The publish/subscribe communication paradigm has gained high popularity because of inherent decoupling of publishers from subscribers in terms of time, space and synchronization. The basic security mechanism such as authentication and confidentiality is highly challenging in a content based publish/subscribe system. Authentication of publisher and subscribers is difficult to achieve due to loose coupling of publisher and subscriber. The authentication and confidentiality of publisher and subscribers of events ensured by adapting the pairing based cryptography mechanism. Furthermore, an algorithm to cluster subscriber according to their subscriptions preserves a weak notion of subscription confidentiality.