The Science Behind Keyless Entry - HighWay HiFi

The Science Behind Keyless Entry


It seems like everything today can be done with the press of a button, so why should unlocking your car be any different? If you’re still putting a key into the door of your vehicle, it’s time to make the switch to keyless entry. But how does this process work? Here we’ll break down the science behind keyless entry.

The fob that you carry on your keychain is actually a small radio transmitter. Pushing one of the buttons turns on the transmitter and sends a code to the receiver in your car. In modern security systems, there is a small chip that creates something called the “hopping” or “rolling” code to provide security so that anyone with a radio scanner in a mall parking lot isn’t able to unlock your vehicle. Here’s how it works:

  • When you press a button on your keychain, the transmitter’s controller chip sends a 40-bit code and a function code that tells your car to unlock the doors, pop the trunk, or set off the alarm.
  • The receiver’s controller chip knows the 40-bit code that it should be receiving, so when it gets the code it expects it’s able to perform the right function.
  • Both the transmitter and receiver use the same pseudo-random number generator. As they send and receive codes, the number generator picks a new code to save in memory. This way the sender and receiver are always synced-up with rolling codes and the receiver knows the right code to expect each time.

With rolling codes, multiple transmitters, and a random number generator to avoid desynchronization, there’s about a one-in-a-billion chance that a stranger’s transmitter could open your car doors. That doesn’t even take into account different security systems from different manufacturers or advances in security technology. Capturing the code in a rolling transmitter is useless since there is no way to predict which random number the transmitter and receiver has chosen as the next code, making it virtually impossible to hack a keyless entry system.
It may be a bit confusing, but all you need to do is press a button, hop in the driver’s seat, and know that your car is safe and secure. Here at Highway Hifi, we offer mobile security systems to keep your car safe, up-to-date, and easy to use. Stop by today to upgrade your vehicle to keyless entry.

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