Use your smartphone to unlock your house

There are a few locks in this space, all somewhat different.

I got more interested in them back when I first learned of Airbnb (2008 or 2009), and thought about how much of a pain handling keys would be; a reprogrammable lock would be ideal. Unfortunately, until BT 4.0LE on the iPhone 4S, there wasn't really a good way to do this other than conventional NFC (giving people tags in advance, and then remote-acl modifications to let them into units), which required wifi or other data on every lock.

So there's August (BT 4.0 LE, no local network). Probably the nicest industrial design. Fits over the inside part of a single cylinder deadbolt. Lack of network in the lock makes it harder to do a networked audit log.

Lockitron (a YC company) -- I kind of hated the first generation of their product, but the second generation, shipping soon, is close to the August, plus has built-in Wifi. I'm not sure if it can work in entirely-local mode, which IMO is a key feature.

Neither of these replaces the actual lock. This is both a plus and a minus.

Schlage, ilco, etc. have a combination of consumer and commercial locks with NFC, touchscreen, or bluetooth. Some have monthly service charges.

Sadly, no one makes a really good cryptographic lock (i.e. something which does challenge response authentication, rather than just passing a string), as far as I can tell. I haven't looked at the August or Lockitron 2.0 protocols, though, but all the big commercial lock company products are a bit mediocre for security. This doesn't matter so much for doors as it does for safes or other security containers. I had really high hopes for the smartcard/iButton based locks, but those just send a serial number, too, and are thus easily intercepted or spoofed.

Kaba-Mas makes probably the best electromechanical lock, the X09 (and new X10 coming); they're about $1k. Unfortunately even those only work as locks and are deficient as seals.

The gold standard seems to be the integrated building system where everything is networked and centrally managed (HID or whatever), but I think there's a great opportunity beyond the single-door residential that all of these seem to be going after, but below the integrated facility system. Something designed for <200 users, 2-5 doors, cloud managed for changes, and local config pushed to the locks for instant access.

Maybe could make it work using Lockitron or August hardware, or some commodity hardware from one of the lock companies.