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How to Protect Your Car Key Fob from Relay Attacks

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25.04.2025

Car theft has entered the digital age — and unfortunately, so have the thieves. As car manufacturers move toward keyless technology, a new type of threat has emerged: the relay attack. Unlike traditional break-ins, this high-tech method allows criminals to steal a vehicle without touching the keys — or even breaking a window.

Imagine this: your car is parked safely outside your house. Your key fob is inside, hanging on a hook by the front door. You're fast asleep. But outside, two individuals with small electronic devices are working together. One stands near your front door, scanning for a signal from your key fob. The other waits by your car. Within seconds, your key’s signal is captured, extended, and transmitted to your car. It unlocks, starts, and drives away — and you might not notice until morning.

This is not science fiction. It's called a relay attack, and it's one of the fastest-growing vehicle theft methods worldwide.

Why Relay Attacks Are So Effective

The key to this technique is exploiting the constant communication between your car and its fob. Most keyless entry systems are designed for convenience — you don’t even need to press a button. The car automatically detects the presence of the key fob and unlocks when you approach.

This convenience is exactly what makes it vulnerable. Relay devices — which are cheap, portable, and easy to use — can mimic the signal and trick the car into thinking the key is nearby, even when it’s inside your home.

Security experts have raised the alarm about this method for years, but many drivers still don’t realize how easily their vehicles can be accessed. In the UK alone, keyless car theft now accounts for more than 90% of vehicle thefts involving high-end models, according to the AA. And with the rise of online tutorials and black-market tools, the problem is growing globally.

So, What Can You Do to Stay Safe?

Fortunately, protecting your vehicle doesn’t require advanced tech or a huge investment — just awareness and a few smart habits.

One of the most effective ways to block relay attacks is also the simplest: store your keys in a signal-blocking container. Often called a Faraday pouch or Faraday box, this lined case prevents radio signals from escaping. When your keys are stored inside, they can’t be scanned or cloned, no matter how close a thief gets to your home.

Placement also matters. Many drivers leave their keys near the front door or on an entryway table — spots that are easy to access from outside. Moving your keys to the center of your home, an upper floor, or even a metal box can reduce signal exposure dramatically.

Some newer key fobs allow you to manually disable the signal when it’s not in use. This feature is often hidden in the manual and rarely mentioned by dealers. Taking a moment to learn whether your key supports this — and how to activate it — can make a big difference.

It’s also worth checking whether your vehicle’s software is up to date. Many automakers periodically release firmware updates that strengthen encryption or reduce signal range. In some cases, updates can even detect and block suspicious unlock attempts.

And while it may seem old-fashioned, physical security still works. Devices like steering wheel locks or gear shift immobilisers can be powerful visual deterrents. Even if a thief manages to unlock your vehicle, the sight of a bulky lock inside may be enough to send them looking for an easier target.

If you're looking for practical solutions beyond GPS, check out our blog: Do Car Keys Have GPS? What You Need to Know About Key Tracking.

In summary, here are a few key takeaways to keep your keys and vehicle safer:

Store your fob in a signal-blocking pouch or metal container

Keep keys away from entry points like doors or windows

Disable keyless signals if your fob supports it

Update your car’s firmware regularly

Use visible anti-theft devices as a deterrent

Looking Ahead: Smarter Cars, Smarter Drivers

Relay attacks are part of a larger trend — one where modern technology makes life more convenient, but also creates new risks. Just like we’ve learned to secure our phones and passwords, we now need to think about how we secure our vehicles.

As carmakers explore more secure solutions — like Ultra Wideband (UWB) tech and biometric verification — drivers still need to take responsibility for their vehicle’s safety. The tools are already out there, and many of them cost less than a meal out. It’s not just about avoiding theft; it’s about peace of mind.

So next time you get home, before tossing your keys on the hallway table, take a second to think: are they really safe there?

