NOTE: I am not trying to break the law or figure out how to hack my employer’s computer network. I’m just curious about how these devices work.
I have a laptop issued by my employer. To dial in remotely, I have to enter, among other things, a 6 digit number which appears in an LCD display, on a little locketlike device that I carry with my badge. This number changes every 60 seconds, and I have to enter the number that’s currently being displayed, or I can’t get in.
Now here’s my question. The generation of the number appears to be random, so when I key it at login time, how does my employer’s network, or even my PC, “know” what the correct number is? It implies that the number I’m entering must be recognized by the network, but how is that possible? There can’t be two separate random number devices running in parallel, can there?