4 ms·

That's diabolically clever. I'm curious how any technology can overcome that, and why BT is apparently more susceptible?

by tux1968 5y ago

xaduha 5y ago
> I'm curious how any technology can overcome that Faraday cage/foil wallets for things that don't require any auth or PINs or even a button press.
- tux1968 5y ago
  Okay, but that would work for a BT device too. I was mostly curious why BT was seen as a bad choice and more vulnerable than another option.
  - xaduha 5y ago
    This whole comment tree kinda got derailed into bikeshedding about BT with confusion between replay and repeater attacks to boot. It probably isn't any more susceptible than similar RF alternatives. Personally I wouldn't want a BT key because I used smart rings, namely a contactless payment ring and an OMNI ring. They aren't without issues, but they are miles ahead of a device like Chameleon Tiny Pro (which I also used) when it comes to usability. There might be smaller BLE devices out there, but it is pretty small. About the same as Google Titan BLE based on the images.
istjohn 5y ago
You just need a technology that only works across spaces no larger than a couple feet.
- PeterisP 5y ago
  There really aren't common technologies that *only* work across spaces no larger than a couple feet; the technologies that normally are limited to very close range can actually be used at larger distances with proper (large, directional) antennas and more powerful radio hardware.
  - hoseja 5y ago
    NFC stands for Near-field communication.
    - randomswede 5y ago
      Yes, but you have to distinguish what it is supposed to do, and what it can actually do. With directional antennas, practical NFC relays have been done, <a href="https://hal.inria.fr/hal-01632735/document">this https://hal.inria.fr/hal-01632735/document">this paper</a> cites distances of up to 100 metres.
    - PeterisP 5y ago
      Yes, it's designed for close-range communication, IIRC with proper hardware you can listen into NFC communications from as much 10m / 30feet; and with a relay attack, you can "extend the range" arbitrarily.
ema 5y ago
If you can make the response fast enough that the speed of light delay dominates you can measure the latency and have an upper bound on how far away the key can be.

That's diabolically clever. I'm curious how any technology can overcome that, and why BT is apparently more susceptible?

xaduha 5y ago

> I'm curious how any technology can overcome that Faraday cage/foil wallets for things that don't require any auth or PINs or even a button press.

tux1968 5y ago
Okay, but that would work for a BT device too. I was mostly curious why BT was seen as a bad choice and more vulnerable than another option.
- xaduha 5y ago
  This whole comment tree kinda got derailed into bikeshedding about BT with confusion between replay and repeater attacks to boot. It probably isn't any more susceptible than similar RF alternatives. Personally I wouldn't want a BT key because I used smart rings, namely a contactless payment ring and an OMNI ring. They aren't without issues, but they are miles ahead of a device like Chameleon Tiny Pro (which I also used) when it comes to usability. There might be smaller BLE devices out there, but it is pretty small. About the same as Google Titan BLE based on the images.

istjohn 5y ago

You just need a technology that only works across spaces no larger than a couple feet.

PeterisP 5y ago
There really aren't common technologies that *only* work across spaces no larger than a couple feet; the technologies that normally are limited to very close range can actually be used at larger distances with proper (large, directional) antennas and more powerful radio hardware.
- hoseja 5y ago
  NFC stands for Near-field communication.
  - randomswede 5y ago
    Yes, but you have to distinguish what it is supposed to do, and what it can actually do. With directional antennas, practical NFC relays have been done, <a href="https://hal.inria.fr/hal-01632735/document">this https://hal.inria.fr/hal-01632735/document">this paper</a> cites distances of up to 100 metres.
  - PeterisP 5y ago
    Yes, it's designed for close-range communication, IIRC with proper hardware you can listen into NFC communications from as much 10m / 30feet; and with a relay attack, you can "extend the range" arbitrarily.

ema 5y ago

If you can make the response fast enough that the speed of light delay dominates you can measure the latency and have an upper bound on how far away the key can be.