Decentralized identifiers (DIDs) are a type of globally unique identifier that enables anyone and anything to be identified in a manner that is verifiable, persistent, and does not require the use of a centralized registry. DIDs enable a new model of decentralized digital identity that is often referred to as self-sovereign identity (SSI).

A W3C DID Working Group developed a specification for decentralized identifiers to standardize the core architecture, data model, and representation of DIDs and version 1.0 of this specification was approved as a W3C Recommendation in 2022. This page provides a validation service for DID Documents - a set of data describing the DID subject and result of the resolution process when resolving a DID.

Semantic Overlay Architecture (SOyA) is a data model authoring and publishing platform and also provides functionalities for validation and transformation. It builds on W3C Resource Description Framework (RDF) and related semantic web technologies to provide a lightweight approach for data integration and exchange.

At the core of SOyA is a YAML-based data model for describing data structures with bases and optional overlays, which provide additional information and context. This website validates DID Documents with the SOyA structure z3wmSSwhcQN4bgJHtgYqSLmdqRvv8Tnv189krACn1GtJE.

This website is just a frontend for the underlying technology of validating DID Documents. You can also use this service via an REST API by calling one of the following API endpoints:

• GET /api/validate/:did: provide a DID identifier (:did) and the service automatically resolves and validates the DID document;
  example:

  curl https://didlint.ownyourdata.eu/api/validate/did:oyd:zQmZZbVygmbsxWXhP2BH5nW2RMNXSQA3eRqnzfkFXzH3fg1

• POST /api/validate: provide a DID document in the body of a POST request;
  example:

  cat did_document.jsonld | curl -H 'Content-Type: application/json' -d @- -X POST https://didlint.ownyourdata.eu/api/validate

• GET /api/resolve/:did: resolve a DID and return its DID document

did:oyd is resolved through the OYDID resolver, all other DID methods through the Universal Resolver.

Swagger API of this service is available here: https://didlint.ownyourdata.eu/api-docs
Docker image can be downloaded here: https://hub.docker.com/r/oydeu/didlint

All functionality provided on this website leverages tools available on the command line. With soya-cli (npm install -g soya-cli@latest), jq and Ruby installed and the DID Lint repository checked out, you can perform the complete validation process locally.

The process of validation actually comprises of 3 steps:

1. Pre-processing DID Documents to be usable by the soya-cli with prep.sh
2. Executing the SHACL validation with the SOyA structure and the input DID document:
   cat did_document.jsonld | script/prep.sh | soya validate z3wmSSwhcQN4bgJHtgYqSLmdqRvv8Tnv189krACn1GtJE
3. Verifying the correct JSON-LD context is not within the scope of SHACL and requires a separate step with verify_context.rb:
   cat did_document.jsonld | script/verify_context.rb

To validate a list of DIDs with this service and get one line per DID, use iterate.sh.

A typical sequence of commands in a checkout of the repository is:

cat pytest/02_input/valid_example_9.json | script/prep.sh | soya validate z3wmSSwhcQN4bgJHtgYqSLmdqRvv8Tnv189krACn1GtJE
cat pytest/02_input/valid_example_9.json | script/verify_context.rb

This service is a Proof-of-Concept to demonstrate the validation overlay capabilities of SOyA, i.e., show-case an easy but still machine-readable format to describe DID Documents and use the built-in mechanisms of SOyA to either validate conformance or list identified violations.

The current DID Document SOyA structure is most certainly not a complete and correct representation of the DID Core Spec and we would like to encourage everyone to report issues or even provide pull-requests on the public DID Lint Github repository.