Anti-Theft Car Key Case: How to Protect Your Car from Relay Attacks in Lithuania

Why this matters more today than ever

Over the past two years, car thefts have come back to Lithuania. Not as isolated cases – systematically. Official data from the Information Technology and Communications Department (IRD) show that 284 vehicle thefts were registered in 2023, 397 (+39.8%) in 2024 and 457 (+15.1%) in 2025. Police statistics for the first half of 2025 are even more alarming: around 210 passenger car thefts were recorded in six months, which is 40% more than in the same period a year earlier.

It is not only the numbers that have changed. The thieves have changed too. According to insurer Lietuvos draudimas, the average value of a stolen car was €11,300 in 2022 and €19,600 in 2024, and in 2025 it passed the €20,200 mark. Cars are stolen quietly, without smashed windows, most often at night in apartment-block courtyards. This is not a classic break-in. It is a relay attack, also known as signal amplification.

In this article we explain in plain language how it works, why almost every modern keyless car is vulnerable, and how a key case with a Faraday cage – costing about as much as dinner for two – may be the only thing standing between your BMW, Toyota or Audi and its disappearance in 30 seconds.

A quick tip up front: if you are in a hurry, our customers' most popular choice is the Tech-Protect KLR400 key case with Faraday cage (black). It is designed for larger modern smart key fobs and blocks not only RFID but also NFC, Bluetooth, Wi-Fi and GPS signals.

Which cars are stolen most in Lithuania today

According to data from Lietuvos draudimas and Swedbank P&C Insurance, around half of all insured car thefts in 2025 were Toyota RAV4 models. Also near the top of the list are the Audi A6, Lexus RX, Toyota Land Cruiser, BMW and newer-generation Toyota Corolla and VW Passat. BTA representative Andrius Žiukelis confirmed to the media: “More and more customers are contacting us about thefts of newer and more luxurious cars – newer Toyota and Lexus cars are being stolen.”

Geographically, this is no longer just a problem for Vilnius, Kaunas and Klaipėda. In the border districts (Šiauliai, Mažeikiai), Toyota and Lexus thefts doubled in 2024–2025. Thefts are also spreading to residential suburbs – apartment-block courtyards, most often between 2 and 5 a.m.

The common denominator is the keyless entry and start system (Keyless Go / Keyless Entry). It was designed for convenience: when you walk up to the car, the doors unlock by themselves; once you are inside, pressing a button is enough to start the engine. That convenience has become the weakest link.

How a relay attack actually works (in plain terms)

A modern key fob constantly “listens” for its car nearby. Every few seconds the car sends out a weak low-frequency (125–135 kHz) “wake-up” signal with a real range of just 1–2 metres. When the fob “hears” this signal, it replies with an encrypted code at 433.92 MHz (in Europe), and the car unlocks.

Thieves use two small devices – signal relays, often called “range extenders” or “repeaters”:

1. The first thief goes up to your front door, windows or letterbox, close to where the key would normally be lying (in the hallway, on a hook, in the kitchen). Their device picks up the car's “wake-up” signal and passes it on over the air – to the courtyard, say.
2. The second thief stands next to your car. Their device replays this signal as if the key were right there at the door handle.
3. The fob (still lying in your home) responds. The response travels back to the car over the same “bridge”.
4. The car unlocks. The Start button is pressed. The engine starts. Within 20–30 seconds the car is gone.

A study by researchers at ETH Zurich (Francillon, Danev, Capkun, NDSS 2011) showed that the distance between the thieves can be up to 50 metres, even through walls, and newer experiments by TU Darmstadt and ADAC reached up to 100 m using directional antennas. Most importantly: the car does not stop if the fob “disappears” along the way. Only a brief warning appears on the dashboard. The thieves refuel with the engine running and calmly drive across the border.

The equipment costs thieves anything from €80–100 for a simple kit to thousands for professional gear. Asked whether this is a problem in Lithuania, representatives of the Lithuanian Motorists' Guarantee Association and experts from the State Police of neighbouring Latvia answer unanimously: yes. The Latvian police officially recommend special signal-blocking cases as the first line of defence.

Why almost all keyless cars are vulnerable

The German automobile club ADAC has been testing production cars for relay-attack resistance since 2016. As of early 2026, more than 800 models have been tested, and only about 15% managed to defend themselves. All the others – including most current Audi, BMW, Mercedes, Toyota, Lexus, Volkswagen, Hyundai, Kia, Ford and Mazda models – were borderline or failed to defend themselves at all.

