CIPHER BASED ACKNOWLEDGEMENT SCHEME FOR MANET by Neha
MANET is a collection of independent networks. In mobile ad-hoc network, mobile devices are connected through various wireless links. The MANET works on a constrained bandwidth. The network topologies are rapidly changing and may vary from time to time. Each and every device must act as a router and route their packet for transferring any information among each other. Due to its topology, resource constraints, no centralized infrastructure and less security, it is endangered to different attacks and black hole attack is one of them. In this attack, the malicious node claim itself as having the smallest path to the destination and falsely replies to the route requests, and drops all receiving packets. In the past various models and approaches, had been proposed for performance enhancement and detection of malicious nodes in MANET. Various modifications has been done to routing protocols and best path selection, IDS based system has been developed but all of above modification does not provide better data wholeness. To overcome this problem in MANET, in the proposed work malicious node detection and encryption based approach has been used. In the proposed work, AES based encryption approach has been used with AODV routing protocol so that data integrity and confidentiality can be achieved. In this process data messages has been first converted to hexadecimal and then round sub keys were used. After this process shifting of rows and mixing of column has been done so that data can be encrypted and convert to cipher text. Cipher data can be decrypted using on key at decryption process that is reverse of encryption strategy using AES. In the proposed work reverse tracking mechanism has been used for detection of attacker nodes, that degrades performance of the network. In the process of reverse tracking mechanism all the nodes that are one hop neighbor from the source node has been identified by transmitting a message and the reply message has been verified if any message is received from other than single hop communication node then the detection mechanism becomes active for detection of black hole and grey hole attack over the network. Mobility speed is the major concern in MANET that affect the performance of the network. High mobility degrades performance of the network due to lack of route establishment. In the simulation various performance evaluation parameters have been analyzed, which were used for validation of proposed work. These parameters (packet delivery ratio, end to end delay, throughput and network overhead) have been evaluated with respect to time as well as mobility. On the basis of obtained results, it was concluded that proposed approach provide better performance than EAACK approach.