On Friday, February 28, 2014 11:14:32 AM UTC-5, wrote:
On Fri, 28 Feb 2014 02:51:22 -0600, Dean Hoffman

" wrote:





Thieves have some gizmo that disables car alarms and unlocks

the doors. From CBS Chicago: http://tinyurl.com/mzx7shg



There are actually 2 paths these sort of things can exploit. I believe

this one just overloads the key fob receiver by sending all of the

available codes in a short period of time.

It would sure have to be one crappy design if the car allows
that to happen. More logical would be if it gets too many
codes in a short time, it ignores any more for some period of
time. And I would think that there isn't a list of codes, it's
a pseudo random rolling sequence, like garage door openers have
used for decades, apparently successfully. The car and the fob
are synched and generate pseudo random codes to the same algorithmn,
but even that is based on a random starting point. Not clear to
me how you can easily overcome any of that.



The more insidious devices

crack into the "OnStar" (or similar) interface. That gives them even

more capability.

If you can crack into that, unless you crack into and have access
to the Onstar system at it's source, i would think you'd face
problems similar to the above.