Whoa! After reading this, I took our "Faraday" cookie tin (stainless steel) out to my wife's Flex (jeep is loaned out) to check. The prox door lock opened and I was able to start the car. I was floored.
The same way you don't press a key on the fob to start the car. Your fob and the car both have radios that always talk to each other. The only security feature is location and proximity. Aka, when you use as advertised you put key in pocket, sit down and start the car with the press to start. It all works without you knowing but the car and key in your pocket are talking. Now what thieves are doing with those funky antennae and backpacks with computers in them, is sniffing the signal from your key with backpack #1 then via communication with backpack #2 near and then in your car, "moving" your keys signal into the car just like it was there. The car can see no difference, it "sees" your actual key because electronically they moved the signal close and then into your car. There is no cloning, or replaying, those are other attacks that can work depending on the car and when it was made. Most modern cars have solved the "cloning and replay" attacks with hardware based encryption and public/private cryptography. You cant stop moving the actual key into the car. Unless you have a 2nd factor of authentication needed to start the car, aka Ravelco, Tazer, IGLA, your choice of immobilizer.
We have those for our spare keys, and this box for our main keys.. Everything works.
I've been debating potting the star connector there for this reason...
I should add, that it also transmits the coded signal when you depress a button on the fob and there's a good battery in place.
There may come a day when access to that connector is needed. Maybe just put some kind of physical plate/enclosure, blocking access, requiring multiple fasteners to be removed, to slow them down a lot and unexpectedly.
