A novel approach for security and robustness in wireless embedded systems

Security and robustness are paramount in wireless embedded systems due to the vulnerability of the underlying communication medium. To institute security and reliability, most of the existing schemes perform periodic re-establishment of authentication credentials and share secrets among various participating nodes. However, such measures result in overheads in an energy-constrained wireless environment. To alleviate this problem, we propose a software approach that exploits the features of the underlying communication protocol and uses the concept of steganography and covert channels. The highlight of our approach is that it does not require any changes to the protocol and relies only on the modification of frame contents without degrading the protocol performance. We argue that our covert-channel based communication scheme provides security and robustness at low cost and it neither requires centralized authority nor does it disrupt the overall network operation. We evaluate the security benefits of our proposed method in terms of the difficulty of detecting the covert channel by the adversary and compare our technique with other existing schemes. Performance evaluation is done by determining the bandwidth efficiency of the channel, backward compatibility with the standard MAC as well as the ease of implementation.