Unified Data Access Profiles (UDAP)

Replaces manual, out-of-band registration with an automated, standards-based process. A client presents a software statement—a signed JSON Web Token (JWT) containing its metadata and public key—to a UDAP server endpoint. The server validates the signature against a trusted certificate chain and, upon success, issues a unique client_id instantly. This eliminates weeks of administrative overhead and human error, enabling scalable federation across thousands of endpoints.

UDAP leverages a hierarchical Public Key Infrastructure (PKI) rooted in mutually trusted Certificate Authorities (CAs). Unlike shared secrets or bearer tokens, trust is established through X.509 certificates issued to both clients and servers. This creates a cryptographically verifiable chain of trust that scales across organizational boundaries without pairwise credential management. The framework supports both chained trust (intermediate CAs) and direct trust models, allowing communities to define their own trust anchors.

UDAP harmonizes two distinct authorization tiers within a single ecosystem:

• Consumer-Facing (UDAP Tier 1): Extends SMART on FHIR for individual patient access, using user-facing OAuth flows where a patient authorizes an app to access their own data.
• Business-to-Business (UDAP Tier 2): Enables organizational-level access for population queries, bulk data operations, and cross-institutional research without a human in the loop. This dual-tier architecture ensures a single FHIR server can securely serve both individual patients and large healthcare organizations.

UDAP defines a Trust Community construct—a set of organizations that agree to common policies, certificate authorities, and operational rules. Membership is managed through resolvable endpoints that publish community metadata, including:

• A list of trusted CAs and their certificates
• Required software statement claims
• Supported authentication and authorization protocols New entities can discover and join a community programmatically by fetching this metadata, enabling a truly self-service federation model without centralized gatekeepers.

UDAP is purpose-built for HL7 FHIR APIs, not as a generic security wrapper. It defines how FHIR-specific scopes, resource types, and operations map to OAuth 2.0 permissions. Key integrations include:

• FHIR Bulk Data Access: Securing asynchronous export jobs for population-level analytics
• SMART Backend Services: Providing the authentication layer for server-to-server FHIR transactions
• Consent Resource Binding: Linking access tokens to patient-directed privacy policies This tight coupling ensures security controls are semantically aligned with clinical data operations.