Scalable Access Control for Privacy-Aware Media Sharing

The prevalence of social networks has made it easier than ever for users to share their photos, videos, and other media content with anybody from anywhere. However, the easy access of user-generated media content also brings about privacy concerns. Traditional access control mechanisms, where a single access policy is made for a specific piece of content, cannot satisfy the user privacy requirements in large-scale media sharing systems. Instead, configuring multiple levels of access privileges for the shared media content is desired. On one hand, it conforms to the principle of social networks in information propagation. On the other hand, it accords with the diverse and complex social relationship among social network users. In this paper, we propose a scalable media access control (SMAC) system to enable such a configuration in a secure and efficient manner. The proposed SMAC system is empowered by the scalable ciphertext policy attribute-based encryption algorithm as well as a comprehensive key-management scheme. We provide formal security proof to prove the security of the proposed SMAC system. In addition, we conduct extensive experiments on mobile devices to demonstrate its efficiency.