Dead Man's Switch

This is a simple implementation of a Dead Man's Switch.

Use at your own risk. Check the f****(as in friendly) code.

screenshot

Dead man's switches are designed to require positive action or they will automatically deploy. They are ideal for situations where you are worried about unforeseen death, kidnapping, or memory loss. If you don’t engage the trigger for a certain amount of time, the switch automatically sends the desired message.

Features

Simple: Easy to use and setup.
Reliable: Implemented in Rust.
Minimal: Very few dependencies and needs minimal resources.
Warning: Sends a warning email before the final email.
Attachments (Optional): Send attachments with the final email.
Tor (Optional, on by default): Expose the web interface as a Tor onion service and send the notification emails over Tor, using arti.

How it Works

If you want a very simple explanation and the motivation behind the project, check my blog post here.

Upon starting the program it will create a config.toml file in an OS-agnostic config file location:

Linux: $XDG_CONFIG_HOME, i.e. $HOME/.config, /home/alice/.config
macOS: $HOME/Library/Application Support, i.e. /Users/Alice/Library/Application Support
Windows: {FOLDERID_RoamingAppData}, i.e. C:\Users\Alice\AppData\Roaming

Edit the config.toml file to your liking. Some default values are provided for inspiration.

Dead Man's Switch comprises of two timers:

Warning Timer: This timer is set to the timer_warning (seconds) value in the config.toml file. If the user do not check-in before timer reaches 0, it will send a warning email to the users' own specified email address, the from in the config.toml.
Dead Man's Timer: After the warning timer expires, the timer will change to a Dead Man's timer, and the timer will be set to the timer_dead_man (seconds). If the user do not check-in before timer reaches 0, it will send the final email to the specified email address in the config.toml, i.e. the to in the config.toml.

If you want to send attachments with the Dead Man's email, you can specify the attachments option config in the config.toml and provide the absolute path to the file you want to attach.

To check-in, you just need to press the c key as in check-in.

Installation

There are several ways to install Dead Man's Switch:

Crates.io: cargo install --locked dead-man-switch-tui.
GitHub: cargo install --git --locked https://github.com/storopoli/dead-man-switch -p dead-man-switch-tui.
From source: Clone the repository and run cargo install --locked --path ..
Using Nix: nix run github:storopoli/dead-man-switch.

Using Nix Flakes: add this to your flake.nix:

{
  # ...
  inputs.dead-man-switch = {
    url = "github:storopoli/dead-man-switch";
    inputs = {
      nixpkgs.follows = "nixpkgs";
      flake-parts.follows = "flake-parts";
    };
  };

  outputs = inputs @ { self, ... }:
  {
    imports = [
      {
        nixpkgs.overlays = [
          # ...
          inputs.dead-man-switch.overlays.default
        ];
      }
    ];
  };

}

Then dead-man-switch will be available as pkgs.dead-man-switch;

Using as a Library

Dead Man's Switch can be used as a library. This includes all the functions necessary to configure and send emails; along with the timers.

To do so you can add the following to your Cargo.toml:

[dependencies]
dead-man-switch = "0.10.0"

Web Interface

The Dead Man's Switch is also available as a web interface.

web interface

To use the web interface, please follow the instructions below:

Change the configuration template file with your own values:

mkdir my-config-dir
cp config.example.toml my-config-dir/config.toml

Copy the Docker Compose example file:

cp docker-compose.example.yml docker-compose.yml

Run the Docker Compose:
```
docker-compose up --detach
```
Make sure to reverse proxy the web interface with proper security measures such as HTTPS.

Tor (arti)

Both the base crate and the web interface can route through the Tor network using the pure-Rust arti implementation — no external tor daemon is required. When enabled:

Inbound: the web interface is exposed as a Tor onion service, so it can be reached anonymously at a stable <base32>.onion address without exposing a clearnet host. The address is available (behind authentication) at the GET /api/tor endpoint and is logged on startup.
Outbound: the warning and dead-man notification emails are delivered to your SMTP server over Tor.

Tor support is compiled in by default (the tor Cargo feature). It is controlled at runtime by the configuration:

tor_enabled   = true        # route the web UI and emails through Tor
tor_nickname  = "deadman"   # onion service nickname / keystore subdirectory
# tor_state_dir = "/path"   # optional; defaults to <config_dir>/deadman/tor

arti persists its identity keys under tor_state_dir, so the .onion address remains stable across restarts. The first start takes longer while the Tor client bootstraps; the clearnet listener stays available in the meantime.

A few things to be aware of:

Outbound mail uses STARTTLS on the submission port (e.g. smtp_port = 587). Implicit-TLS (SMTPS, port 465) is not supported (the non-Tor path has the same requirement).
The clearnet listener is not disabled when Tor is enabled — the web UI is still served on 0.0.0.0:3000 in addition to the onion service. If you only want it reachable over Tor, restrict that port at the firewall / container level.
No clearnet fallback for email: if Tor cannot bootstrap, notification emails are deferred (not sent over the clearnet) and the failure is logged repeatedly; GET /api/tor reports a failed status. This is intentional to avoid leaking your network location, but it means a permanently-unreachable Tor network will prevent delivery.

To build without Tor (a smaller binary, e.g. for the TUI), disable the default feature: cargo build -p dead-man-switch --no-default-features.

License

The source code is licensed under an AGPL v3 License

dead-man-switch 0.10.0