Relay Channels with Confidential Messages

Abstract

We consider a relay channel where a relay helps the transmission of messages from one sender to one receiver. The relay is considered not only as a sender that helps the message transmission but as a wire-tapper who can obtain some knowledge about the transmitted messages. In this paper we study the coding problem of the relay channel under the situation that some of transmitted messages are confidential to the relay. A security of such confidential messages is measured by the conditional entropy. The rate region is defined by the set of transmission rates for which messages are reliably transmitted and the security of confidential messages is larger than a prescribed level. In this paper we give two definition of the rate region. We first define the rate region in the case of deterministic encoder and call it the deterministic rate region. Next, we define the rate region in the case of stochastic encoder and call it the stochastic rate region. We derive explicit inner and outer bounds for the above two rate regions and present a class of relay channels where two bounds match. Furthermore, we show that stochastic encoder can enlarge the rate region. We also evaluate the deterministic rate region of the Gaussian relay channel with confidential messages.

20 pages, 6 figures, submitted to IEEE Transactions on Information Theory, Special issue on Information Theoretic Security

Cited by in corpus (6)

• Cooperation with an Untrusted Relay: A Secrecy Perspective
• The Wiretap Channel with Feedback: Encryption over the Channel
• Secure Degrees of Freedom of One-hop Wireless Networks
• The Secrecy Rate Region of the Broadcast Channel
• Secure Degrees of Freedom Regions of Multiple Access and Interference Channels: The Polytope Structure
• Secure Degrees of Freedom of Multi-user Networks: One-Time-Pads in the Air via Alignment