An Improved Feedback Coding Scheme for the Wire-tap Channel

Secure and reliable transmission over communication channels is first characterized by Wyner’s wiretap channel (WTC) model. In recent years, the WTC with noiseless feedback (WTC-NF) attracts a lot attention, and it has been shown that the legal receiver’s feedback enlarges the secrecy capacity of the WTC. Even so, the current feedback strategy for the WTC mainly focuses on generating key used for encrypting the transmitted message, and this strategy does not achieve the secrecy capacity of the WTC-NF. In this paper, a new coding strategy for the WTC-NF is presented. Besides used for generating key, the legal receiver’s feedback of this new strategy is also used to produced a help information which helps the legal receiver to ameliorate his decoding performance. For the WTC-NF, the proposed new feedback strategy is shown to be better than the already existing one, and a binary example is given to further explain these results.