msporny · June 12, 2021 15:25
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 <body data-cite="infra rfc3986 HTML INFRA URL WEBIDL DOM FETCH" class="h-entry"><div class="head">
    <a class="logo" href="https://www.w3.org/"><img alt="W3C" width="72" height="48" src="https://www.w3.org/StyleSheets/TR/2016/logos/W3C"></a> <h1 id="title" class="title">The Plain CBOR Representation v1.0</h1>
    <h2 id="subtitle" class="subtitle">Expressing a DID Document using the application/did+cbor media type</h2>
    <h2>
      W3C Working Group Note
      <time class="dt-published" datetime="2021-06-12">12 June 2021</time>
    </h2>
    <dl>
      <dt>This version:</dt><dd>
              <a class="u-url" href="https://www.w3.org/TR/2021/NOTE-did-representation-cbor-20210612/">https://www.w3.org/TR/2021/NOTE-did-representation-cbor-20210612/</a>
            </dd><dt>Latest published version:</dt><dd>
              <a href="https://www.w3.org/TR/did-representation-cbor/">https://www.w3.org/TR/did-representation-cbor/</a>
            </dd>
      <dt>Latest editor's draft:</dt><dd><a href="https://w3c.github.io/did-representation-cbor/">https://w3c.github.io/did-representation-cbor/</a></dd>
      
      
      
      
      
      <dt>Editors:</dt>
      <dd class="editor p-author h-card vcard" data-editor-id="3096">
    <a class="u-url url p-name fn" href="https://github.com/jonnycrunch">Jonathan Holt</a> (<a class="p-org org h-org" href="https://transendx.com/">TranSendX</a>)
  </dd><dd class="editor p-author h-card vcard" data-editor-id="41758">
    <a class="u-url url p-name fn" href="http://manu.sporny.org/">Manu Sporny</a> (<a class="p-org org h-org" href="https://digitalbazaar.com/">Digital Bazaar</a>)
  </dd>
      
      <dt>Author:</dt><dd class="editor p-author h-card vcard" data-editor-id="3096">
    <a class="u-url url p-name fn" href="https://github.com/jonnycrunch">Jonathan Holt</a> (<a class="p-org org h-org" href="https://transendx.com/">TranSendX</a>)
  </dd>
      <dt>Participate:</dt><dd>
    <a href="https://github.com/w3c/did-cbor-note/">GitHub w3c/did-cbor-note</a>
  </dd><dd>
    <a href="https://github.com/w3c/did-cbor-note/issues/">File an issue</a>
  </dd><dd>
    <a href="https://github.com/w3c/did-cbor-note/commits/main">Commit history</a>
  </dd><dd>
    <a href="https://github.com/w3c/did-cbor-note/pulls/">Pull requests</a>
  </dd>
    </dl>
    
    
    
    <p class="copyright">
    <a href="https://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
    ©
    2021
    
    <a href="https://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href="https://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>,
    <a href="https://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href="https://www.keio.ac.jp/">Keio</a>,
    <a href="https://ev.buaa.edu.cn/">Beihang</a>). 
    W3C <a href="https://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
    <a href="https://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a rel="license" href="https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document">permissive document license</a> rules
    apply.
  </p>
    <hr title="Separator for header">
  </div>
  <section id="abstract" class="introductory"><h2>Abstract</h2>

    <p>
 This document defines the <a href="https://www.w3.org/TR/did-core/#production">production</a>
 and <a href="https://www.w3.org/TR/did-core/#consumption">consumption</a> rules
 for a CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a> for
 DID Documents [<cite><a class="bibref" data-link-type="biblio" href="#bib-did-core" title="Decentralized Identifiers (DIDs) v1.0">DID-CORE</a></cite>].
    </p>

  </section>

  <section id="sotd" class="introductory"><h2>Status of This Document</h2><p><em>This section describes the status of this
      document at the time of its publication. Other documents may supersede
      this document. A list of current <abbr title="World Wide Web Consortium">W3C</abbr> publications and the latest revision
      of this technical report can be found in the
      <a href="https://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> technical reports index</a> at
      https://www.w3.org/TR/.</em></p>

    <p>
 The <abbr title="World Wide Web Consortium">W3C</abbr> Decentralized Identifier Working Group has published this document as a
 <abbr title="World Wide Web Consortium">W3C</abbr> NOTE and is requesting that software developers provide experimental
 implementations designed to test the implementability of all of the features in
 this document.
    </p>

    <div class="issue" id="issue-container-number-4"><div role="heading" class="issue-title marker" id="h-issue" aria-level="3"><a href="https://github.com/w3c/did-cbor-note/issues/4"><span class="issue-number">Issue 4</span></a><span class="issue-label">: Debate related to purpose of format</span></div><p class="">
 The <abbr title="World Wide Web Consortium">W3C</abbr> Decentralized Identifier Working Group attempted to normatively
 define the content in this document in the [<cite><a class="bibref" data-link-type="biblio" href="#bib-did-core" title="Decentralized Identifiers (DIDs) v1.0">DID-CORE</a></cite>] specification. A lack
 of implementations and tests resulted in the removal of the
 <code>application/did+cbor</code> representation from [<cite><a class="bibref" data-link-type="biblio" href="#bib-did-core" title="Decentralized Identifiers (DIDs) v1.0">DID-CORE</a></cite>] and the
 publication of that content in this document. There remains an unresolved
 debate related to whether or not this representation is appropriate for
 implementation.  Other, more compact CBOR representations that take
 advantage of the compactness of data format might be a better fit for a
 variety of use cases.
    </p></div>

    <p>
 Comments regarding this document are welcome. Please file issues
 directly on <a href="https://github.com/w3c/did-core/issues/">GitHub</a>,
 or send them
 to <a href="mailto:[email protected]">[email protected]</a> (
 <a href="mailto:[email protected]?subject=subscribe">subscribe</a>,
 <a href="https://lists.w3.org/Archives/Public/public-did-wg/">archives</a>).
    </p>

  <p>
    This document was published by the <a href="https://www.w3.org/2019/did-wg/">Decentralized Identifier Working Group</a> as a
    Working Group Note. 
    
  </p><p>
    <a href="https://github.com/w3c/did-cbor-note/issues/">GitHub Issues</a> are preferred for
          discussion of this specification.
        
    Alternatively, you can send comments to our mailing list.
          Please send them to
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  </p><p>
      Publication as a Working Group Note does not imply endorsement
      by the <abbr title="World Wide Web Consortium">W3C</abbr> Membership. 
    </p><p>This is a draft document and may be updated, replaced
  or obsoleted by other documents at any time. It is inappropriate to cite this
  document as other than work in progress.
  </p><p></p><p>
    
        This document was produced by a group
        operating under the
        <a href="https://www.w3.org/Consortium/Patent-Policy/"><abbr title="World Wide Web Consortium">W3C</abbr> Patent
          Policy</a>.
       
