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<!DOCTYPE html>
<html>
<head>
<title>Bitstring Status List v1.0</title>
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shortName: "vc-bitstring-status-list",
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subtitle: "Privacy-preserving status information for Verifiable Credentials",
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<body>
<section id='abstract'>
<p>
This specification describes a privacy-preserving, space-efficient, and
high-performance mechanism for publishing status information such as
suspension or revocation of Verifiable Credentials through use of bitstrings.
</p>
</section>
<section id='sotd'>
</section>
<section class="informative">
<h2>Introduction</h2>
<p>
It is often useful for an [=issuer=] of [=verifiable credentials=]
[[VC-DATA-MODEL-2.0]] to link to a location where a [=verifier=] can check to see
if a credential has been suspended or revoked. There are a variety of privacy
and performance considerations that are made when designing, publishing, and
processing status lists.
</p>
<p>
One such privacy consideration happens when there is a one-to-one mapping
between a [=verifiable credential=] and a URL where the status is
published. This type of mapping enables the website that publishes the URL to
correlate the [=holder=], time, and [=verifier=] when the status is
checked. This could enable the [=issuer=] to discover the type of interaction
the [=holder=] is having with the [=verifier=], such as providing an age
verification credential when entering a bar. Being tracked by the [=issuer=]
of a driver's license when entering an establishment violates a privacy
expectation that many people have today.
</p>
<p>
Similarly, there are performance considerations that are explored when designing
status lists. One such consideration is where the list is published and the
burden it places from a bandwidth and processing perspective, both on the server
and the client fetching the information. In order to meet privacy expectations,
it is useful to bundle the status of large sets of credentials into a single
list to help with group privacy. However, doing so can place an impossible
burden on both the server and client if the status information is as much as a
few hundred bytes in size per credential across a population of
hundreds of millions of [=holders=].
</p>
<p>
The rest of this document proposes a highly compressible, bitstring-based
status list mechanism with strong privacy-preserving characteristics,
that is compatible with the architecture of the Web, is highly space-efficient,
and lends itself well to content distribution networks. As an example of
using this specification to achieve a number of beneficial privacy and
performance goals, it is possible to create a status list that can be
constructed for 100,000 [=verifiable credentials=] that is roughly
12,500 bytes in size in the worst case. In a case where a few hundred
credentials have been revoked, the size of the list is less than a
few hundred bytes while providing privacy in a group of 100,000 individuals.
</p>
<section class="informative">
<h3>Conceptual Framework</h3>
<p>
This section outlines the core concept utilized by the status list
mechanism described in this specification. At the most basic level, status
information for all [=verifiable credentials=] issued by an [=issuer=]
is expressed as items in a list. Each [=issuer=] manages a list
of all [=verifiable credentials=] that it has issued. Each
[=verifiable credential=] is associated with an item in its list.
When a single bit specifies a status, such as "revoked" or "suspended",
then that status is expected to be true when the bit is set (`1`) and
false when unset (`0`).
</p>
<p>
One of the benefits of using a bitstring is that it is a highly compressible
data format since, in the average case, large numbers of credentials will
remain unrevoked. This will ensure long sections of bits that are the same
value and thus highly compressible using run-length compression techniques
such as GZIP [[RFC1952]]. The default status list size is 131,072 entries,
equivalent to 16 KB of single bit values. When only a handful of
[=verifiable credentials=] are revoked, GZIP compresses the bitstring
to a few hundred bytes.
</p>
<p>
Another benefit of using a bitstring is that it enables large numbers of
[=verifiable credential=] statuses to be placed in the same list.
This specification uses a minimum list length of 131,072. This
size ensures an adequate amount of group privacy in the average case.
If better group privacy is required, the bitstring can be made larger.
