verifyVC

How to call the API from an app

Identify Snap connects to your currently connected Metamask account by default. To learn how apps can connect to Identify Snap using a non-metamask(external) account, refer to this documentation.

Then, depending on whether you're trying to connect to a metamask account or a non-metamask account, you can call the snap API in the following way:

const snapId = `npm:@tuum-tech/identify`

const verifiableCredential = {
  credentialSubject: {
    profile: {
      name: 'KP'
    },
    id: 'did:pkh:eip155:1:0x2e5ff0267b678a0faf9a9f5b0fbf7ac9638b5b57'
  },
  issuer: {
    id: 'did:pkh:eip155:1:0x2e5ff0267b678a0faf9a9f5b0fbf7ac9638b5b57'
  },
  type: ['VerifiableCredential', 'ProfileNamesCredential'],
  '@context': ['https://www.w3.org/2018/credentials/v1'],
  issuanceDate: '2023-04-05T14:34:47.000Z',
  expirationDate: '2024-04-05T14:34:47.000Z',
  proof: {
    type: 'JwtProof2020',
    jwt: 'eyJhbGciOiJFUzI1NksiLCJ0eXAiOiJKV1QifQ.eyJleHAiOjE3MTIzMjc2ODcsInZjIjp7IkBjb250ZXh0IjpbImh0dHBzOi8vd3d3LnczLm9yZy8yMDE4L2NyZWRlbnRpYWxzL3YxIl0sInR5cGUiOlsiVmVyaWZpYWJsZUNyZWRlbnRpYWwiLCJQcm9maWxlTmFtZXNDcmVkZW50aWFsIl0sImNyZWRlbnRpYWxTdWJqZWN0Ijp7InByb2ZpbGUiOnsibmFtZSI6IktQIn19fSwic3ViIjoiZGlkOnBraDplaXAxNTU6MToweDJlNWZmMDI2N2I2NzhhMGZhZjlhOWY1YjBmYmY3YWM5NjM4YjViNTciLCJuYmYiOjE2ODA3MDUyODcsImlzcyI6ImRpZDpwa2g6ZWlwMTU1OjE6MHgyZTVmZjAyNjdiNjc4YTBmYWY5YTlmNWIwZmJmN2FjOTYzOGI1YjU3In0.CR1A_XpG001_PCaAt3VN9G5Lt75gTm2M5YSt6trqhkEoW0wce9rU7SrsZnQ0drmaG2tee4IMrZFx241yi8UsLg'
  }
}

const metamaskAddress = '0x2e5fF0267b678A0FAF9A9f5b0FBf7Ac9638B5b57'
const params = {
  metamaskAddress,
  verifiableCredential
  /* 
    Uncomment the below line if you want to connect to a non-metamask account
  */
  // ...externalAccountParams
}

const handleVerifyVCAPI = async () => {
  await window.ethereum.request({
    method: 'wallet_invokeSnap',
    params: {
      snapId,
      request: {
        method: 'verifyVC',
        params: params
      }
    }
  })
}

Notes:

• Identify Snap currently supports generating VC using jwt proof format however, it still supports the verification of other types of VCs with other proof formats such as lds and EthereumEip712Signature2021.

How the API is handled between the app and snap

What the API does

1. Retrieves the currently connected account and the blockchain network the user has selected on Metamask. If it's the first time, the account info is also saved in snap state.

2. Checks to see whether the passed Verifiable Credential(VC) is a valid VC such as checking for the valid signature and whether or not the did in the VC is resolvable and whether or not it has the correct proofformat.

3. Returns a boolean value depending on the result.

Some example responses:

true

How the API works

https://github.com/tuum-tech/identify/blob/main/packages/snap/src/rpc/vc/verifyVC.ts

import { W3CVerifiableCredential } from '@veramo/core';
import { IdentitySnapParams } from '../../interfaces';
import { getVeramoAgent } from '../../veramo/agent';

/**
 * Function to verify VC.
 *
 * @param identitySnapParams - Identity snap params.
 * @param vc - Verifiable Credential.
 */
export async function verifyVC(
  identitySnapParams: IdentitySnapParams,
  vc: W3CVerifiableCredential,
): Promise<boolean | null> {
  const { state } = identitySnapParams;
  // Get Veramo agent
  const agent = await getVeramoAgent(snap, state);

  // Verify the verifiable credential(VC)
  const result = await agent.verifyCredential({ credential: vc });
  if (result.verified === false) {
    console.log('result: ', JSON.stringify(result, null, 4));
    console.log(
      'VC Verification Error: ',
      JSON.stringify(result.error, null, 4),
    );
  }
  return result.verified;
}

Live Demo on CodePen

Some things to keep in mind while interacting with the above demo

• If you're getting any errors with the live demo, make sure you go through the FAQs section to learn about what you may be missing. You need to install Metamask in your browser for the live demo to work

• Whenever there is a new version of the IdentifySnap, always make sure to first uninstall the old version of the snap from Metamask and only then try the above demo so it can install the latest version

To ease the integration of Identify Snap on an application, we have created a template web application that you can run locally and check out the code in its entirety to learn how you can integrate and interact with various APIs exposed by Identify Snap. Check out the full source code at template application github repository.

You can also check out the API reference to learn how each API works.