Keyless Car Technology Explained: How It Works and Security Risks

Summary

• Keyless entry uses radio signals: Your car detects the fob's signal and unlocks automatically when you approach.
• Relay attacks are a real threat: Thieves can amplify your key fob's signal to steal your car in under 60 seconds.
• Simple precautions work: Faraday pouches, steering locks, and tracker systems dramatically reduce theft risk.

Keyless entry and start has become standard on most new cars. It's wonderfully convenient — walk up to your car and it unlocks. Press a button and the engine starts. No fumbling with keys.

But this convenience comes with a significant security risk. Here's what you need to know.

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How Keyless Technology Works

A keyless system uses short-range radio signals between your key fob and the car. When the fob is within range (usually 1-2 metres), the car detects its signal and allows you to:

• Unlock the doors: Touch the door handle and it unlocks
• Start the engine: Press a button on the dashboard
• Lock the doors: Press a button on the door handle as you walk away

The key fob transmits a unique encrypted code. The car's receiver verifies this code before granting access. Each time you lock or unlock, a new code is generated.

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What Is a Relay Attack?

A relay attack is the most common method thieves use to steal keyless cars. It works like this:

1. Two thieves work together with relay devices (which cost as little as £20 online)
2. One stands near your front door where your key fob is likely kept
3. Their device picks up the key fob's signal and transmits it to the second device
4. The second thief stands next to your car with the relay device
5. Your car thinks the key fob is nearby and unlocks
6. They start the engine and drive away

The whole process takes under 60 seconds. Thefts often happen at night when the key fob is sitting on a hall table near the front door.

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Which Cars Are Most at Risk?

Any car with keyless entry is potentially vulnerable. However, some models are targeted more frequently:

• Range Rover: Consistently the most stolen car in the UK
• BMW: Particularly the 3 Series, 5 Series, and X5
• Mercedes: C-Class and E-Class are popular targets
• Ford Fiesta and Focus: High-volume models with valuable parts
• Volkswagen Golf: Popular with thieves for parts

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How to Protect Your Keyless Car

• Use a Faraday pouch: Store your key fob in a signal-blocking pouch. These cost £5-£15 and block the radio signal completely
• Keep keys away from doors and windows: Don't leave them on the hall table. Store them in a drawer or another room
• Use a steering wheel lock: A visible deterrent that makes the car harder to drive away
• Fit a tracking device: If the car is stolen, a tracker helps police recover it quickly
• Check if your key has a motion sensor: Some newer fobs go to sleep when not moving, blocking relay attacks
• Turn off keyless entry: Some cars let you disable keyless mode in the settings
• Use a driveway post or gate: Physical barriers slow thieves down

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What Are Manufacturers Doing?

Car makers are fighting back against relay theft:

• Ultra-wideband (UWB) technology: Newer systems measure the exact distance between fob and car, making relay attacks much harder
• Motion-sensing key fobs: Fobs that go to sleep after being stationary for a few minutes
• PIN-to-drive: Some cars require a PIN code on the touchscreen before starting
• Smartphone digital keys: Using your phone as a key with extra security layers

If you're buying a new car, ask the dealer about their keyless security features. Models from 2022 onwards generally have much better protection.

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