Cloak: A ten-fold way for reliable covert communications

Xiapu Luo, Edmond W.W. Chan, Kow Chuen Chang

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

35 Citations (Scopus)


In this paper, we propose Cloak-a new class of reliable timing channels-which is fundamentally different from other timing channels in several aspects. First, Cloak encodes a message by a unique distribution of N packets over X TCP flows. The combinatorial nature of the encoding methods increases the channel capacity largely with (N, X). Second, Cloak offers ten different encoding and decoding methods, each of which has a unique tradeoff among several important considerations, such as channel capacity and the need for packet marking. Third, the packet transmissions modulated by Cloak could be carefully crafted to mimic the normal TCP flows in a typical TCP-based application session. Although Cloak's basic idea is simple, we show in this paper how we tackle a number of challenging issues systematically. Our experiment results collected from PlanetLab nodes and a test bed suggest that Cloak is feasible under various network conditions and different round-trip delays.
Original languageEnglish
Title of host publicationComputer Security - ESORICS 2007 - 12th European Symposium on Research in Computer Security, Proceedings
Number of pages16
Publication statusPublished - 1 Dec 2007
Event12th European Symposium on Research in Computer Security, ESORICS 2007 - Dresden, Germany
Duration: 24 Sept 200726 Sept 2007

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4734 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference12th European Symposium on Research in Computer Security, ESORICS 2007


  • Attack models
  • Covert channel analysis
  • Network security

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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