    
                <abbr title="World Wide Web Consortium">W3C</abbr> maintains a
                <a rel="disclosure" href="https://www.w3.org/groups/wg/did/ipr">public list of any patent disclosures</a>
          made in connection with the deliverables of
          the group; that page also includes
          instructions for disclosing a patent. An individual who has actual
          knowledge of a patent which the individual believes contains
          <a href="https://www.w3.org/Consortium/Patent-Policy/#def-essential">Essential Claim(s)</a>
          must disclose the information in accordance with
          <a href="https://www.w3.org/Consortium/Patent-Policy/#sec-Disclosure">section 6 of the <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
        
    
  </p><p>
                  This document is governed by the
                  <a id="w3c_process_revision" href="https://www.w3.org/2020/Process-20200915/">15 September 2020 <abbr title="World Wide Web Consortium">W3C</abbr> Process Document</a>.
                </p></section><nav id="toc"><h2 class="introductory" id="table-of-contents">Table of Contents</h2><ol class="toc"><li class="tocline"><a class="tocxref" href="#introduction"><bdi class="secno">1. </bdi>Introduction</a><ol class="toc"><li class="tocline"><a class="tocxref" href="#conformance"><bdi class="secno">1.1 </bdi>Conformance</a></li></ol></li><li class="tocline"><a class="tocxref" href="#the-plain-cbor-representation"><bdi class="secno">2. </bdi>The Plain CBOR Representation</a><ol class="toc"><li class="tocline"><a class="tocxref" href="#production"><bdi class="secno">2.1 </bdi>Production</a></li><li class="tocline"><a class="tocxref" href="#consumption"><bdi class="secno">2.2 </bdi>Consumption</a></li></ol></li><li class="tocline"><a class="tocxref" href="#iana-considerations"><bdi class="secno">A. </bdi>IANA Considerations</a><ol class="toc"><li class="tocline"><a class="tocxref" href="#application-did-cbor"><bdi class="secno">A.1 </bdi>application/did+cbor</a></li></ol></li><li class="tocline"><a class="tocxref" href="#references"><bdi class="secno">B. </bdi>References</a><ol class="toc"><li class="tocline"><a class="tocxref" href="#normative-references"><bdi class="secno">B.1 </bdi>Normative references</a></li><li class="tocline"><a class="tocxref" href="#informative-references"><bdi class="secno">B.2 </bdi>Informative references</a></li></ol></li></ol></nav>

  <section class="informative" id="introduction">
    <h2 id="x1-introduction"><bdi class="secno">1. </bdi>Introduction<a class="self-link" aria-label="§" href="#introduction"></a></h2><p><em>This section is non-normative.</em></p>

    <p>
 The Decentralized Identifier specification [<cite><a class="bibref" data-link-type="biblio" href="#bib-did-core" title="Decentralized Identifiers (DIDs) v1.0">DID-CORE</a></cite>] defines a data model
 that can be expressed in a variety of representation formats. This document
 specifies the production rules for converting the DID document data model to a
 plain CBOR representation as well as the consumption rules for taking a plain
 CBOR  DID document representation and converting that back into the DID document
 data model.
    </p>

    <section id="conformance"><h3 id="x1-1-conformance"><bdi class="secno">1.1 </bdi>Conformance<a class="self-link" aria-label="§" href="#conformance"></a></h3><p>As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.</p><p>
        The key words <em class="rfc2119">MAY</em> and <em class="rfc2119">MUST</em> in this document
        are to be interpreted as described in
        <a href="https://datatracker.ietf.org/doc/html/bcp14">BCP 14</a>
        [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc2119" title="Key words for use in RFCs to Indicate Requirement Levels">RFC2119</a></cite>] [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc8174" title="Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words">RFC8174</a></cite>]
        when, and only when, they appear in all capitals, as shown here.
      </p></section>
  </section>

  <section class="notoc informative">
    <h2 id="terminology">Terminology<a class="self-link" aria-label="§" href="#terminology"></a></h2><p><em>This section is non-normative.</em></p>

    <div><p>
 This section defines the terms used in this specification and throughout
 <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-1">decentralized identifier</a> infrastructure. A link to these terms is
 included whenever they appear in this specification.
 </p>

 <dl class="termlist">

  
  

  <dt><dfn data-lt="authenticated|authenticate" id="dfn-authenticated" tabindex="0" aria-haspopup="dialog">authenticate</dfn></dt>
  <dd>
 Authentication is a process by which an entity can prove it has a specific
 attribute or controls a specific secret using one or more <a href="#dfn-verification-method" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-verification-method-1">verification
 methods</a>. With <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-2">DIDs</a>, a common example would be proving control of the
 cryptographic private key associated with a public key published in a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-1">DID
 document</a>.
  </dd>

  
  

  
  

  <dt><dfn data-lt="decentralized identifiers|DID|DIDs|decentralized identifier" data-plurals="dids|did" id="dfn-decentralized-identifiers" tabindex="0" aria-haspopup="dialog">decentralized identifier</dfn> (DID)</dt>

  <dd>
 A globally unique persistent identifier that does not require a centralized
 registration authority and is often generated and/or registered
 cryptographically. The generic format of a DID is defined in <a href="https://www.w3.org/TR/did-core/#did-syntax">Decentralized Identifiers (DIDs) v1.0</a>. A specific <a href="#dfn-did-schemes" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-schemes-1">DID scheme</a> is defined in a <a href="#dfn-did-methods" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-methods-1">DID
 method</a> specification. Many—but not all—DID methods make use of
 <a href="#dfn-distributed-ledger-technology" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-distributed-ledger-technology-1">distributed ledger technology</a> (DLT) or some other form of decentralized
 network.
  </dd>

  

  

  

  

  <dt><dfn data-lt="did controllers|did controller(s)|DID controller" id="dfn-did-controllers" tabindex="0" aria-haspopup="dialog">DID controller</dfn></dt>

  <dd>
 An entity that has the capability to make changes to a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-3">DID document</a>. A
 <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-5">DID</a> might have more than one DID controller. The DID controller(s)
 can be denoted by the optional <code>controller</code> property at the top level of the
 <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-4">DID document</a>. Note that a DID controller might be the <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-1">DID
 subject</a>.
  </dd>

  <dt><dfn id="dfn-did-delegate" tabindex="0" aria-haspopup="dialog">DID delegate</dfn></dt>

  <dd>
 An entity to whom a <a href="#dfn-did-controllers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-controllers-1">DID controller</a> has granted permission to use a
 <a href="#dfn-verification-method" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-verification-method-3">verification method</a> associated with a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-6">DID</a> via a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-5">DID
 document</a>. For example, a parent who controls a child's <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-6">DID document</a>
 might permit the child to use their personal device in order to
 <a href="#dfn-authenticated" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-authenticated-1">authenticate</a>. In this case, the child is the <a href="#dfn-did-delegate" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-delegate-1">DID delegate</a>. The
 child's personal device would contain the private cryptographic material
 enabling the child to <a href="#dfn-authenticated" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-authenticated-2">authenticate</a> using the <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-7">DID</a>. However, the child
 might not be permitted to add other personal devices without the parent's
 permission.
  </dd>

