Distributed protocols against mobile eavesdroppers

  • P. Spirakis
  • B. Tampakas
  • H. Antonopoulou
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 972)


We propose and study the following pursuit-evation problem in distributed enviroments: Members of a team of guards (e.g. antivirus programs) traverse the links of a network represented by a graph G, in pursuit of a fugitive (e.g. worm) which moves along the links of the graph without any other knowledge about the locations of the guards than whatever it can collect as it moves (e.g. the worm is oblivious to dynamic network behaviour). The fugitive's purpose is just to read local information at each node and to stay in the net as long as possible. When a guard meets a fugitive, the fugitive is destroyed. We combinatorially characterize and compare such problems, and we present network protocols that allow an efficient (in terms of number of guards and messages) elimination of the fugitive. Note that the problem we study is fundamentally different from distributed graph searching, since the fugitive does not know the locations of the guards. Our protocols make use of accidental meetings in random walks. The analysis and the proof techniques are based on a novel extension of multiple, parameterized random walk properties which may be of independent theoretical interest.


Theory of Distributed Computation Privacy and Security Algorithms and Data Structures 


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Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • P. Spirakis
    • 1
  • B. Tampakas
    • 1
  • H. Antonopoulou
    • 1
  1. 1.Computer Technology InstitutePatrasGreece

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