Secrecy rates of binary wiretapper channels using feedback schemes

In this paper, we propose a feedback scheme to achieve a strictly positive secrecy rate over an eavesdropped communication link when the eavesdropper´s channel is less noisy than the legitimate receiver´s channel. All channels are assumed binary and symmetric (BSC). The proposed scheme exploits the channel randomness inherent in feedback channels. We show that our feedback scheme can further increase the secrecy rate achievable by the Wyner´s method when the eaves-dropper´s channel is worse. Some pre-/post-processing schemes to intentionally improve and degrade the equivalent wiretapper channels, respectively, are also proposed to further enhance the overall secrecy rate.