Discrete Memoryless Interference and Broadcast Channels With Confidential Messages: Secrecy Rate Regions

• Published in: IEEE transactions on information theory 2008-06, Vol.54 (6), p.2493-2507
• Main Authors: Ruoheng Liu, Maric, I., Spasojevic, P., Yates, R.D.
• Format: Article
• Language: English
• Subjects: Broadcast channels; Broadcasting; channel capacity; Channels; Communication channels; Communication system security; Communication systems; Communications systems; Computer memory; Data integrity; Data transmission; Eavesdropping; Encoding; equivocation rate; Information security; information-theoretic secrecy; Interference; Interference channels; Messages; Multiplexing; Mutual information; Network security; Receivers; Relays; secrecy capacity region; Switches; telecommunication security; Transmitters; Wireless communication
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/TIT.2008.921879

We study information-theoretic security for discrete memoryless interference and broadcast channels with independent confidential messages sent to two receivers. Confidential messages are transmitted to their respective receivers while ensuring mutual information-theoretic secrecy. That is, each receiver is kept in total ignorance with respect to the message intended for the other receiver. The secrecy level is measured by the equivocation rate at the eavesdropping receiver. In this paper, we present inner and outer bounds on secrecy capacity regions for these two communication systems. The derived outer bounds have an identical mutual information expression that applies to both channel models. The difference is in the input distributions over which the expression is optimized. The inner bound rate regions are achieved by random binning techniques. For the broadcast channel, a double-binning coding scheme allows for both joint encoding and preserving of confidentiality. Furthermore, we show that, for a special case of the interference channel, referred to as the switch channel, derived bounds meet. Finally, we describe several transmission schemes for Gaussian interference channels and derive their achievable rate regions while ensuring mutual information-theoretic secrecy. An encoding scheme in which transmitters dedicate some of their power to create artificial noise is proposed and shown to outperform both time-sharing and simple multiplexed transmission of the confidential messages.