  <dt><dfn data-lt="DID documents|DID document" data-plurals="did documents" id="dfn-did-documents" tabindex="0" aria-haspopup="dialog">DID document</dfn></dt>

  <dd>
 A set of data describing the <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-2">DID subject</a>, including mechanisms, such as
 cryptographic public keys, that the <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-3">DID subject</a> or a <a href="#dfn-did-delegate" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-delegate-2">DID delegate</a>
 can use to <a href="#dfn-authenticated" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-authenticated-3">authenticate</a> itself and prove its association with the
 <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-8">DID</a>. A DID document might have one or more different
 <a href="#dfn-representations" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-representations-1">representations</a> as defined in <a href="https://www.w3.org/TR/did-core/#representations">Decentralized Identifiers (DIDs) v1.0</a> or in the
 <abbr title="World Wide Web Consortium">W3C</abbr> DID Specification Registries [<cite><a class="bibref" data-link-type="biblio" href="#bib-did-spec-registries" title="DID Specification Registries">DID-SPEC-REGISTRIES</a></cite>].
  </dd>

  <dt><dfn data-lt="DID fragments|DID fragment" id="dfn-did-fragments" tabindex="0" aria-haspopup="dialog">DID fragment</dfn></dt>

  <dd>
 The portion of a <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-1">DID URL</a> that follows the first hash sign character
 (<code>#</code>). DID fragment syntax is identical to URI fragment syntax.
  </dd>

  <dt><dfn data-lt="DID methods|DID method" id="dfn-did-methods" tabindex="0" aria-haspopup="dialog">DID method</dfn></dt>

  <dd>
 A definition of how a specific <a href="#dfn-did-schemes" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-schemes-2">DID method scheme</a> is implemented. A DID method is
 defined by a DID method specification, which specifies the precise operations by
 which <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-9">DIDs</a> and <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-7">DID documents</a> are created, resolved, updated,
 and deactivated. See <a href="https://www.w3.org/TR/did-core/#methods">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn data-lt="DID paths|DID path" id="dfn-did-paths" tabindex="0" aria-haspopup="dialog">DID path</dfn></dt>

  <dd>
 The portion of a <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-2">DID URL</a> that begins with and includes the first forward
 slash (<code>/</code>) character and ends with either a question mark
 (<code>?</code>) character, a fragment hash sign (<code>#</code>) character,
 or the end of the <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-3">DID URL</a>. DID path syntax is identical to URI path syntax.
 See <a href="https://www.w3.org/TR/did-core/#path">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn data-lt="DID queries|DID query" id="dfn-did-queries" tabindex="0" aria-haspopup="dialog">DID query</dfn></dt>

  <dd>
 The portion of a <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-4">DID URL</a> that follows and includes the first question
 mark character (<code>?</code>). DID query syntax is identical to URI query
 syntax. See <a href="https://www.w3.org/TR/did-core/#query">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn id="dfn-did-resolution" tabindex="0" aria-haspopup="dialog">DID resolution</dfn></dt>

  <dd>
 The process that takes as its input a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-10">DID</a> and a set of resolution
 options and returns a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-8">DID document</a> in a conforming <a href="#dfn-representations" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-representations-2">representation</a>
 plus additional metadata. This process relies on the "Read" operation of the
 applicable <a href="#dfn-did-methods" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-methods-2">DID method</a>. The inputs and outputs of this process are
 defined in <a href="https://www.w3.org/TR/did-core/#did-resolution">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn data-lt="DID resolvers|DID resolver" id="dfn-did-resolvers" tabindex="0" aria-haspopup="dialog">DID resolver</dfn></dt>

  <dd>
 A <a href="#dfn-did-resolvers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-resolvers-2">DID resolver</a> is a software and/or hardware component that performs the
 <a href="#dfn-did-resolution" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-resolution-1">DID resolution</a> function by taking a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-11">DID</a> as input and producing a
 conforming <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-9">DID document</a> as output.
  </dd>

  <dt><dfn data-lt="DID schemes|DID method scheme|DID scheme" id="dfn-did-schemes" tabindex="0" aria-haspopup="dialog">DID scheme</dfn></dt>

  <dd>
 The formal syntax of a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-12">decentralized identifier</a>. The generic DID scheme
 begins with the prefix <code>did:</code> as defined in <a href="https://www.w3.org/TR/did-core/#did-syntax">Decentralized Identifiers (DIDs) v1.0</a>. Each <a href="#dfn-did-methods" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-methods-3">DID method</a> specification defines a specific
 DID method scheme that works with that specific <a href="#dfn-did-methods" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-methods-4">DID method</a>. In a specific DID
 method scheme, the DID method name follows the first colon and terminates with
 the second colon, e.g., <code>did:example:</code>
  </dd>

  <dt><dfn data-lt="DID subjects|DID subject" id="dfn-did-subjects" tabindex="0" aria-haspopup="dialog">DID subject</dfn></dt>

  <dd>
 The entity identified by a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-13">DID</a> and described by a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-10">DID document</a>.
 Anything can be a DID subject: person, group, organization, physical thing,
 digital thing, logical thing, etc.
  </dd>

  <dt><dfn data-lt="DID URLs|DID URL" id="dfn-did-urls" tabindex="0" aria-haspopup="dialog">DID URL</dfn></dt>

  <dd>
 A <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-14">DID</a> plus any additional syntactic component that conforms to the
 definition in <a href="https://www.w3.org/TR/did-core/#did-url-syntax">Decentralized Identifiers (DIDs) v1.0</a>. This includes an optional <a href="#dfn-did-paths" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-paths-1">DID
 path</a> (with its leading <code>/</code> character), optional <a href="#dfn-did-queries" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-queries-1">DID query</a>
 (with its leading <code>?</code> character), and optional <a href="#dfn-did-fragments" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-fragments-1">DID fragment</a>
 (with its leading <code>#</code> character).
  </dd>

  <dt><dfn id="dfn-did-url-dereferencing" tabindex="0" aria-haspopup="dialog">DID URL dereferencing</dfn></dt>

  <dd>
 The process that takes as its input a <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-5">DID URL</a> and a set of input
 metadata, and returns a <a href="#dfn-resources" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-resources-1">resource</a>. This resource might be a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-11">DID
 document</a> plus additional metadata, a secondary resource
 contained within the <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-12">DID document</a>, or a resource entirely
 external to the <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-13">DID document</a>. The process uses <a href="#dfn-did-resolution" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-resolution-2">DID resolution</a> to
 fetch a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-14">DID document</a> indicated by the <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-15">DID</a> contained within the
 <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-6">DID URL</a>. The dereferencing process can then perform additional processing
 on the <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-15">DID document</a> to return the dereferenced resource indicated by the
 <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-7">DID URL</a>. The inputs and outputs of this process are defined in
 <a href="https://www.w3.org/TR/did-core/#did-url-dereferencing">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn data-lt="DID URL dereferencers|DID URL dereferencer" id="dfn-did-url-dereferencers" tabindex="0" aria-haspopup="dialog">DID URL dereferencer</dfn></dt>

