> For the complete documentation index, see [llms.txt](https://astral-protocol.gitbook.io/astral/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://astral-protocol.gitbook.io/astral/archive/geodids/did-primer.md).

# DID Primer

A primer on DIDs before we go into the Core Specification of GeoDIDs

## What is a DID?

[Decentralized identifiers](https://www.w3.org/TR/did-core/#dfn-decentralized-identifiers) (DIDs) are a new type of identifier that enables verifiable, decentralized digital identities. A [DID](https://www.w3.org/TR/did-core/#dfn-decentralized-identifiers) identifies any subject (e.g., a person, organization, thing, data model, abstract entity, etc.) that the controller of the [DID](https://www.w3.org/TR/did-core/#dfn-decentralized-identifiers) decides that it identifies. [DIDs](https://www.w3.org/TR/did-core/#dfn-decentralized-identifiers) are URIs that associate a [DID subject](https://www.w3.org/TR/did-core/#dfn-did-subjects) with a [DID document](https://www.w3.org/TR/did-core/#dfn-did-documents) allowing trustable interactions associated with that subject.

Each [DID document](https://www.w3.org/TR/did-core/#dfn-did-documents) can express cryptographic material, verification methods, or [service endpoints](https://www.w3.org/TR/did-core/#dfn-service-endpoints), which provide a set of mechanisms enabling a [DID controller](https://www.w3.org/TR/did-core/#dfn-did-controllers) to prove control of the [DID](https://www.w3.org/TR/did-core/#dfn-decentralized-identifiers).

![Figure 1: The basic architecture of the DID](https://327435336-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MOlX2pSUdTM59utmjsi%2Fuploads%2Fgit-blob-6dbaa47a0e850e7ffcf6cb97f26c9a69a11c1a74%2FScreen%20Shot%202021-01-10%20at%2010.40.34%20AM.png?alt=media)

To learn more about DIDs and why they're useful:

* [W3C DID Core](https://w3c.github.io/did-core/)
* [Ceramic Network](https://ceramic.network)
* [Decentralized identifiers fundamentals and deep dive](https://www.youtube.com/watch?v=SHuRRaOBMz4)