Publish subscribe communication paradigm has been recognized as the most promising communication paradigms for information dissemination in large scale distributed environment. It has been used in a variety of applications ranging from personalized information dissemination to a wide range of group communications. So publish subscribe system needs to fulfill the basic security demands of these information dissemination applications. Confidentiality, authentication, data integrity and non repudiation are the most important security services in security environment. Encryption and signature are the basic cryptographic tools for achieving these security services in communication system. This paper presents a novel approach to provide all the basic aspects of security such as confidentiality, authentication, integrity and Non-repudiation in broker-less content based publish subscribe system along with forward secrecy and unforgeability. The scheme use identity based signcryption technique and that can effectively reduces the computational cost and communication overhead.

Openly available communication signals, in wireless adhoc network poses high security risk. The adhoc networks are very much vulnerable to Dos attacks on the network layer. Blackhole and Grayhole attacks are the widespread attacks on adhoc networks. Here the malicious nodes interrupt data transmission in the network by transmitting false routing information. A realization of these enabled us to approach the subject of data security in wireless adhoc networks with a different perspective so as to have a communication route, free from all previously mentioned security threats. The purpose of this paper is to present an efficient Adhoc On-demand Distance Vector (AODV) protocol that removes the malicious node by isolating it, thereby ensuring secure communication. In order to achieve this goal, the intermediate nodes receiving false routing information from its neighbour node is programmed to consider that neighbour node as malicious. In adhoc network, nodes can join or leave at any time. So, an efficient security mechanism is needed. So, the nodes are arranged in spanning tree fashion. An RSA key exchange and two encryption techniques are used among authenticated neighbours in the adhoc network to provide more security and thus avoid group rekeying problems.

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Intermittently connected mobile Network systems represent a challenging environment for networking research, due to the problems of ensuring messages delivery in spite of frequent disconnections and random meeting patterns. These networks fall into general category of Delay Tolerant Networks. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc networks, etc. In this context, traditional routing schemes fail, because they try to establish complete end-to-end paths, before any packet is sent. To deal with such networks, researches introduced flooding based routing schemes which leads to high probability of delivery. But the flooding based routing schemes suffered with contention and large delays. Here the proposed protocol “Spraying with performed by a node upon reception of an Acknowledgment message”, sprays a few message copies into the network, neighbors receives a copy and by that relay nodes we are choosing the shortest route and then route that copy towards the destination, if packets reach its destination which that node diffuse Acknowledment with Autonomic behaviour and discard messages. Previous works assumption is that there is no contention and unreachable nodes. But we argue that contention and unreachable nodes must be considered for finding efficiency in routing. So we are including a network which has contention and unreachable nodes and we applied the proposed protocol. So, we introduce new routing mechanism for Diffusion Based Efficient Spray Routing in Intemittently Connected Mobile Networks with Multiple Copies.

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