An RFID blocking CARD?

[jhsachs]

I'm searching for a good solution to protecting my key fob from hacking without making it making it unduly difficult to get out when I need it. I ran across a thing called an RFID card which is supposed to protect credit cards if placed in your wallet.

Is this real protection? I always thought that a Faraday cage protects its contents by enclosing them in a radio-opaque envelope. I can see that a radio-opaque card would protect objects behind it, but... turn around, and the card is behind the objects, and what good does it do then?

I found some products that might work for me from the usability end, but they use these cards for RF protection, so this is a real question for me, not idle curiosity.

 

[dwd999]

IDK I bought one of those wallets that's supposed to have a lining that blocks rfid so the credit cards are supposed to be protected when the wallet is folded closed. But I have no idea how to test such a thing.

 

[bill001g]

Not sure about a key fob but they make all kinds of wallets and bags that will block radio signals. They are in effect a Faraday cage but I never looked into how they really work.

You commonly see this in the school systems that try to enforce a no cell phone policy. They kids have small bags/pouches that the phone go in that block the signals. I would bet someone sells one that you can drop a key fob into.