It turns out that this has already been made before.
A dead man's switch for your computer?
11–20 of 74 posts
Re: A dead man's switch for your computer?
#12I built a program that automatically locks my OSX machine when I get far enough away from it. It uses iBeacon ranging and I have the beacon in my pocket. Debated on sharing with others but I never managed to clean it up enough to be proud of sharing it.
There's a program for Linux that does the same, but using your phone (or other Bluetooth device) called blueproximity. It had a slight tendency for false positives, though - sometimes it locked the screen even with the device less than a meter away.
Re: A dead man's switch for your computer?
#13Reminds me of Jacob Applebaum's udev rules for mouse jigglers: https://github.com/ioerror/udev_antiforensics
Re: A dead man's switch for your computer?
#14Dual Core (nerdcore rapper) wrote a bunch of anti-forensics scripts a couple of years ago, some quite kooky, which he presented at DerbyCon. Talk is worth watching [1], and the code [2].
Re: A dead man's switch for your computer?
#15While a dead man failsafe is a good idea - facial recognition would be my preference for situations like that described in court, the bigger issue is compartmentalization. Whole disk encryption sounds good, but the flip side is whole disk decryption and that doesn't sound so good and didn't work out well when it mattered.
Based on the testimony everything was encoded from the same one time pad so to speak. That kinda' misses the point of one time pads.
Anyway enough thinking like a criminal or a spy for one day.
Re: A dead man's switch for your computer?
#16I thought about this too when I read about how the FBI seized Ulbricht's laptop. I decided that a simple string isn't sufficient. You want the loop to be either a conductor or fiber optic, so that the system can detect when the cord is cut (not just when a USB device is pulled out).
How about a lanyard that has a magnetic connector (like Apple charging ports). So it just a small amount of force to disconnect, but easy to stick back together if you forget it was there when you got up to visit the rest room.
Another thought, what about a little coin-sized watch battery device that does bluetooth low-energy. Press a button it locks your computer (or triple click wipes something, etc).
Re: A dead man's switch for your computer?
#17I built a program that automatically locks my OSX machine when I get far enough away from it. It uses iBeacon ranging and I have the beacon in my pocket. Debated on sharing with others but I never managed to clean it up enough to be proud of sharing it.
Carrying a beacon in your pocket seems like a really impractical solution if you own a smartphone.
Re: A dead man's switch for your computer?
#18I like the idea of having a separate decryption device. OS reads encrypted data from hard disk, sends it over an encrypted link to your cell phone, which partially decrypts the data block (using one pass phrase), and sends it back over the encrypted link to the laptop. OS driver then finishes decrypting that block using a second key before passing it to your program. Writing back data just requires a public key, so write operations don't have to go to your cell phone. The idea is that your drive would never be fully unlocked, and the computer wouldn't ever have the full decryption key on it (neither would your phone).
Add in the always-on voice recognition that some Android phones have, and have the key wipe itself as soon as it hears "Freeze... FBI".
Re: A dead man's switch for your computer?
#19It's kind of pointless. If the police have already identified you as a target, there are too many other tactics they can use. For example, they could just set up a hidden camera that records you when you are using your PC.
Re: A dead man's switch for your computer?
#20I thought about this too when I read about how the FBI seized Ulbricht's laptop. I decided that a simple string isn't sufficient. You want the loop to be either a conductor or fiber optic, so that the system can detect when the cord is cut (not just when a USB device is pulled out).
How about a lanyard that has a magnetic connector (like Apple charging ports). So it just a small amount of force to disconnect, but easy to stick back together if you forget it was there when you got up to visit the rest room. Another thought, what about a little coin-sized watch battery device that does bluetooth low-energy. Press a button it locks your computer (or triple click wipes something, etc).
You should use the scenario of a pair of strong, well trained soldiers physically holding you or otherwise preventing you from performing actions. So anything requiring being aware that you're being raised then doing something like triple click might not be feasible.
I think a system would need to highly tend towards false positives, giving you a short ~5 second grace period to perform some positive challenge that things are OK.
And if this means that every day you end up accidentally having to reboot and start up Tor, well small price for physical security. But really, you should be far more focused on getting your online opsec right so you don't have to worry about thugs. If they're physically grabbing you it's very likely game over.
One countermeasure would be to find people and pay them anonymously to look like you. That is, proxy through their laptop, maybe even have them do some lightweight writing or chatting. Use their life details to leak things, like about weather or other local goings on. Essentially using them as a canary. If they get tackled, you know it's time to burn everything and hide.