Twitter in disaster mode: security architecture

Recent natural disasters (earthquakes, floods, etc.) have show that people heavily use platforms like Twitter to communicate and organize in emergencies. However, the fixed infrastructure supporting such communications may be temporarily wiped out. In such situations, the phones' capabilities of infrastructure-less communication can fill in: By propagating data opportunistically (from phone to phone), tweets can still be spread, yet at the cost of delays. In this paper, we present Twimight and its network security extensions. Twimight is an open source Twitter client for Android phones featured with a "disaster mode", which users enable upon losing connectivity. In the disaster mode, tweets are not sent to the Twitter server but stored on the phone, carried around as people move, and forwarded via Bluetooth when in proximity with other phones. However, switching from an online centralized application to a distributed and delay-tolerant service relying on opportunistic communication requires rethinking the security architecture. We propose security extensions to offer comparable security in the disaster mode as in the normal mode to protect Twimight from basic attacks. We also propose a simple, yet efficient, anti-spam scheme to avoid users from being flooded with spam. Finally, we present a preliminary empirical performance evaluation of Twimight.