  <dd>
 A software and/or hardware system that performs the <a href="#dfn-did-url-dereferencing" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-url-dereferencing-1">DID URL dereferencing</a>
 function for a given <a href="#dfn-did-urls" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-urls-8">DID URL</a> or <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-16">DID document</a>.
  </dd>

  <dt><dfn data-lt="distributed ledger technology|DLT|distributed ledger" id="dfn-distributed-ledger-technology" tabindex="0" aria-haspopup="dialog">distributed ledger</dfn> (DLT)</dt>

  <dd>
 A non-centralized system for recording events. These systems establish
 sufficient confidence for participants to rely upon the data recorded by others
 to make operational decisions. They typically use distributed databases where
 different nodes use a consensus protocol to confirm the ordering of
 cryptographically signed transactions. The linking of digitally signed
 transactions over time often makes the history of the ledger effectively
 immutable.
  </dd>

  <dt><dfn data-plurals="public key descriptions" id="dfn-public-key-description" tabindex="0" aria-haspopup="dialog">public key description</dfn></dt>

  <dd>
 A data object contained inside a <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-17">DID document</a> that contains all the
 metadata necessary to use a public key or a verification key.
  </dd>

  <dt><dfn data-lt="resources|resource" id="dfn-resources" tabindex="0" aria-haspopup="dialog">resource</dfn></dt>

  <dd>
 As defined by [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc3986" title="Uniform Resource Identifier (URI): Generic Syntax">RFC3986</a></cite>]: "...the term 'resource' is used in a general sense
 for whatever might be identified by a URI." Similarly, any resource might serve
 as a <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-4">DID subject</a> identified by a <a href="#dfn-decentralized-identifiers" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-decentralized-identifiers-16">DID</a>.
  </dd>

    <dt><dfn data-lt="representations|representation" id="dfn-representations" tabindex="0" aria-haspopup="dialog">representation</dfn></dt>

  <dd>
 As defined for HTTP by [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc7231" title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">RFC7231</a></cite>]: "information that is intended to reflect a
 past, current, or desired state of a given resource, in a format that can be
 readily communicated via the protocol, and that consists of a set of
 representation metadata and a potentially unbounded stream of representation
 data." A <a href="#dfn-did-documents" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-documents-18">DID document</a> is a representation of information describing a
 <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-5">DID subject</a>. See <a href="https://www.w3.org/TR/did-core/#representations">Decentralized Identifiers (DIDs) v1.0</a>.
  </dd>

  <dt><dfn data-lt="service|services" id="dfn-service" tabindex="0" aria-haspopup="dialog">services</dfn></dt>
  <dd>
 Means of communicating or interacting with the <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-6">DID subject</a> or
 associated entities via one or more <a href="#dfn-service-endpoints" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-service-endpoints-1">service endpoints</a>.
 Examples include discovery services, agent services, social networking
 services, file storage services, and verifiable credential repository services.
  </dd>

  <dt><dfn data-lt="service endpoints|service endpoint" id="dfn-service-endpoints" tabindex="0" aria-haspopup="dialog">service endpoint</dfn></dt>

  <dd>
 A network address, such as an HTTP URL, at which <a href="#dfn-service" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-service-1">services</a> operate on
 behalf of a <a href="#dfn-did-subjects" class="internalDFN" data-link-type="dfn" id="ref-for-dfn-did-subjects-7">DID subject</a>.
  </dd>

  

  

    <dt><dfn data-lt="verifiable credentials|verifiable credential" id="dfn-verifiable-credentials" tabindex="0" aria-haspopup="dialog">verifiable credential</dfn></dt>

  <dd>
 A standard data model and representation format for cryptographically-verifiable
 digital credentials as defined by the <abbr title="World Wide Web Consortium">W3C</abbr> Verifiable Credentials specification
 [<cite><a class="bibref" data-link-type="biblio" href="#bib-vc-data-model" title="Verifiable Credentials Data Model 1.0">VC-DATA-MODEL</a></cite>].
  </dd>

  

  

  

  

  <dt><dfn data-lt="" data-plurals="verification methods" id="dfn-verification-method" tabindex="0" aria-haspopup="dialog">verification method</dfn></dt>

  <dd>
    <p>
 A set of parameters that can be used together with a process to independently
 verify a proof. For example, a cryptographic public key can be used as a
 verification method with respect to a digital signature; in such usage, it
 verifies that the signer possessed the associated cryptographic private key.
    </p>
    <p>
 "Verification" and "proof" in this definition are intended to apply broadly. For
 example, a cryptographic public key might be used during Diffie-Hellman key
 exchange to negotiate a shared symmetric key for encryption. This guarantees the
 integrity of the key agreement process. It is thus another type of verification
 method, even though descriptions of the process might not use the words
 "verification" or "proof."
    </p>
  </dd>

  

  

  

  

 </dl>
 </div>

    <p>
 In addition to the terminology above, this specification also uses terminology
 from the [<cite><a class="bibref" data-link-type="biblio" href="#bib-infra" title="Infra Standard">INFRA</a></cite>] specification to formally define the <a href="https://www.w3.org/TR/did-core/#data-model">data model</a>. When [<cite><a class="bibref" data-link-type="biblio" href="#bib-infra" title="Infra Standard">INFRA</a></cite>] terminology is used, such as
 <a href="https://infra.spec.whatwg.org/#strings">string</a>, <a href="https://infra.spec.whatwg.org/#ordered-set">set</a>, and <a href="https://infra.spec.whatwg.org/#maps">map</a>, it is linked directly to that specification.
    </p>

  </section>

  <section id="the-plain-cbor-representation">
      <h2 id="x2-the-plain-cbor-representation"><bdi class="secno">2. </bdi>The Plain CBOR Representation<a class="self-link" aria-label="§" href="#the-plain-cbor-representation"></a></h2>

      <p>
 This section defines the <a href="https://www.w3.org/TR/did-core/#production">production</a>
 and <a href="https://www.w3.org/TR/did-core/#consumption">consumption</a> rules
 for a CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a> for DID Documents.
      </p>

      <section id="production">
        <h3 id="x2-1-production"><bdi class="secno">2.1 </bdi>Production<a class="self-link" aria-label="§" href="#production"></a></h3>

        <p>
 The <a href="https://www.w3.org/TR/did-core/#dfn-did-document">DID document</a>, DID document data structures, and
 representation-specific entries <a href="https://infra.spec.whatwg.org/#maps">map</a> <em class="rfc2119">MUST</em> be
 serialized to the CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a> according to the following
 <a href="https://www.w3.org/TR/did-core/#production">production</a> rules:
        </p>