</p>
<figure id="bitstring">
<img style="margin: auto; display: block; width: 75%;"
src="diagrams/BitstringStatusListConcept.svg" alt="
diagram showing a list of boxes at the top of the image with two of
them in red depicting revoked credentials. Text beside the boxes to
the right reads 16 kilobytes. An depiction of the boxes being GZIP
compressed into a cylinder on the bottom of the page shows that
compression has resulted in a final size of 135 bytes.">
<figcaption style="text-align: center;">
A visual depiction of the concepts outlined in this section.
</figcaption>
</figure>
<p class="note"
title="Status information is about the verifiable credential">
The status information associated with a particular [=verifiable credential=]
is about the [=verifiable credential=] itself and might not apply to any
underlying or backing [=credential=], such as an educational degree. For
example, in the case of such an educational degree, it is possible for a
[=verifiable credential=] to be revoked because the mechanism used to
create its digital signature has been compromised, while the backing educational
degree remains valid.
</p>
</section>
<section class="informative">
<h3>Terminology</h3>
<p>
Terminology used throughout this document is defined in the
<a data-cite="VC-DATA-MODEL-2.0#terminology">Terminology</a> section of the
[[[VC-DATA-MODEL-2.0]]] specification.
</p>
</section>
<section id="conformance" class="normative">
<p>
A <dfn>conforming document</dfn> is any concrete expression of the
data model that follows the relevant normative requirements in Section
<a href="#data-model"></a>.
</p>
<p>
A <dfn>conforming processor</dfn> is any algorithm realized
as software and/or hardware that generates and/or consumes a
[=conforming document=] according to the relevant normative statements in
Section <a href="#algorithms"></a>. Conforming processors MAY choose to only
support bitstring entry sizes of 1. Conforming processors MUST produce errors
when non-conforming documents are consumed.
</p>
</section>
</section>
<section class="normative">
<h2>Data Model</h2>
<p>
There are numerous ways to express status information associated with digital
credentials. Some of these mechanisms include Certificate Revocation Lists (CRL)
[[?RFC5280]], the Online Certificate Status Protocol (OCSP) [[?RFC2560]], Bloom
Filters [[?RFC8932]], and cryptographic accumulators [[?ALLOSAUR]]. This
specification optimizes for a variety of requirements that are different from
other mechanisms. These requirements include:
</p>
<table class="simple" id="#pfatable">
<thead>
<tr>
<th style="text-align: center;">Technology</th>
<th style="text-align: center;">CRL</th>
<th style="text-align: center;">OCSP</th>
<th style="text-align: center;">Bloom</th>
<th style="text-align: center;">Accumulator</th>
<th style="text-align: center;">Bitstring</th>
</tr>
</thead>
<tbody>
<tr>
<td>
Provides tunable group privacy
</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Does not require signed assertion for each credential
</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Resistant to [=issuer=] tracking when fetched by [=verifier=]
</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Caching is space efficient with many revocations
</td>
<td class="missing">✗</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Highly compressible (>90% average compression)
</td>
<td class="missing">✗</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Updates are efficient (fast and entire population does not need to update)
</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Uses cryptographic primitives approved by IETF
</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
No false positives
</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Can be delivered by [=holder=] (stapling)
</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
<td class="supported">✓</td>
</tr>
<tr>
<td>
Easily profiled for usage with [=verifiable credentials=]
</td>
<td class="missing">✗</td>
<td class="missing">✗</td>
<td class="missing">✗</td>
<td class="missing">✗</td>
<td class="supported">✓</td>
</tr>
</tbody>
</table>
<section>
<h3>BitstringStatusListEntry</h3>
<p>
When an [=issuer=] desires to enable status information for a
[=verifiable credential=], they MAY add a `credentialStatus`
property that uses the data model described in this section. Any
expression of the data model in this section MUST be expressed in a
conforming [=verifiable credential=] as defined in [[VC-DATA-MODEL-2.0]].
</p>
<table class="simple">
<thead>
<tr>
<th style="white-space: nowrap">Property</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>id</td>
<td>
An optional identifier for the status list entry. The constraints on the `id`
property are listed in the Verifiable Credentials Data Model specification
[[VC-DATA-MODEL-2.0]]. If present, the value is expected to be a URL that
identifies the status information associated with the <a>verifiable
credential</a>. It MUST NOT be the URL for the status list. The value is not
used during the verification or validation process, and does not need to be
related to the `statusListCredential` value. If necessary, the value can be used
to uniquely identify the `BitstringStatusListEntry` object, such as when it is
stored in a database.
