Online Social Networks have evolved to be the primary service on the World Wide Web. Facebook claims to have a base of over 800 million of active users. Future communication systems aim at supporting social and collaborative communications: the evolving topologies are expected to resemble the actual social networks of the communicating users and information on their characteristics can be a powerful aid for any network operation.
New emerging technologies that use information on the social characteristics of their participants raise entirely new privacy concerns and require new reflections on Security problems such as trust establishment, secure routing, or data dissemination. This special section comprises of three articles that are extended from initial publications at the IEEE PerCom Workshop on Security and Social Networking (SESOC). The first paper entitled ''Data obfuscation with Network Coding'' authored by Dirk Westhoff, Alban Hessler, Heiner Perrey and Takahiro Kakumaru proposes an obfuscation mechanism for network coding techniques which seem to be very promising for data dissemination in any unreliable medium. Instead of encrypting the data, authors only encrypt the corresponding coefficients
and use the underlying encoding mechanism to obfuscate messages. This mechanism obviously reduces the cost cryptographic operations since data is not encrypted anymore. The second paper by Iain Parris and Tristan Henderson is entitled ''Privacy-enhanced Social-Network routing''. Authors analyze the problem of privacy in Social Network routing. Friendlists are used to improve routing performance in opportunistic networks. Because of the sensitiveness of such ''personal'' information, authors propose a dedicated obfuscation mechanism being applied to messages before they are sent. Finally, the third paper of this special section, ''LotusNet: Tunable Privacy for Distributed Online Social Network Services'' by Luca Maria Aiello and Giancarlo Ruffo explores introduces a framework for the development of Social Networking services on decentralized systems following the peer-to-peer paradigm. Leveraging the rationale that storing the data in a distributed fashion prevents direct exploitation through the provider and employing cryptography to restrict access without centralized access control methods, LotusNet strives to allow the data owners to apply fine-grained authorization to chosen parties, only.
