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Messaging App Weaves Smartphones Into an Alternative Internet

FireChat can link Android and Apple phones into a long-range communications network even when the cell network is down.

Being able to communicate using smartphones even when cellular networks are down could be useful in many situations, for example after natural disasters.

What do people in Manila watching the Pope give Mass, Russian and Hong Kong protesters, and U.S. festivalgoers have in common? They have all turned to FireChat, an app that creates hyperlocal chat rooms that work even when cell networks are down by connecting phones within Wi-Fi range of one another (see “The Latest Chat App for the iPhone Needs No Internet Connection”).

An upgrade to FireChat released today could make the app much more useful and powerful. It makes it possible to communicate with other FireChat users beyond the roughly 70 meters that your device can reach with Wi-Fi. Private and public messages can now travel longer distances by hopping between FireChat users until they get to the intended recipient—an approach known as mesh networking. Messages are encrypted as they travel through intermediate devices.

“We’re creating an entirely new way for networks to form themselves,” says Christophe Daligault, chief marketing officer at Open Garden, the company that develops FireChat. “We’ve seen pockets of users who get together and form networks, but now we have a way to connect those islands.”

The new version of FireChat works on Apple devices and those running Google’s Android operating system. Open Garden has tested it with “OMs”—offline messages—making as many as five hops between different devices before they reach their destination, says Daligault. Copies of a new message fan out across the network of linked devices searching for a way to reach its recipient; cleanup algorithms later tidy up versions that don’t make it. If a message reaches a phone with FireChat that does have access to the Internet, it will also try and route the message that way like a regular messaging app.

Open Garden’s engineers believe their app can work at much larger scales, even linking up whole towns if enough people install FireChat. As an extreme example, they calculate that it would need 5 percent or less of smartphones in a dense city like New York to be able to get messages anywhere in the city in about 10 minutes.

However, to be effective at large scale in the event of, say, an earthquake or other disaster, FireChat will first have to find a place on people’s phones alongside conventional, Internet-reliant messaging apps. To use FireChat offline you first have to download it and register a unique username—both things you can only do if you’re connected.

Open Garden says FireChat will always be free, and hopes to see humanitarian organizations make it part of disaster resilience plans in parts of the world with fragile communications infrastructure. The company plans to make money from the technology by offering to help companies build the off-the-grid communication functions into their own products.

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