Jamming-based

Jamming-based secure communication protocols exploit the superposition property of the wireless medium, by intentionally creating interference to confuse an illegitimate eavesdropper.

Secret Key Agreement by Public Discussion from Common Information
The result by Csisz$\overset{´}{a}$r and K$\overset{¨}{o}$rner for the Broadcast channel with confidential messages, suggests that positive secrecy rates are only achievable when legitimate receivers enjoy more favorable channel conditions than eavesdroppers. In an attempt to disprove this suggestion in a different setting, Maurer considered a modified version of the secrecy problem introduced by Shannon where both the main and eavesdropper's channels are noiseless. The modification lies in the assumption that the legitimate receiver is active and can transmit bits that are received by the message source and the eavesdropper through binary symmetric channels with crossover probabilities $\epsilon$ and $\delta$, respectively.