forked from w3c/vc-data-model
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathindex.html
More file actions
7657 lines (7019 loc) · 314 KB
/
index.html
File metadata and controls
7657 lines (7019 loc) · 314 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html>
<html>
<head>
<title>Verifiable Credentials Data Model v2.0</title>
<meta http-equiv='Content-Type' content='text/html;charset=utf-8'/>
<!--
=== NOTA BENE ===
For the three scripts below, if your spec resides on dev.w3 you can check them
out in the same tree and use relative links so that they'll work offline,
-->
<script src='https://www.w3.org/Tools/respec/respec-w3c' class='remove'></script>
<script src="./common.js" class="remove"></script>
<script class="remove"
src="https://cdn.jsdelivr.net/gh/digitalbazaar/respec-vc@2.0.1/dist/main.js"></script>
<script class="removeOnSave"
src="https://unpkg.com/reqlist/lib/reqlist.js"></script>
<link class="removeOnSave" rel="stylesheet" type="text/css"
href="https://unpkg.com/reqlist/lib/reqlist.css" />
<script class="remove">
var respecConfig = {
group: "vc",
// specification status (e.g., WD, LCWD, NOTE, etc.). If in doubt use ED.
specStatus: "CRD",
// the specification's short name, as in http://www.w3.org/TR/short-name/
shortName: "vc-data-model-2.0",
// subtitle for the spec
//subtitle: "Expressing information with verifiable provenance",
// if you wish the publication date to be other than today, set this
//publishDate: "2024-01-23",
crEnd: "2024-03-23",
//prEnd: "2019-10-01",
implementationReportURI: "https://w3c.github.io/vc-data-model-2.0-test-suite/",
//errata: "https://w3c.github.io/vc-data-model/errata.html",
previousMaturity: "REC",
previousPublishDate: "2022-03-03",
// if there is a previously published draft, uncomment this and set its YYYY-MM-DD date
// and its maturity status
// previousPublishDate: "1977-03-15",
// previousMaturity: "WD",
// extend the bibliography entries
localBiblio: vcwg.localBiblio,
doJsonLd: true,
// Uncomment these to use the respec extension that generates a list of
// normative statements:
preProcess: [/*prepare_reqlist*/],
postProcess: [
restrictRefs,
window.respecVc.createVcExamples
/*add_reqlist_button*/
],
github: "https://github.com/w3c/vc-data-model/",
includePermalinks: false,
// if there a publicly available Editor's Draft, this is the link
edDraftURI: "https://w3c.github.io/vc-data-model/",
// if this is a LCWD, uncomment and set the end of its review period
// lcEnd: "2009-08-05",
// editors, add as many as you like
// only "name" is required
editors: [
{ name: "Manu Sporny", url: "https://www.linkedin.com/in/manusporny/",
company: "Digital Bazaar", companyURL: "https://digitalbazaar.com/",
note: "v1.0, v1.1, v2.0", w3cid: 41758},
{ name: "Ted Thibodeau Jr", url: "https://github.com/TallTed",
company: "OpenLink Software", companyURL: "https://www.openlinksw.com/",
note: "v2.0", w3cid: 42501},
{ name: "Ivan Herman", url: "https://www.w3.org/People/Ivan/",
company: "W3C", companyURL: "https://www.w3.org",
note: "v2.0", w3cid: 7382, orcid: "0000-0003-0782-2704"},
{ name: "Michael B. Jones", url: "https://self-issued.info/",
company: "Invited Expert",
note: "v2.0", w3cid: 38745},
{ name: "Gabe Cohen", url: "https://github.com/decentralgabe",
company: "Block", companyURL: "https://block.xyz/",
note: "v2.0", w3cid: 116851},
],
formerEditors: [
{ name: "Grant Noble", url: "https://www.linkedin.com/in/grant-noble-8253994a/",
company: "ConsenSys", companyURL: "https://consensys.net/",
note: "v1.0", w3cid: 110600},
{ name: "Dave Longley", url: "https://github.com/dlongley",
company: "Digital Bazaar", companyURL: "https://digitalbazaar.com/",
note: "v1.0", w3cid: 48025},
{ name: "Daniel C. Burnett", url: "https://www.linkedin.com/in/daburnett/",
company: "ConsenSys", companyURL: "https://consensys.net/",
note: "v1.0", w3cid: 37473},
{ name: "Brent Zundel", url: "https://www.linkedin.com/in/bzundel/",
company: "Evernym", companyURL: "https://www.evernym.com/",
note: "v1.0", w3cid: 102128},
{ name: "Kyle Den Hartog", url: "https://www.linkedin.com/in/kyledenhartog/",
company: "MATTR", companyURL: "https://mattr.global/",
note: "v1.1", w3cid: 103517},
{ name: "Orie Steele", url: "https://github.com/OR13",
company: "Transmute",
companyURL: "https://transmute.industries/",
note: "v2.0", w3cid: 109171},
{ name: "Oliver Terbu", url: "https://github.com/awoie",
company: "Spruce Systems", companyURL: "https://spruceid.com/",
note: "v2.0", w3cid: 110059}
],
// authors, add as many as you like.
