Smart Health Card

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Revision as of 16:29, 27 October 2021 by Tom (talk | contribs) (Embedding in QR codes)

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Full Title or Meme

A (usually virtual) Smart Card containing at least some Identity and some Health Information, typically vaccination data,

The Smart Health Card is one of a series of SMART health specifications initiated by Boston Children's Hospital often with Harvard and other Boston hospitals.


Design Goals

  1. Support end-to-end workflow where users receive and present relevant healthcare data
  2. Enable workflow with open standards
  3. Support strong cryptographic signatures
  4. Enable privacy preserving data presentations for specific use cases

Use Cases

Technical Details

The overall JWS payload matches the following structure (before it is minified and compressed):

 "iss": "<<Issuer URL>>",
 "nbf": 1591037940,
 "vc": {
   "type": [
     "<<Additional Types>>",
   "credentialSubject": {
     "fhirVersion": "<<FHIR Version, e.g. '4.0.1'>>",
       "resourceType": "Bundle",
       "type": "collection",
       "entry": ["<<FHIR Resource>>", "<<FHIR Resource>>", "..."]

Embedding in QR codes

  • The Smart Health Card is typically embedded in a JWS (JOSE) format with a header, payload and signature block for verification. While it can be transported in many media, the commonly used method is in a QR code displayed on paper in stored as a photo in a smart phone.
  • Each JWS string that appears in the Verifiable Credential of a .smart-health-card file can be embedded in one or more QR codes. We aim to ensure that printed (or electronically displayed) codes are usable at physical dimensions of 40mmx40mm. This constraint allows us to use QR codes up to Version 22, at 105x105 modules. When embedding a JWS string in QR codes, the JWS string SHALL be encoded as Numerical Mode QR codes consisting of the digits 0-9 (see Encoding Chunks as QR codes).
  • On iPhones the default behavior of scanning a QR Smart Health Card is to ask to store the VC in the Apple Wallet.
  • WARNING the size recommended above can be scanned by modern (in 2021) smart phone with a high resolution camera, but cannot be resolved by most PC cameras or less expensive smart phones.