You may like the idea to have multifunctional mobile phone.
I mean the phone as a remote control that will have function, for exam, to turn on and off television set, or as a key to home. How it will work?

There is nothing special. It will be an ordinary phone equipped with the infrared adapter. It will enable you to do many things automatically in a short period of time. All the data (for opening the door, for exam) will be saved in the phone and will be available by entering the codes and passwords.
As a result, you don't have to worry if your phone has been lost as nobody can activate the personal information in it.