Secret-key generation and convexity of the rate region using infinite compound sources

Nima Tavangaran, Rafael F. Schaefer, H. Vincent Poor, Holger Boche

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


In secret-key generation using a compound source, the actual statistics of the source are unknown to the participants. It is assumed rather that the actual source belongs to a set (compound set) which is known to the participants. The secret-key generation protocol should guarantee in this case reliability and security of the generated secret-key simultaneously for all elements of the compound set. In this paper, secret-key generation based on a three-party compound source is studied in which an eavesdropper's side information is also taken into account and strong secrecy is guaranteed. At the same time, the public communication rate constraint between the legitimate users is part of the secret-key generation protocol. In this setting, the achievable secret-key rates for finite compound sources are first reformulated as a region of secret-key rate versus communication rate constraint pairs. It is shown that this region is in general convex, even if the compound set is infinite. Based on this, the secret-key capacity results are extended to be valid for arbitrary (possibly infinite) compound sources with a finite set of marginals. In this case, the secret-key capacity is completely characterized as a function of the forward communication rate parameter between the legitimate users.

Original languageEnglish (US)
Pages (from-to)2075-2086
Number of pages12
JournalIEEE Transactions on Information Forensics and Security
Issue number8
StatePublished - Aug 2018

All Science Journal Classification (ASJC) codes

  • Safety, Risk, Reliability and Quality
  • Computer Networks and Communications


  • Common randomness
  • Compound source
  • Continuity
  • Convexity
  • Secret-key capacity
  • Source uncertainty


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