SignalBoost - Broadcast anonymous messages on Signal

In the Mattermost Tech Team I saw that someone asked about installing SignalBoost onto global infrastructure. Currently there is no response but I think it might be worth exploring installing this on branch infrastructure if it’s not available globally.

Here’s a bit of a rundown from the website:

Signalboost gives grassroots organizers the power to communicate with mass audiences securely and directly via message broadcasts and hotlines.

Reach thousands of people directly

  • Organizers need quick and direct ways to disseminate information. However, on social media platforms, important info is often obscured by algorithms and other posts. Signalboost messages go directly to subscribers’ message inboxes.
  • Organizing in big group chats gets messy quickly and unnecessarily exposes strangers’ phone numbers to each other. Broadcasts offer a quick way disseminate information directly to thousands of people.

Respond to people individually and privately

  • Subscribers to Signalboost channels can send in anonymous messages to the hotline and admins can respond directly and privately to that susbcriber.
  • Subscribers do not see other subscribers’ messages to the hotline. Only admins can see them.

Stay safe from surveillance

  • Signalboost sends messages over Signal, the most secure encrypted messaging service for phones.
  • By obscuring personal phone numbers, enforcing disappearing messages, and controlling who is allowed to join their channel, Signalboost empowers organizers to stay safe while speaking freely

It looks as though there is a public server that is available for use however the numbers of organisers and subscribers are stored in a database accessible to the server administrator. The project is open source with a GPL license and so it could be deployed onto our branch server. Obviously our system administrators would then have access to the phone number database.

When a new broadcast channel is setup a phone number is registered. Organisers then send their broadcasted message to that number and it’s then sent to all subscribers. This means that the organiser doesn’t need to store the subscriber list on their phone. When a subscriber responds to the message it’s sent to the organiser from the channel number.

It costs $1 (USD) a month to maintain a phone number for a channel. Presumably we could remove channels and the attached number if they’re no longer needed.

I can see this as being hugely beneficial for contacting marshals, conscientious protectors, action teams, etc. It can also be used a cheap alternative to SMS blasts (sending messages over Signal is free so you’re just paying the $1 monthly fee).

Will report back here with the thoughts from other techies in Mattermost and whether it’s deployed on Global Infrastructure. In the mean time I’d be useful to gage interest in us adopting this software. So do share your thoughts.

Sounds awesome. I can see huge benefits for the XR Vic actions group and most likely for multiple AusMM working groups. We would just have to be judicious about how we decide who gets to send mass-messages.

I have a bit of a query about this - say we sent a message to each of the 291 pledgees from the XR Vic pledge action once - would that be $291 for the month and for each month after that? Or is it $1 for the phone number generated to send and receive the message?

I’ve just updated the original post to be clearer. It’s $1 USD a month for the phone number generated not per organiser/subscriber. So the pricing scales nicely.

In my mind this would fall under national infrastructure and so costs would be covered by the Finance Alliance (if approved).

It’s so cheap that we’d be able to fund it from state or local groups if we had to with no major issues.

General response from others is that they’re wary of hosting phone numbers. Was also raised that the service would have to be opt-in (for GDPR).

What’s that about specifically? We already have thousands of phone numbers…