Decentralized Social Networks: System architecture, Protocol Design and Implementation

Monday, May 11, 2015
POB 2.444

Due to the privacy concerns of existing centralized Online Social Networks (OSN),  researchers and developers have tried to design, implement and deploy decentralized social networks (DSN) in  recent years. Despite numerous attempts and efforts, only a small portion of those projects have managed to achieve actual deployment status and none but one of them have more than one million users. We argue that the major hurdle for the widespread adoption of DSN is the lack of a smooth transition path which would allow users to gradually migrate away from the existing Social Networking Services (SNS) without cutting ties with their friends who would remain on the centralized OSNs. Towards this end, we have built a lightweight Python-based middleware, SNSAPI, to unify the interfaces and data structures of heterogeneous SNS. Unlike most prior works, this middleware is user-oriented and requires no infrastructure support.  OSN users can readily manipulate their social channels in a programmable and cross-platform fashion. This gives an effective way to gradually detach users from centralized OSN service providers. In this talk, we will first present the design and implementation of the open-source SNSAPI project.  By taking advantage of the multi-interfacing nature of SNSAPI, users can connect with each other via all kinds of channels, including traditional Online Social Network (OSN) and other means of communications like Email and RSS. In this way, a Decentralized Social Network (DSN) can be constructed in an ad hoc manner. We have emulated a 6000-node SNSAPI-based DSN on PlanetLab and evaluated its performance by replaying real-world OSN activity traces collected from a mainstream OSN. Our experience with SNSAPI has also helped us to identify new challenges in the realization of DSN services. In the 2nd part of the talk, we will describe our recent work in tackling two of such challenges. Firstly, we will present a distributed control protocol which coordinates the information dissemination in DSN while avoiding congestion. Secondly, we will discuss how to enable distributed, privacy-preserving community detection in DSNs. 


Associate Professor
Chinese University of Hong Kong

Wing Cheong Lau is currently an Associate Professor in the Department of Information Engineering and the Director of the Mobile Technologies Center at the Chinese University of Hong Kong (CUHK).  Before joining CUHK, he spent 10 years in the US with Bell Labs, Holmdel and Qualcomm, San Diego.  Wing received his BSEE degree from the University of Hong Kong and MS and PhD degrees in Electrical and Computer Engineering from the University of Texas at Austin.  His research interests include System Modeling, Networking Protocol Design and Performance Analysis, Network/Systems Security and Mobile Computing. His recent research projects include: Online Social Network Privacy and Vulnerabilities, Authenticated 2D barcodes, Decentralized Social Networking protocols/systems and Resource allocation for Large-scale Computing Clusters. He serves on the Technical Program Committee for various international conferences including ACM Sigmetrics, IEEE Infocom, ICC, Globecom, WCNC, VTC, and ITC. He also served as the Guest Editor for the Special Issue on High-Speed Network Security of the IEEE Journal of Selected Areas in Communications (JSAC). Wing holds 17 US patents with a few more pending. His research findings have been published in more than 80 scientific papers in major international journals and conferences. Wing is a Senior Member of IEEE and a member of ACM and Tau Beta Pi.