Locking doors with phones is slowly becoming the next best thing of the 21st century. Okidokeys has previewed the latest in 256-bit AES encryption in smartphone-based doorlocks. The module hooks up to a standard door lock. It does this from the inside to disguise the fact that there is a wireless locking system installed; this also allows you to unlock your door with a regular key.
Triggering the lock can be done using the mobile app (Android or iOS only) which transmits a signal via Bluetooth 4.0. It can also detect a wide range of other media to be used as keys. At worst, it can be unlocked from the inside by pressing a button. The system will cost US$179 and ship in the spring.