Presentation of "I Am Safe"

I Am Safe is a communication system that allows people in areas without Internet connection to inform friends and families about their basic situation.

Usual messaging applications rely on a server-client model. This makes the infrastructure efficient and predictable. The server is the highest authority that stores or forwards all messages and that defines who is a legitimate user and which messages are valid. Even for peer-to-peer connections between two devices, a central server is often still needed to establish the connection.

Some people, however, can become disconnected for many days or weeks. This can be caused by a government, a natural catastrophe or even financial limits.

Disconnected people often live in the same area, but some of them might still have occasional access via satellite or by traveling to other regions that are not affected.

Some devices can therefore form a link between connected and disconnected areas. This creates the opportunity to transport the messages of many people.

Compared to a Internet connection, this form of transport can be slow and inefficient.

The network in disconnected areas is based on manual exchange of messages over local networks and on physical displacement of devices to other devices. There are no predictable routes for a message. It must therefore spread widely in order to increase its chances, supported by the know-how of local users to find other devices and to identify people who are likely to travel across the border of a disconnected area

This network is only a remedy to a situation where otherwise no information would go in or out. Experience has shown that not knowing about the well-being of friends and family after a catastrophic event or during violent conflicts can be a huge mental stress. A slow and inefficient network is therefore a "better than nothing" solution, which still can have a huge value for those who eventually receive a message.

The proposed architecture brings about many challenges that affect performance and reliability and that make it vulnerable to attacks. It therefore has to rely on rules that are enforced on every device, even when relaying other messages. This is the only way we can keep the message pool slim and prioritise messages that are likely to be relevant.

First of all, messages are extremely short and standardised. This does not only keep them small and makes it easy to decide which message to discard in favour of others, it also makes them uninteresting for authoritarian regimes, because their limited information content and the slowness of propagation can hardly be perceived as a threat.

Furthermore, from each sender to a recipient, only the latest message is transmitted. For each sign of life sent from one person to another, only the latest update is relevant.

Similarly, all messages that have exceeded a maximum lifetime gradually drop out of the message pool. Users can customise the resources that they make available on their device to help others. It is a system that is based on solidarity.

The system protects personal information by encryption and ensures validity by cryptographic signatures. An initial signup at a central server is also required to prevent the flooding with fake messages.