Opportunistic networks are a special type of Mobile Ad hoc network which are wirelessly interlinked nodes with the absence of end to end connectivity. All nodes in an opportunistic network are free to move in an environment. Due to the high degree of mobility of nodes, opportunistic networks differ significantly from the existing traditional networks and it works on store, carry &forward mechanism in which, each node has a communication range. Within its proximity, if any node comes, it can send and receive messages. In an opportunistic network, there is no proper infrastructure available for communication and node have limited storage and computational capabilities. The major problem being faced in an opportunistic network is the identification of normal and malicious nodes because due to the open nature of the opportunistic network, malicious nodes also can join the network and perform some malicious activities like Sybil attack. We propose a remedy to address the authentication and privacy issue that can arise in an opportunistic network. According to the findings of the simulation, the proposed research work satisfies the authentication and privacy criteria of an opportunistic network
