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- Vehicle remote key security 1 answer
I am wondering how car key security works.
Do cars keys just send a simple "lock" and "unlock" signal that works with any car from the manufacturer or any car of the same model? Or are specific keys registered to a car and then only those keys have the signal that unlocks that car?
I also have an idea for how the security should work. (Forgive me I know very little how encryption and radio signals and security works). Please tell me what you think.
Keys and cars are each given their own encryption key upon manufacture. Upon purchase of a car, the keys and cars are registered to each other.The car gets a copy of the encryption keys from the car keys and the car keys each get a copy of the car's encryption key. Then the unlocking process. Car key requests unlock from the car. Car verifies it is a registered key then asks for the special number it sent earlier (encrypted) to the key. Key sends special number back (encrypted using the key's encryption) and the car decrypts it using its copy of the car key's encryption key and verifies the numbers are the same. Then the car is unlocked.
Then the car encrypts a new special number and sends it to the key, which the key decrypts using its copy of the car's encryption key then encrypts using its own encryption keys. This new number will be used on the next unlock request. This ensures the unlock signal changes every time so that people cannot simply copy the unlock signal from the air and unlock the car.
If I was not clear on anything please specify in comments, I can provide more detail.
Remember that I have no background in computer security. I was just thinking about this after hearing about a major series of car thefts somewhere.