        <table class="simple" id="cbor-representation-production">
          <thead>
            <tr>
              <th>
 Data&nbsp;Type
              </th>
              <th>
 CBOR Representation Type
              </th>
            </tr>
          </thead>

          <tbody>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#maps">map</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR map</a> (major type 5), where each
 entry is represented as a member of the CBOR map. The entry key is expressed
 as a <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR string</a> (major type 3) as the
 key, and the entry value according to its type, as defined in this table.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#list">list</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> (major type 4), where each
 element of the list is added, in order, as a value of the array according to its
 type, as defined in this table.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#ordered-set">set</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> (major type 4), where each
 element of the list is added, in order, as a value of the array according to its
 type, as defined in this table.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://www.w3.org/TR/did-core/#dfn-datetime">datetime</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR string</a> (major type 3) formatted as
 an <a href="https://www.w3.org/TR/xmlschema11-2/#dateTime">XML Datetime</a> normalized to
 UTC 00:00 and without sub-second decimal precision. For example:
 <code>2020-12-20T19:17:47Z</code>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#string">string</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR string</a> (major type 3).
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://www.w3.org/TR/did-core/#integer">integer</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR integer</a> (major type 0 or 1),
 choosing the shortest byte representation.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://www.w3.org/TR/did-core/#double">double</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR floating-point number</a> (major type
 7). All floating point values <em class="rfc2119">MUST</em> be encoded as 64-bits (additional type
 value 27), even for integral values.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#boolean">boolean</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.3">CBOR simple value</a> (major type 7,
 subtype 24) with a simple value of 21 (true) or 20 (false).
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://infra.spec.whatwg.org/#null">null</a>
              </td>
              <td>
 A <a href="https://tools.ietf.org/html/rfc8949#section-3.3">CBOR simple value</a> (major type 7,
 subtype 24) with a simple value of 22 (null).
              </td>
            </tr>
          </tbody>
        </table>

        <p>
 In addition to the data type production rules above, the following rules apply
 for <a href="https://www.w3.org/TR/did-core/#dfn-conforming-producer">conforming producers</a> that
 serialize CBOR <a href="https://www.w3.org/TR/did-core/#representations">representations</a>:
        </p>
        <ol>
          <li>
 Indefinite-length items are not allowed and <em class="rfc2119">MUST</em> be made a <a href="https://tools.ietf.org/html/rfc8949#section-3.2.2">CBOR definite length.</a>
          </li>
          <li>
 All CBOR tags <em class="rfc2119">MUST</em> be retained regardless of whether they are optional.
          </li>
          <li>
 All four <a href="https://tools.ietf.org/html/rfc8949#section-4.2.1">Canonical CBOR rules</a>
 listed in [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc8949" title="Concise Binary Object Representation (CBOR)">RFC8949</a></cite>] <em class="rfc2119">MUST</em> be applied to all relevant data types.
          </li>
        </ol>

        <p>
 All entries of a <a href="https://www.w3.org/TR/did-core/#dfn-did-document">DID document</a> <em class="rfc2119">MUST</em>
 be included in the root <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR map</a> (major
 type 5). Entries <em class="rfc2119">MAY</em> contain additional data substructures subject to the value
 representation rules in the list above. When serializing a <a href="https://www.w3.org/TR/did-core/#dfn-did-document">DID document</a> to its CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a>, a <a href="https://www.w3.org/TR/did-core/#dfn-conforming-producer">conforming producer</a> <em class="rfc2119">MUST</em>
 specify a media type of <code>application/did+cbor</code> to downstream
 applications such as described in the section on <a href="https://www.w3.org/TR/did-core/#did-resolution-metadata">DID Resolution Metadata</a>.
        </p>

        <p>
 The following examples express the CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a> of a <a href="https://www.w3.org/TR/did-core/#dfn-did-documents">DID document</a> in hexidecimal notation,
 and in CBOR diagnostic notation:
        </p>

      <div class="example" id="example-1-did-document-encoded-as-cbor-hexadecimal">
        <div class="marker">
    <a class="self-link" href="#example-1-did-document-encoded-as-cbor-hexadecimal">Example<bdi> 1</bdi></a><span class="example-title">: DID Document encoded as CBOR (hexadecimal)</span>
  </div> <pre class="nohighlight">A2626964781E6469643A6578616D706C653A313233343536373839616263
 6465666768696E61757468656E7469636174696F6E81A462696478256469
 643A6578616D706C653A313233343536373839616263646566676869236B
 6579732D316474797065781A45643235353139566572696669636174696F
 6E4B6579323031386A636F6E74726F6C6C6572781E6469643A6578616D70
 6C653A3132333435363738396162636465666768696F7075626C69634B65
 79426173653538782C483343324156764C4D7636676D4D4E616D33755641
 6A5A70666B634A437744776E5A6E367A3377586D715056</pre>
      </div>

      <div class="example" id="example-2-did-document-encoded-as-cbor-diagnostic-notation">
        <div class="marker">
    <a class="self-link" href="#example-2-did-document-encoded-as-cbor-diagnostic-notation">Example<bdi> 2</bdi></a><span class="example-title">: DID Document encoded as CBOR (diagnostic notation)</span>
  </div> <pre style="font-size: 50%" class="nohighlight">A2                                   # map(2)
 62                                   # text(2)
   6964                              # "id"
 78 1E                                # text(30)
   6469643A6578616D706C653A313233343536373839616263646566676869 # "did:example:123456789abcdefghi"
 6E                                   # text(14)
   61757468656E7469636174696F6E      # "authentication"
 81                                   # array(1)
   A4                                # map(4)
      62                             # text(2)
         6964                        # "id"
      78 25                          # text(37)
         6469643A6578616D706C653A313233343536373839616263646566676869236B6579732D31 # "did:example:123456789abcdefghi#keys-1"
      64                             # text(4)
         74797065                    # "type"
      78 1A                          # text(26)
         45643235353139566572696669636174696F6E4B657932303138 # "Ed25519VerificationKey2020"
      6A                             # text(10)
         636F6E74726F6C6C6572        # "controller"
      78 1E                          # text(30)
         6469643A6578616D706C653A313233343536373839616263646566676869 # "did:example:123456789abcdefghi"
      6F                             # text(15)
         7075626C69634B6579426173653538 # "publicKeyMultibase"
      78 2C                          # text(44)
         483343324156764C4D7636676D4D4E616D337556416A5A70666B634A437744776E5A6E367A3377586D715056 # "zH3C2AVvLMv6gmMNam3uVAjZpfkcJCwDwnZn6z3wXmqPV"</pre>
      </div>

      </section>

      <section id="consumption">
        <h3 id="x2-2-consumption"><bdi class="secno">2.2 </bdi>Consumption<a class="self-link" aria-label="§" href="#consumption"></a></h3>

