Strong secrecy for cooperative broadcast channels

Ziv Goldfeld, Gerhard Kramer, Haim H. Permuter, Paul Cuff

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

A broadcast channel (BC) where the decoders cooperate via a one-sided link is considered. One common and two private messages are transmitted and the private message to the cooperative user should be kept secret from the cooperation-aided user. The secrecy level is measured in terms of strong secrecy, i.e., a vanishing information leakage. An inner bound on the capacity region is derived by using a channel-resolvability-based code that double-bins the codebook of the secret message, and by using a likelihood encoder to choose the transmitted codeword. The inner bound is shown to be tight for semi-deterministic and physically degraded BCs, and the results are compared with those of the corresponding BCs without a secrecy constraint. Blackwell and Gaussian BC examples illustrate the impact of secrecy on the rate regions. Unlike the case without secrecy, where sharing information about both private messages via the cooperative link is optimal, our protocol conveys parts of the common and non-confidential messages only. This restriction reduces the transmission rates more than the usual rate loss due to secrecy requirements. An example that illustrates this loss is provided.

Original languageEnglish (US)
Article number7707384
Pages (from-to)469-495
Number of pages27
JournalIEEE Transactions on Information Theory
Volume63
Issue number1
DOIs
StatePublished - Jan 2017

All Science Journal Classification (ASJC) codes

  • Information Systems
  • Computer Science Applications
  • Library and Information Sciences

Keywords

  • Broadcast channel
  • channel resolvability
  • conferencing
  • cooperation
  • likelihood encoder
  • physical-layer security
  • strong secrecy

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