So what would happen if you were driving legitimately and the keyfob batter= y died? I'd take exception to a sudden panic stop on the interstate.=20 I suspect that once the vehicle is started, that they keep everything going= till the car is shut down again for exactly that reason. -----Original Message----- From: piclist-bounces@mit.edu On Behalf Of Timmot= hy Relerford Sent: Monday, July 9, 2018 9:50 AM To: Microcontroller discussion list - Public. Subject: RE: [EE]:: Wrapping key-FOBs in tinfoil If the key fob was inside someone's house and a thief used some method of = repeating the signal to start the car and drive away, what happens after t= hey get some distance away? Does the car shut off? =20 In other words, doesn't that fob signal have to remain in proximity of the= car to keep it going? After all, if you're the rightful owner, and you have the fob in your pock= et and you get into your car and drive away, no matter where you go, that = signal will be in proximity of the car. After all, you're sitting in the = front seat. =20 But if the signal is being repeated, at some point, that signal will disap= pear. Will the car turn off now? If it does, then the thief would only g= et a short distance away before the car stops and he won't be able to get = it started again unless he copies the signal and programs a piece of electr= onic equipment to act as the fob from that point. I guess they could stri= p it or tow it after that, but that would seem risky to me. =20 =20 =20 Regards, Jim > -------- Original Message -------- > Subject: Re: [EE]:: Wrapping key-FOBs in tinfoil > From: Denny Esterline > Date: Mon, July 09, 2018 10:25 am > To: "Microcontroller discussion list - Public." >=20 >=20 > > > > > > It seems to me the only way the key fob is going to be able to be=20 > > copied is if someone presses one of the buttons to transmit the=20 > > signal. If it is just sitting on a table or hanging on a wall hook,=20 > > how would someone outside the home (or bldg.) cause the key fob to=20 > > transmit? >=20 >=20 >=20 >=20 > This is a misunderstanding. I cannot claim to know the underlying=20 > technology, but many new car keyfobs today are "proximity devices".=20 > Fob in pocket, press button on dash to start car. Definitely do not=20 > have to press any buttons on the fob. >=20 > I've not read Russell's linked article, but I did recently read an=20 > article claiming thieves were using SDR as a repeater to significantly=20 > boost the range of what the car considers "proximity". The claim was=20 > with your keys on a hook by your front door, they could use a repeater=20 > outside and drive the car away. >=20 > The really fun trick here is they make no effort to capture or crack=20 > any codes, just boost a signal. >=20 >=20 > -Denny > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > View/change your membership options at=20 > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .