did-jwt

did-jwt

Algorithms supported | DID Public Key Types | Claim Specification

The did-JWT library allows you to sign and verify JSON Web Tokens (JWT) using ES256K, ES256K-R and Ed25519 algorithms.

Public keys are resolved using the Decentralized ID (DID) of the signing identity of the claim, which is passed as the iss attribute of the encoded JWT.

DID methods

We currently support the following DID methods:

• ethr
• uport
• https
• nacl
• muport

You will need to install each one you need to support. See each method for how to configure it.

Support for other DID methods should be simple. Write a DID resolver supporting the `did-resolver' interface. Once you've verified that it works, please add a PR adding it to the above list so people can find it.

If your DID method requires a different signing algorithm than what is already supported, please create a PR.

Installation

npm install did-jwt

or if you use yarn

yarn add did-jwt

Example

1. Create a did-JWT

createJWT

In practice you should secure the key passed to SimpleSigner. The key provided in code below is for informational purposes; you will need to create an application identity at My Apps or use our uport-credentials library to generate an ethereum key pair.

const didJWT = require('did-jwt')
const signer = didJWT.SimpleSigner('278a5de700e29faae8e40e366ec5012b5ec63d36ec77e8a2417154cc1d25383f');

let jwt = await didJWT.createJWT({aud: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74', exp: 1957463421, name: 'uPort Developer'},
                 {alg: 'ES256K', issuer: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74', signer})
console.log(jwt);

2. Decode a did-JWT

Try decoding the JWT. You can also do this using jwt.io

//pass the jwt from step 1
let decoded = didJWT.decodeJWT(jwt)
console.log(decoded)

Once decoded a did-JWT will resemble:

{
  header: { typ: 'JWT', alg: 'ES256K' },
  payload: {
    iat: 1571692233,
    exp: 1957463421,
    aud: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
    name: 'uPort Developer',
    iss: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'
  },
  signature: 'kkSmdNE9Xbiql_KCg3IptuJotm08pSEeCOICBCN_4YcgyzFc4wIfBdDQcz76eE-z7xUR3IBb6-r-lRfSJcHMiAA',
  data: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NkstUiJ9.eyJpYXQiOjE1NzE2OTIyMzMsImV4cCI6MTk1NzQ2MzQyMSwiYXVkIjoiZGlkOmV0aHI6MHhmM2JlYWMzMGM0OThkOWUyNjg2NWYzNGZjYWE1N2RiYjkzNWIwZDc0IiwibmFtZSI6InVQb3J0IERldmVsb3BlciIsImlzcyI6ImRpZDpldGhyOjB4ZjNiZWFjMzBjNDk4ZDllMjY4NjVmMzRmY2FhNTdkYmI5MzViMGQ3NCJ9'
}

3. Verify a did-JWT

verifyJWT

You need to provide a did-resolver for the verify function. For this example we will use ethr-did, but there are other methods available above. For more information on configuring the Resolver object please see did-resolver

npm install ethr-did-resolver

const Resolver = require('did-resolver')
const ethrDid =  require('ethr-did-resolver').getResolver({rpcUrl: 'https://mainnet.infura.io/v3/...'})

let resolver = new Resolver.Resolver(ethrDid)

// pass the JWT from step 1 & 2
let verifiedRespone = await didJWT.verifyJWT(jwt, {resolver: resolver, audience: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'})
console.log(verifiedRespone);

A verified did-JWT returns an object resembling:

{
  payload: {
    iat: 1571692448,
    exp: 1957463421,
    aud: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
    name: 'uPort Developer',
    iss: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'
  },
  doc: {
    '@context': 'https://w3id.org/did/v1',
    id: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
    publicKey: [ [Object] ],
    authentication: [ [Object] ]
  },
  issuer: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
  signer: {
    id: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74#owner',
    type: 'Secp256k1VerificationKey2018',
    owner: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
    ethereumAddress: '0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'
  },
  jwt: 'eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NkstUiJ9.eyJpYXQiOjE1NzE2OTI0NDgsImV4cCI6MTk1NzQ2MzQyMSwiYXVkIjoiZGlkOmV0aHI6MHhmM2JlYWMzMGM0OThkOWUyNjg2NWYzNGZjYWE1N2RiYjkzNWIwZDc0IiwibmFtZSI6InVQb3J0IERldmVsb3BlciIsImlzcyI6ImRpZDpldGhyOjB4ZjNiZWFjMzBjNDk4ZDllMjY4NjVmMzRmY2FhNTdkYmI5MzViMGQ3NCJ9.xd_CSWukS6rK8y7GVvyH_c5yRsDXojM6BuKaf1ZMg0fsgpSBioS7jBfyk4ZZvS0iuFu4u4_771_PNWvmsvaZQQE'
}