// This is optional, uncomment if you have authors as well as editors.
// only "name" is required. Same format as editors.
authors:
[
{ name: "Manu Sporny", url: "https://digitalbazaar.com/",
company: "Digital Bazaar", companyURL: "https://digitalbazaar.com/",
w3cid: 41758
},
{ name: "Dave Longley", url: "https://digitalbazaar.com/",
company: "Digital Bazaar", companyURL: "https://digitalbazaar.com/",
w3cid: 48025
},
{ name: "David Chadwick",
url: "https://www.linkedin.com/in/davidwchadwick/",
company: "Crossword Cybersecurity PLC",
companyURL: "https://www.crosswordcybersecurity.com/",
w3cid: 46156
},
{ name: "Orie Steele", url: "https://github.com/OR13",
company: "Transmute",
companyURL: "https://www.transmute.industries/",
note: "v2.0", w3cid: 109171}
],
xref: ["URL", "I18N-GLOSSARY", "INFRA"],
lint: { "informative-dfn": false },
maxTocLevel: 3,
inlineCSS: true
};
</script>
<style>
code {
color: rgb(199, 73, 0);
font-weight: bold;
}
pre {
overflow-x: auto;
white-space: pre-wrap;
}
pre .highlight {
font-weight: bold;
color: Green;
}
pre .subject {
font-weight: bold;
color: RoyalBlue;
}
pre .property {
font-weight: bold;
color: DarkGoldenrod;
}
pre .comment {
font-weight: bold;
color: SteelBlue;
-webkit-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
ol.algorithm {
counter-reset: numsection;
list-style-type: none;
}
ol.algorithm li {
margin: 0.5em 0;
}
ol.algorithm li:before {
font-weight: bold;
counter-increment: numsection;
content: counters(numsection, ".") ") ";
}
</style>
</head>
<body>
<section id='abstract'>
<p>
[=Credentials=] are a part of our daily lives; driver's licenses are used to
assert that we are capable of operating a motor vehicle, university degrees
can be used to assert our level of education, and government-issued passports
enable us to travel between countries. This specification provides a mechanism
to express these sorts of [=credentials=] on the Web in a way that is
cryptographically secure, privacy respecting, and machine-verifiable.
</p>
</section>
<section id='sotd'>
<p>
The Working Group is actively seeking implementation feedback for this
specification. In order to exit the Candidate Recommendation phase, the
Working Group has set the requirement of at least two independent
implementations for each mandatory feature in the specification. Please see
the <a href="https://w3c.github.io/vc-data-model-2.0-test-suite/">
implementation report</a> for more details.
</p>
<p>
Comments regarding this specification are welcome at any time.
Please file issues directly on
<a href="https://github.com/w3c/vc-data-model/issues/">GitHub</a>,
or, if that is not possible, send them to
<a href="mailto:public-vc-comments@w3.org">public-vc-comments@w3.org</a>
(<a href="mailto:public-vc-comments-request@w3.org?subject=subscribe">subscribe</a>,
<a href="https://lists.w3.org/Archives/Public/public-vc-comments/">archives</a>).
</p>
</section>
<section class="informative">
<h2>Introduction</h2>
<p>
[=Credentials=] are a part of our daily lives; driver's licenses are used to
assert that we are capable of operating a motor vehicle, university degrees
can be used to assert our level of education, and government-issued passports
enable us to travel between countries. These [=credentials=] provide
benefits to us when used in the physical world, but their use on the Web
continues to be elusive.
</p>
<p>
Currently it is difficult to express education qualifications, healthcare
data, financial account details, and other sorts of third-party [=verified=]
machine-readable personal information on the Web. The difficulty of expressing
digital [=credentials=] on the Web makes it challenging to receive the same
benefits through the Web that physical [=credentials=] provide us in the
physical world.
</p>
<p>
This specification provides a standard way to express [=credentials=] on the
Web in a way that is cryptographically secure, privacy respecting, and
machine-verifiable.
</p>
<p>
For those unfamiliar with the concepts related to
[=verifiable credentials=], the following sections provide an overview of:
</p>
<ul>
<li>
The components that constitute a [=verifiable credential=]
</li>
<li>
The components that constitute a [=verifiable presentation=]
</li>
<li>
An ecosystem where [=verifiable credentials=] and
[=verifiable presentations=] are expected to be useful
</li>
</ul>
<p>
The use cases and requirements that informed this specification can be found
in [[[VC-USE-CASES]]] [[?VC-USE-CASES]].
</p>
<section class="informative">
<h3>What is a Verifiable Credential?</h3>
<p>
In the physical world, a [=credential=] might consist of:
</p>
<ul>
<li>
Information related to identifying the [=subject=] of the [=credential=]
(for example, a photo, name, or identification number)
</li>
<li>
Information related to the issuing authority (for example, a city government,
national agency, or certification body)
</li>
<li>
Information related to the type of [=credential=] this is (for example, a
Dutch passport, an American driving license, or a health insurance card)
</li>
<li>
Information related to specific attributes or properties being asserted by
the issuing authority about the [=subject=] (for example, nationality,
the classes of vehicle entitled to drive, or date of birth)
</li>
<li>
Evidence related to how the [=credential=] was derived
</li>
<li>
Information related to constraints on the credential (for example,
validity period, or terms of use).
