Given 3 factors of authentication:
- Type 1: something you know
- Type 2: something you have
- Type 3: something you are
Which factor of authentication would be an X.509 certificate, assuming this certificate is stored in the filesystem of the device I use? For example, let's place it in the context of TLS mutual authentication, where the aforementioned certificate is the client certificate. Please note this is not a question about a digital certificate stored on a separate hardware token or similar.
My understanding is that this is still a type 1, not type 2, because it does not relate to the physical posession of device other than the one client is using anyway. Is my understanding correct?