NOTE: These instructions only work for 64-bit Debian-based
Linux distributions such as Ubuntu, Mint etc.

1. Install our official public software signing key:
   wget -O- https://updates.signal.org/desktop/apt/keys.asc | gpg --dearmor > signal-desktop-keyring.gpg
   cat signal-desktop-keyring.gpg | sudo tee /usr/share/keyrings/signal-desktop-keyring.gpg > /dev/null

2. Add our repository to your list of repositories:
   echo 'deb [arch=amd64 signed-by=/usr/share/keyrings/signal-desktop-keyring.gpg] https://updates.signal.org/desktop/apt xenial main' |\
   sudo tee /etc/apt/sources.list.d/signal-xenial.list

3. Update your package database and install Signal:
   sudo apt update && sudo apt install signal-desktop