SSI DID Key

The ssi-did-key package provides a complete implementation of the did:key method for Decentralized Identifiers (DIDs) as specified in the DID Core specification. The did:key method allows DIDs to be derived directly from cryptographic public keys, enabling self-sovereign identity without requiring external registries or resolvers.

Installation

Install the package via NPM:

npm install @blockialabs/ssi-did-key

Key Components

Core Classes

• KeyDIDMethod: Implementation of the did:key method supporting create, resolve, and update operations
• KeyDIDResolver: DID resolver specifically for did:key DIDs

Interfaces

• KeyDIDPrepareOptions: Options for preparing DID creation
• KeyDIDCompleteOptions: Options for completing DID operations

Basic Usage

1. Setup KeyDID Method and Resolver

Initialize the DID method and resolver.

import { KeyDIDMethod, KeyDIDResolver } from '@blockialabs/ssi-did-key';

// Create the DID method implementation
const keyDIDMethod = new KeyDIDMethod();

// Create the resolver
const keyDIDResolver = new KeyDIDResolver(keyDIDMethod);

2. Create a DID from a Public Key

Generate a DID directly from a cryptographic public key.

// Your public key
const publicKeyHex = '0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798';

// Create the DID
const { did, didDocument } = await keyDIDMethod.create({
  publicKeyHex,
  signatureType: 'EcdsaSecp256k1Signature2019',
  keyId: 'controllerKey',
  signature: 'signature',
});

console.log('Created DID:', did);
// Output: did:key:zQ3shP2mP2UQHpB8H7J4KCk7Pg1YCVy9Q3X9ZGJGJGJGJGJ

3. Resolve a DID

Resolve any did:key DID to get its DID document.

const resolutionResult = await keyDIDResolver.resolve(
  'did:key:zQ3shP2mP2UQHpB8H7J4KCk7Pg1YCVy9Q3X9ZGJGJGJGJGJ',
);

if (resolutionResult.didDocument) {
  console.log('DID Document:', resolutionResult.didDocument);
  console.log('Resolution Metadata:', resolutionResult.didResolutionMetadata);
} else {
  console.log('Resolution Error:', resolutionResult.didResolutionMetadata.error);
}

4. Update a DID Document

Update an existing DID document with new information.

// Create an updated DID document
const updatedDocument = {
  ...didDocument,
  // Add services, verification methods, etc.
  service: [
    {
      id: `${did}#linked-domain`,
      type: 'LinkedDomains',
      serviceEndpoint: 'https://example.com',
    },
  ],
};

// Update the DID document
const updatedDIDDocument = await keyDIDMethod.update(did, updatedDocument, {
  publicKeyHex,
  signature: 'update-signature',
  keyId: 'controllerKey',
  signatureType: 'EcdsaSecp256k1Signature2019',
});

DID Key Format

The did:key method uses the following format:

did:key:<method-specific-identifier>

Where <method-specific-identifier> is a base58-encoded representation of the public key.

Integration with SSI DID Package

Using with DID Orchestrator

Integrate with the main SSI DID package for full lifecycle management.

import { DIDOrchestrator, DIDMethodRegistry, DIDResolverRegistry } from '@blockialabs/ssi-did';
import { KeyDIDMethod } from '@blockialabs/ssi-did-key';

// Setup registries
const methodRegistry = new DIDMethodRegistry();
const resolverRegistry = new DIDResolverRegistry();

// Register the key method
const keyMethod = new KeyDIDMethod();
methodRegistry.register('key', keyMethod);
resolverRegistry.register('key', keyMethod);

// Create orchestrator
const orchestrator = new DIDOrchestrator({
  methodRegistry,
  resolverRegistry,
  signatureProviders: {
    Secp256k1: secp256k1SignatureProvider,
  },
});

Building

Run nx build ssi-did-key to build the library.

Running unit tests

Run nx test ssi-did-key to execute the unit tests via Jest.

Running lint

Run nx lint ssi-did-key to check if there are lint errors.

See LICENSE.