RollJam: The next time you tap your wireless key fob to unlock your car, and realize you didn't hear the feature sound only on the second attempt, not due to a technical problem.
Κάποιος hacker όπως ο Samy Kamkar uses μια έξυπνη device close enough to you to monitor and record the command from your wireless key. 
And when this hacker passes from your car a few minutes, hours or even days later, he has only to push a button to get your car.
At the Defcon hacker conference in Las Vegas, Kamkar plans to present the details of a gadget he developed and named "RollJam."
The device's radio transmitter costs $ 32, and is less than one mobile phone. It is designed to intercept not only the security codes used by the “most modern cars and keyless entry systems", but also their alarm systems as well as for the modern garage door opener.
The RollJam, as described by Kamkar, should be hidden near the target vehicle or garage. He will be on hold waiting for the unsuspecting victim to use his key ring.
The victim will only notice that his keychain did not work on the first attempt. But the second one will unlock the car or the garage door.
The intruder with RollJam can return at any time and by pressing a small button to replicate the code he has dubbed to open the car or garage.
"It can be used for any garage that has a wireless remote control, and almost any car that has a wireless key," says Kamkar.
