---
type: "datatype"
title: "Signature"
datatype: "Signature"
---
# Signature

- [Datatypes](/datatypes)
- [Definitions](/datatypes-definitions#Signature)
- [Examples](/datatypes-examples#Signature)
- [Mappings](/datatypes-mappings#Signature)
- [Profiles](/datatypes-profiles#Signature)

## Overview

See also [Examples](datatypes-examples#Signature), [Detailed Descriptions](datatypes-definitions#Signature), [Mappings](datatypes-mappings#Signature), [Profiles](datatypes-profiles#Signature) and [Extensions]([%extensions-location%]extensions-datatypes#Signature)

A [Signature](signatures) holds an electronic representation of a signature and its supporting context in a FHIR accessible form. The signature may either be a cryptographic type (e.g., XML DigSig or a JWS), which is able to provide non-repudiation proof, or it may be a graphical image that represents a signature or a digital-signature process.

\[%dt Signature 15%\]

**Constraints**

\[%dt.constraints Signature%\]

Notes:

-   The Signature datatype can be used to hold a digital-signature, but may also be used to hold electronic-signatures.
-   Electronic-Signatures, such as image of ink signature, do not protect the signed content from change, but do carry details about who signed, when signature happened, and what the signature means.
-   Digital-Signatures (e.g., Xml DigSig or JOSE) do protect the content when implemented properly - see [Signatures](signatures) for further details.

Signature is used in the following places: \[%dtusage Signature%\], and also there is an extension: \[\[\[http://hl7.org/fhir/StructureDefinition/questionnaireresponse-signature\]\]\].

## Elements

- **[Signature.type](/datatypes-definitions#Signature.type)** [0..*]: [Coding](/Coding) An indication of the reason that the entity signed this document. This may be explicitly included as part of the signature information and can be used when determining accountability for various actions concerning the document.
- **[Signature.when](/datatypes-definitions#Signature.when)** [0..1]: [instant](/instant) When the digital signature was signed.
- **[Signature.who](/datatypes-definitions#Signature.who)** [0..1]: Reference(Practitioner|PractitionerRole|RelatedPerson|Patient|Device|Organization) A reference to an application-usable description of the identity that signed (e.g. the signature used their private key)
- **[Signature.onBehalfOf](/datatypes-definitions#Signature.onBehalfOf)** [0..1]: Reference(Practitioner|PractitionerRole|RelatedPerson|Patient|Device|Organization) A reference to an application-usable description of the identity that is represented by the signature.
- **[Signature.targetFormat](/datatypes-definitions#Signature.targetFormat)** [0..1]: [code](/code) A mime type that indicates the technical format of the target resources signed by the signature.
- **[Signature.sigFormat](/datatypes-definitions#Signature.sigFormat)** [0..1]: [code](/code) A mime type that indicates the technical format of the signature. Important mime types are application/signature+xml for X ML DigSig, application/jose for JWS, and image/* for a graphical image of a signature, etc.
- **[Signature.data](/datatypes-definitions#Signature.data)** [0..1]: [base64Binary](/base64Binary) The base64 encoding of the Signature content. When signature is not recorded electronically this element would be empty.

## Bindings

- **Signature.type**: `SignatureType` | strength: value set | reference: valueset-signature-type
- **Signature.targetFormat**: `MimeType`
- **Signature.sigFormat**: `MimeType`

## Summary Elements

- **Signature.type**: In _summary view
- **Signature.when**: In _summary view
- **Signature.who**: In _summary view
- **Signature.onBehalfOf**: In _summary view

## Requirements

- **Signature.onBehalfOf**: used when the signature is on behalf of a non-signer.

## Comments

- **Signature.type**: Examples include attesting to: authorship, correct transcription, and witness of specific event. Also known as a "Commitment Type Indication"
- **Signature.when**: This should agree with the information in the signature
- **Signature.who**: This should agree with the information in the signature
- **Signature.onBehalfOf**: The party that can't sign. For example a child.
- **Signature.targetFormat**: "xml", "json" and "ttl" are allowed, which describe the simple encodings described in the specification (and imply appropriate bundle support). Otherwise, mime types are legal here.
- **Signature.data**: Where the signature type is an XML Signature, the signed content is a FHIR Resource(s). The signature can be XML Signature or JSON Jose form, e.g. XML-Signature can be generated for a Resource in JSON format.