This has been informative. A related query has been raised by my study of the concepts in password security.
The windows os past a certain date makes use of the "ctrl-alt-delete" keyboard sequence as part of login procedure. I have a basic understanding of it that's not more detailed then the explanation given in their help screens. Other than the seemingly simple concept of making remote attacks need to simulate the keystrokes. The tie-in to the original post- much of our world's hardware has a "paperclip reset" or "on board shorting jumper" reset. Intended to either reset a password or return to shipped values. The security model relied upon physical access to the hardware as granting presumption of authority. Blunt simple logic.
If you are touching it, you are presumed to be authorised.
Can the "ctrl-alt-delete" method currently provide a Linux system with reasonable assurance that a user is physically in front of their computer? If not, some other method of convincing the os that the person seeking entrance to the password file is in possession of that computer, and presumed to be allowed access upon proving that. The implications of course open up a new thread and I am doing so.