1. CDS Hooks HL7 WGM Jan 2018 CDS Working Group Tuesday, January 30, 2018
New Orleans, LA

2. Agenda
Connectathon summary Argonaut security assessment summary Specification changes 1.0 release plan Post 1.0 feedback & plans

3. Connectathon Summary 42 CDS Hooks participants - a new record!!!
EHRs, CDS Service Providers, Healthcare organizations
Excellent 1.0 feedback - several issues logged & changes made
Excellent security implementation feedback!
Lots of disparate use cases (Infobutton, opioids, genetics, etc)

4. Univ of Utah Opioid CDS Service

5. Infobutton CDS Service

6. medication-prescribe hook in Cerner

7. Argonaut Security Assessment

8. Argonaut Security Assessment
The Argonaut Project funded a 3rd party security review & assessment, ongoing since October 2017
Dixie Baker, PhD is performing the assessment and also did this for SMART on FHIR
TL;DR - The majority of changes are just documentation improvements :-)
TL;DR = Too Long Didn’t Read

9. Documentation Improvements
Articulate risks and potential threats so that implementers understand them and can make their own choices based upon their tolerance of risk
Strengthen conformance verbiage where appropriate (MUST, SHOULD, MAY, etc)
Document each request/response field with REQUIRED or OPTIONAL

10. fhirAuthorization - Add new subject parameter
"access_token" : "some-opaque-fhir-access-token",
"token_type" : "Bearer",
"expires_in" : 300,
"scope" : "patient/Patient.read patient/Observation.read",
"subject" : "the-cds-service-oauth2-client-id" }
subject
client_id of authorized assessor (CDS Service) for which the access token is being requested

11. JWT Signatures
From implementer feedback (post Sept 2017 Connectathon) and the Argonaut security review, it is clear this is an issue we need to tackle for 1.0
Plan is to align our strategy with that of the SMART Backend Services, which also leverages signed JSON web tokens (JWT)

12. #87 - Specify JWT public key > JWT Changes
JSON Web Token (JWT):
Header: add "kid": "some-opaque-identifier" Payload (no changes): { "iss": " "sub": "client_id", "aud": " "exp": , "iat": , "jti": "ee22b021-e1b ba5b-8eec6a33ac1e", }

13. #87 - Specify JWT public key > JWKs
Issuer makes JWKs available at {iss}/.well-known/jwks.json
JWK endpoint conforms to RFC 7517, JSON Web Key (JWK). Example:
{ "keys": [ { "kty": "EC", "crv": "P-256", "kid": "some-opaque-identifier", "x": "f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU", "y": "x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" } ] }

14. #87 - Specify JWT public key > Summary
Initially intended to be addressed post 1.0, the reality is that all implementers need a solution today
SMART’s use of OpenID Connect already requires JWTs and JWKs
SMART Backend services leverage signed JWTs too and we want to align our strategy
Adopting two existing IETF standards allows us to leverage existing OSS libraries and work
JSON Web Signature (rfc7515)
JSON Web Key (rfc7517)

15. Notable Specification Changes

16. #109 - Hooks define their own context
Lesson learned: Code and examples are more important than specification doc :P
Context is now an object, the contents of which defined by each hook
Specification
Sandbox
Examples
Implementers
Context Data Type
object
array

17. #119 - Move patient_id and encounter_id to context
{ "hookInstance" : "some-uuid", "fhirServer" : " "hook" : "patient-view", "user" : "Practitioner/example", "patient" : "123", "encounter" : "456", "prefetch" : { .. }, "context" : { ... }, "fhirAuthorization" : { ... } }
{ "hookInstance" : "some-uuid", "fhirServer" : " "hook" : "patient-view", "user" : "Practitioner/example", "patient" : "123", "encounter" : "456", "prefetch" : { .. }, "context" : { "patientId" : "123", "encounterId" : "456" }, "fhirAuthorization" : { ... } }

18. #151 - Clarity around prefetch tokens
Today:
{{Patient.id}} {{User.id}}
Proposed:
Hooks indicate which first-level fields can be prefetch tokens
Prefetch tokens have a defined naming convention
{{user}}
{{context.patientId}}
{{context.encounterId}}

19. 1.0 Release Plans

20. 1.0 release in Q1 2018 1.0 Release Plans
Finalize security assessment (early February)
HL7 Jan 2018 WGM feedback (‘informal ballot’ - Now!)
Wrap-up remaining 1.0 milestoned issues
1.0 release in Q1 2018

21. Post 1.0 Feedback & Open Discussion

22. Post 1.0 Feedback & Open Discussion
Decisions?
Additional use cases? (opioids? radiology?)
Anything else?
Continue to log issues on GitHub