I might be dumb for asking, but unless its special type of keys, can someone else not take their key and have access to my things ? such as my basement lock or my apartment.
Key looks like a normal key but as again im no expert.
*Edit: Same key unlocks main apartment entrance, Underground Garage (Manually, if forgot FOB), Washroom for the building.. but also same key is my apartment entrance key, my basement lock key..
In: 15
I would assume your 1 apartment key fits all the locks relevant to your apartment, your neighbours would have a different key and all the locks relevant to *their* apartment would be unlocked by that one key.
Look at your key. See the teeth? Each one a number and each is a different height. The height is the value of that number.
If you’ve got a key that fits your personal door and a bunch of keys that fit a communal door, the communal door is only looking at the first few teeth (or last few). If you compare keys, the teeth at the front or back are going to be the same.
123456
vs
987656
The communal door is only asking for ….56
A key’s teeth are cut to specific heights. The lock checks those heights. If they’re right, you can turn they key.
Those heights are usually numbered, so a key could be “18472” and the lock checks to make sure that the key is exactly this set of heights.
The lock doesn’t have to check all of them, though. It can only check some. For instance, your key could be 29463 and your neighbor’s key could be 19463. The building door and garage could ignore the first 3 teeth and only check for the 63 at the end. Then, everybody’s keys will have some of the teeth cut the same and other teeth cut differently. The same-cut teeth go to the locks everybody can open, and the different-cut teeth go to the locks that are only yours.
If you get a chance to see a neighbor’s key, you can compare to your own and see this in action. You’ve got to look closely, though, as the key teeth are pretty small.
Instead of a physical key, imagine if the access used a pinpad where you type in a code number.
You don’t get to pick the code number, it’s assigned to you by your landlord. Everyone gets a different code and you’re not supposed to tell your neighbor your code.
There’s a pinpad on the common front door to the building, and one on each apartment door. You type the same code number into the building’s front door as you do to your own apartment door. Even though everyone in the building has a different code from each other and can’t open each other’s doors, they’re still all able to open the common front door.
But why? You and your neighbors decide to break the rules and tell each other your code numbers to see what’s going on. Five of you get together and compare codes. It turns out your five codes look like this:
49301315
49302128
49309401
49305811
49301012
And you all notice, “Hey, our codes all start with 4930. They’re different after that but they all start with 4930”.
So you experiment and play with the front door a bit trying all kinds of other numbers, with this result:
49309999 – opens building door
49308888 – opens building door
91293401 – does not open building door
49445841 – does not open building door
49309513 – opens building door
30129513 – does not open building door
11119513 – does not open building door
49309513 – opens building door
Yup, sure enough, as long as the code *starts with* 4930, it opens the building door and the remaining 4 numbers don’t matter. You conclude that the building door only pays attention to the first half of the code and ignores the rest of the numbers. Meanwhile your apartment doors read the whole number, not just the first half, which is why your different codes all work on the building door but not on each others doors.
Replace the idea of digits with the teeth on a key and you get basically what’s happening with your apartment keys. The shared communal locks aren’t using all the teeth of the key, just a subset of the teeth on the key, and the rest of the teeth aren’t relevant in those locks but are relevant in your individual apartment locks.
If you did a thing similar to that story of telling your neighbors your number codes, but instead you compared your physical keys with your neighbors, you’d see a similar effect. Your key and your neighbors’ keys will have some of their teeth matching, while other teeth don’t match. The ones that match are the ones the communal doors are using.
Locks recognise the shape of a key – they key is shaped to a particular code. Usually this is by cutting notches in the key to a specific depth, and the lock recognises the code and will operate if it is correct.
However, a lock can be designed to recognise multiple codes.
So if you have a 6 digit code (6 cuts) on the key, then the lock would normally check that each digit matches the code before opening.
So, for example, if you have a key cut with notches of depths : 1, 3, 4, 6, 5, 7, then normally the lock would check that notch one is 1 deep, notch 2 is 3 deep, and so on.
However, it is possible to build a lock to accept multiple notch depth. So, you could make a lock which accepts notch 1 if it is 1 deep, or 5 deep. You could even make the lock ignore one or more notches completely.
In a communal lock like this, all the apartment keys would share some part of the code. The front door lock would only check the shared part of the code.
The problem with this approach is that it massively reduces the security of the locks. The shared code gives a lot of clues, if you can see a couple of apartment keys (you can work out the shared code) and once you know the shared bit, you now have a much reduced range of keys for the apartments.
Because of the security problem it causes, this type of communal keying is not usually recommended – and instead communal doors should have their own separate key. In practice, however, mechanical locks are not good for this type of front door in anything other than small blocks. If you have 20 apartments, then the front door lock will wear out rapidly – and you will also have problems with making sure that there are no spare front door keys lying around.
The proper approach to apartments is to use electronic key fobs for the communal areas. These are more secure and don’t wear out in the same way. This way if a key is lost, or a tenant leaves and doesn’t return their key, that individual key can be deactivated.
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