index.js

const {
  BbsBlsSignature2020,
  BbsBlsSignatureProof2020,
  deriveProof
} = require("@mattrglobal/jsonld-signatures-bbs");

const { extendContextLoader, sign, verify, purposes } = require("jsonld-signatures");
const { resolver }  = require('@transmute/did-key.js');
const { documentLoaders } = require("jsonld");
const bs58 = require('bs58');

const document = {
  "@context": [
    "https://www.w3.org/2018/credentials/v1",
    "https://w3id.org/citizenship/v1",
    "https://w3id.org/security/bbs/v1"
  ],
  "id": "https://issuer.oidp.uscis.gov/credentials/83627465",
  "type": ["VerifiableCredential", "PermanentResidentCard"],
  "issuer": "did:example:489398593",
  "identifier": "83627465",
  "name": "Permanent Resident Card",
  "description": "Government of Example Permanent Resident Card.",
  "issuanceDate": "2019-12-03T12:19:52Z",
  "expirationDate": "2029-12-03T12:19:52Z",
  "credentialSubject": {
    "id": "did:example:b34ca6cd37bbf23",
    "type": ["PermanentResident", "Person"],
    "givenName": "JOHN",
    "familyName": "SMITH",
    "gender": "Male",
    "image": "data:image/png;base64,iVBORw0KGgokJggg==",
    "residentSince": "2015-01-01",
    "lprCategory": "C09",
    "lprNumber": "999-999-999",
    "commuterClassification": "C1",
    "birthCountry": "Bahamas",
    "birthDate": "1958-07-17"
  }
}

const { Bls12381G2KeyPair } = require('@transmute/did-key-bls12381')

const main = async () => {

  const keyPair = await Bls12381G2KeyPair.generate()

  // Mattrs BbsBlsSignature2020 library needs private and public key in base58 format
  // transmutes library dont encodes that as base58, so encode it with the buffers
  keyPair.privateKeyBase58 = bs58.encode(keyPair.privateKeyBuffer)
  keyPair.publicKeyBase58 = bs58.encode(keyPair.publicKeyBuffer)
  document.issuer = keyPair.controller
  // the keypair id must be an IRI, otherwise JSON-LD throws an error.  transmutes id only contains the #id ... so add the controller before
  keyPair.id = keyPair.controller + keyPair.id;
  const didDoc = await resolver.resolve(keyPair.controller)
  const docLoader = (url) => {
    // when the loader requests the controller did document, return the did doument in plain
    if(url === keyPair.controller) {
      return {
        contextUrl: null, // this is for a context via a link header
        document: didDoc, // this is the actual document that was loaded
        documentUrl: url // this is the actual context URL after redirects
      };
    }
    // when the loader requests the specific key from the controller, return the Mattr Keypair compliant structure (with the base58 stuff)
    if(url === keyPair.id) {
      return {
        contextUrl: null, // this is for a context via a link header
        document: keyPair, // this is the actual document that was loaded
        documentUrl: url // this is the actual context URL after redirects
      };
    }
    return documentLoaders.node()(url);
  }

  const documentLoader = extendContextLoader(docLoader);

  const signedDocument = await sign(document, {
    suite: new BbsBlsSignature2020({ key: keyPair }),
    purpose: new purposes.AssertionProofPurpose(),
    documentLoader
  });

  console.log(signedDocument)

  let verified = await verify(signedDocument, {
    suite: new BbsBlsSignature2020(),
    purpose: new purposes.AssertionProofPurpose(),
    documentLoader
  });

  console.log(verified);
  if(verified.results[0].error) {
    console.log(verified.results[0].error)
    console.log(verified.results[0].error.details.frame)
  }
}

main()

package.json

{
  "name": "diwala-did-testing",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "@decentralized-identity/ion-tools": "^0.0.8",
    "@mattrglobal/bbs-signatures": "^0.5.0",
    "@mattrglobal/jsonld-signatures-bbs": "^0.9.0",
    "@mattrglobal/node-bbs-signatures": "^0.11.0",
    "@transmute/did-key-bls12381": "^0.2.1-unstable.42",
    "@transmute/did-key.js": "^0.2.1-unstable.42",
    "jsonld": "^5.2.0",
    "jsonld-document-loader": "^1.2.0"
  },
  "scripts": {
    "start": "node index.js"
  }
}