Gone are the days of opening your car door by inserting a key in a lock. Now you can pop open your trunk, open a door, or even start the car with a key fob. Keyless ignition systems come with fobs that transmit a unique low-frequency signal to a car’s computer system. The system then validates the signal and allows you to push a button on the dashboard or console to unlock doors and start the engine. Unfortunately, key fobs are convenient for both car owners and car thieves. Car thieves can compromise the security of your parking business and put your customers’ vehicles at risk.
Relay Attacks on the Rise
According to FBI reports, car theft is on the rise. Any car with an automatic-open key fob is susceptible, even if it isn’t push-to-start. Hackers can use cheap relay boxes to copy and transmit the signal from a key fob while it’s still inside a valet stand, your garage or in an employee or customer’s pocket. This is called a relay attack or RFID skimming. RFID is short for radio-frequency identification. It’s easy for thieves as long as they have a partner. 
Here’s how it works. Each person carries a relay box, which can be purchased for as little as $20 online. The boxes can pick up the radio frequency from a car key fob that’s inside on a reception or security desk, dangling from a key rack, or in a purse or pocket. The relay boxes allow one person to stand nearby to pick up and amplify the key fob signal and transmit it to the second box, which the other person holds outside the door of a car. Once the key fob signal reaches the second box, it unlocks the door. Now the criminals just have to drive away without getting caught and later change the locks.
When to Worry
Some manufacturers like Ford are providing RFID protection by fitting key fobs with motion sensors that put them into “sleep mode” if they haven’t moved in several seconds. According to Richard Billyeald, Chief Technology Officer for U.K.-based car safety and security organization Thatcham Research, “it doesn’t fundamentally change how the keyless system works, but it’s a pretty good countermeasure”. He noted that other manufacturers have begun to implement a new type of technology called ultra wide band, which can be used to achieve the same functionality. “That system allows the position of the key to be identified much more accurately, and therefore, isn’t susceptible to the attack in the same way.” Tesla even requires a PIN to start the ignition on some models. Though it doesn’t prevent thieves from gaining entry to a car and stealing items, it at least stops them from driving off in it. Of course, none of these measures will protect a vehicle if it has an always-on key fob. As long as the key’s in range, anyone can open the car and the system will think it’s the owner. That’s why newer car models won’t unlock until the key fob is within a foot.
The RFID Key Fob Pouch
Some experts have suggested surrounding car keys with metal to block the signal. For example, wrapping them in tinfoil. Others have even recommended storing keys in a refrigerator or microwave. Of course, these options don’t make sense for a valet or parking business, especially when there’s a much better solution—an RFID-blocking bag or pouch. 
Also known as a Faraday bag, this enclosure blocks all electromagnetic fields. Similar technology is used to protect cell phones and credit cards from skimming.