Paper 2005/250

The topology of covert conflict

Shishir Nagaraja and Ross Anderson


Often an attacker tries to disconnect a network by destroying nodes or edges, while the defender counters using various resilience mechanisms. Examples include a music industry body attempting to close down a peer-to-peer file-sharing network; medics attempting to halt the spread of an infectious disease by selective vaccination; and a police agency trying to decapitate a terrorist organisation. Albert, Jeong and Barabasi famously analysed the static case, and showed that vertex-order attacks are effective against scale-free networks. We extend this work to the dynamic case by developing a framework based on evolutionary game theory to explore the interaction of attack and defence strategies. We show, first, that naive defences don't work against vertex-order attack; second, that defences based on simple redundancy don't work much better, but that defences based on cliques work well; third, that attacks based on centrality work better against clique defences than vertex-order attacks do; and fourth, that defences based on complex strategies such as delegation plus clique resist centrality attacks better than simple clique defences. Our models thus build a bridge between network analysis and evolutionary game theory, and provide a framework for analysing defence and attack in networks where topology matters. They suggest definitions of efficiency of attack and defence, and may even explain the evolution of insurgent organisations from networks of cells to a more virtual leadership that facilitates operations rather than directing them. Finally, we draw some conclusions and present possible directions for future research.

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Published elsewhere. Computer Laboratory, Technical Report 637, University of Cambridge
anonymityinformation hidingterrorismscale-free networkscomplex networksevolutionary game theoryresilienceconflict
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sn275 @ cam ac uk
2005-08-01: last of 4 revisions
2005-07-31: received
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      author = {Shishir Nagaraja and Ross Anderson},
      title = {The topology of covert conflict},
      howpublished = {Cryptology ePrint Archive, Paper 2005/250},
      year = {2005},
      note = {\url{}},
      url = {}
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