I have a friend who uses an electronic key fob to enter and exit his apartment building. The fob isn’t metal, but it grants access electronically.
He occasionally engages in private activities.
My question is: Does this key fob log every entry/exit? He’s cautious with cell phones and leaves them at home, but wonders if the key fob could potentially cause problems.
Generally the key fobs have a circuit and antenna inside and the circuit has a code that it broadcasts when it is near the transceiver. Some systems are more complex, but at the lowest level the system disrupts a magnetic field around the transceiver in a certain way to generate the code or is powered up by the transceiver and transmits the code using that power. That way no battery is required and it can fit inside a thin card or fob. Some older ones have a very small battery to increase range or create a more complex or modifiable code or for proximity use rather than touch.
That code is then authorized or not to open the door in the security system. And yes every time the fob is used, it is logged. And depending on if the fob has a battery, it is possible it tracks leaving. If they don’t have to touch the fob to a panel and just need to have it on them, then it logs any time they approach the door regardless of entering or leaving. If it requires touching or bringing it close to a panel and they don’t have to do that when leaving then it probably doesn’t log them by proximity.
Whether or not the log has the person’s name or just the code or ID of the fob depends on how old or cheap the system is. But there’s definitely some document somewhere that lists the peoples’ names and which fob they were assigned if it’s not in the system. So it’s easy enough to find out.
Any system that has the same code in every fob would be either super old or super cheap and unlikely to be used on secure doors. Having unique codes means that if a fob is lost or stolen it can be deactivated among other things. Which is a no-brainer for security if there is no real significant cost. The only reason older systems didn’t is because the tech couldn’t create long enough codes on the circuits that existed. And super cheap systems don’t want to create too many different codes since it’s cheaper to mass produce the same one over and over. Basically why car fobs can often open other people’s cars. Either they’re old or the car company’s too cheap and it’s not their security at risk, so they don’t care.