</td>
</tr>
<tr>
<td>type</td>
<td>
The `type` property MUST be `BitstringStatusListEntry`.
</td>
</tr>
<tr>
<td>statusPurpose</td>
<td>
The purpose of the status entry MUST be a string. While the value of the
string is arbitrary, the following values MUST be used for their intended
purpose:
<table class="simple">
<thead>
<tr>
<th style="white-space: nowrap">Value</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>`refresh`</td>
<td>
Used to signal that an updated [=verifiable credential=] is available via the
credential's <a data-cite="VC-DATA-MODEL-2.0#refreshing">refresh service</a>
feature. This status does not invalidate the [=verifiable credential=] and is
not reversible.
</td>
</tr>
<tr>
<td>`revocation`</td>
<td>
Used to cancel the validity of a [=verifiable credential=]. This status is
not reversible.
</td>
</tr>
<tr>
<td>`suspension`</td>
<td>
Used to temporarily prevent the acceptance of a [=verifiable credential=].
This status is reversible.
</td>
</tr>
<tr>
<td>`message`</td>
<td>
Used to convey an arbitrary message related to the status of the
[=verifiable credential=].
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr>
<td>statusListIndex</td>
<td>
The `statusListIndex` property MUST be an arbitrary size integer
greater than or equal to 0, expressed as a string in base 10. The value identifies the
position of the status of the [=verifiable credential=]. Implementations
SHOULD assign indexes randomly, such that inferences — such as the recency
of the assignment or the size of the group — cannot be easily drawn from
that position.
</td>
</tr>
<tr>
<td>statusListCredential</td>
<td>
The `statusListCredential` property MUST be a URL to a
[=verifiable credential=]. When the URL is dereferenced, the resulting
[=verifiable credential=] MUST have `type` property that
includes the `BitstringStatusListCredential` value.
</td>
</tr>
<tr>
<td id="statusSize">statusSize</td>
<td>
The `statusSize` indicates the size of the status entry in bits. `statusSize`
MAY be provided. If `statusSize` is not present as a property of the
`credentialStatus`, then `statusSize` MUST be processed as `1`. If present,
`statusSize` MUST be an integer greater than zero. If `statusSize` is provided
and is greater than `1`, then the property `credentialStatus.statusMessage`
MUST be present, and the number of status messages MUST equal the
number of possible values.
</td>
</tr>
<tr>
<td id="statusMessage">statusMessage</td>
<td>
If present, the `statusMessage` property MUST be an array, the length
of which MUST equal the number of possible status messages indicated
by `statusSize` (e.g., `statusMessage` array MUST have 2 elements if
`statusSize` has 1 bit, 4 elements if `statusSize` has 2 bits, 8
elements if `statusSize` has 3 bits, etc.). `statusMessage` MAY be
present if `statusSize` is `1`, and MUST be present if `statusSize` is
greater than `1`. If the `statusMessage` array is not present, the
message values associated with the `status` bit values of `1` and `0`
are "set" and "unset", respectively. If the `statusMessage` array is
present, each element MUST contain the two properties described below,
and MAY contain additional properties.
<ul>
<li id="status">
`status`, a string representing the hexadecimal value of the status prefixed
with `0x`
</li>
<li id="message">
`message`, a string used by software developers to assist with debugging
which SHOULD NOT be displayed to end users.
</li>
</ul>
Implementers MAY add additional values to objects in the `statusMessage` array.
Implementers MAY use the string value of `undefined` in the value to indicate
that a corresponding status is not defined for the associated status value, but
that it may be defined in the future. Rules for how to handle various status
messages are outside the scope of normative requirements in this document, but
it is assumed that implementers will document rules for processing various
status codes.
