# Bitstring Status List

Bitstring Status List is a working document from the W3C to support a privacy-preserving, space-efficient, and high-performance mechanism for publishing status information such as suspension or revocation of JSON and JSON-LD Verifiable Credentials.

Using DID-Linked Resources, we have been able to natively support Bitstring Status List on cheqd directly.

## Get started

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><mark style="color:blue;"><strong>Create Status List</strong></mark></td><td>Create a Status List on-ledger as a DID-Linked Resource using Veramo</td><td><a href="bitstring-status-list/bitstring-statuslist-resources">bitstring-statuslist-resources</a></td></tr><tr><td><mark style="color:blue;"><strong>Status List within a Verifiable Credential</strong></mark></td><td>Issue a Verifiable Credential with a cheqd Status List within the body.</td><td><a href="bitstring-status-list/issuing-a-verifiable-credential-referencing-status-list">issuing-a-verifiable-credential-referencing-status-list</a></td></tr></tbody></table>

## Understanding Bitstring Status List

Bitstring Status List utilises [bitstrings](https://w3c-ccg.github.io/vc-status-list-2021/#conceptual-framework) to represent whether a Verifiable Credential has been suspended/revoked or not. A bitstring can be thought of as a long list of 1s and 0s, where, if the binary value of the position in the list is 1 (one), the [verifiable credential](https://w3c-ccg.github.io/vc-status-list-2021/#dfn-verifiable-credentials) is revoked, if it is 0 (zero) it is not revoked.

![Graphic showing the Bitstring Status List bitstring](https://3569764573-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPVAMvpKH7PYzvXA6u6Cn%2Fuploads%2Fgit-blob-2492fcec68cad93f0f40cb0c328ba0f137188ffd%2FStatusList21%20Bitstring.png?alt=media)

***Figure 1**: Graphic showing the Bitstring Status List bitstring*

Each issued Credential correlates with a position and index on the bitstring, so that a verifier will be able to correlate the value within the Credential against the public bitstring to ascertain whether the Credential has been revoked or not, using a [validate algorithm](https://w3c-ccg.github.io/vc-status-list-2021/#validate-algorithm) as well as a [bitstring expansion algorithm](https://w3c-ccg.github.io/vc-status-list-2021/#bitstring-expansion-algorithm).

### Where is the Status List usually published?

The issuer keeps a bitstring list of all Verifiable Credentials it has issued. The Status List is usually published by the issuer **in the format of its own Verifiable Credential.** This Verifiable Credential is generally hosted publicly on a centralised server or domain to enable third-party read-access.

### Where does cheqd store the Status List?

cheqd stores each Status List and subsequent entries on-ledger as [DID-Linked Resource](https://docs.cheqd.io/product/architecture/adr-list/adr-002-did-linked-resources) versions. This has notable benefits, including the provenance, legitimacy and security of the Status List. For a full list of benefits, see [the context for creating DID-Linked Resources](https://docs.cheqd.io/product/studio/did-linked-resources/understanding-dlrs/context).

## Alternatives

Below are a list of alternatives for creating cheqd Status Lists.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><mark style="color:blue;"><strong>cheqd Studio</strong></mark></td><td>Our API product enables users to <strong>use cheqd's functionality with minimal complexity</strong> and easily integrate APIs into existing apps. </td><td><a href="../../getting-started/studio">studio</a></td><td><a href="https://3569764573-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPVAMvpKH7PYzvXA6u6Cn%2Fuploads%2Fgit-blob-7f1ffe5c0546f0ee4f106ac1a71308c5ee5ad7c8%2Fcheqd_logo_card.jpg?alt=media">cheqd_logo_card.jpg</a></td></tr><tr><td><mark style="color:blue;"><strong>DID Registrar</strong></mark></td><td>Simple setup for building cheqd DIDs into existing applications using REST APIs, building into the <a href="https://uniregistrar.io/">Universal Registrar</a>.</td><td><a href="../../advanced/did-registrar">did-registrar</a></td><td><a href="https://3569764573-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPVAMvpKH7PYzvXA6u6Cn%2Fuploads%2Fgit-blob-a95d1f6e14a4b976289d6f2bd705a8a324f2032f%2FDIF.png?alt=media">DIF.png</a></td></tr></tbody></table>