Preserving Privacy with PrPl: a Decentralized Social Networking Infrastructure

This paper presents PrPl, a decentralized infrastructure that lets users participate in online social networking without loss of data ownership. PrPl adopts a person-centric architecture, where each individual uses a Personal-Cloud Butler service that provides a safe haven for one’s personal digital asset and supports sharing with fine-grain access control. A user can choose to run the Butler on a home server, or use a paid or ad-supported vendor of his choice. Each Butler provides a federation of data storage; it keeps a semantic index to data that can reside, possibly encrypted, in other storage services. It uses the standard, decentralized OpenID management system, so users can use their established personas in accessing the data. One pre-requisite to the success of a platform is the availability of applications, which means that ease of application development is essential. We have developed a language called SociaLite, based on Datalog, that allows developers to use a simple declarative database query to access the large collection of private data served up by the Butlers in our social circle running under different administrative domains. We have developed a prototype of the PrPl infrastructure and implemented a number of simple social applications on the system. We found that the applications can be written in a small number of lines of code using SociaLite. Preliminary experimental results suggest that it is viable to enable sharing of private social data between close friends with a decentralized architecture.