Secure Broadcasting Using Independent Secret Keys

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Rafael F. Schaefer - , Technical University of Berlin (Author)
  • Ashish Khisti - , University of Toronto (Author)
  • H. Vincent Poor - , Princeton University (Author)

Abstract

The problem of secure broadcasting with independent secret keys is studied. The particular scenario is analyzed in which a common message has to be broadcast to two legitimate receivers, while keeping an external eavesdropper ignorant of it. The transmitter shares independent secret keys of sufficiently high rates with both legitimate receivers, which can be used in different ways: They can be used as one-Time pads to encrypt the common message, as fictitious messages for wiretap coding, or as a hybrid of these. In this paper, capacity results are established when the broadcast channels involving the three receivers are degraded. If both legitimate channels are degraded versions of the eavesdropper's channel, it is shown that the one-Time pad approach is optimal for several cases, yielding corresponding capacity expressions. Alternatively, the wiretap coding approach is shown to be optimal if the eavesdropper's channel is degraded with respect to both legitimate channels, establishing capacity in this case as well. If the eavesdropper's channel is neither the strongest nor the weakest, an intricate scheme that carefully combines both concepts of one-Time pad and wiretap coding with fictitious messages turns out to be capacity-Achieving. Finally we also obtain some results for the general non-degraded broadcast channel.

Details

Original languageEnglish
Pages (from-to)644-661
Number of pages18
JournalIEEE Transactions on Communications
Volume66
Issue number2
Publication statusPublished - Feb 2018
Peer-reviewedYes
Externally publishedYes

External IDs

ORCID /0000-0002-1702-9075/work/165878319

Keywords

ASJC Scopus subject areas

Keywords

  • Broadcast channel, common message, fictitious messages, one-Time pad, secrecy capacity, secret key, wiretap coding