</li>
</ul>
<p>
A [=verifiable credential=] can represent all of the same information that a
physical [=credential=] represents. The addition of technologies, such as
digital signatures, makes [=verifiable credentials=] more tamper-evident and
more trustworthy than their physical counterparts.
</p>
<p>
[=Holders=] of [=verifiable credentials=] can generate
[=verifiable presentations=] and then share these
[=verifiable presentations=] with [=verifiers=] to prove they possess
[=verifiable credentials=] with certain characteristics.
</p>
<p>
Both [=verifiable credentials=] and [=verifiable presentations=] can be
transmitted rapidly, making them more convenient than their physical
counterparts when trying to establish trust at a distance.
</p>
<p>
While this specification attempts to improve the ease of expressing digital
[=credentials=], it also attempts to balance this goal with a number of
privacy-preserving goals. The persistence of digital information, and the ease
with which disparate sources of digital data can be collected and correlated,
comprise a privacy concern that the use of [=verifiable=] and easily
machine-readable [=credentials=] threatens to make worse. This document
outlines and attempts to address a number of these issues in Section
<a href="#privacy-considerations"></a>. Examples of how to use this data model
using privacy-enhancing technologies, such as zero-knowledge proofs, are also
provided throughout this document.
</p>
<p>
The word "verifiable" in the terms
[=verifiable credential=] and [=verifiable presentation=]
refers to the characteristic of a [=credential=] or [=presentation=]
as being able to be [=verified=] by a [=verifier=],
as defined in this document. Verifiability of a credential does not imply
the truth of [=claims=] encoded therein. Rather, once the authenticity and
currency of a [=verifiable credential=] or [=verifiable presentation=] are
established, a [=verifier=] validates the included claims using their own
business rules before relying on them. Such reliance only occurs after
evaluating the issuer, the proof, the subject, and the claims, against one or
more verifier policies.
</p>
</section>
<section class="informative">
<h3>Ecosystem Overview</h3>
<p>
This section describes the roles of the core actors and the relationships
between them in an ecosystem where [=verifiable credentials=] are expected
to be useful. A role is an abstraction that might be implemented in many
different ways. The separation of roles suggests likely interfaces and
protocols for standardization. The following roles are introduced in this
specification:
</p>
<dl>
<dt>[=holder=]</dt>
<dd>
A role an [=entity=] might perform by possessing one or more
[=verifiable credentials=] and generating [=verifiable presentations=]
from them. Example holders include students, employees, and customers.
</dd>
<dt>[=issuer=]</dt>
<dd>
A role an [=entity=] performs by asserting [=claims=] about one or
more [=subjects=], creating a [=verifiable credential=] from these
[=claims=], and transmitting the [=verifiable credential=] to a
[=holder=]. Example issuers include corporations, non-profit organizations,
trade associations, governments, and individuals.
</dd>
<dt>[=subject=]</dt>
<dd>
An [=entity=] about which [=claims=] are made. Example subjects include
human beings, animals, and things. In many cases the [=holder=] of a
[=verifiable credential=] is the subject, but in certain cases it is not. For
example, a parent (the [=holder=]) might hold the
[=verifiable credentials=] of a child (the [=subject=]), or a pet owner
(the [=holder=]) might hold the [=verifiable credentials=] of their pet
(the [=subject=]). For more information about these special cases, see the
<a href="https://www.w3.org/TR/vc-imp-guide/#subject-holder-relationships">
Subject-Holder Relationships</a> section in the Verifiable Credentials
Implementation Guide [[VC-IMP-GUIDE]].
</dd>
<dt>[=verifier=]</dt>
<dd>
A role an [=entity=] performs by receiving one or more
[=verifiable credentials=], optionally inside a
[=verifiable presentation=], for processing. Example verifiers include
employers, security personnel, and websites.
</dd>
<dt>[=verifiable data registry=]</dt>
<dd>
A role a system might perform by mediating the creation and [=verification=]
of identifiers, keys, and other relevant data, such as
[=verifiable credential=] schemas, revocation registries, issuer public keys,
and so on, which might be required to use [=verifiable credentials=]. Some
configurations might require correlatable identifiers for [=subjects=].
Example verifiable data registries include trusted databases, decentralized
databases, government ID databases, and distributed ledgers. Often
there is more than one type of verifiable data registry utilized in an
ecosystem.
</dd>
</dl>
<figure id="roles">
<img style="margin: auto; display: block; width: 75%;"
src="diagrams/ecosystem.svg" alt="diagram showing how
credentials flow from issuer to holder and
presentations flow from holder to verifier where all
three parties can use information from a logical
verifiable data registry">
<figcaption style="text-align: center;">
The roles and information flows forming the basis for this specification.