        <p>
 The <a href="https://www.w3.org/TR/did-core/#DID-document">DID document</a> and any DID document
 data structures expressed by the <a href="https://www.w3.org/TR/did-core/#data-model">data
 model</a> <em class="rfc2119">MUST</em> be deserialized into the <a href="https://www.w3.org/TR/did-core/#data-model">data
 model</a> according to the following <a href="https://www.w3.org/TR/did-core/#consumption">consumption</a> rules:
        </p>

        <table class="simple column-width-50" id="cbor-representation-consumption">
          <thead>
            <tr>
              <th>
 CBOR Representation Type
              </th>
              <th>
 Data&nbsp;Type
              </th>
            </tr>
          </thead>

          <tbody>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR map</a> (major type 5)
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#maps">map</a>, where each data item of the
 CBOR map is added as an entry to the map with the entry key being the
 data item name and the value converted based on the CBOR type and, if available,
 entry definition, as defined here; as no order can be enforced for general CBOR
 maps, no insertion order is guaranteed.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> (major type 4), where the <a href="https://www.w3.org/TR/did-core/#data-model">data model</a> entry value is a <a href="https://infra.spec.whatwg.org/#list">list</a> or unknown
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#list">list</a>, where each value of the <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> is added to the list in order,
 converted based on the CBOR type of the array value, as defined in this table.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> (major type 4), where the <a href="https://www.w3.org/TR/did-core/#data-model">data model</a> entry value is a <a href="https://infra.spec.whatwg.org/#ordered-set">set</a>
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#ordered-set">set</a>, where each value of
 the <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR array</a> is added to the
 set in order, converted based on the CBOR type of the array value as defined in
 this table.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR string</a> (major type 3) where the <a href="https://www.w3.org/TR/did-core/#data-model">data model</a> entry value is a <a href="https://www.w3.org/TR/did-core/#dfn-datetime">datetime</a>
              </td>
              <td>
 A <a href="https://www.w3.org/TR/did-core/#dfn-datetime">datetime</a>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR string</a> (major type 3), where the <a href="https://www.w3.org/TR/did-core/#data-model">data model</a> entry value type is <a href="https://infra.spec.whatwg.org/#string">string</a> or unknown.
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#string">string</a>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR integer</a> (major type 0 or 1),
 choosing the shortest byte representation
              </td>
              <td>
 An <a href="https://www.w3.org/TR/did-core/#dfn-integer">integer</a>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR floating-point number</a> (major type
 7)
              </td>
              <td>
 A <a href="https://www.w3.org/TR/did-core/#dfn-double">double</a>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.3">CBOR simple value</a> (major type 7,
 subtype 24) with a simple value of 21 (True) or 20 (False)
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#boolean">boolean</a>.
              </td>
            </tr>
            <tr>
              <td>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.3">CBOR simple value</a> (major type 7,
 subtype 24) with a simple value of 22 (Null)
              </td>
              <td>
 A <a href="https://infra.spec.whatwg.org/#null">null</a> value.
              </td>
            </tr>
          </tbody>
        </table>

        <p>
 In addition to the data type consumption rules above, the following rules apply
 for <a href="https://www.w3.org/TR/did-core/#dfn-conforming-consumer">conforming consumers</a> that
 deserialize CBOR <a href="https://www.w3.org/TR/did-core/#dfn-conforming-consumer">conforming
 consumers</a>  that deserialize CBOR <a href="https://www.w3.org/TR/did-core/#representations">representations</a>:
        </p>

        <ol>
          <li>
 <a href="https://tools.ietf.org/html/rfc8949#section-3.2.2">CBOR
 indefinite-length items</a> are not allowed and <em class="rfc2119">MUST</em> produce an error.
          </li>
          <li>
 A duplicate key in the same CBOR map <em class="rfc2119">MUST</em> produce an error.
          </li>
          <li>
 All CBOR tags <em class="rfc2119">MUST</em> be retained for CBOR <a href="https://www.w3.org/TR/did-core/#production">production</a> regardless of whether they are
 optional.
          </li>
        </ol>

        <p>
 If media type information is available to a <a href="https://www.w3.org/TR/did-core/#dfn-conforming-consumer">conforming consumer</a> and the media
 type value is <code>application/did+cbor</code>, then the data structure being
 consumed is a <a href="https://www.w3.org/TR/did-core/#did-document">DID document</a>, and the
 root element <em class="rfc2119">MUST</em> be a <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR map</a> (major
 type 5) where all members of the object are entries of the <a href="https://www.w3.org/TR/did-core/#did-document">DID document</a>. A <a href="https://www.w3.org/TR/did-core/#did-document">DID document</a>. A <a href="https://www.w3.org/TR/did-core/#dfn-conforming-consumer">conforming consumer</a> for a CBOR <a href="https://www.w3.org/TR/did-core/#representations">representation</a> that is consuming a <a href="https://www.w3.org/TR/did-core/#representations">representation</a> that is consuming a <a href="https://www.w3.org/TR/did-core/#did-document">DID document</a> with a root element that is
 not a <a href="https://tools.ietf.org/html/rfc8949#section-3.1">CBOR map</a> (major type 5) <em class="rfc2119">MUST</em> report
 an error.
        </p>


      </section>
    </section>
  

  <section class="appendix" id="iana-considerations">
    <h2 id="a-iana-considerations"><bdi class="secno">A. </bdi>IANA Considerations<a class="self-link" aria-label="§" href="#iana-considerations"></a></h2>

    <p>
 This section will be submitted to the Internet Engineering Steering Group
 (IESG) for review, approval, and registration with IANA when this specification
 becomes a <abbr title="World Wide Web Consortium">W3C</abbr> Proposed Recommendation.
    </p>

    <section id="application-did-cbor">
      <h3 id="a-1-application-did-cbor"><bdi class="secno">A.1 </bdi>application/did+cbor<a class="self-link" aria-label="§" href="#application-did-cbor"></a></h3>
      <dl>
        <dt>Type name:</dt>
        <dd>application</dd>
        <dt>Subtype name:</dt>
        <dd>did+cbor</dd>
        <dt>Required parameters:</dt>
        <dd>None</dd>
        <dt>Optional parameters:</dt>
        <dd>None</dd>
        <dt>Encoding considerations:</dt>
        <dd>
 See <a href="https://tools.ietf.org/html/rfc8949#section-4.2.1">RFC&nbsp;8949, section 4.2.1</a>.
        </dd>
        <dt>Security considerations:</dt>
        <dd>
 See <a href="https://tools.ietf.org/html/rfc8949#section-10">RFC&nbsp;8949, section 10</a> [<cite><a class="bibref" data-link-type="biblio" href="#bib-rfc8949" title="Concise Binary Object Representation (CBOR)">RFC8949</a></cite>].
        </dd>
        <dt>Interoperability considerations:</dt>
        <dd>Not Applicable</dd>
        <dt>Published specification:</dt>
        <dd>http://www.w3.org/TR/did-core/</dd>
        <dt>Applications that use this media type:</dt>
        <dd>
 Any application that requires an identifier that is decentralized, persistent,
 cryptographically verifiable, and resolvable. Applications typically consist of
 cryptographic identity systems, decentralized networks of devices, and
 websites that issue or verify <abbr title="World Wide Web Consortium">W3C</abbr> Verifiable Credentials.
        </dd>
        <dt>Additional information:</dt>
        <dd>
          <dl>
            <dt>Magic number(s):</dt>
            <dd>Not Applicable</dd>
            <dt>File extension(s):</dt>
            <dd>.didcbor</dd>
            <dt>Macintosh file type code(s):</dt>
            <dd>TEXT</dd>
          </dl>
        </dd>
        <dt>Person &amp; email address to contact for further information:</dt>
        <dd>Ivan Herman &lt;[email protected]&gt;</dd>
        <dt>Intended usage:</dt>
        <dd>Common</dd>
        <dt>Restrictions on usage:</dt>
        <dd>None</dd>
        <dt>Author(s):</dt>
        <dd>Drummond Reed, Manu Sporny, Markus Sabadello, Dave Longley, Christopher Allen</dd>
        <dt>Change controller:</dt>
        <dd><abbr title="World Wide Web Consortium">W3C</abbr></dd>
      </dl>