</td>
</tr>
<tr>
<td id="statusReference">statusReference</td>
<td>
An implementer MAY include the `statusReference` property. If present, its
value MUST be a URL or an array of URLs [[URL]] which dereference to material
related to the status. Implementers using a `statusPurpose` of `message` are
strongly encouraged to provide a `statusReference`.
<p class="note" title="Details around reference">
`statusReference` is especially important when interpretation of the status for
a credential may involve some understanding of the business case involved.
</p>
</td>
</tr>
</tbody>
</table>
<p>
Status list entries can be used to express the purpose of a
status associated with a [=verifiable credential=] by using the
`statusPurpose` property.
</p>
<p>
The use of `revocation` or `suspension` as the status purpose
includes the semantics of the status, with `revocation`
indicating that a status bit expresses whether a
[=verifiable credential=] has been revoked and `suspension`
indicating that a status bit expresses whether a
[=verifiable credential=] has been suspended. The example below
demonstrates the use of these status purposes:
</p>
<pre class="example nohighlight"
title="Example StatusListCredential using simple entries">
{
"@context": [
"https://www.w3.org/ns/credentials/v2",
"https://www.w3.org/ns/credentials/examples/v2"
],
"id": "https://example.com/credentials/23894672394",
"type": ["VerifiableCredential", "EmployeeIdCredential"],
"issuer": "did:example:12345",
"validFrom": "2024-04-05T14:27:42Z",
<span class="highlight">"credentialStatus": [{
"id": "https://example.com/credentials/status/3#94567",
"type": "BitstringStatusListEntry",
"statusPurpose": "revocation",
"statusListIndex": "94567",
"statusListCredential": "https://example.com/credentials/status/3"
}, {
"id": "https://example.com/credentials/status/4#23452",
"type": "BitstringStatusListEntry",
"statusPurpose": "suspension",
"statusListIndex": "23452",
"statusListCredential": "https://example.com/credentials/status/4"
}]</span>,
"credentialSubject": {
"id": "did:example:6789",
"type": "Person",
"employeeId": "A-123456"
}
}
</pre>
<p>
The use of `message` as the status purpose enables an issuer to
define an arbitrary number of custom, descriptive messages about
the status of the [=verifiable credential=]. The [=issuer=] commits to
the set of messages that may be associated with a particular entry
(i.e., with a particular [=verifiable credential=]) through the
`statusSize`, `statusMessage`, and optional `statusReference` properties,
at the time of [=verifiable credential=] issuance. This is to ensure that
the [=holder=] knows what sort of information might be associated with a
particular [=verifiable credential=] they keep in their possession, that
could then be discoverable by a [=verifier=] that later receives that
credential.
</p>
<p class="note">
It is important to note that `statusListIndex` is the only link between
the [=verifiable credential=] and its status in the list. Other
properties such as `credentialSubject.id` are not used for
this purpose.
</p>
<pre class="example nohighlight"
title="Example StatusListCredential using more complex entries">
{
"@context": [
"https://www.w3.org/ns/credentials/v2",
"https://www.w3.org/ns/credentials/examples/v2"
],
"id": "https://example.com/credentials/2947478373",
"type": ["VerifiableCredential", "BillOfLadingExampleCredential"],
"issuer": "did:example:12345",
"validFrom": "2024-04-05T03:52:31Z",
<span class="highlight">"credentialStatus": {
"id": "https://example.com/credentials/status/8#492847",
"type": "BitstringStatusListEntry",
"statusPurpose": "message",
"statusListIndex": "492847",
"statusSize": 2,
"statusListCredential": "https://example.com/credentials/status/8",
"statusMessage": [
{"status":"0x0", "message":"pending_review"},
{"status":"0x1", "message":"accepted"},
{"status":"0x2", "message":"rejected"},
...
],
"statusReference": "https://example.org/status-dictionary/"
}</span>,
"credentialSubject": {
"id": "did:example:6789",
"type": "BillOfLading",
...
