Present a Verifiable Credential (AnonCreds)

Present a Verifiable Credential, signed by a did:cheqd Decentralized Identifier (DID), using Credo.

Verifiable Credentials signed by a did:cheqd can be securely presented using the AnonCreds proof format and the Present Proof Protocol v2 within the Credo framework. This enables trust-minimised, selective disclosure of credential data between a Holder and a Verifier.

Prerequisites

Before presenting a credential:

• A Verifiable Credential must have been issued and accepted by the Holder

• A Credo Agent is running for both the Verifier and the Holder

• A DIDComm connection exists between Holder and Verifier (via OOB or another method)

• Both agents are configured with:

  • @credo-ts/anoncreds

  • @credo-ts/didcomm

Step 1: Create a Connection with Holder

Use any supported method to create a connection with the Holder. Automated out-of-band protocol is recommended. You can follow the same steps as described in Issue a Verifiable Credential.

Step 2: Send Proof Request

After connection is established, the Verifier can send a proof request to the Holder.

Verifier/Issuer

await this.agent.modules.proofs.requestProof({
  protocolVersion: 'v2',
  connectionId: connectionRecord.id,
  proofFormats: {
    anoncreds: {
      name: 'proof-request',
      version: '1.0',
      requested_attributes: {
        name: {
          name: 'name',
          restrictions: [
            {
              cred_def_id: this.credentialDefinition?.credentialDefinitionId,
            },
          ],
        },
      },
    },
  },
})

Step 3: Holder sends Presentation Proof

Holder can get the stored credentials from own wallet and format a proof to send to the Verifier.

When we want to send a proof, we have to listen to incoming proof requests and handle accordingly. In this example we do not have any user interaction, but is likely that your application would have a user-interface which would display the request.

Holder

this.agent.events.on(ProofEventTypes.ProofStateChanged
  async ({ payload }: ProofStateChangedEvent) => {
    if (payload.proofRecord.state === ProofState.RequestReceived) {
      const requestedCredentials = await this.agent.modules.proofs.selectCredentialsForRequest({
        proofRecordId: payload.proofRecord.id,
      })
      await this.agent.modules.proofs.acceptRequest({
        proofRecordId: proofRecord.id,
        proofFormats: requestedCredentials.proofFormats,
      })
    }
})

What’s Happening Behind the Scenes?

• The Verifier sends a proof request with specific attributes and credential requirements

• The Holder uses locally stored credentials to generate a selective disclosure proof

• The proof is signed using AnonCreds and returned to the Verifier over DIDComm

• The Verifier cryptographically validates the proof and the issuing DID (did:cheqd)

Next Steps

For more tutorials and examples, visit Credo Docs.