Our locks are getting smarter all the time. There are already plenty of them that can be controlled with an iPhone. The Igloohome Smart Padlock is also worth a look. It combines with your smartphone to let you grant access remotely. You can manage and send pins and keys via the Igloohome app.
This heavy-duty lock can take some serious abuse as it is impact and water resistant. It has a hidden battery compartment that can’t be accessed unless the Padlock is unlocked. You can track dates and times of unlocks on your phone.[where to get it]