       <p>
 Fragment identifiers used with
 <a href="https://www.w3.org/TR/did-core/#application-did-cbor">application/did+cbor</a> are treated
 according to the rules defined in <a href="https://www.w3.org/TR/did-core/#fragment">Decentralized Identifiers (DIDs) v1.0</a>.
      </p>
    </section>

  </section>



 <section id="references" class="appendix"><h2 id="b-references"><bdi class="secno">B. </bdi>References<a class="self-link" aria-label="§" href="#references"></a></h2><section id="normative-references">
    <h3 id="b-1-normative-references"><bdi class="secno">B.1 </bdi>Normative references<a class="self-link" aria-label="§" href="#normative-references"></a></h3>
    <dl class="bibliography"><dt id="bib-did-core">[DID-CORE]</dt><dd><a href="https://www.w3.org/TR/did-core/"><cite>Decentralized Identifiers (DIDs) v1.0</cite></a>. Drummond Reed; Manu Sporny; Markus Sabadello; Dave Longley; Christopher Allen.  W3C. 15 May 2021. W3C Candidate Recommendation. URL: <a href="https://www.w3.org/TR/did-core/">https://www.w3.org/TR/did-core/</a></dd><dt id="bib-infra">[INFRA]</dt><dd><a href="https://infra.spec.whatwg.org/"><cite>Infra Standard</cite></a>. Anne van Kesteren; Domenic Denicola.  WHATWG. Living Standard. URL: <a href="https://infra.spec.whatwg.org/">https://infra.spec.whatwg.org/</a></dd><dt id="bib-rfc2119">[RFC2119]</dt><dd><a href="https://tools.ietf.org/html/rfc2119"><cite>Key words for use in RFCs to Indicate Requirement Levels</cite></a>. S. Bradner.  IETF. March 1997. Best Current Practice. URL: <a href="https://tools.ietf.org/html/rfc2119">https://tools.ietf.org/html/rfc2119</a></dd><dt id="bib-rfc8174">[RFC8174]</dt><dd><a href="https://tools.ietf.org/html/rfc8174"><cite>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</cite></a>. B. Leiba.  IETF. May 2017. Best Current Practice. URL: <a href="https://tools.ietf.org/html/rfc8174">https://tools.ietf.org/html/rfc8174</a></dd><dt id="bib-rfc8949">[RFC8949]</dt><dd><a href="https://tools.ietf.org/html/rfc8949"><cite>Concise Binary Object Representation (CBOR)</cite></a>. C. Bormann; P. Hoffman.  IETF. December 2020. Internet Standard. URL: <a href="https://tools.ietf.org/html/rfc8949">https://tools.ietf.org/html/rfc8949</a></dd><dt id="bib-xmlschema11-2">[XMLSCHEMA11-2]</dt><dd><a href="https://www.w3.org/TR/xmlschema11-2/"><cite>W3C XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes</cite></a>. David Peterson; Sandy Gao; Ashok Malhotra; Michael Sperberg-McQueen; Henry Thompson; Paul V. Biron et al.  W3C. 5 April 2012. W3C Recommendation. URL: <a href="https://www.w3.org/TR/xmlschema11-2/">https://www.w3.org/TR/xmlschema11-2/</a></dd></dl>
  </section><section id="informative-references">
    <h3 id="b-2-informative-references"><bdi class="secno">B.2 </bdi>Informative references<a class="self-link" aria-label="§" href="#informative-references"></a></h3>
    <dl class="bibliography"><dt id="bib-did-spec-registries">[DID-SPEC-REGISTRIES]</dt><dd><a href="https://w3c.github.io/did-spec-registries/"><cite>DID Specification Registries</cite></a>. Orie Steele; Manu Sporny.  Decentralized Identifier Working Group. W3C Editor's Draft. URL: <a href="https://w3c.github.io/did-spec-registries/">https://w3c.github.io/did-spec-registries/</a></dd><dt id="bib-rfc3986">[RFC3986]</dt><dd><a href="https://datatracker.ietf.org/doc/html/rfc3986"><cite>Uniform Resource Identifier (URI): Generic Syntax</cite></a>. T. Berners-Lee; R. Fielding; L. Masinter.  IETF. January 2005. Internet Standard. URL: <a href="https://datatracker.ietf.org/doc/html/rfc3986">https://datatracker.ietf.org/doc/html/rfc3986</a></dd><dt id="bib-rfc4122">[RFC4122]</dt><dd><a href="https://tools.ietf.org/html/rfc4122"><cite>A Universally Unique IDentifier (UUID) URN Namespace</cite></a>. P. Leach; M. Mealling; R. Salz.  IETF. July 2005. Proposed Standard. URL: <a href="https://tools.ietf.org/html/rfc4122">https://tools.ietf.org/html/rfc4122</a></dd><dt id="bib-rfc7231">[RFC7231]</dt><dd><a href="https://httpwg.org/specs/rfc7231.html"><cite>Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content</cite></a>. R. Fielding, Ed.; J. Reschke, Ed..  IETF. June 2014. Proposed Standard. URL: <a href="https://httpwg.org/specs/rfc7231.html">https://httpwg.org/specs/rfc7231.html</a></dd><dt id="bib-vc-data-model">[VC-DATA-MODEL]</dt><dd><a href="https://www.w3.org/TR/vc-data-model/"><cite>Verifiable Credentials Data Model 1.0</cite></a>. Manu Sporny; Grant Noble; Dave Longley; Daniel Burnett; Brent Zundel.  W3C. 2019-11-19. W3C Recommendation. URL: <a href="https://www.w3.org/TR/vc-data-model/">https://www.w3.org/TR/vc-data-model/</a></dd></dl>
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      <p><b>Referenced in:</b></p>
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    <li>
    <a href="#ref-for-dfn-decentralized-identifiers-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-decentralized-identifiers-2" title="Reference 2">(2)</a>   <a href="#ref-for-dfn-decentralized-identifiers-5" title="Reference 5">(5)</a> <a href="#ref-for-dfn-decentralized-identifiers-6" title="Reference 6">(6)</a> <a href="#ref-for-dfn-decentralized-identifiers-7" title="Reference 7">(7)</a> <a href="#ref-for-dfn-decentralized-identifiers-8" title="Reference 8">(8)</a> <a href="#ref-for-dfn-decentralized-identifiers-9" title="Reference 9">(9)</a> <a href="#ref-for-dfn-decentralized-identifiers-10" title="Reference 10">(10)</a> <a href="#ref-for-dfn-decentralized-identifiers-11" title="Reference 11">(11)</a> <a href="#ref-for-dfn-decentralized-identifiers-12" title="Reference 12">(12)</a> <a href="#ref-for-dfn-decentralized-identifiers-13" title="Reference 13">(13)</a> <a href="#ref-for-dfn-decentralized-identifiers-14" title="Reference 14">(14)</a> <a href="#ref-for-dfn-decentralized-identifiers-15" title="Reference 15">(15)</a> <a href="#ref-for-dfn-decentralized-identifiers-16" title="Reference 16">(16)</a>   
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      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-controllers-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-delegate-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-delegate-2" title="Reference 2">(2)</a> 
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-documents-1" title="§ Terminology">§ Terminology</a>  <a href="#ref-for-dfn-did-documents-3" title="Reference 3">(3)</a> <a href="#ref-for-dfn-did-documents-4" title="Reference 4">(4)</a> <a href="#ref-for-dfn-did-documents-5" title="Reference 5">(5)</a> <a href="#ref-for-dfn-did-documents-6" title="Reference 6">(6)</a> <a href="#ref-for-dfn-did-documents-7" title="Reference 7">(7)</a> <a href="#ref-for-dfn-did-documents-8" title="Reference 8">(8)</a> <a href="#ref-for-dfn-did-documents-9" title="Reference 9">(9)</a> <a href="#ref-for-dfn-did-documents-10" title="Reference 10">(10)</a> <a href="#ref-for-dfn-did-documents-11" title="Reference 11">(11)</a> <a href="#ref-for-dfn-did-documents-12" title="Reference 12">(12)</a> <a href="#ref-for-dfn-did-documents-13" title="Reference 13">(13)</a> <a href="#ref-for-dfn-did-documents-14" title="Reference 14">(14)</a> <a href="#ref-for-dfn-did-documents-15" title="Reference 15">(15)</a> <a href="#ref-for-dfn-did-documents-16" title="Reference 16">(16)</a> <a href="#ref-for-dfn-did-documents-17" title="Reference 17">(17)</a> <a href="#ref-for-dfn-did-documents-18" title="Reference 18">(18)</a>  
  </li>
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    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-fragments" aria-label="Links in this document to definition: DID fragment">
      <span class="caret"></span>
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        <a class="self-link" href="#dfn-did-fragments" aria-label="Permalink for definition: DID fragment. Activate to close this dialog.">Permalink</a>
         
