Webauthn expecting userHandle web-auth/webauthn-lib v5.1.0

WebAuthn (Web Authentication) is a decentralized authentication protocol that enables users to sign in to websites and applications using their own strong authenticators, such as FIDO2 security keys, biometric sensors, or mobile devices. It provides a more secure and convenient alternative to traditional username/password authentication methods.

The userHandle is an optional parameter in the WebAuthn protocol that allows an application to associate a specific identifier with a user during the registration process. This identifier can be used to distinguish between different users who may be using the same authenticator. The userHandle is represented as a PublicKeyCredentialUserEntity object, which includes the user's name, display name, and an optional icon.

The error message "Webauthn expecting userHandle" suggests that the application is expecting the user to provide a userHandle during the registration process, but it is not being provided. This could be due to a few reasons:

The application code is not properly configured to support the userHandle parameter. In this case, the application code may need to be updated to include the userHandle parameter in the registration request.
The authenticator device does not support the userHandle parameter. In this case, the user may need to use a different authenticator device that supports the userHandle parameter.
The user is not providing the userHandle during the registration process. In this case, the user may need to be instructed to provide a userHandle during the registration process.

To resolve the issue, the application code should be reviewed to ensure that it is properly configured to support the userHandle parameter. If the authenticator device supports the userHandle parameter, the user should be instructed to provide one during the registration process. If the user is unable to provide a userHandle, they may need to use a different authenticator device that supports this feature.

Here's an example of how to register a user with a userHandle using the webauthn-lib library in Node.js:

const WebAuthn = require('webauthn-lib');

const publicKeyCredential = await navigator.credentials.create({
  rp: { name: 'My Website' },
  user: { name: 'John Doe', id: '[email protected]' },
  challenge: new TextEncoder().encode('some-random-value'),
  pubKeyCredParams: [
    { type: 'public-key' },
    { type: 'userver', id: 'user:[email protected]' }
  ],
  attestation: 'direct',
  userHandle: new Uint8Array([1, 2, 3, ...]) // userHandle as a Uint8Array
});

const credential = new WebAuthn.PublicKeyCredential(publicKeyCredential);
console.log(credential.toJSON());

In this example, the userHandle is represented as a Uint8Array and should be populated with the appropriate value. The userHandle value can be generated randomly or can be derived from the user's name or other identifying information.

By properly configuring the application code to support the userHandle parameter and instructing the user to provide one during the registration process, the "Webauthn expecting userHandle" error can be resolved.