Talk:Rolling code

Rolling codes ALWAYS repeat

Any rolling code will repeat itself. The good ones have a repeat cycle in the billions or higher. So this article is incorrect. Rolling codes do repeat. Hcobb (talk) 06:20, 26 September 2012 (UTC)

That's not correct. If there were a billion codes, and a user pressed the button once a day, it would take almost 3 million years before the code repeated. Even with 100 key presses a day, nobody would come close to getting to the point where things would repeat. If you assume a 20 year lifespan for an opener, then the person would have to use the opener almost 140,000 times a day. In that case, it won't last 20 years. It would be impossible to make a remote control with a lifespan of that many keypresses. So it would be theoretically impossible to get to the point where a code could repeat. You are basing your assumption on a remote control with a theoretical infinite lifespan and a garage door or car that will last equally long.Hagrinas (talk) 21:11, 17 September 2013 (UTC)

Pseudo OTP?

Is this like a pseudo one time pad? — Preceding unsigned comment added by 69.255.170.233 (talk) 16:14, 29 December 2012 (UTC)

Pairing

What's missing here is a discussion of the pairing process. Obviously the opener/vehicle needs to keep track of each opener or fob, so pairing is essential. But there's no mention of how it works. If sending out the "next random code" and whatever goes with it were enough information for the opener/vehicle to know what codes to generate next, it would be equally likely to crack by capturing any transmission, assuming that the transmission during the pairing process were no different from at any other time. That's also assuming that the transmitter is not also a receiver that can spit out information at pairing time only. So something needs to be added to the explanation to make it clear how the receiver came up with something it could store that would recognize a given transmitter, have a seed it could use, or have anything else that's unique to the remote that couldn't be captured later.Hagrinas (talk) 21:19, 17 September 2013 (UTC)

Your suspicion is correct -- the transmission during the pairing process is *different* than the normal transmission. (Typically simultaneously pushing "unlock" and "lock" buttons on the keyfob tells it to transmit the secret seed/key.). I was one of the people that wrote up a description of the pairing process at https://crypto.stackexchange.com/questions/18311/how-does-a-rolling-code-work which links to app notes that go into even more detail. Feel free to improve this article by inserting a summary of the pairing process in an appropriate level of detail. Thank you. --DavidCary (talk) 17:38, 25 February 2021 (UTC)

So if I had someone's fob and I was far away from their car...

I could permanently screw it up by pressing it 257 times? Ouch. - Immigrant laborer (talk) 20:32, 29 January 2022 (UTC)