Why do key fobs/garage doors openers use rolling codes instead of PGP or SSL encryption? Wouldn't they be more secure if they used the same encryption technology computers use for remote access?
I can think of several issues with using PGP or TLS:


Both PGP and TLS require certificate management (unless password based), it would be tricky to get a PKI going for this;
PGP and TLS are overkill for key fobs / garage doors and would put unnecessary strain on the choice of processor and battery;
PGP and TLS require access to a secure random number generator, which is also pretty expensive to put in a key fob.
The TLS handshake requires two way communication;
Both TLS and GPG require intricate implementation of the message protocol (stuff you can do without for a door opener).


Even from a technical standpoint TLS is overkill; you're really just interested in authenticating a command that cannot be replayed. This explains the choice of a rolling code I guess.



Those are the technical reasons. I guess most of the manufacturers aren't that IT savvy either. They might not even know about PGP or TLS. They're more likely to be interested in motor &amp; hinge design and picking the right color for your door.



That said, there's likely some kind of home automation that can


open a door and
uses some kind of transport protocol or message authentication.


I doubt if these two "heavy weight" protocols are used towards the door though.