Car key remotes, like garage remotes, use rolling code to authenticate access.
Rolling code is basically just code that changes every time so that no one can use it later.
For RollJam to work, the hacker has to place a wallet-size unit somewhere on the targeted car.
This has been sort of a theoretical attack for many, many years.
This is not by any means brand new or a big surprise.
Unfortunately, I think it is a big problem.
Remember, Kamkar doesnt build such devices to make it make easier for criminals to steal stuff.
In fact he doing the opposite.
His latest nifty gadget built out of $32 worth of electronics.
source: www.techworm.net