}
}
</pre>
</section>
<section>
<h3>BitstringStatusListCredential</h3>
<p>
When a status list [=verifiable credential=] is published, it MUST be a
conforming document, as defined in [[VC-DATA-MODEL-2.0]], that expresses the
data model in this section. The following section describes the format of
the [=verifiable credential=] that encapsulates the status list.
</p>
<p>
The status list is expressed inside a [=verifiable credential=] in order to
enable a [=holder=] to provide it directly to a [=verifier=]. This mechanism,
sometimes called "certificate stapling", increases privacy for the [=holder=] by
ensuring that the [=verifier=] does not need to contact the [=issuer=] to
retrieve the status list. Still, a [=verifier=] might choose to ignore the
[=holder=]-provided status list, even when its authenticity is verifiable,
if it desires a more recent version of a status list, for instance.
</p>
<p>
[=Issuers=] and [=verifiers=] are advised that the [=issuer=] of a
[=verifiable credential=] and the [=issuer=] of an associated
`BitstringStatusListCredential` might not be the same. There are technical,
legal, institutional, political, and other reasons that might make it
appropriate to separate the authority over the original credential from the
authority to revoke, or otherwise change the status of, such a credential.
Therefore, the `issuer` value of a [=verifiable credential=] containing a
`BitstringStatusListEntry` MAY be different from the `issuer` value of a
`BitstringStatusListCredential`.
</p>
<table class="simple">
<thead>
<tr>
<th style="white-space: nowrap">Property</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>id</td>
<td>
The [=verifiable credential=] that contains the status list MAY
express an `id` property that matches the value specified in
`statusListCredential` for the corresponding
`BitstringStatusListEntry` (see <a href="#bitstringstatuslistentry"></a>).
</td>
</tr>
<tr>
<td>type</td>
<td>
The [=verifiable credential=] that contains the status list MUST
express a `type` property that includes the
`BitstringStatusListCredential` value.
</td>
</tr>
<tr>
<td>validFrom</td>
<td>
The earliest point in time at which the status list is valid. This property is
defined in the Verifiable Credentials Data Model specification in
<a href="https://www.w3.org/TR/vc-data-model-2.0/#validity-period">
Section 4.6: Validity Period</a>.
</td>
</tr>
<tr>
<td>validUntil</td>
<td>
The latest point in time at which the status list is valid. This property is
defined in the Verifiable Credentials Data Model specification in
<a href="https://www.w3.org/TR/vc-data-model-2.0/#validity-period">
Section 4.6: Validity Period</a>.
</td>
</tr>
<tr>
<td>credentialSubject.type</td>
<td id="BitstringStatusList">
The `type` of the credential [=subject=], which is the
status list, MUST be `BitstringStatusList`.
</td>
</tr>
<tr>
<td id="statusPurpose">credentialSubject.statusPurpose</td>
<td>
The value of the purpose property of the status entry, `statusPurpose`, MUST be
one or more strings. While the value of each string is arbitrary, the following
values MUST be used for their intended purpose:
<table class="simple">
<thead>
<tr>
<th style="white-space: nowrap">Value</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>`refresh`</td>
<td>
Used to signal that an updated [=verifiable credential=] is available via the
credential's <a data-cite="VC-DATA-MODEL-2.0#refreshing">refresh service</a>
feature. This status does not invalidate the [=verifiable credential=] and is not reversible.
</td>
</tr>
<tr>
<td>`revocation`</td>
<td>
Used to cancel the validity of a [=verifiable credential=]. This status is
not reversible.
</td>
</tr>
<tr>
<td>`suspension`</td>
<td>
Used to temporarily prevent the acceptance of a [=verifiable credential=].
This status is reversible.
</td>
</tr>
<tr>
<td>`message`</td>
<td>
Used to indicate a status message associated with a <a>verifiable
credential</a>. The status message descriptions MUST be defined in
`credentialSubject.statusMessages`. `credentialSubject.statusSize` MUST be
specified when this `statusPurpose` value is used.
