3 ms·

The latency check is usually not sensitive enough to prevent a car being stolen from the drive-way from a relayed key that lies near the front door. For refere

by rocqua 3y ago

The latency check is usually not sensitive enough to prevent a car being stolen from the drive-way from a relayed key that lies near the front door. For reference 20 meters is about 66 nano-seconds.

gruez 3y ago
Why not? A 2GHz is very attainable in modern CPUs and translates to 0.0005ns per cycle. This isn't theoretical either. 802.11mc[1] is a real standard and is accurate to 1-2m. [1] https://en.wikipedia.org/wiki/IEEE_802.11mc https://en.wikipedia.org/wiki/IEEE_802.11mc
- hanche 3y ago
  Aren’t you off by three orders of magnitude? 2GHz translates to 0.5ns per cycle. Or perhaps you meant to write ms.
  - gruez 3y ago
    Whoops, you're right!
gsich 3y ago
So, solvable?
sebk 3y ago
UWB is augmenting Bluetooth for car keys solving this exact issue; The Car Connectivity Consortium came up with the Digital Key 3.0 standard that's available today, as implemented by some makes like BMW and the Hyundai/Kia group and Apple, and resists relay and replay attacks through precise ranging.