Back to ProjectsAward-winning Project · Team Leader (team PepeLab)

MedSSI — Decentralized Health Credential Verification

A decentralized credential verification system built on Self-Sovereign Identity standards, demonstrated on health records — the setting where re-submitting the same credential is most costly, and where the consequences of over-disclosing are most serious.

Problem

Cross-institution digital credential verification in Taiwan's public sector lacks interoperable infrastructure; citizens must repeatedly submit the same credentials to different institutions. Health records make the cost concrete: a patient collecting medication, joining a study, or filing an insurance claim hands over far more of their record than any of those three actually needs.

Solution

A three-party SSI system — hospital issuer, patient-held wallet, and verifier — in which the credential is issued once and each verifier receives only the fields its scope permits. Disclosure policies address individual fields by FHIR path, so “medication pickup” and “research authorisation” resolve to different subsets of the same credential, each gated behind its own minimum identity assurance level. The backend speaks the Ministry of Digital Affairs' digital credential wallet sandbox protocol rather than a private scheme, so credentials stay interoperable outside the demo.

My Role — Team Leader

  • Designed the overall system architecture for the SSI platform
  • Oversaw integration of VC and DID standards
  • Managed backend development and coordinated frontend integration
  • Steered the project from requirement analysis and tech stack selection through to deployment
  • Translated government interoperability requirements into technical specs

System Architecture

MedSSI system architectureA hospital issuer sends a credential offer as a QR code to a patient-held wallet. The wallet presents a verifiable presentation to a verifier — a pharmacy or a research body — which checks it against the FastAPI backend. The backend holds the issuance and verification session store, applies a disclosure policy addressed by FHIR paths, enforces an identity assurance level, and calls Taiwan’s official issuer and verifier sandboxes.IssuerHospitalFHIR Condition · MedicationDispenseWalletPatientHolder DID · selective disclosureVerifierPharmacy · ResearchRequests a minimum scopeQR offerVPFastAPI backendIssuanceVC templatesSession store5-minute QR expiryDisclosure policyFields as FHIR pathsVerificationIAL · scope · field checkMODA digital credential wallet sandboxissuer-sandbox.wallet.gov.tw · verifier-sandbox.wallet.gov.tw
Three scopes are defined — medication pickup, research authorisation and insurance application — each mapped to its own verification template and a minimum identity assurance level.

Demo

An animated walkthrough with real clips: MedSSI's 2025 run against the Ministry of Digital Affairs' wallet sandbox, and its story page re-run locally in 2026. The patient is fictional.

Recognition

Merit Award (學生組優選)

Digital Credential Scenario Innovation Challenge, hosted by the Ministry of Digital Affairs, Taiwan — Nov 2025

Tech Stack

SSIW3C VCDIDFHIRSelective disclosureFastAPIPythonReactVite

Links

github.com/zuemen/pepelab_v2