The good news: some of the latest models are getting UWB (Ultra-Wideband) technology, which measures the exact distance to the key and cannot be fooled by a relay. UWB is already used in the latest Jaguar Land Rover models, the BMW iX and most of the VW Group (Audi A3, Q4 e-tron, VW Golf 8, the ID. series, Škoda Enyaq). Since 2018, BMW has also used motion sensors – if the fob is not moved for 2 minutes, it simply “goes to sleep”. However, most of the cars on Lithuanian roads – built in 2016–2023 – have no such protection.

The practical takeaway: if your Toyota RAV4, Lexus RX, Audi A6 or BMW X5 has a “Start/Stop” button and unlocks when you touch the door handle, you are very likely vulnerable. The question is not “could this happen to me?” but “are there two people with backpacks in my courtyard tonight?”

How a key case with a Faraday cage protects you

The solution is amazingly simple and old – a Faraday cage, described by Michael Faraday in 1836. It is an enclosed layer of conductive mesh (silver, copper or nickel microfibre) that stops radio waves from getting in or out. Once the key is inside such a case, the car's “wake-up” signal no longer reaches the fob, and the fob's reply does not get out. The thieves' devices hear only silence. No reply – no attack.

For a case to really work, it must:

• Cover the key completely – even a fraction of a millimetre gap lets the signal slip through.
• Have a reliable closure (Velcro or a magnetic clasp) – ADAC found that cheap magnetic flaps tend to come open.
• Block all the relevant frequencies: 125 kHz, 315 / 433 / 868 MHz, 2.4 GHz Bluetooth and, ideally, NFC and GPS.

Myths worth forgetting

“Aluminium foil is enough.” ADAC rejects this outright: foil “does not always provide reliable protection” – it tears, leaves gaps when folded, and wrapping by hand never gives an even covering. It is for emergencies, not for every day.

“The fridge or the microwave.” A microwave is theoretically a Faraday cage, but it is practically impossible to test (you can't take it to your car), and the fob's electronics suffer from moisture and cold. Are you really going to put your key in the fridge every day?

“A Faraday case lasts forever.” A 1,200-cycle flex test by the British magazine Auto Express showed that cheap foil linings crack after 6–18 months of use. A proper case with layered nano-fibre fabric (like the Tech-Protect range) keeps its original properties much longer.

“My car is old, I don't need one.” Even if your car has no factory keyless system, thieves can program their own fob through the OBD port in a few minutes. Safe key storage + a mechanical steering wheel lock + a GPS tracker work together.

A 30-second home test

ADAC officially recommends:

1. Put the key in the case and close it securely.
2. Go within 1 metre of the car.
3. Try to unlock it by touching the handle or pressing the fob button through the case.
4. If the car responds, the case does not work. If nothing happens, your key is safe.

Repeat the test at several doors and at the boot. The phone signal test (calling a phone placed in the case) is less reliable, because mobile frequencies differ from car key frequencies.

Tech-Protect KLR series buyer's guide: KLR100, KLR300 or KLR400?

Tech-Protect is a Polish brand and one of the most popular accessory makers in Central Europe. The Kama.lt range includes three lines of signal-blocking key cases – you'll find the full selection in our car key case collection. Which one is right for you?

Tech-Protect KLR400 – the premium Anti-Theft choice (our recommendation)

The Tech-Protect KLR400 key case (black) is the newest member of the series and a bestseller with our customers. It stands out in several important ways: multi-layer nano-fibre shielding that blocks not only RFID but also NFC, Bluetooth, Wi-Fi and GPS signals, a 360° swivel carabiner for attaching it to a bag or belt, and a larger interior (~12 × 9.6 cm) made for bulkier modern smart key fobs (BMW, Mercedes, Audi, newer Toyota / Lexus, the VW ID. series).

A premium feel, a clean black colour and a classic design – it suits a business suit as well as everyday wear. Alongside the key you can also keep a contactless bank card in it, which is then protected from skimming too.

👉 If you drive a newer (post-2018) BMW, Audi, Mercedes, Toyota RAV4, Lexus RX or any keyless car, the KLR400 is the easy choice.

Tech-Protect KLR100 – a classic for everyday use

The KLR100 series are flat wallet-style cases (133 × 90 mm) with a Velcro closure, a double RF shielding layer and a metal carabiner. Reliable, simple, budget-friendly. Three versions to suit your style:

• KLR100 Brown – classic brown with a “natural leather” look. Suits a business style.
• KLR100 Black & Red – a sporty two-tone accent for those who like a distinctive detail.
• KLR100 Black Carbon – a carbon-fibre texture pattern, masculine and modern.

