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Comment by smhg | Hacker News Reader

Logitech's dongles (and possibly others) mimic a USB connection while still being wireless. They also allow you to access your BIOS.

Things being what they are, I don't think Bluetooth is the right setup for input devices.

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They are also a major proprietary hassle, whereas with Bluetooth and a Logitech K380 keyboard, which is cheap, readily available everywhere and reliable as heck I can switch between three machines at the press of a button.

I use that and an M720 Bluetooth mouse to switch between two work machines and a personal one on the same desktop, which is something you just can't do with the Logitech Logi Bolt dongle - even if you buy multiple ones.

Also, I've been using this setup with Macs for ages (that's one of the machines above), and never ran into the same problem.

Pros and cons? With the Logitech (and others) dongles you can also just plug them into a KVM and swap that way which isn't an option with Bluetooth, the device specifically has to support multiple devices.

But to use a KVM you have to have some form of commonality between devices (one of mine only has USB-C ports), plus you have to have all the cabling. And most consumer KVMs only take 2 outputs.

I'll take Bluetooth _any day_ over having another mess of cables, another box, and what boils down to less ease of use.

I use a USB C hub with my KVM for my laptop. The hub takes the KVM USB A cable and the DP cable. One cable connects the laptop and I can switch PCs with a touch of a single button. I don't like switching inputs on my monitor manually through the OSD. You can get KVMs that do 3 or 4 computers with multiple monitors, although granted they do cost more. Again, pros and cons! I find it pretty slick though.

I added a small udev rule to send a "change input" dcc command to the monitor when my USB switch connects or disconnects. The monitor has a USB-C input, and I connect the USB ports it provides to my USB switch.

Cheaper than a KVM, though it only works if the computer that has the rules is turned on (that monitor accepts commands from inactive sources).

If somebody knows a ready-made "reverse dock" (USB-C dock connector -> USB-PD out + DP in + USB device), I'm all ears!

I'm always uncomfortable when typing a password on a wireless keyboard.

Entirely reasonable stance. Previous story[0] about keyboard “security”: 8/10 tested were vulnerable to sniffing or injection. A handy summary table someone put together

  Protocol   Sniffing   Injection
  Plexgear   Yes        Yes
  Rapoo      Yes        Yes
  Logitech   No         Yes
  Corsair    Yes        Yes
  iiglo      Yes        Yes
  Exibel     Yes        Yes
  Razer      No         No

[0] https://news.ycombinator.com/item?id=33123406

The comments for that article also point out that Bluetooth is more secure.

Oh, come on. All of it is now end-to-end encrypted. Unless you're using some cheap Chinese setup.

Or Logitech Unifying and did not install a firmware update manually

Well, Bluetooth does the encryption part "properly", at least.

"Properly" or properly? Quotes imply some sort of caveat, like it actually doesn't do it properly.

BT 3.0, 4.0 and 5.0 have slightly different twaks on that. You could spoof connections in older versions, although the details have slipped my mind.

And what about side channels? It should be relatively easy to link timing to each key pressed, for instance, if not outright extracting the encryption key from emitted signal power fluctuations.

These approaches are not just theoretical, they have been shown to work. And that's assuming the protocol itself is not vulnerable and has been implemented correctly. Moreover, I tend to use my keyboards a long time, making it likely that a new attack becomes possible over its lifetime.

Personal question, feel free not to answer: what is your occupation that someone would find so interesting as to drag over a truckload of RF equipment near your location to try to home in on your 2.4Ghz keyboard, which operates in one of the most saturated frequency ranges known to modern man? :)

Oh, I'm mostly worried about "dragnet" approaches and script kiddies.

I still occasionally use a wireless keyboard to type in a password, but by avoiding these, I also lower the probability of interception.

It makes me most uncomfortable when I am typing log-in credentials to my personal home server, that could be used to log in over the internet.

Other than that, I work at a lab, which sounds like a juicy target for leaving a passive Bluetooth sniffer in a closet somewhere.

I've just played enough with BackTrack (now Kali Linux) in my teens to know that other people may be doing the same.

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