Secure group instant messaging using cryptographic primitives

Instant Messaging (IM) services over the last few years have evolved from a casual communication tool to a formal business communication tool. Security requirements change drastically when instant messaging systems are employed in the corporate world as sensitive data needs to be transmitted. Many security enhancements have been proposed for instant messaging from the perspective of peer-to-peer talk. In this paper, we study the extension of secure instant messaging for group settings. We also propose a scheme, IBECRT, which uses ID-based encryption and the Chinese Remainder Theorem. The scheme does not require a central trusted entity for key distribution and achieves uniform work-load distribution. Additionally, the protocol has the following properties: hiding the users' identity in a conference, authentication of senders, and integrity protection of the messages exchanged.