      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-fragments-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-methods" aria-label="Links in this document to definition: DID method">
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        <a class="self-link" href="#dfn-did-methods" aria-label="Permalink for definition: DID method. Activate to close this dialog.">Permalink</a>
         
      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-methods-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-methods-2" title="Reference 2">(2)</a> <a href="#ref-for-dfn-did-methods-3" title="Reference 3">(3)</a> <a href="#ref-for-dfn-did-methods-4" title="Reference 4">(4)</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-paths-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-queries-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-resolution" aria-label="Links in this document to definition: DID resolution">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-resolution-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-resolution-2" title="Reference 2">(2)</a> 
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-resolvers" aria-label="Links in this document to definition: DID resolver">
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        <a class="self-link" href="#dfn-did-resolvers" aria-label="Permalink for definition: DID resolver. Activate to close this dialog.">Permalink</a>
         
      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
     <a href="#ref-for-dfn-did-resolvers-2" title="Reference 2">(2)</a> 
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-schemes" aria-label="Links in this document to definition: DID scheme">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-schemes-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-schemes-2" title="Reference 2">(2)</a> 
  </li>
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    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-subjects" aria-label="Links in this document to definition: DID subject">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-subjects-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-subjects-2" title="Reference 2">(2)</a> <a href="#ref-for-dfn-did-subjects-3" title="Reference 3">(3)</a> <a href="#ref-for-dfn-did-subjects-4" title="Reference 4">(4)</a> <a href="#ref-for-dfn-did-subjects-5" title="Reference 5">(5)</a> <a href="#ref-for-dfn-did-subjects-6" title="Reference 6">(6)</a> <a href="#ref-for-dfn-did-subjects-7" title="Reference 7">(7)</a>  
  </li>
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    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-urls" aria-label="Links in this document to definition: DID URL">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-urls-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-did-urls-2" title="Reference 2">(2)</a> <a href="#ref-for-dfn-did-urls-3" title="Reference 3">(3)</a> <a href="#ref-for-dfn-did-urls-4" title="Reference 4">(4)</a> <a href="#ref-for-dfn-did-urls-5" title="Reference 5">(5)</a> <a href="#ref-for-dfn-did-urls-6" title="Reference 6">(6)</a> <a href="#ref-for-dfn-did-urls-7" title="Reference 7">(7)</a> <a href="#ref-for-dfn-did-urls-8" title="Reference 8">(8)</a> 
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-did-url-dereferencing" aria-label="Links in this document to definition: DID URL dereferencing">
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        <a class="self-link" href="#dfn-did-url-dereferencing" aria-label="Permalink for definition: DID URL dereferencing. Activate to close this dialog.">Permalink</a>
         
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      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-did-url-dereferencing-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
     
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-distributed-ledger-technology" aria-label="Links in this document to definition: distributed ledger">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-distributed-ledger-technology-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
     
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-resources" aria-label="Links in this document to definition: resource">
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-resources-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-representations-1" title="§ Terminology">§ Terminology</a> <a href="#ref-for-dfn-representations-2" title="Reference 2">(2)</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-service-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-service-endpoints-1" title="§ Terminology">§ Terminology</a> 
  </li>
  </ul>
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      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
     
  </li>
  </ul>
    </div><div class="dfn-panel" hidden="" role="dialog" aria-modal="true" id="dfn-panel-for-dfn-verification-method" aria-label="Links in this document to definition: verification method">
      <span class="caret"></span>
      <div>
        <a class="self-link" href="#dfn-verification-method" aria-label="Permalink for definition: verification method. Activate to close this dialog.">Permalink</a>
         
      </div>
      <p><b>Referenced in:</b></p>
      <ul>
    <li>
    <a href="#ref-for-dfn-verification-method-1" title="§ Terminology">§ Terminology</a>  <a href="#ref-for-dfn-verification-method-3" title="Reference 3">(3)</a>  
  </li>
  </ul>
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