Identity Propagation

The process of embedding a cryptographically signed user identity token into the retrieval request header. This token is propagated through microservices without requiring the user to re-authenticate at each hop.

• JWT Assertions: Uses JSON Web Tokens containing user ID, roles, and attributes.
• Header Forwarding: Proxies and API gateways strip external auth and inject internal identity headers.
• Mutual TLS (mTLS): Establishes certificate-based identity verification between services in the pipeline.

A delegation mechanism where a middleware service, after verifying the original user's identity, obtains a delegated access token to act on behalf of that user when querying the vector database.

• OAuth2 On-Behalf-Of Flow: Exchanges a user token for a new token scoped to the downstream retrieval service.
• Service Account Mapping: Maps the user's abstract permissions to a technical service account for database access.
• Prevents Privilege Escalation: Ensures the retrieval engine does not use its own super-user credentials to fetch data.

The mechanism by which user attributes from the identity token are translated into metadata filters applied directly to the vector database query. This ensures the semantic search only operates over authorized document partitions.

• Attribute Mapping: Transforms LDAP groups or OIDC claims into vector store metadata key-value pairs.
• Dynamic Query Scoping: Injects user.department = 'finance' into the retrieval query automatically.
• Pre-Retrieval Enforcement: Filters the search space before the similarity calculation, preventing data leakage.

Maintains a continuous, verifiable chain of trust from the end-user's initial authentication through every asynchronous event in the RAG pipeline, including re-ranking and generation.

• Trace Context (W3C): Propagates traceparent headers to correlate identity with telemetry across services.
• Immutable Audit Trail: Links every retrieval log entry back to the originating user session.
• Continuous Authorization: Re-validates the user's session status at the Policy Decision Point (PDP) before final output generation.

The authorization engine that evaluates access policies against the propagated user context and the requested resource's attributes to issue a permit or deny decision. The PDP consumes the identity token passed down the pipeline, decomposes it into attributes, and matches them against the applicable ABAC or RBAC policies. It is the brain of the authorization architecture, decoupling policy evaluation from enforcement.

The architectural component that intercepts a retrieval request and acts as a gatekeeper. The PEP calls the PDP with the propagated identity and, upon receiving a decision, enforces it by filtering or blocking the response. In a RAG pipeline, the PEP can be implemented as a proxy, a middleware layer, or a native plugin within the vector database.

The automated synchronization of user access rights from an Identity Provider (IdP) to the vector database. This process ensures that retrieval permissions mirror the source application's authorization logic. Entitlements—such as group memberships or document ACLs—are mapped to metadata filters on vector embeddings, enabling pre-retrieval filtering without requiring a real-time call to the IdP for every query.

Short-lived authentication credentials that automatically expire shortly after issuance. In identity propagation, ephemeral tokens—such as JWTs with a short exp claim—are passed between the application layer, the retrieval engine, and the authorization service. This minimizes the window of opportunity for credential theft and replay attacks, adhering to zero-trust retrieval principles.

An authorization model that dynamically adjusts retrieval permissions based on real-time contextual signals propagated alongside the user identity. Beyond a static role, the system evaluates:

• Location: Is the request coming from a trusted network?
• Device Posture: Is the device compliant with MDM policies?
• Time of Day: Is this access anomalous for the user's pattern? This dynamic evaluation ensures that a compromised session cannot freely exfiltrate data.

A security posture that re-evaluates access policies throughout a session rather than relying on a single authentication event. If the propagated user context changes—for example, a risk score increases due to anomalous behavior—the system can revoke retrieval rights mid-session. This is critical for long-lived RAG interactions where a user's permissions might change while they are actively querying the system.