During the Cold War, the specter of a nuclear “dead man’s switch” was central to the concept of Mutually Assured Destruction (MAD). In the event that one side was annihilated by the other, an automated system would be triggered to deliver a revenge strike that would ultimately destroy the attacker. It was the ultimate defense, as your enemy will never attack if they know doing so will inevitably lead to their own destruction.
The same idea has occasionally been employed by whistleblowers and journalists as well. Should the individual fail to check in regularly, a series of predetermined events will be set into motion. Again, the idea is defensive in nature. If somebody is in possession of information so damning that they could be abducted or even killed to keep it quiet, making arrangements to have that information be released to the public in the event anything should happen to them is a great way to stay safe.
But what about for the average person? In the past, there was no need for most people to think about something as elaborate as a dead man’s switch. But we live in interesting times, to say the least. In an information society such as ours, whistleblowers have never been more common, and the Internet has significantly blurred the definition of what it means to be a journalist.
For those living under a repressive regime or in a war zone, simply posting to social media can provide the outside world with an unfiltered look at what’s actually happening on the ground. A teenager with a cell phone has the potential to reach a wider audience than the legacy media — a powerful, but dangerous, proposition.
Even if you’re not in the middle of political upheaval, there are still reasons you might want to have previously secret information made available in the event of your death or incapacitation. Perhaps you’d like to send your loved ones a final personal message, or make sure the passwords for all your accounts get in the hands of whoever will be handling your estate.
Of course, one could argue that could be accomplished with little more than a notebook hidden in your sock drawer. But this is Hackaday, and over-engineering is the name of the game. So do you have a dead man’s switch? How is it implemented? Or is the whole idea just a bit too out there for you?
The Software Approach
We started discussing this topic internally here at Hackaday a few days ago after I came across LastSignal, an open source dead man’s switch application written by Claudio Benvenuti. It’s by no means the first piece of software of its type, as the idea has been floating around for years and there are both open and proprietary implementations available. But LastSignal has the sort of slick modern design that gets people interested, and the fact that you can self-host it is quite appealing.
LastSignal is designed to let you write encrypted messages that will remain a secret until the system has been triggered, at which point they will be sent off to the recipients you’ve configured. The default behavior is to try and contact you every month via your primary email address, and once the software picks up that you’ve missed enough of your normal check-ins, it will try to get in touch with your emergency contact. If it still doesn’t get a response, then the automated messages start getting sent out.
Again, this is not a new idea. Searching around, you can find other open source tools to achieve the same goal, such as dead-man-hand. If you’re not concerned with the behind-the-scenes implementation, you can even pay a service to handle it all for you. But there is something to be said for using a package that’s already been thoroughly tested and vetted by the community. Otherwise, you could just throw something together yourself with a Python script — although we’d hate to spend eternity roaming the astral plain in torment because our final messages didn’t get delivered due to a library update breaking our script.
Most of the projects we found along these lines are focused on sending messages that would be a secret until the time of their release. That makes sense, but we wondered if there were other tasks you might like your personal dead man’s switch to fire off in the event you’ve signed out permanently. For example, Al Williams suggested that some users might want to have their drives securely wiped in the event of their death. Any speculation as to why this was the first thing Al thought of will be left as an exercise for the reader.
Why Not a Physical Switch?
While a software solution is the easiest way to implement a dead man’s switch, it does have its downsides. As already mentioned, if you’re self-hosting the solution and aren’t careful, some seemingly inconsequential change or update could potentially knock out the software before it even has a chance to run. When we think of all the weirdo software issues we’ve had over the years, it makes us more than a little skeptical about trusting such an important task to the whims of our operating system.
So what about a hardware solution? With so many WiFi capable microcontrollers on the market now, it would be trivial to put together a little dead man box that has just a display and a button on it — the display counts down the remaining time before the switch is triggered, and the button is used to reset the timer. If you don’t press the button in time, the MCU connects to the Internet and performs whatever task you’ve programmed. We bet you could put it together right now using stuff in your parts bin.
Now, we won’t pretend going from a pure software solution to a piece of custom hardware will completely remove the chances of something going wrong. After all, there’s still code being run, and that code could have bugs. But it does take away the innumerable variables that are introduced when said code is being run on a modern operating system. If your DIY dead man’s switch works today, you can be sure it will work the same way in a year from now as the whole system is in a fixed state.
Tin Foil Hat Not Included
Or maybe this is all crazy talk. Perhaps the complexity of either solution makes no sense for the average person, and just writing your important information down and telling your next of kin how to get access it after your passing is enough. Obviously there are downsides to this approach as well, notably the potential for your written information to get stale and no longer be valid when the time comes, but it’s a method that has worked for the vast majority of people for generations.
Is this a problem that needs a modern solution? Is a dead man’s switch best left to secret agents? The fact is, we’re all going to go sooner or later, so it’s something we need to give some thought to while we still have the chance. We’d love to hear what you think in the comments below.
I think the original Star Trek tackled this with the Doomsday Machine.
“encrypted messages that will remain a secret”
Um, no. do you have any idea how juicy a target would be a single site where everyone’s deathbed secrets are kept?
It’s not “a site”, so there’s no reason anyone would ever know of its existence until it’s triggered.
