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How do those hotel door locks work? When I had an apartment with a tap keyfob, it was battery-operated and the fob seemed to be programmed for that specific loc
by lainga 3y ago
How do those hotel door locks work? When I had an apartment with a tap keyfob, it was battery-operated and the fob seemed to be programmed for that specific lock, so I thought they could work offline.
- wombat-man 3y agoYours is probably meant to work indefinitely. I guess hotels look at the card id and see if you have access at that moment.
- _joel 3y agoApartment? I assume your home? The upkeep of locks in a hotel is a bit more involved, as customers lose keys and they need to be reset for the next room guest (for larger hotels, at least)
- glitchc 3y agoIn a modern hotel with tap cards, all the locks are wired to a central system.
- napoleongl 3y agoThese days the locks are online so that you can block a lost keycard from the front desk. Previously you had to open the lock with a never keycard than the lost one to make the lost one inoperable. That works kinda fine in a small hotel but not when you 48000 rooms with millionaires in them.
- foota 3y agoFwiw you could probably build this in a way that it continues to operate without internet. This creates a new attack vector (disable the internet and you can't revoke access) but that's probably acceptable given the physical attacks possible.
- amenghra 3y agoEach key gets a revision number. When the first set of keys are created, they get revision number 0. The lock records a high water mark of the revision numbers it has seen. Only keys matching the water mark get to unlock the door. When you want to revoke a key, you re-issue a new set with a higher revision number. When the guest checks out, you issue the next revision number to the next guest, effectively disabling the previous set. You do all this as a fallback when the network fails. This way, you can still disable keys in real-time when people checkout of their room.
- themerone 3y agoI think this is similar to how most hotel locks work.
- ryukoposting 3y agoCurrently at a reasonably-priced hotel in the boonies. Extended my stay the other day and they had to re-issue the keys. The keys must be aware of the reservation period, and the locks must be aware of the current wall-clock time. Finding a way to tamper with the RTC in the lock could blow up the whole system. Or, you know, a crowbar.
- foota 3y agoI don't think a crowbar attack will work in this case, I doubt you'll be able to get the lock to talk. /s
- themerone 3y agoI've extended stays without needing new keys. There could be wireless updates, or resetting the lock is done when housekeeping preps the room. There are definitely multiple solutions that don't depend on a server to authenticate every unlock.
- ryukoposting 3y agoI'd imagine the locks in most hotels don't require an internet connection. Frankly I'd be horrified if my hotel room's locks depended on this horrendous WiFi.
- darkclouds 3y agoSame tech they use for staff in mental health hospitals and wards, but strangely noone hacks the mental health hospitals.
- caol 3y agoMGM hotel rooms can be unlocked with smartphone NFC tap. You don't even need to visit the front desk to check in, just log in to the app. But if you can't open the app you can't get in your room. I'm guessing the front desk can issue keys to a guest in the event they lost their phone or something, but if the network is down for the front desk too then they might not be able to issue keys.
- bee_rider 3y agoWe often make fun of IOT and unnecessary app stuff, but these features 1000% make sense.
- mason55 3y agoThe problem is it works badly. You have to open the app which has to load and then you can get access to your key. But if you’re on an elevator then you might not have service and the app won’t load and then you can’t get to your key to use the elevator. Or worse if you don’t have great service in the corridor. It needs to work in a way where the key is saved to your phone so it can be accessed quickly and offline.
- lotsofpulp 3y agoI would have thought apple/google wallet already have an API for this.
- mcpherrinm 3y agoSome hotel chains like Hyatt support nfc keys in Apple Wallet. Because whatever microcontroller runs that is low-power, it can continue working after your phone battery is (nearly) dead too. I know other locks use Bluetooth from an app which isn’t supported by Apple Wallet.
- nijave 3y agoAfaik the HID Global app saves a key in the OS key store (at least on Android) and uses the locally stored key with NFC so you just need network access to enroll a key. Not sure what vendor/app these things use (maybe it's all in house)
- alwaysrunning 3y agoI did a project several years ago for mgm that involved BT, player cards, key systems, wifi, etc and I can confirm they hotel locks are controlled centrally for various reasons.
- willcipriano 3y agoI would've thought it would get sent messages like: <Grant access to KEY_ID> <Revoke access from KEY_ID> And it would keep track internally so that if the central system went down it could still function with already issued keys until it is fixed.
- TylerE 3y agoSuch a system seems like it would be incredibly fragile to local attack - and this is one case where you can't just assume "physical access means you've already lost".
- willcipriano 3y ago> physical access means you've already lost I agree, thats why I figured if you can get away with fooling around with a lock, some wires and a laptop in the hallway, you can probably pick the backup key more discreetly.
- wolverine876 3y agoI was wondering the same. It would be an extreme fire hazard if a power or computer outage made the doors unopenable - especially because a fire could and likely would cause an outage.
- gymbeaux 3y agoYou can get from your room to the parking lot without a key at the MGM Grand. I’m sure it’s the same for all others per I assume the fire code.
- StevenXC 3y agoI once was stuck in my hotel room due to a malfunction in the inside door handle, which was an annoying way to discover that the latch wasn't even mechanical on that side.
- squeaky-clean 3y agoI work in "access control" and that could probably get that hotel in a loooot of trouble with the fire marshal.
- dr-detroit 3y ago[dead]
- callalex 3y agoWhat country was that in?
- MathMonkeyMan 3y agopresumably you can still open them from the inside
- vel0city 3y agoThe doors can always open out they just lock to not allow in. In a fire nobody needs a key to leave, but they might need a key to get back in.