Lock+keypad operating independently offline for short term rentals

Product name

Smart Lock, Keypad


Lock with keypad should be able to operate offline, e.g. by internally storing the same algorithm which would generate codes for stays on server side.


One way to go about this would be this:

  1. an algorithm generating codes with encrypted (i) check-in date + time and (ii) check-out date + time as well as (iii) order of code creation (for security reasons) is stored both on server and lock sides;
  2. thanks to encrypted information regarding (i), (ii) and (iii), theoretically no connection is necessary between server and lock - lock can independently expect what another code will look like;
  3. in practice to avoid possible problems with someone trying to break in with multiple random codes, whenever online, lock syncs with server to ensure that lock continuous to operate properly;
  4. due to a lot of info stored, code might need to be e.g. 12 digits long;
  5. after first use typing first 6 digits would open the lock.


We are a short term rental operator. Our guests frequently make last minute booking and want to check in immediately. If the internet does not work at that time at the apartment (which happens more often than power outages), this can’t be done without one of our employees showing up in person, rendering Smart Lock useless when it would be most useful.


Guest makes a last minute booking and wants to check in immediately. In order to do that we don’t have to provide service in person even if internet is down at the apartment.