secure by default, and that every request for access or transaction is verified and validated before granting access or allowing the transaction. Reducing the attack surface means that the exposure and vulnerability of the assets and resources are minimized by implementing granular and dynamic policies, controls, and segmentation.
These two features help to ensure that the organization complies with the security standards and regulations, and that the risks of breaches and incidents are reduced.
References = Certificate of Competence in Zero Trust (CCZT) - Cloud Security Alliance, Zero Trust Training (ZTT) - Module 1: Strategy and Governance

A comprehensive catalogue of all transactions, dependencies, and services with associated IDs is a potential outcome of an effective ZT implementation because it helps to map the data flows and interactions among the assets and entities in the ZTA. This catalogue enables the ZTA to enforce granular and dynamic policies based on the context and attributes of the transactions, dependencies, and services. It also facilitates the monitoring and auditing of the ZTA activities and performance.
References = Certificate of Competence in Zero Trust (CCZT) - Cloud Security Alliance, Zero Trust Training (ZTT) - Module 3: ZTA Architecture and Components

The first step in Zero Trust planning for an organization is to define the scope of the initiative. This involves determining which systems, networks, and data will be covered by the Zero Trust policies and what the specific objectives are. A clearly defined scope helps in prioritizing efforts, allocating resources effectively, and setting clear goals for what the Zero Trust implementation aims to achieve.