Signal, the secure encrypted messenger app, does not provide an app for Chromebooks. The Android version won’t work on Chromebooks either, but using the Chrome OS Linux subsystem makes it easy to install and use Signal. Here̵
Privacy from the ground up
Signal is a free, open-source application published by the Signal Foundation and Signal Messenger LLC. The design started with the need for privacy and security as the first and most important principle. The Signal Messenging Protocol (SMP) has been developed to provide that security.
The protocol source code has been reviewed by an independent team from the German CISPA Helmholtz Center for Information Security, the Swiss ETH Zurich University, Cisco and the Canadian University of Waterloo. They all stated that the coding was world-class and that the code was free of back doors and other weaknesses.
The security of the protocol offers one kind of privacy. Nobody can intercept and read a signal message. Signal has virtually no information about you. It stores the smartphone number you registered with, the date you registered, and the date you last used the service, and that’s it – a phone number and two timestamps.
They don’t store anything about message content, your contacts, your location or anything else. And what little they know they don’t share with anyone else unless a court asks for it. And if that were to happen, the few bits of information Signal was supposed to reveal wouldn’t reveal anything about your use of the system, except when you first started using it and when you last used it.
Within a few days everything was running smoothly again, but it does show the tremendous growth that Signal has experienced.
Linux comes to the rescue
Signal is primarily a smartphone app, but Signal desktop clients are also available for Windows, Mac and Linux computers. Everyone seems to be using Signal, except for Chromebook owners. Signal does not offer a native Chromebook app and while Chromebooks will run Android apps, the Signal Android declares that it is not compatible with your device if you try to install it on your Chromebook.
Modern Chromebooks have a Linux subsystem that adds even more power and flexibility to your Chromebook. You can run Chrome apps, Google Docs, online services, Android apps and Linux apps. We can use the Linux subsystem to install the Signal Linux client and run it on your Chromebook.
Note that you need a Signal account to activate your desktop. There is only one way to sign up for Signal, and that is through your smartphone. So if you’re not using Signal yet, download the Signal app on your smartphone and register an account.
RELATED: Set up and use Linux apps on Chromebooks
Enable the Chrome OS Linux subsystem
If you haven’t already enabled the Chrome OS Linux subsystem, you will need to enable it. It only takes a few clicks. Click the system tray (system tray) to open the Settings menu and click the gear icon.
On the Settings page, type “linux” in the search bar.
Click the “Enable” button next to the “Linux Development Environment (Beta)” item.
A confirmation box will pop up to let you know that a download will take place shortly.
Click on the “Next” button to go to the next page.
Enter a user name and leave the disk size option at the default setting. Click the “Install” button to start the installation process. This is going to take a few minutes. When the installation is complete, you will see the Linux terminal window and a command prompt with a blinking cursor.
Note that the command prompt contains the username you chose earlier. In this example it was ‘dave’.
The Chrome OS Linux subsystem is a version of Debian Linux. Debian uses the Advanced Packaging Tool (APT) to install software, which is what we’ll be using to install Signal.
Copy and paste this command into the terminal window and press ‘Enter’. You have to press “Enter” every time you give Linux a command. It tells the terminal window to execute your instructions.
wget -O- https://updates.signal.org/desktop/apt/keys.asc | sudo apt-key add -
It doesn’t matter if your pasted text runs through your terminal window. Make sure to include the last hyphen ‘
-“Character. Note that if you use the keyboard to paste into the terminal window, the keystrokes are “Ctrl + Shift + V”, not “Ctrl + V”.
This command downloads an encrypted key that is used to verify that the Signal package is the official package and that it has not been tampered with.
When we tell the APT system to install a package for us, it searches different locations to find the package. The following command sets an additional location where APT can search. Copy and paste this into the terminal window and press ‘Enter’.
echo "deb [arch=amd64] https://updates.signal.org/desktop/apt xenial main" | sudo tee -a /etc/apt/sources.list.d/signal-xenial.list
Now we will tell our Linux subsystem to check for updates.
sudo apt update
Now we are ready to install Signal. This is the command you should use.
sudo apt install signal-desktop -y
You will see a lot of text appearing on the screen and a percent counter on the bottom line. When the installation process is complete, you can start Signal.
Start signal on Chrome OS
The “Finder” key is located on the left side of the keyboard. It has a magnifying glass symbol on it. Press the “Finder” key and type “signal” in the search box. You will see the signal icon appear in the search results.
Click the icon to start Signal. You must link this desktop client to your Signal account. The first time Signal starts up, a QR code is displayed.
Below the QR code are some brief instructions for Android phones and iPhones. Open the Signal app on your smartphone and tap the dotted menu button in the top right.
Tap the “Settings” item in the menu.
Tap the “Paired Devices” option.
Signal lists the devices already associated with this account.
Tap the white “+” in the blue circle to add a new device. The Signal QR code scanner appears.
Scan the QR code in the desktop client. When the QR code has been read and decoded, you will be asked if you are sure you want to link the device to your Signal account.
Tap the blue text “Pair device”.
You will be prompted for a name for your Chromebook on the client desktop. This is used to identify your Chromebook in the list of paired devices. It does not appear as an identifier in messages.
Enter a name and click the “Complete Phone Pairing” button.
Signal syncs your contacts and message groups from your smartphone. Note that it does not pull through existing chats and messages. Only messages that arrive after the desktop client has been linked to your Signal account will appear in the client.
When the sync is complete, Signal will display the main window. If you prefer dark mode, click File> Preferences> Dark.
In the main Signal window, click the pencil icon to use Signal.
Your Signal contacts and groups are listed for you.
Add signal to the shelf
You will probably find it useful to add Signal to the pinned apps on your shelf. While Signal is active, right click on the signal icon on your shelf and select “Pin” from the context menu.
Security, privacy, but no camera
You are all set to use Signal and enjoy the security and privacy it offers. Signal on smartphones is great, but sometimes you just want a real keyboard.
There is only one thing: you cannot make video calls. The Chrome OS Linux subsystem cannot access your Chromebook’s webcam, so that option won’t work.
But again, we have to leave something for your smartphone to do.