2007/10/03 by Lifeng Lai, Lai, Lifeng, Hesham El Gamal +3 · 1 citation
Computer Science · Engineering · Mathematics · #Cellular Automata and Applications #Cooperative Communication and Network Coding #Cryptography and Security (cs.CR) #FOS: Computer and information sciences #Information Theory (cs.IT) #Wireless Communication Security Techniques #cs.CR #cs.IT #math.IT
paper · pdf · doi:10.48550/arxiv.0710.0865
To appear in the Proceedings of the 45th Annual Allerton Conference on Communication, Control and Computing, Monticello, IL, September 26 - 28, 2007
arxiv created 2007/10/03 · openalex publication_date 2007/10/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this work, the role of noisy feedback in enhancing the secrecy capacity of the wiretap channel is investigated. A model is considered in which the feed-forward and feedback signals share the same noisy channel. More specifically, a discrete memoryless modulo-additive channel with a full-duplex destination node is considered first, and it is shown that a judicious use of feedback increases the perfect secrecy capacity to the capacity of the source-destination channel in the absence of the wiretapper. In the achievability scheme, the feedback signal corresponds to a private key, known only to the destination. Then a half-duplex system is considered, for which a novel feedback technique that always achieves a positive perfect secrecy rate (even when the source-wiretapper channel is less noisy than the source-destination channel) is proposed. These results hinge on the modulo-additive property of the channel, which is exploited by the destination to perform encryption over the channel without revealing its key to the source.