Keyless Entry System

Currently, car manufacturers use keyless entry systems to lock and unlock car doors. What is the encryption system used by industries to remotely unlock cars and to highly secure them from thieves?

Rolling Codes or Hopping Codes

Rolling Code is a special type of coding technique used widely by current vehicles wherein the transmitter and the receiver both create a new code and the old code will not work anymore. The key fob serves as the transmitter and the receiver is installed inside the vehicle. Whenever you press the button to unlock your car, the exact frequency transmitted by the fob is changed, and the receiver inside the car only grabs onto that particular signal. In other words, the code "rolls" or "hops" each time you use it. A controller chip inside the car receives the signal and is responsible for changing the code each time the lock or unlock button is pushed.

Sample Key Fob

Rolling code was invented to prevent thieves from grabbing code on key fob that sent out just a single signal. This system halts unauthorized person that captures the transmitted code and re-sends to unlock the door. This is because the door lock is now expecting a new code based on an algorithm that both the transmitter and receiver have in common.

In addition, the code is stored inside the car, not within the key fob. A thief would need to break into the car to access the code, which defeats the purpose of getting it in the first place.

The numbers generated when the code hops is random. However, in theory, an astute hacker dead-set on stealing your car could find a way to anticipate the next code in the sequence. For this reason, the codes are encrypted as well, making each electronic key fob have billions of possible codes.


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