Sharing Data with Briar via Wi-Fi, Bluetooth and Internet

By Andrea Brás

After the Internet shutdown in Zimbabwe, user stories began pouring in about everyday people turning to tools like Psiphon and TunnelBear to circumvent the social media blockage. But what tools are available when the Internet is completely down? To answer this question, Localization Lab organized an Ask-Me-Anything (AMA) with Michael Rogers, one of the developers of Briar app.

Briar is a messaging app that syncs over Wifi or Bluetooth, keeping users connected during a shutdown who are in close, short range proximity with each other.

Here are some takeaways from the AMA with Briar:

How can you use Briar to communicate when the Internet is off?

During a total internet shutdown, devices need to be in Wifi or Bluetooth range to exchange data. That’s a 10-20 meter range. Messages can be synced with other devices when you are in range of their devices. That means, if you wanted to communicate with a group on the other side of town, someone would have to travel across town to carry the data to them. For example:

Is Briar a mesh network?

It is not exactly a mesh network. You can't set up a real time connection across the mesh. Instead, it’s more like each device is carrying the data and spreading it to its contacts.

How do you authenticate messages with Briar?

To add a contact, you must scan a QR code from each other’s screens. Those QR codes will allow you to exchange your Briar identities which include cryptographic keys used to sign messages. For example, when someone leaves a message in a forum it will have an icon next to their name indicating if the messenger is someone you know.

How does Briar work in low band-width areas?

Communication over Wifi it's usually very fast, Bluetooth is slower, and if you're connected to the internet it will depend on your connection speed.

Do you get to see all the devices that are within your range? Can you decide who to transmit a particular message to?

You can only see your contacts’ devices if they are in range via Wifi or Bluetooth. Your device will only share things that you’ve chosen to share with them (like a forum you’ve invited them to and vice versa).

How is Briar different from Firechat?

Briar only connects to your contacts whereas Firechat will connect to any other Firechat user who's in range.
With Briar, everything is encrypted and data is only shared with people you choose to share it with whereas Firechat is more like a public square where everything is in the open. Firechat gives anyone in the crowd the ability to join the conversation. Briar gives you a lot more control over who can be part of each conversation, which may be more suitable for an activist group type of scenario rather than a crowd in a public square type scenario

What are some features that you are planning (or thinking about) for the future?

Mailbox feature: We're adding something called a mailbox, which is a second device, like a spare phone or a raspberry pi, that sits in one place and collects data from anyone who comes within range and shares it with people who come in range later. So it's like an extra hop that extends the effective range of your network.
Sharing information with people outside of your contact list: We are considering an option that would allow data to travel further across the network by hopping onto devices that don't belong to your contacts. The data is encrypted so they can't read it, they just carry it.
File sharing: We are currently working on sharing image attachments. Other file types will be supported in future.
iOS version: iOS is difficult because the platform is very strict about what apps can do while they're running in the background. But once we've implemented the mailbox (see comments above) it should be possible to get something working. It won't be possible to support push notifications though.

Where can you download Briar?

You can download Briar from google play or f-droid: https://briarproject.org/download.html. It is currently only available for Android, not iOS.

How can we contact you if we have more questions about Briar?

Feel free to drop by our Mattermost at chat.briarproject.org