Sort of an IRL https://en.wikipedia.org/wiki/Watchdog_timer
Related, with similar intent: https://en.wikipedia.org/wiki/Warrant_canary
Something similar saved a friend’s life. ‘John Doe’, living in the middle of the desert, had an esp32-based box that sent something out to ‘Bill Smith’ if he did not reset a 48-hour watchdog timer. Bill Smith called me. I immediately flew out to John Doe’s place. As I was landing, caught glimpse of something red above the area. Found my dear idiot friend up on the side of the mountain with a leg broken in several places.
If you live alone in the middle of nowhere, design and build something like this, or die alone.
And make sure you have great, reliable friends. With planes. And excellent eyesight.
I’ll be getting a personal locator beacon for exactly that purpose this year.
They’re not that big and not that expensive (roughly $400), and they tap into a statewide radio alert system.
In m,y state (NH), emergency rescue is free so long as it’s an actual emergency.
That’s definitely a good idea… but also… that’s what emergency beacons are designed for, and they’ll actually lead your rescuers to the right place.
Hard problem.
Assuming a nation-state actor wants you to disappear quietly… They cut your cards, associated services, and all known/associated internet the same day.
Host on someone else’s service, its an easy target to silence with a court order.
Host on your own property, its an easy target to silence.
Your best method is probably a block chain contract.
yeah you’re on the same thought i was. the struggle is to find a mechanism that can’t be muted by an advanced persistent threat. I was thinking about how to hide the mechanism, but something like a blockchain that can’t really be destroyed even if your adversary knows it exists might qualify. Though..perhaps a limitation of my own imagination, i don’t know a way to unlock your hidden-in-plain-sight information passively but actively keep it locked.
Hire a lawyer, give him an envelope, and tell him to open it and follow instructions when you die.
If it’s not your existing personal lawyer, this is a very hard to track and circumvent.
Point 1. Any system developed today will have changed by the time I’m likely to die. We can’t even keep an IoT light bulb operating for a decade, so any “dead man’s switch” will likely go the same way. Either the servers shut down, or nobody will be around to read the email because people don’t use emails any longer.
Point 2. I prefer to live like I’d never die, and die like I’d never lived.
I can’t help thinking there is a testing issue with this sort of thing – how do you test it?
And an accident or hack issue – releasing the “bomb” before it was suppised to be released.
They once had a bunch of US soldiers die in Germany when the installation they were working in had the self-destruct go off accidentally.
Seems it is a thing.
It’s odd though since in Iraq and Afghanistan they just let any old maniac walk off with the discarded weapons.
Addendum: I did once hear that when the US closed a base in Afghanistan the locals thought they could their hands on the tents but then found they meticulously shredded them.
I guess tents are more critical than weapons.
The problem with a dead man’s switch is that some alternate actor may want it triggered. The easiest way is to merely kill you.
It’s why I don’t like fingerprint readers, if its important to break in, someone will just cut off your finger. Retina scanners are worse.
Sorry about being so grim, but safety deposit boxes are probably a better idea.
Your heirs can always just get it drilled.
Wow I thought I was kinda paranoid. Some of the people on here are over the top. Nice.
At first I thought if someone had a need for this they would have to be sitting on some really awful stuff but I do see more innocuous reasons for it.
For example. When I get old, or if I get sick there’s certain people I don’t want taking care of me. Nope! They say to put stuff like that in your will I guess but I could still see reasons for having your own thing.
In old age, always have a lawyer on retainer.
Otherwise all the bastards have to do is convince some bendjo judge that they should run your life and they will own you.
Having your own lawyer aprori Fs that plan up.
Of course you have to trust him, but generally good lawyers already steel enough completely legally.
My lawyer knows that if I become incapable of running my own life, he must provide me with sufficient tequila and Tannerite to keep me amused.
It’s in writing.
I’ve got the ammo covered.
Also:
Financial assets in family trust is best protection from tax thieves.
Beware divorce, don’t tell wife if married.
Also also:
Still looking for a teaching hospital that I can donate my body to, for medical student pranks.
Hung like a bear, so great potential fun.
HaHa you’re basically family to me now. Good advice. A good chunk of it doesn’t apply to me. Except the extremely well hung part of course. I’m also seeing people talk about nation state this or that. I don’t think any of that applies to people here. I do think everyone could up their privacy and safety concerns though. Sometimes I wish someone had enough guts to make a down to earth write up for the average person. Maybe one day I will. Unless someone takes me out of course (kidding).
Can’t conceive a reason for having one such device, but a consistant observation is that they all can be hacked. I do have a failsafe system where all my heirs get whatever porion of my estate they earn, but that is a different system
God forbid the Secret Service or FBI get peoples novel pop culture gossip and untouched git clones.. They might steal and patent how to put a Linux SBC in something instead of reverse engineering circuits and hide it in the national archives XD
my wife was diagnosed with cancer in 2013, she was told she had 6 months, she made it till 2019. Unbeknownst to me, she setup something of a deadwomans switch, a week after she died I started getting emails from her. The first set were mostly estate planning, passwords, instructions, etc. In the years since I get little love letters on various dates of significance. I have no idea how many she wrote, or how long they will continue to arrive. There are times I hope they never end, there are times I feel more hurt receiving them than joy. Theyve certainly complicated and probably extended my grieving process, but I dont think I could ever take measures to block their arrival.
So sorry for your loss. Your wife loved and still loves you. She must have been really special. I hope you find peace. This is an amazing use for this type of technology.