Attachment Reference Exchange (ARex)
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Attachment Reference Exchange (ARex) - Local Development build (v0.1.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Extension: ARex Digest (Experimental)

Official URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest Version: 0.1.0
Draft as of 2026-08-12 Computable Name: ARexDigest

A cryptographic digest of the referenced content, computed over the octets as served. Defined as an extension on Attachment because Attachment.hash is defined as SHA-1 in FHIR R4 and is prohibited by this guide.

Context of Use

    This extension may be used on the following element(s)

Usage info

Usages:

You can also check for usages in the FHIR IG Statistics

Formal Views of Extension Content

Description of Profiles, Differentials, Snapshots, and how the XML and JSON presentations work.

This structure is derived from Extension

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..* Extension ARex Digest
... extension 2..* Extension Extension
... Slices for extension Content/Rules for all slices
.... extension:algorithm S 1..1 Extension Extension
..... extension 0..0 Extension
..... url 1..1 uri "algorithm"
..... value[x] S 1..1 code Value of extension
Binding: ARex Digest Algorithm Value Set (required)
.... extension:value S 1..1 Extension Lower-case hexadecimal digest value
..... extension 0..0 Extension
..... url 1..1 uri "value"
..... value[x] S 1..1 string Value of extension
... url 1..1 uri "https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest"

doco Documentation for this format
NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..* Extension ARex Digest
... id 0..1 string Unique id for inter-element referencing
... Slices for extension 2..* Extension Extension
Slice: Unordered, Open by value:url
.... extension:algorithm S 1..1 Extension Extension
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0 Extension
Slice: Unordered, Open by value:url
..... url 1..1 uri "algorithm"
..... value[x] S 1..1 code Value of extension
Binding: ARex Digest Algorithm Value Set (required)
.... extension:value S 1..1 Extension Lower-case hexadecimal digest value
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0 Extension
Slice: Unordered, Open by value:url
..... url 1..1 uri "value"
..... value[x] S 1..1 string Value of extension
... url 1..1 uri "https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest"

doco Documentation for this format

This structure is derived from Extension

Summary

Complex Extension: A cryptographic digest of the referenced content, computed over the octets as served. Defined as an extension on Attachment because Attachment.hash is defined as SHA-1 in FHIR R4 and is prohibited by this guide.

  • algorithm: code: An Extension
  • value: string: An Extension

Differential View

This structure is derived from Extension

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..* Extension ARex Digest
... extension 2..* Extension Extension
... Slices for extension Content/Rules for all slices
.... extension:algorithm S 1..1 Extension Extension
..... extension 0..0 Extension
..... url 1..1 uri "algorithm"
..... value[x] S 1..1 code Value of extension
Binding: ARex Digest Algorithm Value Set (required)
.... extension:value S 1..1 Extension Lower-case hexadecimal digest value
..... extension 0..0 Extension
..... url 1..1 uri "value"
..... value[x] S 1..1 string Value of extension
... url 1..1 uri "https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest"

doco Documentation for this format

Snapshot View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. Extension 0..* Extension ARex Digest
... id 0..1 string Unique id for inter-element referencing
... Slices for extension 2..* Extension Extension
Slice: Unordered, Open by value:url
.... extension:algorithm S 1..1 Extension Extension
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0 Extension
Slice: Unordered, Open by value:url
..... url 1..1 uri "algorithm"
..... value[x] S 1..1 code Value of extension
Binding: ARex Digest Algorithm Value Set (required)
.... extension:value S 1..1 Extension Lower-case hexadecimal digest value
..... id 0..1 string Unique id for inter-element referencing
..... extension 0..0 Extension
Slice: Unordered, Open by value:url
..... url 1..1 uri "value"
..... value[x] S 1..1 string Value of extension
... url 1..1 uri "https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest"

doco Documentation for this format

This structure is derived from Extension

Summary

Complex Extension: A cryptographic digest of the referenced content, computed over the octets as served. Defined as an extension on Attachment because Attachment.hash is defined as SHA-1 in FHIR R4 and is prohibited by this guide.

  • algorithm: code: An Extension
  • value: string: An Extension

 

Other representations of profile: CSV, Excel, Schematron

Terminology Bindings

Path Status Usage ValueSet Version Source
Extension.extension:algorithm.​value[x] Base required ARex Digest Algorithm Value Set 📦0.1.0 This IG

Constraints

Id Grade Path(s) Description Expression