Faraday box for car keys – do they really work?

I’ve been hearing that thieves can pick up the signal from car keys (not sure if it’s just fobs or regular keys too) and gain access to vehicles with keyless entry. Is this only a problem for cars with push-button start? Clear information on this seems hard to find. From what I understand, a Faraday box could block the signal and prevent theft. Any thoughts?

Try keeping them away from doors or putting them in a metal box that blocks signals.

@Samwel
Bit late here, but which Faraday box did you get that actually worked?

This is a real concern, especially for keyless entry and ignition systems. Toyota and Lexus vehicles are often targeted. Thieves use devices that pick up the signal from the fob and relay it to the car, which then thinks the key is nearby and unlocks. These cars are often shipped abroad.

Faraday cages do work, and so does using an old-school steering wheel lock. Keeping your car in a garage or blocked by another vehicle helps too.

Personally, I let my key fob battery die on purpose and just use the manual key. It’s annoying, but it adds a layer of security since manufacturers tend to prioritize convenience over security.

@Ariana
Where did you get your Faraday box?

Herbert said:
@Ariana
Where did you get your Faraday box?

I work in security, so I used an old metal alarm panel box. But you can get consumer Faraday pouches on Amazon—they look like little black bags.

@Ariana
If I don’t have keyless entry, do I still need this? My key only unlocks the car when I press the button.

A Faraday box works for key fobs with push-button start. You could also use a metal-lined box as an alternative.

Search for a Faraday bag on Amazon. They work not only for car key cloning but also to protect credit cards and cell phones from tracking.

Braxton said:
Search for a Faraday bag on Amazon. They work not only for car key cloning but also to protect credit cards and cell phones from tracking.

Be cautious—many of those cheap ‘Faraday cage’ fob holders don’t actually work.

If my car doesn’t have push-button start, am I still at risk of thieves using this cloning trick?

Not sure if it’s a myth, but I bought one just in case after getting two new cars. It was only about $10, and it definitely blocks the signal—the car won’t recognize the key with the lid closed.

Dennis said:
Not sure if it’s a myth, but I bought one just in case after getting two new cars. It was only about $10, and it definitely blocks the signal—the car won’t recognize the key with the lid closed.

What brand did you go with?

RyanLewis said:
You might as well get a tinfoil hat too—pretty sure this is just a myth, which is probably why info is hard to find.

Why spread misinformation? Here’s a video that explains how the relay attacks work.

@Luchivya
[deleted]

Dennis said:
@Luchivya
[deleted]

The video literally shows a relay attack on a car. If you’re ignoring this info, maybe that’s why you’re at a dead end on the topic.

A simple layer of tin foil should work as a quick fix.

Thieves usually catch the signal when you use your fob, so the Faraday box won’t help if the key is active. This is why it’s common in parking lots.

Some cars use rolling codes, which are harder to clone. But with older systems, the key code stays the same, making it easier for thieves to use.

Fun fact—if you hold down the button on certain remotes (like garage or gate remotes), they can block signals from your car key fob.

You can test this out yourself! Try a tin can, a chip bag, or even a metal desk organizer. Put your key fob in and see if the car unlocks. With my car, a tin can and a chip bag both blocked the signal.