VCs in DWNs

In this guide, we'll cover how to write a Verifiable Credential (VC) to a Decentralized Web Node (DWN), how to retrieve that stored VC by querying the DWN for it, and lastly how to parse the VC into a format that your application can work with.

Storing VC in DWN

To store a VC in a DWN, you need to create a record with the VC data. The VC should already be created and in a signed JWT format. This is what that would look like:

const { record } = await web5.dwn.records.create({
  data: signedVcJwt,
  message: {
    schema: 'EmploymentCredential',
    dataFormat: 'application/vc+jwt',
  },
});

// (optional) immediately send record to users remote DWNs
const { status } = await record.send(userDid);

signedVcJwt represents a signed VC JWT. The schema property should be the same as the VC type, and dataFormat specifies the format of the VC which is application/vc+jwt.

Querying VC from DWN

To retrieve a stored VC from a DWN, you can use the records.query() method:

const response = await web5.dwn.records.query({
  from: userDid,
  message: {
    filter: {
      schema: 'EmploymentCredential',
      dataFormat: 'application/vc+jwt',
    },
  },
});

const signedVcJwt = await response[0].data.text();

This will access the first record matching the filters you specified, schema and dataFormat. Keep in mind that this will return a JWT string, which can be converted to a readable JSON object.