SOS Middleware
Figure 1: Any mobile application can run on top of SOS. Facebook, Instagram, and Twitter are shown as example applications and are not currently using the SOS Middleware.

The Secure Opportunistic Schemes (SOS) middleware is a patented [1] technology that facilitates secure message delivery in cases where mobile connectivity is limited, unavailable, or non-existent. The SOS middleware supports real-life delay tolerant social networks on mobile devices. This allows mobile devices to leverage SOS to dynamically deliver messages to interested nodes when network infrastructure is not available and improve message delivery when infrastructure is available. SOS takes a modular approach to abstract away much of the complexity involved in implementing opportunistic routing schemes such as device dicovery, establishing D2D connections, and handling device security and privacy. Demonstrations of SOS powering the AlleyOop Social Research Platform on iOS devices was conducted at the 2017 IEEE ICDCS[2]  and 2017 IEEE INFOCOM[3] conferences. You can learn more about AlleyOop Social and the SOS Middleware by reading our white paper that was accepted into 2017 IEEE ICDCS.



Interest Based Routing
Figure 2

The SOS middleware allows many routing protocols to be ran simultaneously to deliver content. Currently, SOS has two DTN routing protocols implemented (both are written <= 100 lines of Swift code): epidemic routing and interest-based routing. Epidemic routing is a simple routing scheme that achieves effectiveness through gratuitous replication and delivery of messages upon node encounters. The IB routing protocol operates in a similar manner to epidemic routing, except, instead of propagating messages to all users, messages are only propagated to interested users who are subscribed to the publisher of the original message [2]. An example of the IB Routing protocol can be found in Figure 2.