Study And Performance Evaluation Of Security-Throughput Tradeoff With   Link Adaptive Encryption Scheme
  With the ever increasing volume of information over wireless medium, security has assumed an important dimension. The security of transmitted data over a wireless channel aims at protecting the data from unauthorized intrusion. Wireless network security is achieved using cryptographic primitives. Some properties that give encryption mechanism their cryptographic strength also make them very sensitive to channel error as well. Therefore, security for data transmission over wireless channel results in throughput loss. Trade-off between security and throughput is always a major concern in wireless networks. In this paper, a Link Adaptive Encryption scheme is evaluated that adapts to channel variations and enhances the security level of WLANs without making any compromise with the network performance. Numerical results obtained through simulation are compared with the fixed block length encryption technique in two different modes of operation- Electronic Code Book (ECB) & Cipher Block Chaining (CBC). Optimal block length is also computed, which is assumed to be the effective strength of the cipher. It has been observed that security attained with link adaptive scheme operating in ECB mode of cipher is a better solution for security and throughput trade-off. However, it is found that if computational security is a major concern, link adaptive scheme in CBC mode should be preferred. 
Poonam Jindal and Brahmjit Singh
cs.CR