Personal social graph as an anonymous vehicle for P2P applications: The cost of renting trusted connections

We introduce a trusted self-organized network infrastructure for running anonymous P2P applications, which leverages real-life social links and the basic need for privacy that each individual converts into a carefully built structure dubbed Personal Social Graph (PSG). The PSG is a list owned by each person (enacted by a node in the infrastructure graph), with entries that represent strict trust relationships with other individuals. Each entry consists of a friend's identity and a set of encryption keys, established out-of-band for the purpose of secure communication between the owner and the friend. The real-life small-world connections result in a large network of interconnected PSGs, which we refer to as the Personal Social Graph Network (PSGN). The PSGN is meant to be universal, used as a trusted infrastructure by various distributed applications that encompass subsets of PSGN nodes. In this paper we consider only data-exchange applications relying on in-network caching. Since many applications share the trusted resources of this infrastructure, we introduce a cost per social network edge, incurred whenever the application rents the trusted edge for data exchange in the application context. We assume that the cost is zero when both vertices belong to the application. As edge utilization may be accounted for in a distributed way, the overconsumption could be ultimately sanctioned by the excommunication of the application from the PSGN. For dissemination strategies designed to evenly cache the data across peer nodes, we study the cost of the PSGN usage to a P2P application as a function of the application popularity and activity. We find that the dissemination that caches data as linear combinations of different source packets is costlier than simple packet replication in unit-size data-cache buffers, but manages to fully and evenly distributes the content among application nodes. In addition, adapting the dissemination infrastructure to each application by using a PSGN subgraph that encompasses the application nodes, and the nodes directly attached to them, we lower the price of renting. This is position paper that explores the social infrastructure as a shared resource.