Secure relaying: Can publicly transferred keys increase degrees of freedom?

Tùng T. Kim, H. Vincent Poor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Secure communication over a half-duplex relay system in the presence of an external wiretapper is investigated. In such a scenario, conventional relaying protocols generally provide secrecy rates that converge to a finite constant in the high signal-to-noise ratio (SNR) regime. It is shown in this work that strictly superior performance can be achieved by allowing the destination to transfer random keys in the form of known interference to the relay insecurely over the wireless medium. When there is no direct link between the source and the destination, an amplify-and-forward (AF) protocol is shown to achieve a secrecy rate that scales as 1/2 log SNR, if each of the legitimate nodes has a single antenna only. However, in the presence of a direct link between source and destination, this scaling rule no longer applies. The bottleneck of the AF scheme in the presence of a direct source-destination link is identified, motivating the use of multiple antennas at the destination to almost surely guarantee a secure degree of freedom of one half over the channel. The results hold even if the eavesdropper has more antennas than the source and the relay combined.

Original languageEnglish (US)
Title of host publication2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009
Pages1076-1081
Number of pages6
DOIs
StatePublished - Dec 1 2009
Event2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009 - Monticello, IL, United States
Duration: Sep 30 2009Oct 2 2009

Publication series

Name2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009

Other

Other2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009
CountryUnited States
CityMonticello, IL
Period9/30/0910/2/09

All Science Journal Classification (ASJC) codes

  • Communication
  • Control and Systems Engineering
  • Computer Science(all)

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  • Cite this

    Kim, T. T., & Poor, H. V. (2009). Secure relaying: Can publicly transferred keys increase degrees of freedom? In 2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009 (pp. 1076-1081). [5394873] (2009 47th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2009). https://doi.org/10.1109/ALLERTON.2009.5394873