It may be necessary in the event of an emergency or disaster.What kind of mechanism is the “mesh” messaging app?

What I was worried about in the Hong Kong demonstrations reported every day was that young people were contacting in a secret way.It is said that everything is out of tubes and cannot be hidden on the Internet ...

Did you contact me without using the Internet?Is that Noroshi?Transportation Bat?

No, not.The back of the stage behind the Hong Kong protests revealed the messaging app using the "mesh" network.It is an application that allows users to keep in touch with the infrastructure controlled by the government, such as Wi-Fi networks and mobile phone networks.

Such an off-grid messaging app has Bluetooth and Wi-Fi ad hoc mode (smartphones exchange Wi-Fi directly with devices used when connecting smart speakers and home security cameras to the Internet.Use mode) to communicate directly with the device.We are not sending data via a Wi-Fi router or a mobile relay station.

Adhoc communication has a great advantage that monitoring and regulations are difficult because nothing is caught between the conversation.For example, the government and hackers cannot use the hand of invading a mobile relay station to block communication channels, and it is impossible to remove data sent to Internet service providers.It is also useless to attack the website used for contact and make it impossible to use it.

Such apps are called "offline apps" because they operate without logging in to the conventional online network.Or "Pia -to Pia (P2P) app".This is derived from directing users directly instead of getting data from the central server, as in the trend app.

Of course, Bluetooth or Wi-Fi cannot be connected forever.This is exactly where these apps demonstrate wisdom.Just as a relay player passes the baton, the message is transmitted to the other via the device where the same app is installed.

The user of the device does not know whether the message is passed through the message and the content of the message.So don't worry, even if your message goes through dozens of users before you reach your mother.

Similar principles are also used in the loss prevention tags like Tile, and will soon be adopted in Apple's "Find My" app.If you install the app, you can cooperate with the spread of the network without being known.It doesn't matter whether the purpose of the diffusion is tracking the lost MacBook or the distribution of encryption messages.

There is also a problem in this app that can be said to be a drawback.At least in urban areas, Wi-Fi and mobile phones can be received, but on the other hand, even if you move hundreds of kilometers, you can't meet anyone who runs such messaging apps at all.There is also.In order to operate the app efficiently, a large number of app users have to accumulate in a narrow range!

The range is usually said to be a maximum radius of 100 meters, but this is a story if the ideal conditions are in place.If you are in the building or if no one can see it, it will be shorter.However, if you can connect to base stations or Wi-Fi, you can use these to further expand the network range.

Apps such as WhatsApp, IMESAGE, and Signal use end -to -end encryption to prevent eavesdropping, but offline messaging apps are one step ahead and fully depends on the conventional network.It is difficult to cut off, not only monitoring, but also shutdown.

By the way, these apps have no use other than overtaking the power side.It is really useful when you are on a cruise ship or airplane in the event of a place where smartphones such as a campsite are not very small, in the event of a power outage or natural disaster, or on a cruise ship.It can also be used to interact with friends and family at concerts and festival venues.

There are many P2P messaging apps, but "BridgeFy", which supports Android and iOS, is the most reliable and actively developed (Bridgefy is a technology for other applications.We also provide licensing).You can also send messages to everyone in a certain range, not just one -on -one communication.It's like sending the latest information to everyone around you.

"Briar" is also an app worth considering.Only Android is supported, but it is designed for "people who need a safe, easy and stubborn communication means", such as active but very elaborate, such as activists and journalists.Therefore, when Internet connection is available, a TOR network is used to prevent third -party monitoring and eavesdropping.

The best mesh network app so far was "Firechat" (compatible with Android and iOS).Firechat not only accesses the contacts you already know, but also has the function of discovering individuals and groups near you, which was really convenient, but this time it seems to be good this time.It did not work.

Let's look at the hardware.If you use a device such as Gotenna ($ 179, not yet released in Japan), you can form a special off-grid P2P network, connect a mobile phone, and use it instead of Wi-Fi or mobile network.。In other words, all the apps installed on the smartphone are connected to the mesh network -, of course, it is assumed that the person you want to talk about has Gotenna.

It is natural to replace all daily communication with such a device.But when you are camping or a narrow area (radius 6).When there is a person who wants to contact each other in the range of 4 kilometers), when the network is down for some reason ... I never thought that the tower would break in the typhoon and the mobile phone would not be connected ...It is convenient at all.Why don't you try it in case of something?