How unique are keys and remote keys

Question

When you go buy entrance locks at home centers, many of the lower end locks have a code that tells you which locks use the same key.  If you match them up you can get two of three packs.  Of course you can rekey later on.  I often wonder what is the ratio of total locks made versus locks that are keyed alike.  Is it like 1 to 1000?  or more?  or less?

Two weeks ago I went to get my hurricane panel keys.  The property I acquired has accordian shutters over all windows and doors with a key lock but no key.  I removed one of the keys and took it to a local supplier.  The guy at the counter asked me how many keys I want, I said four.  So he took out a rusty box with over 500 keys in them, took my lock and tried his varies keys in the box.  First one he tried was a match.  Total he tried five times, he got four matches.  Now I know hurricane shutters are not meant for theft prevention, but still, 4 out of 5 randomly matched?  So how many unique keys are in his pile of keys?  3?

Years ago when I had a Nissan vehicle with one of the remote keyless system.  I went to a Nissan dealer, parked my car, and of course all around me are new Nissan cars.  As I walked towards their door I pressed the remote to lock my car.  The only problem is I heard more than 1 beep.  There were two other beeps from somewhere.  I walked back a little to make sure my car beeped too.  But it was surprising to me that two other vehicles within the range of that remote reacted, both Nissans of course.

How unique are these doors and remotes?  Ever drove around and try your garage door remote on your neighbors LOL?

William Avery · Answer

I agree with Jerome, I doubt that Kwikset uses very many unique combinations on their retail packaged locks. When you buy two or three packages that are keyed the same look at the rest in the stack that you didn't buy to see how many others are keyed like yours. Who is going to buy those? My guess is someone from the same town and area of town as you.

Anyone that purchases a new house should change their locks. Because of this I don't lose any sleep over how secure the locks are on my remodels. I have one set of locks, that I painted red, that I use during the remodel process. This way, I always have the same keys in my lock-boxes for vendors and contractors to use. And I only have to carry one key for all of my projects.

When the remodel is complete I install a new set of locks so the buyer has new locks and the vendors and contractors are now locked out.

Jerome Kaidor · Answer

To be sure, there are a lot of possible combinations.  Even more for Schlage.  Those have 10 possible values for each pin.  I suspect that the retail packaged locks do not use anywhere near the max possible codes though.   I have been rekeying my own locks for years.

Recently, Kwikset has been pushing locks that have a magic rekeying method.  I hate those locks.  A couple of them broke on me - the locks got internally "confused" and I was unable to fix them.

Garage door openers have a few different systems.  I use a lot of these at one of my complexes.  I use the simplest, cheapest kind that just have a fixed 10-bit code.  There' s a row of dip switches inside the remote, and you just set them to match the dip switches inside the gate receiver.  These are perceived as low-security because a guy with a radio receiver could snarf the code off the air.  Also, if somebody looked inside one of the remotes and wrote down the dip switch positions, he would have the code also.  These considerations are outweighed by the cheapness of this system, and as I tell all the tenants "It's not Fort Knox".  Also, the people I want to keep out are typically not radio/computer nerds.   There is another system that uses very long addresses that are burned inside the remote, and you have your gate receiver "learn" each remote that is going to be used with it.  Yet another system is the Alliance Genie, which uses a rolling code.  With the rolling code, the output of the remote is different every time you use it.

- Jerry Kaidor

Jesse Tsai · Answer

For kwikset locks, which are 90% of resi locks in my area, the number of possible combinations are 7^5 =16807.

Not sure about number of combinations for garage openers though.