did-jwt

The did-JWT library allows you to sign and verify JSON Web Tokens (JWT) using ES256K and Ed25519 algorithms. The non-standard ES256K-R is also supported for backward compatibility reasons.

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

DID methods

All DID methods that can be resolved using the `did-resolver' interface are supported for verification.

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

Installation

npm install did-jwt

or if you use yarn

yarn add did-jwt

Example

1. Create a did-JWT

In practice, you must secure the key passed to ES256KSigner. The key provided in code below is for informational purposes only.

const didJWT = require('did-jwt')
const signer = didJWT.ES256KSigner('278a5de700e29faae8e40e366ec5012b5ec63d36ec77e8a2417154cc1d25383f')

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

You need to provide a did-resolver for the verify function. For this example we will use did:ethr, but there are other methods available. 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
let verificationResponse = await didJWT.verifyJWT(jwt, {
  resolver: resolver,
  audience: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'
})
console.log(verificationResponse)

A verification response is an object resembling:

{
  payload: {
    iat: 1571692448,
    exp: 1957463421,
    aud: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74',
    name: 'uPort Developer',
    iss: 'did:ethr:0xf3beac30c498d9e26865f34fcaa57dbb935b0d74'
  },
  didResolutionResult: {
    didDocumentMetadata: {},
    didResolutionMetadata: {},
    didDocument: {
      '@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'
}