Continuous Access Evaluation Protocol (CAEP)

CAEP operates on the Shared Signals and Events (SSE) framework, a standard developed by the OpenID Foundation. This framework allows a transmitter (e.g., an identity provider) to publish a stream of security-relevant events to which a receiver (e.g., a resource server) subscribes. Unlike polling, this push-based mechanism ensures that critical state changes are communicated asynchronously and in near real-time.

• Event Types: Standardized signals include session revocation, token revocation, and credential compromise.
• Transport: Uses HTTP POST with JSON payloads over a secure channel.

The primary function of CAEP is to terminate active sessions immediately when a critical event occurs, without waiting for a token to expire. When an identity provider detects a risk signal—such as a user disabling an account, a device falling out of compliance, or a credential appearing in a breach database—it transmits a session revoked event.

• Mechanism: The resource server, upon receiving the event, invalidates the session-bound token and terminates the connection.
• Contrast with OAuth 2.0: Standard OAuth relies on token expiration; a compromised token remains valid until its exp claim is reached, creating a window of vulnerability.

CAEP defines a taxonomy of events that signal a security posture change requiring immediate access termination. These triggers go beyond simple authentication failures to include continuous risk evaluation.

• Credential Compromise: A user's password or key is found in a known breach corpus.
• Device Posture Change: A managed device loses its compliance status (e.g., firewall disabled, OS patch missing).
• User Status Change: An account is disabled, deleted, or placed on legal hold.
• Session Hijacking Detection: Anomalous behavior, such as an impossible travel velocity, is detected by User and Entity Behavior Analytics (UEBA).

CAEP enables a shift from static, one-time authentication to continuous verification by tying access to dynamic assurance levels. An initial login might grant access with a high assurance level, but a subsequent event can lower that level below a policy threshold, triggering a step-up authentication challenge or immediate revocation.

• NIST SP 800-63 Alignment: Integrates with digital identity guidelines where Authentication Assurance Levels (AAL) and Federation Assurance Levels (FAL) must be maintained.
• Policy Enforcement Point (PEP) Integration: The PEP subscribes to the CAEP event stream and enforces the authorization decision based on the current assurance level.

Traditional Token Introspection (RFC 7662) requires the resource server to actively query the authorization server to check if a token is still valid. This polling model introduces latency and does not scale efficiently for immediate revocation.

• Polling vs. Push: Introspection is a 'pull' mechanism; CAEP is an event-driven 'push'.
• Latency: CAEP eliminates the delay between a security event and the enforcement action, reducing the window of unauthorized access to milliseconds.
• Efficiency: Reduces unnecessary API calls to the introspection endpoint, as the resource server only acts upon receiving a specific event.

In the context of Retrieval-Augmented Generation (RAG) and AI training data access, CAEP is critical for enforcing Zero-Trust Content Architecture. If an AI agent's session is compromised or its service account's risk profile changes, CAEP instantly revokes access to proprietary vector databases and knowledge graphs.

• Data Sovereignty: Ensures that cross-border access grants are terminated the moment a jurisdictional violation is detected.
• Insider Threat Mitigation: Revokes access to sensitive training corpora if a user's behavior is flagged as anomalous by UEBA, preventing data exfiltration.

The architectural component that evaluates CAEP events against defined authorization policies and returns access decisions. When a CAEP signal indicates a session revocation event—such as device compromise or user termination—the PDP processes this event in real time and instructs the Policy Enforcement Point (PEP) to terminate access to AI training data repositories instantly, without waiting for token expiration.

A cryptographic token cryptographically tied to a specific TLS connection, preventing token theft and replay attacks. In a CAEP-enabled architecture, session-bound tokens are paired with continuous evaluation signals. If CAEP detects a risk change, the token binding ensures the stolen token cannot be replayed on a new connection, providing defense-in-depth against man-in-the-middle attacks targeting AI data pipelines.

An adaptive security mechanism that dynamically adjusts authentication requirements based on calculated risk. CAEP enhances risk-based authentication by providing the real-time signals needed to trigger step-up authentication or session termination:

• Device posture changes (jailbreak detection, missing patches)
• Geolocation anomalies (impossible travel)
• Behavioral deviations (unusual data access patterns) When risk thresholds are crossed, CAEP propagates the signal instantly.

A protocol mechanism defined in RFC 7662 that allows a resource server to query the authorization server for the active state of an access token. In a CAEP-enabled environment, token introspection endpoints reflect real-time revocation status driven by continuous evaluation signals. An AI agent's token may appear structurally valid but will be reported as inactive if a CAEP-triggered revocation has occurred, preventing unauthorized data access.

A write-once, read-many record of events that cannot be altered or deleted. CAEP events—session revocations, risk signal transmissions, and access terminations—must be recorded in an immutable audit trail for compliance verification. This ensures that security teams can reconstruct the exact sequence of continuous evaluation decisions when investigating unauthorized access attempts against AI training data repositories.