Date Added: Mar 2012
Wireless networks are used more and more often to exchange sensitive data. Due to the broadcast nature of the medium, every node in the network is a potential eavesdropper, and securing the transmitted information is critical. Traditionally, security is ensured by network-layer cryptography techniques. These techniques are potentially vulnerable, since they rely on the mostly unproven assumption that certain mathematical functions are hard to invert. Methods exploiting the randomness inherent in noisy channels, known as physical layer security, were proposed to provide an additional level of protection and to achieve perfect secrecy.