</figcaption>
</figure>
<p class="note">
<a href="#roles"></a> above provides an example ecosystem in which to ground the
rest of the concepts in this specification. Other ecosystems exist, such as
protected environments or proprietary systems, where
[=verifiable credentials=] also provide benefit.
</p>
</section>
<section id="conformance" class="normative">
<p>
A <dfn>conforming document</dfn> is a
<a data-cite="JSON-LD11-API#compaction-algorithms">compacted</a> JSON-LD
document that complies with all of the relevant "MUST" statements in this
specification. Specifically, the relevant normative "MUST" statements in
Sections <a href="#basic-concepts"></a>, <a href="#advanced-concepts"></a>, and
<a href="#syntaxes"></a> of this document MUST be enforced.
A conforming document is either a [=verifiable credential=] that MUST be
serialized using the `application/vc+ld+json` media type or a
[=verifiable presentation=] that MUST be serialized using the
`application/vp+ld+json` media type. A conforming document MUST be
secured by at least one securing mechanism as described in Section
<a href="#securing-mechanisms"></a>.
</p>
<p>
A <dfn class="lint-ignore">conforming issuer implementation</dfn> produces
[=conforming documents=], MUST include all required properties in the
[=conforming documents=] that it produces, and MUST secure the [=conforming
documents=] it produces using a securing mechanism as described in Section
<a href="#securing-mechanisms"></a>.
</p>
<p>
A <dfn class="lint-ignore">conforming verifier implementation</dfn>
consumes [=conforming documents=], MUST perform [=verification=] on a
[=conforming document=] as described in Section
<a href="#securing-mechanisms"></a>, MUST check that each
required property satisfies the normative requirements for that property, and
MUST produce errors when non-[=conforming documents=] are detected.
</p>
<p>
This specification includes both required and optional properties. Optional
properties MAY be ignored by [=conforming issuer implementations=] and/or
[=conforming verifier implementations=].
</p>
<p>
This document also contains examples that contain characters that are invalid
JSON, such as inline comments (`//`) and the use of ellipsis
(`...`) to denote information that adds little value to the example.
Implementers are cautioned to remove this content if they desire to use the
information as a valid document.
</p>
</section>
</section>
<section class="normative">
<h2>Terminology</h2>
<p>
The following terms are used to describe concepts in this specification.
</p>
<dl class="termlist definitions">
<dt><dfn class="export" data-lt="claims">claim</dfn></dt>
<dd>
An assertion made about a [=subject=].
</dd>
<dt><dfn class="export" data-lt="credential|credentials">credential</dfn></dt>
<dd>
A set of one or more [=claims=] made by an [=issuer=]. The [=claims=]
in a credential can be about different [=subjects=]. The definition of
credential used in this specification differs from,
<a href="https://csrc.nist.gov/glossary/term/credential">NIST's definitions of
credential</a>.
</dd>
<dt><dfn>data minimization</dfn></dt>
<dd>
The act of limiting the amount of shared data strictly to the minimum
necessary to successfully accomplish a task or goal.
</dd>
<dt><dfn data-lt="decentralized identifiers|DID|DIDs">decentralized identifier</dfn></dt>
<dd>
A portable URL-based identifier, also known as a <strong><em>DID</em></strong>,
associated with an [=entity=]. These identifiers are most often used in a
[=verifiable credential=] and are associated with [=subjects=] such that a
[=verifiable credential=] itself can be easily ported from one
[=repository=] to another without the need to reissue the [=credential=].
An example of a DID is `did:example:123456abcdef`.
</dd>
<dt><dfn class="lint-ignore" data-lt="decentralized identifier documents|DID document|DID documents">decentralized identifier document</dfn></dt>
<dd>
Also referred to as a <strong><em>DID document</em></strong>, this is a document
that is accessible using a [=verifiable data registry=] and contains
information related to a specific [=decentralized identifier=], such as the
associated [=repository=] and public key information.
</dd>
<dt><dfn data-lt="default graph">default graph</dfn></dt>
<dd>
The [=graph=] containing all [=claims=] that are not explicitly part of
a [=named graph=].
</dd>
<dt><dfn data-lt="predicates|derived predicates">derived predicate</dfn></dt>
<dd>
A verifiable, boolean assertion about the value of another attribute in a
[=verifiable credential=]. These are useful in zero-knowledge-proof-style
[=verifiable presentations=] because they can limit information disclosure.
For example, if a [=verifiable credential=] contains an attribute for
expressing a specific height in centimeters, a derived predicate might reference
the height attribute in the [=verifiable credential=] demonstrating that the
[=issuer=] attests to a height value meeting the minimum height requirement,
without actually disclosing the specific height value. For example, the
[=subject=] is taller than 150 centimeters.
</dd>
<dt><dfn class="lint-ignore">digital signature</dfn></dt>
<dd>
A mathematical scheme for demonstrating the authenticity of a digital message.
</dd>
<dt><dfn data-lt="entities|entity's">entity</dfn></dt>
<dd>
Anything that can be referenced in statements as an abstract or concrete noun.
