signalblast

Signalblast is a tool to send encrypted messages anonymously over Signal to a subscriber list. The sender does not know who the subscribers in the list are, nor the subscribers know who the sender is.

A server is required to host the bot, find instructions on how the set it up below.

The idea for this bot came from Signalboost, which unfortunately is no longer alive.

Usage

Once the server is up and running, several commands are available:

• !subscribe send this to sign up to the list
• !broadcast after subscribing any message preceded by this will be broadcasted to every subscriber
• !unsubscribe to stop receiving messages
• !help to be reminded of which commands are available
• !admin send a message only to the list admin, useful for getting technical support

Installation

The only required dependency is docker.

• Run a container for signald

  • docker run -v "./data/signald:/signald" signald/signald:0.18.5-non-root

• Open a second terminal inside the container to configure signald, substitute <container name> with the container name

  • docker exec -it <container name> bash

• Link or register the phone number
  • Linking (easier)
    • Run the link command and scan the QR code, substitute <Your phone number> with your phone number

      • signaldctl account link <Your phone number>

  • Registering (harder)
    • Get the captcha helper from here https://gitlab.com/signald/captcha-helper
      • Run captcha helper bash ./signal-captcha-helper
    • Register the account using the captcha (substitue <nnnnn> for the captcha output)

      • signaldctl account register <Your phone number> --captcha <nnnnn>

    • Verify the account (substitute <nnnnn> for the sms verification code)

      • signaldctl account verify <Your phone number> <nnnnn>

• Verify that signald is properly configured

  • signaldctl message send -a <Your phone number> <recipient phone number> <a message>

• Once signald is configured, lets run a container with signalblast

  •    docker container run \
       --restart=unless-stopped \
       -v "./data/signalblast:/home/user/signalblast/signalblast/data" \
       -v "./data/signald:/home/user/signald" \
       -e SIGNAL_PHONE_NUMBER=<Your phone number> \
       eraxama/signalblast:latest

  • There are two optional parameters
    • -e SIGNALBLAST_PASSWORD=<a password> -> the admin password for signalblast
    • -e SIGNALBLAST_EXPIRATION_TIME=<time> -> an automatic message expiration time in seconds
• Now you can send message to the bot, a good first message is !help. The bot should reply immediately.
• If this is not the case, check the logs at ./data/signalblast/signalblast.log