resourceType: StructureDefinition
id: cdex-digital-signature
url: "http://hl7.org/fhir/us/davinci-cdex/StructureDefinition/cdex-digital-signature"
name: CDexDigitalSignature
title: CDex Digital Signature Profile
status: active
date: "2023-01-15"
description: This Signature DataType profile enforces the various elements of digital signatures documented in [Digital Signature Rules and Guidance For CDEX Bundle and QuestionnaireResponse](https://hl7.org/fhir/us/davinci-cdex/signatures.html#digital-signature-rules-and-guidance-for-cdex-bundle-and-questionnaireresponse).

  # - A `Signature.type` fixed to ASTM Standard, E1762-95(2013) code = “1.2.840.10065.1.12.1.5” (Verification Signature)
  # - A `Signature.who` for the organization or practitioner who signed the Bundle which is either:
  #   1. a reference to US-Core Practitioner, US-Core PractitionerRole, or US-Core Organization or
  #   1. an NPI or Tax ID and name of the organization or practitioner
  # - A `Signature.data` representing the base64 encoded Signature (JWS, image, etc)

  # In addition, the following *mandatory* (min=1) element is inherited from the base standard:
  # - `Signature.when` - a system timestamp when the signature was created

fhirVersion: 4.0.1
kind: complex-type

abstract: false
type: Signature
baseDefinition: "http://hl7.org/fhir/StructureDefinition/Signature"
derivation: constraint
differential:
  element:
    - id: "Signature"
      path: "Signature"
      short: CDex Bundle and QuestionnaireResponse signature
      definition: >-
        A JWS digital signature along with supporting context. This Signature DataType profile enforces the various elements of digital signatures documented in Digital Signature Rules and Guidance For CDEX Bundle and QuestionnaireResponse](https://hl7.org/fhir/us/davinci-cdex/signatures.html#digital-signature-rules-and-guidance-for-cdex-bundle-and-questionnaireresponse).
      # constraint:
      #   - key: cdex-13
      #     severity: error
      #     human: The signature element must have either reference to the signer or the signer's identifier.
      #     expression: >-
      #       who.reference.exists() or who.identifier.exists()

    - id: "Signature.type"
      path: "Signature.type"
      min: 1
      slicing:
        discriminator:
          - type: value
            path: $this
        rules: open
      mustSupport: true

    - id: "Signature.type:verify"
      path: "Signature.type"
      sliceName: verify
      short: Verification Signature
      patternCoding:
        system: "urn:iso-astm:E1762-95:2013"
        code: 1.2.840.10065.1.12.1.5
        display: Verification Signature
      min: 1
      max: "1"
      mustSupport: true

    - id: "Signature.when"
      path: "Signature.when"
      mustSupport: true

    - id: "Signature.who"
      path: "Signature.who"
      short: Organization or practitioner who signed the Bundle
      type:
        - code: Reference
          targetProfile:
            - "http://hl7.org/fhir/us/core/StructureDefinition/us-core-practitioner|3.1.1"
            - "http://hl7.org/fhir/us/core/StructureDefinition/us-core-practitioner|6.1.0"
            - "http://hl7.org/fhir/us/core/StructureDefinition/us-core-practitioner|7.0.0"
            - "http://hl7.org/fhir/us/davinci-hrex/StructureDefinition/hrex-organization"
            - "http://hl7.org/fhir/us/davinci-hrex/StructureDefinition/hrex-practitionerrole"

          _targetProfile:
            - extension:
                - url: >-
                    http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support
                  valueBoolean: true
            - extension:
                - url: >-
                    http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support
                  valueBoolean: true
            - extension:
                - url: >-
                    http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support
                  valueBoolean: true
            - extension:
                - url: >-
                    http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support
                  valueBoolean: true
            - extension:
                - url: >-
                    http://hl7.org/fhir/StructureDefinition/elementdefinition-type-must-support
                  valueBoolean: false

      mustSupport: true

    # - id: Signature.who.reference
    #   path: Signature.who.reference
    #   # min: 0
    #   # condition:
    #   #   - cdex-13
    #   mustSupport: true

    - id: Signature.who.identifier
      path: Signature.who.identifier
      short: NPI or US Tax ID
      definition: NPI or Tax ID representing the Provider or Organization
      min: 1
      # condition:
      #   - cdex-13
      mustSupport: true

    # - id: Signature.who.identifier.type
    #   path: Signature.who.identifier.type
    #   min: 1
    #   mustSupport: true
    #   binding:
    #     strength: required
    #     valueSet: "http://hl7.org/fhir/us/davinci-cdex/ValueSet/cdex-identifier-types"

    - id: Signature.who.identifier.system
      path: Signature.who.identifier.system
      min: 0
      mustSupport: true

    - id: Signature.who.identifier.value
      path: Signature.who.identifier.value
      min: 1
      mustSupport: true

    # - id: Signature.who.display
    #   path: Signature.who.display
    #   # min: 0
    #   # condition:
    #   #   - cdex-13
    #   mustSupport: true

    - id: "Signature.targetFormat"
      path: "Signature.targetFormat"
      short: Canonicalization method
      min: 1
      fixedCode: "application/fhir+json;canonicalization=http://hl7.org/fhir/canonicalization/json#document"
      mustSupport: true

    - id: "Signature.sigFormat"
      path: "Signature.sigFormat"
      short: The JWS mime type
      min: 1
      fixedCode: "application/jose"
      mustSupport: true

    - id: "Signature.data"
      path: "Signature.data"
      # short: base64 encoded JWS-Signature
      short: base64 encoded JSON Web Signature (JWS)
      min: 1
      mustSupport: true