I understand that the ability to unlock or lock a car is based on the frequency of the transmission from the key, but hypothetically wouldn’t some of these eventually overlap and lead to someone being able to unlock someone else’s car?
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Car keys use rolling codes to unlock the car. It’s similar to a lot of garage door openers too. The car has a set of future codes so if it misses one or two it can “authenticate” the next one. Each time you hit your unlock button the codes roll.
At least that’s my understanding.
Car keys use rolling codes to unlock the car. It’s similar to a lot of garage door openers too. The car has a set of future codes so if it misses one or two it can “authenticate” the next one. Each time you hit your unlock button the codes roll.
At least that’s my understanding.
This does sometimes happen. As the other commenter says, newer cars and remotes have some technology that makes this less likely. But it’s still possible in very rare cases, and more common in older cars.
The “protection” against it is – what is the chance that the other car that matches your remote’s frequency/code happens to be nearby? In practice, even with older cars that did not have as sophisticated security, it wasn’t very common for somebody to run into a car that could be opened with the same remote. At a dealership with a bunch of cars of the same model, maybe. In a random parking lot, unlikely
This does sometimes happen. As the other commenter says, newer cars and remotes have some technology that makes this less likely. But it’s still possible in very rare cases, and more common in older cars.
The “protection” against it is – what is the chance that the other car that matches your remote’s frequency/code happens to be nearby? In practice, even with older cars that did not have as sophisticated security, it wasn’t very common for somebody to run into a car that could be opened with the same remote. At a dealership with a bunch of cars of the same model, maybe. In a random parking lot, unlikely
>I understand that the ability to unlock or lock a car is based on the frequency of the transmission from the key
That’s not what it’s based on. The key stores a specific number that is unique to that key, no other key has the exact same number stored in it and that number never leaves the key.
There are some very clever cryptographic algorithms(broadly called [public key cryptography](https://en.wikipedia.org/wiki/Public-key_cryptography)) that make it possible for the car to check that’s it’s communicating to a key that has the correct number stored in it, without revealing that secret number to anyone.
Because there are no other keys storing identical number, it’s not possible for the car to be unlocked by a wrong key.
>I understand that the ability to unlock or lock a car is based on the frequency of the transmission from the key
That’s not what it’s based on. The key stores a specific number that is unique to that key, no other key has the exact same number stored in it and that number never leaves the key.
There are some very clever cryptographic algorithms(broadly called [public key cryptography](https://en.wikipedia.org/wiki/Public-key_cryptography)) that make it possible for the car to check that’s it’s communicating to a key that has the correct number stored in it, without revealing that secret number to anyone.
Because there are no other keys storing identical number, it’s not possible for the car to be unlocked by a wrong key.
Modern keys have a specific handshake code between the car and they key that is set with each locking. So not only does it need to send the correct frequency, but it needs to send the correct code, too.
Authentication is not just based on the fundamental frequency of the transmission from the key.
You can continually vary the phase (shift the waveform around, basically) of the transmission frequency to transmit digital data wirelessly. At that point, your key can talk to your car, in much the same way that your phone can talk to wireless earbuds, or how your computer can talk (wired or wirelessly) to the internet.
Once you’ve got a digital communication line up and running, you can then set up pretty much any sort of digital password mechanism that you like.
Authentication is not just based on the fundamental frequency of the transmission from the key.
You can continually vary the phase (shift the waveform around, basically) of the transmission frequency to transmit digital data wirelessly. At that point, your key can talk to your car, in much the same way that your phone can talk to wireless earbuds, or how your computer can talk (wired or wirelessly) to the internet.
Once you’ve got a digital communication line up and running, you can then set up pretty much any sort of digital password mechanism that you like.
Modern keys have a specific handshake code between the car and they key that is set with each locking. So not only does it need to send the correct frequency, but it needs to send the correct code, too.
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