• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Here's an idea

Is this idea BS

  • No

    Votes: 0 0.0%
  • Yes

    Votes: 0 0.0%

  • Total voters
Not open for further replies.


New Member

I was thinking about how unsecure wireless remote controls are... Most remote controllers are simple one-way devices that transmit a frequency / code to a car to open it. Anyone with a wideband recorder/playback system can "listen in" and repeat the code to open your car.

My idea works very much like modern-day network logins:

1. Client (remote) sends "want to login" token
2. Server(garage/car/whatever) sends random 16-bit hash.
3. Client XORs the hash with the 16-bit login code and sends it back to server.
4. Server unhashes (XOR again) to extract code
5. Compare codes
6. If codes match, open door / whatever.

Of course, this makes for a clunki(er) remote, but it is far more secure. Simply repeating the code will have no effect at all.

Of course, if my idea is complete ********, feel free to tell me.



Active Member
yes its a good idea.

It took me a while to comprehend what you were saying,
cos you weren't using normal language.

The remote shouldn't be much different in its effect.
I dont think it would be notice-ably affected.

Chips to do this are cheap enough.
Maybe it is already done on some cars.

It occurs to me that its only the signal from the
key-fob that is suspect.
The signal from the vehicle to the key-fob would not
be suspect.

That strikes me as an ideal situation for a 'high-encryption' one way, to a 'high-decryption' set
on the car.

Dunno ... its all getting too hi falutin' for me.
And i cant figure out where to vote ....
Its time i gave up

John :)


Active Member
found the vote bit,
it comes up after ...

John :)


Well-Known Member
Now you have to have a sensitive receiver in the remote, with some processing power, in addition to the transmitter. This might be tough to fit into a key or fob.

Nigel Goodwin

Super Moderator
Most Helpful Member
I thought some remote keyfobs always transmitted different codes, in order to stop them being copied?. Both the transmitter and receiver use the same pseudo random sequence - so every time you operate it a different code is used.


New Member
:D idea is ok

yet still not secure enough and too complicated

two timers (one in remote and one in car/garage) could also do it- they produce identical keycodes every few mins. that would make the remote cheaper since it would only have to be one-way
Not open for further replies.

EE World Online Articles