Abstract: Multicast is often used for streaming multimedia applications and offers efficient delivery of data on internet from a source to multiple destinations. A secure and authenticated multicast method for message delivery is based on large scale content distribution. Even though multicast has been very successful at providing an efficient, best-effort data delivery service to huge groups under Gaussian channel and geographic protocol, but poses significant challenges in providing a scalable and secure platform for social networking. In this research, a method called Scalable Secure Multicasting (SSM) is designed based on large scale content distribution to ensure group communication between users in Social Networking. The proposed method is aimed at encouraging users to actively participate in the overlay activities and discourages them from indulging in illegal usage of copyrighted data. The method SSM employs a Feature-based Public Key Broadcast Encryption with trust designer that serves as an effective authentication mechanism, ensuring secure message transfer. Next, an efficient Incremental Hash-based Integrity Validation is designed to ensure integrity of the message being broadcasted and therefore minimizing the computation overhead. Finally, a transformation algorithm is implemented to optimize multicasting by merging similar multicast groups in a principled fashion aiming at improving the scalability when the social network is used by large number of groups. Simulation results are presented to show the efficiency and performance of the proposed method. Using extensive simulation, we show that the proposed method is efficient by achieving secure message transfer, maximizes the scalability by minimizing the packet loss rate and minimizes the computation overhead.