Entities include but are not limited to people, organizations, physical things,
documents, abstract concepts, fictional characters, and arbitrary text. Any
entity might perform roles in the ecosystem, if it is capable of doing so. Note
that some entities fundamentally cannot take actions, e.g., the string "abc"
cannot issue credentials.
</dd>
<dt><dfn data-lt="graphs">graph</dfn></dt>
<dd>
A set of claims, forming a network of information composed of [=subjects=]
and their relationship to other [=subjects=] or data. Each [=claim=] is
part of a graph; this is either explicit in the case of [=named graphs=], or
implicit for the [=default graph=].
</dd>
<dt><dfn class="export" data-lt="holders|holder's|holders'">holder</dfn></dt>
<dd>
A role an [=entity=] might perform by possessing one or more
[=verifiable credentials=] and generating [=verifiable presentations=]
from them. A holder is often, but not always, a [=subject=] of the
[=verifiable credentials=] they are holding. Holders store their
[=credentials=] in [=credential repositories=].
</dd>
<dt><dfn class="lint-ignore"
data-lt="identities|identity's">identity</dfn></dt>
<dd>
The means for keeping track of [=entities=] across contexts. Digital
identities enable tracking and customization of [=entity=] interactions
across digital contexts, typically using identifiers and attributes. Unintended
distribution or use of identity information can compromise privacy. Collection
and use of such information should follow the principle of
[=data minimization=].
</dd>
<dt><dfn data-lt="identity providers|idp">identity provider</dfn></dt>
<dd>
An identity provider, sometimes abbreviated as <em>IdP</em>, is a system for
creating, maintaining, and managing identity information for [=holders=],
while providing authentication services to [=relying party=] applications
within a federation or distributed network. In this case the [=holder=] is
always the [=subject=]. Even if the [=verifiable credentials=] are bearer
[=credentials=], it is assumed the [=verifiable credentials=] remain with
the [=subject=], and if they are not, they were stolen by an attacker. This
specification does not use this term unless comparing or mapping the concepts in
this document to other specifications. This specification decouples the
[=identity provider=] concept into two distinct concepts: the [=issuer=]
and the [=holder=].
</dd>
<dt><dfn class="export" data-lt="issuers|issuer's">issuer</dfn></dt>
<dd>
A role an [=entity=] can perform by asserting [=claims=] about one or
more [=subjects=], creating a [=verifiable credential=] from these
[=claims=], and transmitting the [=verifiable credential=] to a
[=holder=].
</dd>
<dt><dfn data-lt="named graphs">named graph</dfn></dt>
<dd>
A [=graph=] associated with specific properties, such as
`verifiableCredential`. These properties
result in separate [=graphs=] that contain all [=claims=] defined in the
corresponding JSON objects.
</dd>
<dt><dfn class="export" data-lt="presentation|presentations">presentation</dfn></dt>
<dd>
Data derived from one or more [=verifiable credentials=], issued by one or
more [=issuers=], that is shared with a specific [=verifier=].
</dd>
<dt><dfn class="export" data-lt="credential repository|credential repositories|repositories">repository</dfn></dt>
<dd>
A program, such as a storage vault or personal [=verifiable credential=]
wallet, that stores and protects access to [=holders'=]
[=verifiable credentials=].
</dd>
<dt><dfn class="export">selective disclosure</dfn></dt>
<dd>
The ability of a [=holder=] to make fine-grained decisions about what
information to share.
</dd>
<dt><dfn class="export" data-lt="subjects|subject's">subject</dfn></dt>
<dd>
A thing about which [=claims=] are made.
</dd>
<dt><dfn class="lint-ignore">user agent</dfn></dt>
<dd>
A program, such as a browser or other Web client, that mediates the
communication between [=holders=], [=issuers=], and [=verifiers=].
</dd>
<dt><dfn class="export" data-lt="claim validation|validate">validation</dfn></dt>
<dd>
The assurance that a [=claim=] from a specific [=issuer=] satisfies the
business requirements of a [=verifier=] for a particular use. This
specification defines how verifiers verify [=verifiable credentials=] and
[=verifiable presentations=].<br/>
It also specifies that [=verifiers=] validate claims in [=verifiable
credentials=] before relying on them. However, the means for such validation
vary widely and are outside the scope of this specification. It is expected
that [=verifiers=] will trust certain [=issuers=] for certain claims and
apply their own rules to determine which claims in which [=credentials=]
are suitable for use by their systems.
</dd>
<dt><dfn class="export" data-lt="vc|vcs">verifiable credential</dfn></dt>
<dd>
A verifiable credential is a tamper-evident credential that has authorship that
can be cryptographically verified. Verifiable credentials can be used to build
[=verifiable presentations=], which can also be cryptographically verified.
</dd>
<dt><dfn class="export" data-lt="verifiable data registries">verifiable data registry</dfn></dt>
<dd>
A role a system might perform by mediating the creation and [=verification=]
of identifiers, keys, and other relevant data, such as
[=verifiable credential=] schemas, revocation registries, issuer public keys,
and so on, which might be required to use [=verifiable credentials=]. Some
configurations might require correlatable identifiers for [=subjects=]. Some
registries, such as ones for UUIDs and public keys, might just act as namespaces
for identifiers.
