Car theft is a worry. It doesn’t matter whether you have £100,000-worth of Porsche on your drive or a £1,000 Renault Clio, if someone steals your car you’re going to be frustrated, upset and inconvenienced – both financially and in terms of time.
And while the days of thieves hot-wiring your car and driving off into the night are largely behind us thanks to modern immobilisers, more sophisticated forms of car theft still pose a threat.
Chief among these is the remote theft of cars with keyless entry and ignition systems – often known as skimming. This is when criminals use relay signals that replicate those that come from your car’s key fob to unlock and start a car – and thereby steal it.
These are known as Radio Frequency Identification (RFID) signals and, fortunately for us as car owners and not car thieves, there is a simple, relatively low-tech and fairly cost-effective way to prevent this sort of car theft (sometimes known as a signal extended relay attack or SERA). It’s called a Faraday pouch, and might also be referred to as an RFID signal blocker.
Faraday Bags for Car Keys
- What is a Faraday Pouch?
- How are Faraday Bags Constructed?
- Which Cars Need to be Protected from SERA Attacks?
- Is My Car Safe if it Doesn’t Have Keyless Ignition?
- What Else Can You Use a Faraday Pouch For?
- So What About a Biscuit Tin?
- Other Car Security Precautions
What is a Faraday Pouch?
A Faraday pouch or Faraday bag is a type of Faraday cage. The Faraday cage (also sometimes known as a Faraday shield or Faraday box) is an enclosure of conductive material. It works because it diverts the effects of an electromagnetic field around the cage’s conductive material, thus cancelling the field’s effect within the interior of the cage.
Named after scientist Michael Faraday, who invented them in the 1830s, Faraday cages are used to protect sensitive electronic equipment from external radio frequency and electromagnetic interference – a bit like airplane mode on your iPhone, only more so.
As a result, using the same principle in a smaller application can help prevent interference with – effectively the hacking of – your car’s keyless entry system.
How are Faraday Bags Constructed?
Faraday pouches tend to be a composite of some sort of fabric material (cotton, leather or similar) combined with a conductive mesh – often copper or aluminium – which provides the conductive signal-blocking layer. To be effective, a Faraday pouch also needs to insulate the car key fob inside from contact with the conductive material.
Some of these products are more sophisticated than others, but there’s no need to go for military-grade quality; a decent, high-quality Faraday pouch can be bought inexpensively from online retailers such as Amazon.
Which Cars Need to be Protected from SERA Attacks?
Any car with a remote key fob is susceptible to a SERA attack. However, if your car is locked and unlocked with a button, but you need to insert a key into the ignition to start it, thieves can ‘only’ easily break into your car; they won’t be able to start it and drive away – at least not via SERA attack. However, if your car has a start button, then the thieves may well be able to simply start the car and drive off if they can get a relay signal from the key in your home to your car.
Is My Car Safe if it Doesn’t Have Keyless Ignition?
In a word: no. If a thief can get into your car using a signal relay attack, they can then drive the car away if they have the correct equipment: it does have to be a keyless entry car, but not having keyless ignition won’t necessarily stop well-equipped criminals. If they can connect to your car’s OBDII port (which garages use to diagnose faults with your car), and if they have the right hardware, they can access your car’s ECU and use it to reprogramme a blank key and steal your car within a few minutes. And an immobiliser won’t stop them.
What Else Can You Use a Faraday Pouch For?
A Faraday pouch stops car key skimming theft because it stops RFID. This is also how contactless debit and credit cards work, so a Faraday pouch can be used to prevent scammers from identity theft by protecting your payment cards.
A Faraday pouch also blocks WiFi, GPS and Bluetooth signals, so it’s useful for protecting mobile phones, tablets, smart watches and handheld GPS devices from unwanted interference – essentially any electronic devices. It can also be used to protect these devices from an attack by an electromagnetic pulse (EMP) or more general electromagnetic interference (EMI).
So What About a Biscuit Tin?
It’s said that putting your car keys in a biscuit tin can act as an improvised Faraday box. But does this actually work? In theory, anything that creates a sufficiently effective Faraday cage can block Wifi RFID, Bluetooth, mobile phone signals and other radio signals – and therefore protect your car from theft by relay signal. However, simply dropping your keys into a biscuit tin may not provide you much in the way of protection when it comes to blocking your car key signal. It might also crush your biscuits.
To make a homemade Faraday cage/box more effective, you need a container made of some sort of alloy (rather than tin). Galvanised steel is quite effective, but the metal container itself also needs to shut tightly. Another important point is that the key should either be wrapped with a non-conductive material such as bubblewrap or rubber, or the box should be lined in a similar way. Otherwise, the key can make contact with the metal of the box, effectively creating an antenna.
Other Car Security Precautions
Of course, if you’ve not got a car with keyless entry or keyless start, then your car could still be at risk from thieves. However, there are several sensible anti-theft precautions you can take:
Keep your Car Keys Away from Doors and Windows
Thieves have been known to use long, thin metal poles poked through letterboxes to literally fish car keyrings from hooks near doors or shelves and tables in your hallway. Keeping your car keys in secure drawers or cupboards well away from your front door will help mitigate this risk. You can also fit particular types of letterboxes with interior covers that prevent this sort of ‘fishing’.
Keep Your Car in a Garage
Obviously, this is only really practical if you happen to have a garage – and it’s big enough/empty enough to fit your car in. Plus, even if you do have one, you should still practice good car key security… and garage key security for that matter.
Invest in Security Cameras
This won’t necessarily prevent criminals from going after your pride and joy, but smarter thieves will be put off even by the presence of cameras, much as households with dogs tend to be less likely to be the victims of burglary. Systems can range from expensive CCTV security camera set-ups to internet-connected doorbell cameras. And if the worst does happen, then you at least have a better chance of catching the thieves.
Fit Your Car with a Tracker
This certainly won’t prevent your car from getting stolen, but it will vastly increase your chances of getting it back.
Try Old-School Physical Security Devices
A metal gearshift lock or steering wheel lock seems like a brutal approach to vehicle security, but it can’t be worked around without using noisy, time-consuming and expensive cutting tools. In fact, just having a steering lock or similar fitted could be enough to put thieves off and send them searching after easier victims.
Related Topics:
- Preventing Car Theft: How to Reduce the Risk of Your Car Being Stolen
- The Most Popular New and Used Cars in the UK
- How Much Does it Cost to Charge an Electric Car?
