Qubes-Community-Content/docs/privacy/signal.md

Signal
======

What is [Signal]?

[According to Wikipedia:][signal-wikipedia]

> Signal is an encrypted instant messaging and voice calling application
> for Android and iOS. It uses end-to-end encryption to secure all
> communications to other Signal users. Signal can be used to send and receive
> encrypted instant messages, group messages, attachments and media messages.
> Users can independently verify the identity of their messaging correspondents
> by comparing key fingerprints out-of-band.
> 
> Signal is developed by Signal Technology Foundation and Signal Messenger LLC.
> The mobile clients for  are published as free and open-source software under
> the GPLv3 license, while the desktop client and server are published under the
> AGPL-3.0-only license.

How to install Signal Desktop in Qubes
--------------------------------------

**CAUTION:** Before proceeding, please carefully read [On Digital Signatures and Key Verification][qubes-verifying-signatures].
This website cannot guarantee that any PGP key you download from the Internet is authentic.
Always obtain a trusted key fingerprint via other channels, and always check any key you download against your trusted copy of the fingerprint.

The following adapts the official [Linux (Debian-based) Install Instructions][signal-debian-instructions] from Signal's website for Qubes.

1. (Optional) Create a TemplateVM (Debian 11 is used as an example):

       [user@dom0 ~]$ sudo qubesctl --skip-dom0 --targets=debian-11 --show-output state.sls update.qubes-vm

2. Open a terminal in Debian 11 (or your previously chosen template):

       [user@dom0 ~]$ qvm-run -a debian-11 gnome-terminal
       
3. Use these commands in your terminal (if you chose a different distribution, such as `buster`, substitute that for `xenial` in the fourth command):

       [user@debian-11 ~]$ sudo apt-get install curl  # (Optional)
       [user@debian-11 ~]$ sudo apt-get install dunst  # (for better Signal notifications)
       [user@debian-11 ~]$ curl --proxy 127.0.0.1:8082 -s https://updates.signal.org/desktop/apt/keys.asc | gpg --dearmor | sudo tee -a /usr/share/keyrings/signal-desktop-keyring.gpg > /dev/null
       [user@debian-11 ~]$ echo 'deb [arch=amd64 signed-by=/usr/share/keyrings/signal-desktop-keyring.gpg] https://updates.signal.org/desktop/apt xenial main' | sudo tee -a /etc/apt/sources.list.d/signal-xenial.list
       [user@debian-11 ~]$ sudo apt update && sudo apt full-upgrade && sudo apt install --no-install-recommends signal-desktop

5. Shutdown the TemplateVM (substitute your template name if needed):

        [user@dom0 ~]$ qvm-shutdown debian-11
        
6. Create an AppVM based on this TemplateVM.
7. With your mouse, select the `Q` menu -> `Domain: "AppVM Name"` -> `"AppVM Name": Qube Settings` -> `Applications` (or in Qubes Manager `"AppVM Name"` -> `Settings` -> `Applications`). Select `Signal` from the left `Available` column, move it to the right `Selected` column by clicking the `>` button and then `OK` to apply the changes and close the window.

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[qubes-verifying-signatures]: https://www.qubes-os.org/security/verifying-signatures/
[Signal]: https://signal.org/
[signal-debian-instructions]: https://www.signal.org/download/linux/
[signal-wikipedia]: https://en.wikipedia.org/wiki/Signal_(software)
[shortcut]: https://support.whispersystems.org/hc/en-us/articles/216839277-Where-is-Signal-Desktop-on-my-computer-
[shortcut-desktop]: https://www.qubes-os.org/doc/managing-appvm-shortcuts/#tocAnchor-1-1-1
[message]: https://groups.google.com/d/msg/qubes-users/rMMgeR-KLbU/XXOFri26BAAJ
[mailing list]: https://www.qubes-os.org/support/