</dd>
<dt><dfn class="export" data-lt="vp|vps">verifiable presentation</dfn></dt>
<dd>
A verifiable presentation is a tamper-evident presentation encoded in such a way
that authorship of the data can be trusted after a process of cryptographic
verification. Certain types of verifiable presentations might contain data that
is synthesized from, but do not contain, the original [=verifiable
credentials=] (for example, zero-knowledge proofs).
</dd>
<dt><dfn class="export" data-lt="verify|verified|verifying|verifiable|verifiability">verification</dfn></dt>
<dd>
The evaluation of whether a [=verifiable credential=] or [=verifiable
presentation=] is an authentic and current statement of the issuer or
presenter, respectively. This includes checking that: the credential (or
presentation) conforms to the specification; the proof method is satisfied; and,
if present, the status check succeeds. Verification of a credential does not
imply evaluation of the truth of [=claims=] encoded in the credential.
</dd>
<dt><dfn class="export" data-lt="verifier|verifiers|verifier's|credential verifiers|credential verifier's">verifier</dfn></dt>
<dd>
A role an [=entity=] performs by receiving one or more
[=verifiable credentials=], optionally inside a
[=verifiable presentation=] for processing. Other specifications might refer
to this concept as a <dfn data-lt="relying parties">relying party</dfn>.
</dd>
<dt><dfn data-lt="verification material">verification material</dfn></dt>
<dd>
Information that could be a cryptographic public key or any other data used to
verify a proof.
</dd>
<dt><dfn data-lt="URL|URLs">URL</dfn></dt>
<dd>
A Uniform Resource Locator, as defined by [[URL]]. URLs can be dereferenced such
that they result in a resource, such as a document. The rules for dereferencing,
or fetching, a URL are defined by the URL [=url/scheme=]. This specification
does not use the term URI or IRI because those terms have been deemed to be
confusing to Web developers.
</dd>
</dl>
</section>
<section class="informative">
<h2>Core Data Model</h2>
<p>
The following sections outline core data model concepts, such as [=claims=],
[=credentials=], [=presentations=], [=verifiable credentials=], and
[=verifiable presentations=], which form the foundation of this
specification.
</p>
<p class="note"
title="The difference between a credential and a verifiable credential">
Readers might note that some concepts described in this section, such as
[=credential=] and [=presentation=], do not have media types defined by
this specification. However, the concepts of a [=verifiable credential=] or a
[=verifiable presentation=] are defined as [=conforming documents=] and do
have associated media types. The concrete difference between these concepts
— between [=credential=] and [=presentation=] vs. [=verifiable
credential=] and [=verifiable presentation=] — is simply the fact
that the "verifiable" objects are secured in a way that is cryptographically
verifiable, and the others are not. For more details, see Section
<a href="#securing-mechanisms"></a>.
</p>
<section class="informative">
<h3>Claims</h3>
<p>
A [=claim=] is a statement about a [=subject=]. A [=subject=] is a
thing about which [=claims=] can be made. [=Claims=] are expressed using
<strong><em>subject</em></strong>-<dfn data-lt="property|properties">
property</dfn>-<dfn class="lint-ignore">value</dfn> relationships.
</p>
<figure id="basic-structure">
<img style="margin: auto; display: block; width: 50%;"
src="diagrams/claim.svg" alt="subject has a property which
has a value">
<figcaption style="text-align: center;">
The basic structure of a claim.
</figcaption>
</figure>
<p>
The data model for [=claims=], illustrated in <a href="#basic-structure"></a>
above, is powerful and can be used to express a large variety of statements. For
example, whether someone graduated from a particular university can be expressed
as shown in <a href="#basic-example"></a> below.
</p>
<figure id="basic-example">
<img style="margin: auto; display: block; width: 60%;"
src="diagrams/claim-example.svg" alt="Pat has an alumniOf
property whose value is Example University">
<figcaption style="text-align: center;">
A basic claim expressing that Pat is an alumni of "Example University".
</figcaption>
</figure>
<p>
Individual [=claims=] can be merged together to express a [=graph=] of
information about a [=subject=]. The example shown in
<a href="#multiple-claims"></a> below extends the previous [=claim=] by
adding the [=claims=] that Pat knows Sam and that Sam is employed as a
professor.
</p>
<figure id="multiple-claims">
<img style="margin: auto; display: block; width: 75%;"
src="diagrams/claim-extended.svg" alt="extends previous
diagram with another property called knows whose value is
Sam, and Sam has a property jobTitle whose value is Professor">
<figcaption style="text-align: center;">
Multiple claims can be combined to express a graph of information.
</figcaption>
</figure>
<p>
To this point, the concepts of a [=claim=] and a [=graph=] of information
are introduced. To be able to trust [=claims=], more information is
expected to be added to the graph.
