tz-did-resolver

W3C compliant DID Resolver for the Tezos DID Method

tz DID Resolver

This library is intended to use Tezos accounts and smart contract addresses as fully self-managed Decentralized Identifiers and wrap them in a DID Document

It supports the proposed did:tz method spec spec from did-tezos.

It requires the did-resolver library, which is the primary interface for resolving DIDs.

DID method

To encode a DID for a Tezos address on the Tezos mainnet, simply prepend did:tz:

eg:

did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8

Multi-network DIDs are also supported, if the proper configuration is provided during setup.

For example: did:tz:granadanet:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8 gets resolved on the Granadanet testnet, and represents a distinct identifier than the generic one, with different DID Documents and different key rotation history.

DID Document

The minimal DID Document for a Tezos address did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8 with no transactions to the registry looks like this:

{
  "@context": [
    "https://www.w3.org/ns/did/v1",
    "https://w3id.org/security/v1"
  ],
  "id": "did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8",
  "verificationMethod": [
    {
      "id": "did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8#blockchainAccountId",
      "type": "Ed25519PublicKeyBLAKE2BDigestSize20Base58CheckEncoded2021",
      "controller": "did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8",
      "blockchainAccountId": "tezos:NetXdQprcVkpaWU:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8"
    }
  ],
  "authentication": [
    "did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8#blockchainAccountId"
  ],
  "assertionMethod": [
    "did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8#blockchainAccountId"
  ]
}

Building a DID document

The DID Document is not stored as a file, but is built by using tzip-16 views functions present on the DID Manager smart contract.

Please see the spec for details of how the DID document and corresponding metadata are computed.

Resolving a DID document

The library presents a resolve() function that returns a Promise including the DID Document. It is not meant to be used directly but through the did-resolver aggregator.

You can use the getResolver() method to produce an entry that can be used with the Resolver constructor:

import { Resolver } from 'did-resolver'
import { getResolver } from 'tz-did-resolver'

const tzResolver = getResolver()

const didResolver = new Resolver({
  ...tzResolver
  //...you can flatten multiple resolver methods into the Resolver
})

didResolver.resolve('did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8').then(({ didDocument }) => console.log(didDocument))

// You can also use ES7 async/await syntax
const { didDocument } = await didResolver.resolve('did:tz:tz1TzrmTBSuiVHV2VfMnGRMYvTEPCP42oSM8')
console.log(didDocument)