It sounds like an internet myth or a TikTok hack gone viral, but an increasing number of drivers are seriously wrapping their car keys in aluminum foil before leaving home. At first glance, it may seem absurd. But behind this growing trend lies a very real risk – and a surprisingly simple way to protect yourself.
The idea isn’t new, but it’s only now that more people are catching on, thanks to rising car thefts using high-tech methods most vehicle owners are completely unaware of.
The hidden vulnerability in modern car keys
Today’s vehicles often come with keyless entry systems, allowing drivers to unlock and start their cars without physically inserting a key. Convenient? Yes. Secure? Not always.
Thieves have adapted. Using inexpensive signal amplifiers and relay devices, they can intercept and extend the signal from your car key, even if it’s inside your home. In less than 60 seconds, your car is unlocked, started, and gone — with no broken glass, no alarm, and no sign of forced entry.
“It’s silent, fast, and leaves almost no trace. That’s what makes it so effective,”
says Martin S., an independent car security consultant based in Manchester.
The worst part? Many victims don’t even realize what happened until it’s too late.
Why aluminum foil works — for now
The theory behind the foil is simple: aluminum can block electromagnetic signals, including the radio frequency your key constantly emits. By wrapping your key fob in a tight layer of foil, you prevent it from “talking” to potential relay devices nearby.
It’s not a high-tech solution, but it’s cheap, accessible, and surprisingly effective. Security experts confirm that foil can reduce or block the signal enough to thwart most casual relay attacks — at least temporarily.
This basic measure won’t stop determined professionals with expensive gear, but it does raise the bar and adds a layer of protection most people currently lack.
What you can do to stay safer
- Keep your key fob in a signal-blocking pouch or metal container when not in use
- Avoid leaving keys near the front door or windows
- Use steering wheel locks or other visual deterrents for extra protection
- Ask your dealer if your car’s keyless system can be disabled or timed out when not in use
- If you have a second set of keys, protect them too — they’re just as vulnerable
Some automakers are starting to respond. A few new models now come with “sleep modes” that deactivate the key fob when idle, but most older vehicles remain exposed.
From low-tech fix to national habit?
What began as a niche online tip is now becoming a real-world habit for thousands of drivers across Europe and North America. Several police departments, including in France and the UK, have issued public statements acknowledging the rise of relay theft and recommending signal-blocking methods — including, yes, good old aluminum foil.
While it’s not the most elegant solution, for many it’s a practical one. As one Reddit user posted:
“A £1 roll of foil is cheaper than a £30,000 car. You do the math.”
Signal-blocking pouches and wallets are becoming more common in stores, and some car owners are even turning to DIY solutions involving cookie tins or Faraday cages.
For now, foil remains a stopgap, not a permanent answer. But as long as thieves exploit wireless convenience, drivers will need to think twice — and maybe reach for the kitchen drawer before going to bed.