</p>
</section>
<section class="informative">
<h3>Credentials</h3>
<p>
A [=credential=] is a set of one or more [=claims=] made by the same
[=entity=]. [=Credentials=] might also include an identifier and metadata
to describe properties of the [=credential=], such as the
[=issuer=], the validity date and time period, a representative image,
[=verification material=], the revocation
mechanism, and so on. The metadata might be signed by the [=issuer=]. A
[=verifiable credential=] is a set of tamper-evident [=claims=] and
metadata that cryptographically prove who issued it.
</p>
<figure id="basic-vc">
<img style="margin: auto; display: block; width: 50%;"
src="diagrams/vc.svg" alt="a Verifiable
Credential contains Credential Metadata, Claim(s), and
Proof(s)">
<figcaption style="text-align: center;">
Basic components of a verifiable credential.
</figcaption>
</figure>
<p>
Examples of [=verifiable credentials=] include digital employee
identification cards, digital birth certificates, and digital educational
certificates.
</p>
<p class="note">
[=Credential=] identifiers are often used to identify specific instances
of a [=credential=]. These identifiers can also be used for correlation. A
[=holder=] wanting to minimize correlation is advised to use a selective
disclosure scheme that does not reveal the [=credential=] identifier.
</p>
<p>
<a href="#basic-vc"></a> above shows the basic components of a
[=verifiable credential=], but abstracts the details about how [=claims=]
are organized into information [=graphs=], which are then organized into
[=verifiable credentials=].
</p>
<p>
<a href="#info-graph-vc"></a> below shows a more complete depiction of a
[=verifiable credential=] using an [=embedded proof=] based on [[?VC-DATA-INTEGRITY]].
It is composed of at least two information [=graphs=].
The first of these information [=graphs=], the [=verifiable credential graph=] (which is the [=default graph=]),
expresses the [=verifiable credential=] itself, through [=credential=] metadata and other [=claims=].
The second information [=graph=], referred to by the `proof` property, is the <dfn>proof graph</dfn>
of the [=verifiable credential=], and is a separate [=named graph=].
The [=proof graph=] expresses the digital proof, which, in this case, is a digital
signature.
</p>
<figure id="info-graph-vc">
<img style="margin: auto; display: block; width: 100%;"
src="diagrams/vc-graph.svg" alt="Diagram with a collections of
claims for a 'verifiable credential graph' on top
connected via a proof property (or predicate) to a 'verifiable credential proof
graph' on the bottom. The claims for a verifiable credential include 'Credential
123' as a subject with 4 properties: 'type' of value ExampleAlumniCredential,
'issuer' of Example University, 'validFrom' of 2010-01-01T19:23:24Z, and
credentialSubject of Pat, who also has an alumniOf property with value of
Example University. The verifiable credential proof graph has an object
'Signature 456' subject with 5 properties: 'type' of DataIntegrityProof,
'verificationMethod' of Example University Public Key 7, 'created' of
2017-06-18T21:19:10Z, a 'nonce' of 34dj239dsj328, and 'proofValue' of
'zBavE110…3JT2pq'. The verifiable credential graph is also annotated with the
parenthetical remark '(the default graph)', the verifiable credential proof
graph is annotated with the parenthetical remark '(a named graph)'.">
<figcaption style="text-align: center;">
Information graphs associated with a basic verifiable credential, using an [=embedded proof=]
based on [[[VC-DATA-INTEGRITY]]] [[?VC-DATA-INTEGRITY]].
</figcaption>
</figure>
<p>
<a href="#info-graph-vc-jwt"></a> below shows the same [=verifiable credential=]
as <a href="#info-graph-vc"></a>, but using JOSE based on [[?VC-JOSE-COSE]].
The payload contains a single information graph, that being the [=verifiable credential graph=]
containing [=credential=] metadata and other [=claims=].
</p>
<figure id="info-graph-vc-jwt">
<img style="margin: auto; display: block; width: 100%;"
src="diagrams/vc-jwt.svg"
alt="Diagram with, on the left, a box, labeled as
'SD-JWT (Decoded)', and with three textual labels stacked vertically,
namely 'Header', 'Payload', and 'Signature'. The 'Header' label is
connected, with an arrow, to a separate rectangle on the right hand
side containing six text fields: 'kid: aB8J-_Z', 'alg: ES384', and
'cty: vc+ld+json', iss: https://example.com, iat: 1704690029, and typ:
vc+ld+json+sd-jwt The 'Payload' label on the left side is connected,
with an arrow, to a separate rectangle, containing a single graph. The
rectangle has a label: 'verifiable credential graph (serialized in
JSON)' The claims in the graph include 'Credential 123' as a subject
with 4 properties: 'type' with value 'ExampleAlumniCredential',
'issuer' with value 'Example University', 'validFrom' with value
'2010-01-01T19:23:24Z', and 'credentialSubject' with value 'Pat', who
also has an 'alumniOf' property with value 'Example University'.
Finally, the 'Signature' label on the left side is connected, with an
arrow, to a separate rectangle, containing a single text field:
'DtEhU3ljbEg8L38VWAfUA...'.
">
<figcaption style="text-align: center;">
Information graphs associated with a basic verifiable credential, using an [=enveloping proof=]
based on [[[VC-JOSE-COSE]]] [[?VC-JOSE-COSE]].