</td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr>
<td id="encodedList">credentialSubject.encodedList</td>
<td>
The `encodedList` property of the credential [=subject=] MUST be a
<a data-cite="VC-DATA-INTEGRITY#multibase-0">Multibase-encoded base64url (with
no padding)</a> [[RFC4648]] representation of the GZIP-compressed [[RFC1952]]
bitstring values for the associated range of [=verifiable credential=]
status values. The uncompressed bitstring MUST be at least 16KB in size. The
bitstring MUST be encoded such that the first index, with a value of zero (`0`),
is located at the left-most bit in the bitstring and the last index, with a
value of one less than the length of the bitstring (`bitstring_length - 1`), is
located at the right-most bit in the bitstring. Further information on bitstring
encoding can be found in Section <a href="#bitstring-encoding"></a>.
</td>
</tr>
<tr>
<td id="ttl">credentialSubject.ttl</td>
<td>
The `ttl` is an OPTIONAL property that indicates the "time to live" in
milliseconds before a refresh SHOULD be attempted. If not present, no default
value is assumed. The value does not override or replace the
<a data-cite="VC-DATA-MODEL-2.0#validity-period">validity period</a>
of the `BitstringStatusList`. Implementations that publish the status list
SHOULD align any protocol-specific caching information, such as the HTTP
`Cache-Control` header, with the value in this field.
</td>
</tr>
</tbody>
</table>
<p>
The example below demonstrates how the `BitstringStatusListEntry` is used
with a `BitstringStatusListCredential` to provide the [=verifier=] with
the information necessary to determine the status of a particular
[=verifiable credential=].
</p>
<pre class="example nohighlight" title="Example BitstringStatusListCredential">
{
"@context": [
"https://www.w3.org/ns/credentials/v2"
],
"id": "<span class="highlight">https://example.com/credentials/status/3</span>",
"type": ["VerifiableCredential", "<span class="highlight">BitstringStatusListCredential</span>"],
"issuer": "did:example:12345",
"validFrom": "2021-04-05T14:27:40Z",
"credentialSubject": {
"id": "https://example.com/status/3#list",
"type": "<span class="highlight">BitstringStatusList</span>",
"statusPurpose": "<span class="highlight">revocation</span>",
"encodedList": "<span class="highlight">uH4sIAAAAAAAAA-3BMQEAAADCoPVPbQwfoAAAAAAAAAAAAAAAAAAAAIC3AYbSVKsAQAAA</span>"
}
}
</pre>
</section>
</section>
</section>
<section class="normative">
<h2>Algorithms</h2>
<p>
The following section outlines the algorithms that are used to generate
and validate status lists as described by this document.
</p>
<p>
If an implementation of any of the algorithms in this section processes a property
defined in Section <a href="#data-model"></a> whose value is malformed due to
not complying with associated "MUST" statements, a
<a data-cite="VC-DATA-MODEL-2.0#MALFORMED_VALUE_ERROR">MALFORMED_VALUE_ERROR</a>
MUST be raised.
</p>
<section class="normative">
<h3>Generate Algorithm</h3>
<p>
The following process, or one generating the exact output, MUST be followed
when producing a
<a href="#bitstringstatuslistcredential">BitstringStatusListCredential</a>.
The algorithm takes a list of |issued credentials| as input and either throws
an error or returns a status list credential as output.
</p>
<ol class="algorithm">
<li>
Let |issued credentials| be a list of all issued
[=verifiable credentials=].
</li>
<li>
Let |statusListCredential| be an unsigned
<a href="#bitstringstatuslistcredential">BitstringStatusListCredential</a>
without the `encodedList` property set.
</li>
<li>
Generate a |compressed bitstring| by passing
|issued credentials| to the
<a href="#bitstring-generation-algorithm">Bitstring Generation Algorithm</a>.
</li>
<li>
Set the `encodedList` to |compressed bitstring|.
</li>
<li>
Generate a proof for the |statusListCredential| and publish it to the
endpoint listed in the [=verifiable credential=].
</li>
</ol>