Privacy preserving online social network

Abstract

Over the last years, online social networks have become a popular mean for users to interact and engage in social activities, such as sharing information, exchanging opinions, organizing events, and publishing advertisements. The volume of data handled by social networks is staggering: there are about 3000 pictures uploaded to Flickr each minute, 190 million tweets posted from all over the world each day, 70 billion pieces of contents shared on Facebook as well as 92 billion page views on Youtube. Such huge ocean of data is a mine hiding valuable information for every business who wants to develop high quality market research and top marketing campaigns.

However, today's online social networking requires users to trust the service provider for the confidentiality and integrity of their data. Social network providers have the access to all users' data. They not only can share it with external parties, like targeted advertisement companies but also can tamper sensitive data without the permission of the owner. Users' lack of full control over their own data has raised an emerging threat about privacy invasion.

Our project aims to help users to overcome these privacy issues. We first designed a cryptography-based framework for building online social networking services. The framework allows users to sign and encrypt their posted content at the client before transferring it to the server so that it guarantees confidentiality as well as integrity of users' data towards the provider. With the design, users are now able to protect the privacy and integrity of their data from a potentially malicious provider, while preserving the availability, reliability, and usability benefits of centralized social network. Based on the framework design, we have developed two systems: PTwitter which supports "Twitter-liked" services and EFacebook which provides "Facebook-like functions".