Keyless Entry? What IS that?

Posted on October 26, 2010 by Jaece Hogue

You just bought a new car and have one those keyless entry remotes on your keychain. Since your purchase, you have probably been asking yourself a couple of questions:

  • What will this thing do if I push the buttons?
  • How does it unlock a door from 20 feet away?
  • Is it secure?
  • Can I open just my car with this or will it open other cars?

The two most common remote keyless-entry devices are:

  • A fob that goes on your key ring (this works to lock/unlock your doors and can also unlock your truck and turn your alarm off/on).
  • A small controller that hangs from the sun visor of your car to open/close the garage door.

The key fob or controller is a small radio transmitter. When you push one of those buttons, it turns on the transmitter to emit a code to the receiver. It works similarly to a radio-controlled car.

These transmitters have come a long way and A-1 Locksmith has been in business long enough to see these changes evolve. In the 1950s, the transmitters were extremely simple. A signal was sent out and the garage door either opened or closed; however, as this idea became more popular, this simplicity caused many problems—absolutely anyone could drive down the road with ANY transmitter and open ANY garage door. By the 1970s, a controller chip and DIP switch was being used. A DIP switch had eight small switches that would provide 256 possible combinations that at least made it so several neighbors weren’t opening each other’s garage doors but did not provide REAL security. Now, in the 21st century, security is a HUGE issue.

How do you think some stranger would react if you opened their car with your key fob in a crowded parking lot?

We have so much to think about today especially with the use of radio scanners. These scanners can get the codes that a transmitter sends and once a scammer has your code, it is a simple matter to re-transmit the code to open YOUR car. Scary thought, isn’t it? This PDF describes a 40-bit rolling code system and explains how it provides security; 40-bits provide about 1 trillion possible codes. Wow, that is quite a few.

Ok, so what does all this mean? Can anyone open my car?

Taking into account the given 40-bit code, four transmitters and up to 256 possibilities of number combinations, there is a one-in-a-billion chance of your personal transmitter opening another’s car doors. Thinking that different manufacturers use different systems and that the newest system maybe contain more bits (technology is growing daily), it’s clearly obvious that it’s next to impossible for any given key fob to open any other car’s door. And, of course, someone who REALLY wanted to do get that code could scan through all the possibilities but, that would take YEARS to do that.

For all of your keyless entry needs, call A-1 Locksmith at (972) 284-7500 for the call center or for Emergency service, call (972) 284-7516. A-1 Locksmith offers competitive pricing and years of experience.

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