I was trying to implement passkeys in an app. I have a doubt on this. While logging in to the application, the application shows a bunch of users who were registered earlier on that device. So when the user tries to login with the passkey in that bunch of passkeys in the device, so as a developer how do I know which passkey is used (So that I can retrieve the username for that specific passkeys)
Passkeys implementation in Swift
When your server receives and decodes the assertion response, one of the fields is the credentialID
. That identifies the specific passkey that was used, and can be mapped to a specific user account on the backend.