Architecture · Security Architecture
Zero Trust Architecture
A reference design in which every access request is authenticated, authorised and encrypted per session, with policy enforced close to the resource.
AdvancedUpdated 2026-09-01
Overview
The architecture separates a policy decision point, which evaluates identity, device, workload and session signals, from policy enforcement points placed in front of each resource. Trust is never inherited from network position.
Practically, this means every application behind SSO with conditional policy, device posture as a required signal, brokered access instead of flat network reach, and segmentation that limits what a compromised session can touch.
Sequence
- 1Access request
- 2Identity verification
- 3Device posture check
- 4Policy evaluation
- 5Least privilege authorization
- 6Encrypted session to one resource
- 7Continuous re-evaluation
Layer model
Signals
User identity and riskDevice compliance and healthLocation and network contextApplication sensitivitySession behaviour
Policy
Decision engineAuthentication requirementsAuthorization scopeSession controls and re evaluation
Enforcement
Identity provider gatesApplication proxy / ZTNA brokerMicro-segmentationData protection and rights management
Design considerations
- Sequence delivery: identity and device foundations, then application access, then segmentation and data controls.
- Inventory applications and their authentication methods; legacy applications need brokers or isolation.
- Instrument first and enforce second, using report only telemetry to size the impact.
- Define measurable milestones rather than declaring an end state.
Security considerations
- Protect and monitor the policy engine; tampering with policy is equivalent to disabling the architecture.
- Avoid new implicit trust, enrolment alone is not compliance, and a private network is not an authorisation.
Failure points
- Policy engine outage with no defined fail open or fail closed decision.
- Broker becoming a single point of failure for all application access.
- Legacy exceptions that grow rather than shrink.