Security & ScamsWireless Security

The Relay Theft

Thieves can stretch your car key's signal from inside your house

Your car key sits on a hook inside the house, yet two people outside drive off with your car. How is that even possible?

You'll find out

  • How a keyless car checks for its key
  • How two boxes stretch the signal
  • What actually stops the trick

Why it matters

Many cars open with no button press, and knowing how the trick works shows why a simple pouch beats strong encryption.

About 3 min6 interactive slides · 5 questionsLesson 235 · Zone 27

Play this lesson

Free to play in your browser or on iPhone

More in this zone

  1. 236Distributed SystemsThe Byzantine GeneralsHow do you agree on a plan when some messengers lie?
  2. 237RelativityTime Runs Faster UpstairsAtomic clocks tick faster just 33 centimeters higher
  3. 238Phase TransitionsWater That Freezes on CommandA quiet liquid can stay below freezing until something disturbs it
  4. 239Threat AnalysisThe 99% Test That's Usually WrongWith a rare condition, most positive results can be false alarms
  5. 240ConcurrencyDeadlockTwo programs can wait for each other forever
  6. 241Wireless CommunicationWhy Wi-Fi Slows Down in a CrowdOnly one device can speak on a channel at a time
  7. 242Computational PhotographyPanorama GlitchesMoving people turn into monsters in panoramic photos
  8. 243AlgorithmsBill Gates' Pancake ProblemHis only research paper was about flipping pancakes