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How to use replacement key delivery services Replacement key delivery refers to services that cut and program a new car key and deliver it (or have it fitted) to your location—whether your holiday base, airport car park or home driveway. Steps to follow: Have vehicle details ready: make, model, year, registration number, VIN if available. Choose service: For UK and travel users, many auto-locksmiths offer mobile services that come to you. Confirm delivery logistics: Where is the vehicle parked? Will you be present when the key is delivered or fitted? If abroad, is the company able to support your location? Understand key type: Basic mechanical, transponder chip key, keyless fob—all vary in price and logistics. Check old key de-activation: A top provider will delete the lost key’s code so it cannot be used in future—critical for security. 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Short answer: Yes. You can order a replacement car key online in the UK and have it delivered in 3–4 days. Choose the right key type, provide a photo or key code for cutting, and have a local locksmith program it when it arrives. Why trust this guide: With over 25 years in the locksmith trade and more than 650,000 satisfied customers, Mr-Key explains exactly how online key replacement works — clearly, securely, and step by step. When online replacement works (and when it doesn’t) Ordering online is ideal if you need a spare, a like-for-like remote, or a replacement for a lost or damaged key. It’s the fastest and most convenient way to get OEM-grade parts delivered to your door. You simply order the correct key, have it cut from a photo or key code, then let a local locksmith program it to your vehicle. Online ordering doesn’t replace immobiliser pairing. Modern vehicles still require professional programming once the key arrives. Key types explained Transponder keys These have a mechanical blade and an electronic chip that communicates with your car’s immobiliser. Remote fobs Include lock/unlock buttons plus a built-in transponder. We supply the pre-cut blade (if requested) and tested electronics. Proximity or smart keys Keyless entry and push-start units. Delivered ready for your locksmith to pair with the car. Key shells & batteries Replace worn housings or dead batteries without any programming. Also available: caravan keys, ATV keys , roof-rack keys , mailbox keys, towbar keys , and more. Browse our full range at mr-key.com . How online ordering works 1. Identify your key Use your vehicle make, model, and year. Match your key shape, button layout, and frequency markings. 2. Choose how to cut it By photo: send a clear image of your existing key. By key code: provide the manufacturer’s key code for factory-accurate cutting. 3. We cut and test Keys are machine-cut and tested for precision. Electronics are checked before dispatch. 4. Delivery in 3–4 days Typical UK delivery with tracking and updates. 5. Local programming Arrange a nearby automotive locksmith to pair the key. Most jobs take 15–30 minutes. What affects cost Key type — proximity and smart keys cost more than basic transponders. Electronics and frequency — differ by brand and year. Cutting method — photo or code; standard or laser blade. Programming complexity — varies by model. Extras — spare shells, emergency blades, or upgraded housings. Pro tip: Order two keys now — you’ll save money on future locksmith visits and prevent lockouts. Programming: DIY vs local locksmith Modern immobilisers are secure by design. Mr-Key does not supply pairing or programming kits. A professional locksmith uses diagnostic tools to safely program your new key and verify vehicle ownership. It’s faster, safer, and ensures full functionality. Shipping, warranty & returns Delivery: 3–4 days across the UK. Warranty: 12-month full coverage on keys and electronics. Returns: Contact support before programming — unused items are easier to exchange. Dealer vs local locksmith vs online Option Speed Convenience Programming Best for Main dealer Medium–slow Appointment required Dealer tools Brand-new cars, under warranty Local locksmith Fast Mobile visit Done on site Emergencies, quick help Online (Mr-Key) 3–4 days Order from home Done by locksmith Planned replacements, spares Most UK drivers choose online ordering + local locksmith pairing — the fastest, most cost-efficient combination. Troubleshooting after delivery Key turns but car won’t start Blade fits, but immobiliser isn’t paired yet. Book a locksmith. Remote buttons not working Replace the battery and re-pair during programming. Proximity key not detected Use the emergency start position (usually near the steering column) and ask your locksmith to register it. Blade feels rough Use light graphite lubricant or send a photo for recheck. How to avoid another lockout Order a second key and keep it at home. Replace weak remote batteries yearly. Label your spare with the vehicle reg. For keyless cars, store keys away from doors and use a signal-blocking pouch. FAQ Can I order a replacement car key online and get it delivered? Yes. Send your key photo or code, receive delivery in 3–4 days, and have it programmed locally. Do I need proof of ownership? Your locksmith may ask for it. For UK vehicle documentation, see GOV.UK – V5C log book . What’s the difference between key types? Transponder keys start the car; remote fobs add buttons; proximity keys enable keyless entry/start. Can you cut my key from a photo? Yes. Clear, well-lit images allow accurate decoding and cutting. Can I program the key myself? No. Only an automotive locksmith can safely pair it. How long does delivery take? Usually 3–4 days within the UK. Do you cover my vehicle? Almost all brands plus caravans, ATVs, lockers, and more. What warranty do I get? 12-month full warranty on all keys and electronics. What if the battery is dead? Replace it with the correct cell. If issues continue, have the locksmith check frequency and pairing. What if I’ve lost all keys? Order online and arrange programming. Mobile locksmiths can often attend on site. Can I order two keys? Yes — it’s the smartest option to prevent future emergencies. Shop now: https://mr-key.com

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