</figcaption>
</figure>
<p class="note">
It is possible to have a [=credential=], such as a marriage certificate,
containing multiple [=claims=] about different [=subjects=] that are not
required to be related.
</p>
<p class="note">
It is possible to have a [=credential=] that does not contain any
[=claims=] about the [=entity=] to which the [=credential=] was issued.
For example, a [=credential=] that only contains [=claims=] about a
specific dog, but is issued to its owner.
</p>
</section>
<section class="informative">
<h3>Presentations</h3>
<p>
Enhancing privacy is a key design feature of this specification. Therefore, it
is important for [=entities=] using this technology to be able to express
only the portions of their persona that are appropriate for a given situation.
The expression of a subset of one's persona is called a
[=verifiable presentation=]. Examples of different personas include a
person's professional persona, their online gaming persona, their
family persona, or an incognito persona.
</p>
<p>
A [=verifiable presentation=] can express data from multiple
[=verifiable credentials=] and contain arbitrary additional data encoded as
JSON-LD. They are used by a [=holder=] to present [=claims=] to a
[=verifier=]. It is also possible to present [=verifiable credentials=]
directly.
</p>
<p>
The data in a [=presentation=] is often about the same [=subject=], but
might have been issued by multiple [=issuers=]. The aggregation of this
information typically expresses an aspect of a person, organization, or
[=entity=].
</p>
<figure id="basic-vp">
<img style="margin: auto; display: block; width: 50%;"
src="diagrams/presentation.svg" alt="A Verifiable
Presentation contains Presentation Metadata, Verifiable
Credential(s), and Proof(s)">
<figcaption style="text-align: center;">
Basic components of a verifiable presentation.
</figcaption>
</figure>
<p>
<a href="#basic-vp"></a> above shows the components of a
[=verifiable presentation=], but abstracts the details about how
[=verifiable credentials=] are organized into information [=graphs=],
which are then organized into [=verifiable presentations=].
</p>
<p id="info-graph-vp-explanation">
<a href="#info-graph-vp"></a> below shows a more complete depiction of a
[=verifiable presentation=] using an [=embedded proof=]
based on [[?VC-DATA-INTEGRITY]].
It is composed of at least four information [=graphs=].
The first of these information [=graphs=], the [=verifiable presentation graph=]
(which is the [=default graph=]), expresses the [=verifiable presentation=]
itself through [=presentation=] metadata.
The [=verifiable presentation=] refers, via the `verifiableCredential` property,
to a [=verifiable credential=].
This [=credential=] is a self-contained [=verifiable credential graph=] containing [=credential=] metadata and other [=claims=].
This [=credential=] refers to a [=verifiable credential=] [=proof graph=] via a `proof` property,
expressing the proof (usually a digital signature) of the [=credential=].
This [=verifiable credential graph=], and its linked [=proof graph=], constitute
the second and third information [=graphs=], respectively, and each is a separate [=named graph=].
The [=presentation=] also refers, via the `proof` property, to
the [=presentation=]'s [=proof graph=], which is the fourth information [=graph=] (another [=named graph=]).
This [=presentation=] [=proof graph=] represents the digital signature of the [=verifiable presentation graph=],
the [=verifiable credential graph=], and the [=proof graph=] linked from the [=verifiable credential graph=].
</p>
<figure id="info-graph-vp">
<img style="margin: auto; display: block; width: 100%;"
src="diagrams/vp-graph.svg" alt="Diagram with a
'verifiable presentation graph' on top connected via a 'proof' to
a 'verifiable presentation proof graph on the bottom. The verifiable
presentation graph has and object 'Presentation ABC' with 3 properties: 'type'
of value VerifiablePresentation, 'termsOfUse' of value 'Do Not Archive'. The
graph is annotated with the parenthetical remark '(the default graph)'. This
graph is connected, through 'verifiableCredential', to the part of the figure
which is identical to Figure 6, except that the verifiable credential graph is
annotated to be a named graph instead of a default graph.
The verifiable presentation proof graph has an object with 'Signature 8910'
with 5 properties: 'type' with value 'DataIntegrityProof'; 'verificationMethod' with value 'Example
Presenter Public Key 11'; 'created' with value '2018-01-15T12:43:56Z';
'nonce' with value 'd28348djsj3239'; and 'proofValue' with value
'zp2KaZ...8Fj3K='. This graph is annotated with the parenthetical remark '(a
named graph)'">
<figcaption style="text-align: center;">
Information [=graphs=] associated with a basic [=verifiable presentation=] that is using an [=embedded proof=]
based on [[[VC-DATA-INTEGRITY]]] [[?VC-DATA-INTEGRITY]].
</figcaption>
</figure>
<p>
<a href="#info-graph-vp-jwt"></a> below shows the same [=verifiable
presentation=] as <a href="#info-graph-vp"></a>, but using an [=enveloping
proof=] based on [[?VC-JOSE-COSE]]. The payload contains only two information
graphs: the [=verifiable presentation graph=] expressing the [=verifiable
presentation=] itself through presentation metadata; and the corresponding