Security Enhanced Adaptive TCP for Wireless Ad Hoc Networks

TCP is a reliable transport protocol designed to perform well in wired networks where packet losses are due congestion. However in wireless ad hoc networks, where packet losses are due to channel errors or link failures between mobile nodes, TCP degrades its performance. Further, it lacks certain protection mechanisms from internal and external malicious nodes. In this paper, a security enhanced and adaptive TCP, namely SA-TCP, has been proposed for wireless ad hoc networks. SA-TCP uses network layer information to detect various types of packet losses and adjusts the value of congestion window dynamically according to the conditions of the dynamic network. It works normally to collect the samples of congestion window and calculates the mean from these samples to set the value of future congestion window. SA-TCP also adjusts the value of congestion window limit according to network conditions. In order to make SA-TCP suitable in highly vulnerable wireless ad hoc networks, a less complex identity-based public key cryptography has been integrated with the proposed protocol. The three-way handshaking process of SA-TCP is made secure by generating a secret session key on-fly between source-destination. Simulation results show that SA-TCP gives higher throughput compared to the popular New Reno and ATCP in different wireless ad hoc network scenarios.