Post by thread:IR Remotes and B&E (Breaking and Entering)

>a system immune to both. The one difficulty is that federal government reg- >ulations make it hard to use any secure code over 40 bits long, and codes >of that length may be subject to "birthday" attacks. I could nonetheless >tell anyone interested how to make a system that was secure, though such >advice could well steer someone into a patent violation since many such sys- >tems are already patented. Well, "our" own dear Microchip has a line of keyloc chips intended to solve this very problem. I haven't used them, but couldn't help but notice them while perusing their web site. So perhaps the answer is very close at hand! The keyloc systems rotate codes, but don't frequency hop. The latest scheme is to always change the code AND the frequency, so that a record and playback attack is impossible. If someone is going to go to the trouble of cracking the encryption AND frequency just to get my car, then I am not going to be able to stop them. But if they want it that bad, they can just do what some thieves did to an expensive, fuel-cutoff alarm supplied car, and just shove it into a panel truck and drive off. In one of the James Bond movies, a would be car thief is killed when 007's car responds not with an alarm, but a large self-destruction explosion. Hey, did the bad guys think of a "denial of service" attack? :-) ==Doug Claar

>In one of the James Bond movies, a would be car thief is killed when >007's car responds not with an alarm, but a large self-destruction >explosion. Hey, did the bad guys think of a "denial of service" attack? :-) Why not use an efficient roll code for the remote (no complex frequency hoping) to allow getting in - then require the car owner to have a secondary alarm inhibit AS WELL - like pressing a certain accessory button a preset number of times etc - Or another press of the remote (The alarm knows the door is open and that some other function is requested so that the car is allowed to start only after this sequence of 2 or 3 events has occured). If a thief wants to get access (by circumventing the IR using a recorder) then let him in and give him a nice sizable shock to the bum from an EHT coil under the seat - then lock the doors and turn on all the horns etc. Liability can be covered by playing a concise warning message (from EPROM) and printed on the dash etc. Then you'd have the option of suing the thief for 'extraneous psychological' issues once he's caught - not to mention any previous 'proceeds of crime' etc since most professional thieves have built up quite a nice nest egg... Rgds Mike