Install Signal without a smartphone

Imagine you do not want to have a smartphone for some reasons, but still need to have a little bit of privacy. Signal is considered one of the most secure and private app for messaging, using a very advanced end to end encryption technology, and being open source and developed by a Foundation caring for our privacy and not an evil corporation. Besides, it is super user friendly and easy to use. However, most people consider that it requires the use of a smartphone. Well, good news: this is not True ! there is a way to use a desktop version of Signal on a computer (MacOs, Windows or Linux). You just need to be able to receive a One Time Password by SMS. This can be done on a regular “brick” phone, a burner or a Virtual Phone.

I followed the recipe described here.

You first need to install three things on your computer:

1. The desktop version of Signal corresponding to your OS:
2. java
3. The signal-cli command line program

For this last one you should download the signal-cli-*.tar.gz archive.

you can verify the download in the following way:

1. download the signature signal-cli-*.tar.gz.asc
2. Download the public PGP key:

   gpg --recv-key FA10826A74907F9EC6BBB7FC2BA2CD21B5B09570

3. Verify it:

   gpg --verify [filename.asc] [filename]

4. Check the “Good Signature” appearing

• Remove all VPNs if you have any active, and possibly deactivate anti tracking addons on your browser temporarily
• go to this website, and solve the captcha. If proposed to automatically open a link with signal, refuse it, then right-click and copy the link associated with the new “Open Signal” text on the page

• Open a terminal, and go to the repository where you uploaded signal cli, using the

  cd

  command, then enter the bin repository

• Enter the command

  ./signal-cli -u [PHONE NUMBER STARTING BY +] register --captcha [PASTE THE COPIED LINK HERE]

• If everything goes well, you should see no error, and then receive a SMS with a One Time Password on your phone.
• Enter then

  ./signal-cli -u [PHONE NUMBER STARTING BY +] verify [RECEIVED ONE TIME PASSWORD]

• You can now open the signal-desktop client with

  signal-desktop

  . Note that if you already are using signal and want to create a new separate signal account, create a repository on your computer and enter:

  signal-desktop --user-data-dir=[PATH_TO_YOUR_REPOSITORY]

• You should see a QR Code appearing. Take a screenshot of it and save it as a picture for example.
• download this file and open it
• Click on open file, browse to the QR code.

• You should see a link starting by sgnl appearing. Copy it.
• Go back to your terminal and enter

  ./signal-cli -u [PHONE NUMBER STARTING BY +] addDevice --uri "tsdevice:/[PASTE THE COPIED LINK HERE]"

• Then everything should work. If Signal hangs at “syncing contacts” you can turn it off then on.

• Final setup: go to preferences

• click on your name and set up a name and a username. Note down your username: this is what you are going to give to people so they can contact you.

• Go to Privacy/Phone Number (Change) and set both option to “Nobody”

• You can now use Signal !