Interesting developments in the game of leapfrog between security researchers and criminals. Looks like the criminals figured something out before the white-hats this time. The prevailing theory on the matter is that thieves have figured out how to open cars that use fobs (plastic bits that replace the need for a key; the driver can operate the car simply by having a fob in their pocket) by using a signal amplifier. The signal amplifier in effect increases the range so that the car is fooled into thinking the fob is in close proximity. That is to say, thieves may have figured out that they can buy a $20 amplifier that will amplify the signal of your fob. The amplification of the fob’s signal means that the challenge/response communication between the fob and the vehicle can happen from 500 feet away instead of twenty feet, for example.
In the linked articles researchers suggest that keeping your fob wrapped in tinfoil will block the signal from being amplified. They also suggest keeping your fob in a freezer. They suggest that the freezer acts as a Faraday cage. I suspect that it does not act as a Faraday cage but rather has lots of insulation that prevents the signal from getting out. I don’t think that there is a lot of electricity going through my freezer’s door. If it works though, it works.