The KLR100 is a great fit for small and medium-sized keys – e.g. fobs for older VW Passat, Toyota Corolla, Škoda Octavia and Ford Focus models.

Tech-Protect KLR300 Pink – a stylish compact

The KLR300 Pink is a hard box-shaped case with a zip and an internal chain to attach the key. At 100 × 68 × 35 mm it sits comfortably in a handbag, and its soft pink shade makes it a stylish gift or personal choice. It suits a second family key (the spare) or a smaller keyless key card.

Quick comparison table

When a case isn't enough: extra tips from the police and insurers

The Lithuanian police (policija.lrv.lt) and insurers say it in unison: one layer of protection is one obstacle. Several layers are several obstacles that push thieves towards an easier target. Alongside a key case, it is worth:

• Keeping your keys at least 3–5 metres from outside doors and windows – ideally in a room further inside. The hallway key hook is the worst place.
• Using a mechanical steering wheel lock – a visible deterrent and extra time for the thief.
• Considering an OBD port lock – so that no outside fob can be programmed through it.
• Fitting a hidden GPS tracker – according to insurers, cars with a tracker are recovered in over 80% of cases.
• Not leaving the registration certificate in the car – BTA representative Andrius Žiukelis calls this one of the most common mistakes.
• Parking in a well-lit spot, closer to your windows or a camera.
• Getting a case for your additional (spare) key too – it is often forgotten in a drawer, but a thief can reach it through an open window.

FAQ – frequently asked questions

Does a key case really work against a relay attack?

Yes, if the case is good quality and closed properly. Independent tests by ADAC, Thatcham Research and Auto Express confirm that a properly made Faraday cage blocks 125 kHz, 433 MHz and 2.4 GHz signals. Once the key is inside, the car can no longer “talk” to it – the attack becomes impossible.

How can I check whether my case really blocks the signal?

Put the key in the case, close it securely and go within 1 metre of the car. Try to unlock it by touching the handle or pressing the fob button through the case. If the car responds, the case does not work. If there is no reaction, the protection works. Repeat at several doors.

Does the Tech-Protect case fit all cars?

Yes. The Faraday principle is brand-neutral – it blocks radio waves whether you drive a Toyota, BMW, Audi, Mercedes, Lexus, VW, Volvo, Ford, Hyundai or Kia. The only difference is the size of the key: for larger modern smart key fobs choose the KLR400, for smaller ones the KLR100.

What is the difference between the KLR100, KLR300 and KLR400?

The KLR100 is a classic flat case (133 × 90 mm) with Velcro – a reliable choice for standard keys. The KLR300 is a compact hard box (100 × 68 × 35 mm) with a zip, often chosen for a handbag or as a gift. The KLR400 is the premium version with multi-layer nano-fibre shielding, NFC blocking, a 360° carabiner and a larger interior for modern fobs.

Do I need a case if my car is old and has no keyless system?

A direct relay attack is not a threat to you, but protection is still useful: thieves can program a new fob through the OBD port, and an RFID case protects contactless bank cards, ID documents and other RFID chips you may carry with you.

Is it safe to keep the key in the fridge or microwave?

Neither ADAC nor Lithuanian insurers recommend this popular “trick”. A fridge is not perfectly sealed, and moisture and cold damage the fob's electronics and battery. With a microwave, there is a risk of accidentally switching it on with the key inside. A professional case costs several times less than a damaged fob.

How long does the shielding last? Does the case lose its effectiveness?

A quality Tech-Protect case with layered nano-fibre fabric keeps its properties for many years. Cheap cases with a foil lining may start to weaken after 6–18 months of heavy use. We recommend doing the home test described above every 2–3 months.

One step that protects you today

Thieves don't wait until you're ready. A case from €15 or a lost car worth €20,000+ – it's a simple equation that insurers see every day. The Lithuanian police, Lietuvos draudimas, BTA and the Latvian State Police all point to a Faraday case as the first line of defence against relay attacks.

👉 Order the Tech-Protect KLR400 key case with Faraday cage today and sleep more soundly. If you prefer a classic, choose the KLR100 in brown, KLR100 in black and red or KLR100 in carbon fibre. For a stylish choice or a gift – the KLR300 in pink. You'll find all models and colours in our car key case collection.

Thieves look for the easiest way in. Make it hard for them.