Enhancing Secrecy Rate Region for Recent Messages for a Slotted Multiple Access Wiretap Channel to Shannon Capacity Region
This addresses security constraints in communication systems for scenarios like wireless networks, though it appears incremental as it builds on existing wiretap channel models.
The paper tackles the rate-loss problem in wiretap channels by proposing a coding scheme for a two-user multiple access wiretap channel that uses previous messages as keys to enhance secrecy rates, achieving the Shannon capacity region without a wiretapper and securing recent messages against eavesdroppers. It also extends this to a fading channel, showing the capacity region can be achieved in an ergodic sense.
Security constraint results in \textit{rate-loss} in wiretap channels. In this paper we propose a coding scheme for two user Multiple Access Channel with Wiretap (MAC-WT), where previous messages are used as a key to enhance the secrecy rates of both the users until we achieve the usual capacity region of a Multiple Access Channel (MAC) without the wiretapper (Shannon capacity region). With this scheme all the messages transmitted in the recent past are secure with respect to all the information of the eavesdropper till now. To achieve this goal we introduce secret key buffers at both the users, as well as at the legitimate receiver (Bob). Finally we consider a fading MAC-WT and show that with this coding/decoding scheme we can achieve the capacity region of a fading MAC (in ergodic sense).