# Signal > [!toc] Table of Contents > > Credit: The article is a translation of the [LG Wiki](https://wiki.letztegeneration.org/de/home) Signal section. > [!tip] Tip {static} > > In addition to the following practical guides, we have a general > [article](https://wiki.aktivismus.org/books/it-sicherheit-esc-it/page/messenger), in which we discuss the advantages and > disadvantages of Signal and other messengers. ## Set up registration PIN It is very important that you set up a PIN in Signal. This protects against unauthorized re-registration. Your network provider is required by law to forward SMS messages to the police. Without a PIN, the police can read your Signal messages – However, you would notice it if someone tries to re-register your device. Only one mobile phone can be registered with Signal, so you would be logged out of your Signal account. To set up a PIN: - iOS: tap your avatar » Settings » Account - Android: Settings » Account » Registration Lock ## Self-destructing messages In individual chats/groups: - Click on the name at the top of the chat - “Self-destructing messages” You can also set a default period of time for the feature to be automatically activated for new chats: - “Settings” - `Privacy` - “Self-destructing messages” - “Default expiration time” for new chats ## Create usernames Usernames make it possible to share your contact without revealing your phone number. For more information, see Signal's [blog](https://signal.org/blog/phone-number-privacy-usernames/). - `Settings` - Click on your mobile phone number at the top - Set a username after the `@` The username must end with a period and at least two digits, e.g.: `username.12`. However, there can also be more digits after the period. ## Disable `Find by phone number` You can prevent your Signal account from being found using your phone number. This will make it harder for people who know your phone number to find out if you are using Signal, which is important if you live in a country where Signal usage may be suspicious or illegal. - `Settings` - `Privacy` - `Phone number` - “Who can see my number”: `Nobody` - “Who can find me by my number?” `Nobody` ## Multiple Signal accounts on one device There are various options for using multiple Signal accounts on one device. The options depend on your operating system: ### Multiple Signal accounts on PC The easiest way is to download the tool `signal-account-switcher`. This allows you to use four additional Signal accounts at the same time. To do this 1. Click on this link: [https://github.com/kmille/signal-account-switcher/releases/tag/v0.1.0](https://github.com/kmille/signal-account-switcher/releases/tag/v0.1.0) 2. Download the tool for your operating system. At the bottom of the page: “signal-account-switcher.exe” for Windows, “signal-account-switcher” for Linux and “signal-account-switcher-mac-{amd,arm}” for Mac (depending on your [CPU](https://thetechylife.com/how-do-i-know-if-i-have-amd64-or-arm64/)). 3. Start the tool (Windows may complain at first because it is “unsafe” to run a file from the Internet) and simply click on “Start Signal Account #1.” A new signal-desktop instance will open. If you don't want to install an extra tool for using multiple signal profiles on your PC, you can also do it yourself with a little manual configuration: - Instructions for Windows: [https://www.youtube.com/watch?v=TejhH80jktE](https://www.youtube.com/watch?v=TejhH80jktE) - Instructions for Mac: 1. open the command line/terminal 2. paste the following command inside the terminal and hit `Enter` ```bash mkdir $HOME/Library/Application/Signal-Account-1 /Applications/Signal.app/Contents/MacOS/Signal --user-data-dir=“$HOME/Library/Application/Signal-Account-1” ``` ### Multiple Signal Accounts on Android #### Molly There is a Signal fork called [Molly](https://molly.im/), which can be installed alongside the normal Signal app and set up with a different account. > [!technical] What is a fork? > > In software development, a fork is an application that is created by duplicating an > existing codebase, in this case the Signal codebase, and subsequently modifying it > independently of the original. Molly modifies the Signal codebase to add functionality > such as having multiple accounts. 1. If you haven't already, install [F-Droid](https://f-droid.org/), a free and open source app store: - Download the F-Droid.apk file from the website. - Install f-droid by opening the .apk file you downloaded. - Allow “Installation of apps from unknown sources” when prompted. - Allow “Install apps from this source” if necessary. 2. Add Molly's [package source](https://molly.im/download/fdroid/) to your F-Droid by following these [instructions](https://f-droid.org/tutorials/add-repo/) on the F-Droid website. Molly is not automatically included in F-Droid and therefore needs to be manually added. - Go to and select Molly (if you are reading this on your phone), or scan the QR code if you are reading this article on your PC. **Select Molly, not Molly-FOSS, unless you know what you are doing** (e.g., no Google Play services). - Open F-Droid and refresh once by swiping down from the top edge of your phone; this will load information about all available apps, which can take up to 2 minutes. 3. Install Molly via F-Droid - Search for Molly in F-Droid and install it. If necessary, allow “install from this source” for F-Droid again. Molly is now ready and you can set up the app as you would normally set up Signal. However, you will be asked at the beginning whether you want to use additional _password encryption_. Your choice cannot be changed later. This is useful for sensitive accounts. Create a Signal PIN that you can remember for sure, or save it in your secure [password manager](https://wiki.aktivismus.org/countermeasures/passwords.md#password-manager), but don't write it down on a piece of paper! This could be used by the police to intercept messages intended for you after a house search. #### App clones Some manufacturers offer a dual app feature to run multiple accounts on one phone. Search online to see if your device has this feature. Starting with Android 14, this option may be available by default on many devices. You can also use this feature to clone Signal and Molly, which would enable you to use up to four different Signal accounts. You could also do without Molly and use Signal twice, but Molly is more useful because it has slightly better encryption and security mechanisms, which offer an advantage in the event of a house search. You can easily activate the feature in the Android settings: Samsung: `Settings` > `Advanced features` > `Dual Messenger` Huawei: `Settings` > `Apps` > `App Twin` LG: `Settings` > `General` > `Dual App` A menu with all clonable apps should then appear, where you can simply select Signal (and any other apps you want to clone) and duplicate them. #### Additional Android profiles Android offers the option of creating multiple user profiles, just like Linux, MacOS, and Windows. For more information, visit the responding Android [support page](https://support.google.com/android/answer/2865483?hl=en).