Stream: fhir/infrastructure-wg
Topic: FHIR-I Fri Q3
Michael Donnelly (Feb 07 2020 at 04:02):
@Rick Geimer had to take off, so I'm picking up minutes part way through Q3.
Michael Donnelly (Feb 07 2020 at 04:03):
J#18445 - How is the scope of a signature determined? - N-Infra #133
Michael Donnelly (Feb 07 2020 at 04:09):
Lloyd: we know how to canonicalize a signature on a single resource but not on broader or narrower concepts.
Grahame: why does IHE need this?
John Moehrke: Not certain
GG: Are we content to wait for an implementer to push on this, or should we do so?
MD: wait for implementers
John: agree, though this is time wasted where nothing is used
GG: assign back to balloter?
LM: that's me
LM: e.g. Provenance can apply to multiple resources, so it's unclear how this would work.
Michael Donnelly (Feb 07 2020 at 04:11):
Lloyd and John discussed details of stitching, of metadata. A signature element contains a manifest of what was signed.
Michael Donnelly (Feb 07 2020 at 04:13):
MD: How soon are we to the point where this will trip up someone?
LM: hasn't happened yet; could be tomorrow
John: that's why we have a "here be dragons" indication on this non-normative content
Michael Donnelly (Feb 07 2020 at 04:15):
John: the stitching problem is addressed because a signature in and of itself isn't a signature of a single item, it's a sig of everything in the manifest. When you validate, you rely only on what's in the signature blob.
Michael Donnelly (Feb 07 2020 at 04:34):
[John Moehrke/Grahame Grieve: 6-0-0]
Will adjust the XML language as follow:
This specification defines the following method for canonicalizing FHIR resources, when represented as XML:
Each XML instance or fragment that is part of the collection being signed SHALL
- Contain no white-space other than single spaces in attribute values and in the XHTML in the Narrative
- Use default namespaces for the FHIR and XHTML namespaces
- Omit all comments
- Always use the Unicode character representation for any XML entities (e.g. ' instead of ")
- Include the XML processing instruction <?xml version="1.0" encoding="UTF-8"?>
- Using the XML canonical method Canonical XML 1.1 (http://www.w3.org/2006/12/xml-c14n11)
Will change the JSON as follows:
This specification defines the following method for canonicalizing FHIR resources, when represented as JSON:
The signed set of fragments SHALL be transformed such that:
- No whitespace is included other than single spaces in property values and in the xhtml in the Narrative
- Properties are ordered alphabetically within each object
- Multiple fragments are concatenated with no intervening white-space in the order defined by the element with the Signature data type.
Michael Donnelly (Feb 07 2020 at 04:35):
The WG adjourned the quarter at 15:32.
Lloyd McKenzie (Feb 07 2020 at 06:13):
Thanks @Michael Donnelly
Last updated: Apr 12 2022 at 19:14 UTC
