Question about keyless entry

[HondasTrail]

So im thinking about making my car keyless entry. However, I remember back in the day people could look up the signal with a PDA and automatically be able to open the locks and disarm the alarm in one shot. My question is, did technology ever catch up with this? Did they ever find a way to circumvent this problem?

[ryanman]

I never heard about people using PDA's to unlock cars. Can someone enlighten me on this?

[Talus]

You're thinking of 'Gone in 60 Seconds'

[wild.irish]

it was possible to intercept the signal, and to reconstruct it. not with the PDA though, from what i remember.
technology has moved forward with systems which generate a new signal each time a system is used. basically each signal is unique this way, and even if you intercept it and record it, you won't be able to use it. So depending on the system you'd have to catch a number of generated signals, analyze it and try to hack the algorithm how it generates them, and then create a signal that will work. but that's just speculation - easier to smash the window out and short-cut ignition wires ;)

[Weston]

it was possible to intercept the signal, and to reconstruct it. not with the PDA though, from what i remember.
technology has moved forward with systems which generate a new signal each time a system is used. basically each signal is unique this way, and even if you intercept it and record it, you won't be able to use it. So depending on the system you'd have to catch a number of generated signals, analyze it and try to hack the algorithm how it generates them, and then create a signal that will work. but that's just speculation - easier to smash the window out and short-cut ignition wires ;)

Yup. This is what systems with anti-code-grabbing technology do... the transmitter and receiver are both programmed from the factory with the same list of codes (or same algorythm for generating the codes), and the transmitter sends a new one every time. The receiver will only accept each code once, so a thief can't simply record your transmission and send it again when you aren't around. It will allow you to jump ahead in the list of codes (in case you press a button and the receiver doesn't get it), but any codes that get skipped should become invalid.

It's a good system, but mass production and cost cutting introduce weaknesses... after enough uses, the codes will repeat in most systems. And everyone who buys the same alarm model (or possibly just brand) gets the same list of authentication codes, so they aren't really entirely secret. What keeps one transmitter from working on multiple alarms is it'd ID code that it sends out. When the alarm is initially setup and associated with a transmitter, it just learns it's ID code and current position in the authentication code list... the ID codes are unique (or reasonably unique), but they don't change and the transmitters for that model of alarm all get the same list of authentication codes. So, it is possible to crack it, and I can think of a relatively simple way to do it (using a "man in the middle" scheme), but it would still be simpler and faster for a thief to get into the car and disable the alarm by other means.

[Talus]

What's the cheapest way to get keyless entry? Would I have to get an alarm that had that as an option? If it was offered as a factory option could I find an OEM system and use it on my car?

[preludeshfan]

What's the cheapest way to get keyless entry? Would I have to get an alarm that had that as an option? If it was offered as a factory option could I find an OEM system and use it on my car?

i wouldnt worry about the chance of someone grabbing your code. the chances of that are so remote thats its not worth worrying about. most theives would rather just break a window rather than mess with that level of technology.

as for a keyless i would just get an alarm with keyless it takes the same amount of installation time and you might as well have the bennifit of a security system

i can get them for about 50 bux

[Talus]

as for a keyless i would just get an alarm with keyless it takes the same amount of installation time and you might as well have the bennifit of a security system

i can get them for about 50 bux
Wow. How much to install? (97 jetta)

[preludeshfan]

Wow. How much to install? (97 jetta)

that depends, does your car have vacume actuated locks or electric or does it have power locks at all?

[Talus]

that depends, does your car have vacume actuated locks or electric or does it have power locks at all?
They are power and are the vac operated ones.

[preludeshfan]

They are power and are the vac operated ones.

i figured they might be good ol german engineering!
anyway vac systems can be tricky to get interfaced correctly. i would say at least 40 bucks give or take 10 depending on how long it takes to hook into them.