Install Signal

What Signal is

Signal is a messaging app. You chat, call and send files, one to one or in groups, and everything sent is encrypted the whole way between sender and recipient. That means neither the operator of the service nor anyone who happens to be on the same wifi can read the content. The app is free and run by a foundation, not by a company that sells ads.

For a business that is worth something concrete. You will talk about prices, about customers and sometimes about people, and that kind of conversation belongs somewhere other than in a large group chat where people outside the company read along. Signal is also a reasonable answer when a customer asks how you handle sensitive information.

What you need before you start

Signal is based on a phone number. The app is installed on a phone first, with Android or iPhone, and the number is registered there. The desktop version cannot stand on its own, it is linked to the phone.

Installing on Windows

Go to signal.org and download Signal for Windows. Run the installer, start the program and choose to link with your phone. A QR code appears on the screen. Open Signal on your phone, go into the settings, choose to link a new device and point the camera at the code.

Installing on Linux Mint

Signal has its own package repository for Debian and Ubuntu based systems, and Linux Mint is one of those. Open a terminal with Ctrl plus Alt plus T and paste the lines one at a time. The terminal asks for your password when a line starts with sudo, and the characters are not shown while you type it. This is normal and does not mean the keyboard has stopped working.

curl 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
curl -o signal-desktop.sources https://updates.signal.org/static/desktop/apt/signal-desktop.sources
cat signal-desktop.sources | sudo tee /etc/apt/sources.list.d/signal-desktop.sources > /dev/null
sudo apt update
sudo apt install signal-desktop

The lines come from Signal's own download page. The first two add the key the computer uses to check that the updates really come from Signal, the next two point out the package repository, and the last ones fetch and install the program. Then start Signal from the menu and link it to your phone the same way as on Windows.

Three things to do first

1. Create the group for the company and give it a name that says what it is for. If you need more than one: one for everything and one for what concerns customers, no more than that.
2. Turn on disappearing messages in the group, for example four weeks. Then old conversations are cleared out on their own, and what you wrote long ago does not stay around and clutter things up.
3. Write down your Signal PIN somewhere safe. Without it you will not get back into the account if the phone is replaced or lost.

The most common trap

Believing that the computer is the account. It is not. The desktop version is a linked device. Since 2025, you can choose to transfer the chat history and the last 45 days of media when you link it, but that is a choice you make during the linking itself, not something that happens automatically afterward. Decline the transfer, or link the computer without thinking about it, and it only sees what comes in after linking.

If someone uninstalls the app on the phone, or registers the number on a new phone without moving the account over, the desktop version stops working. Link the computer early, then, before you have important conversations in the thread, and treat the phone as the original.