---
res:
bibo_abstract:
- In a distributed system with attacks and defenses, both attackers and defenders
are self-interested entities. We assume a reward-sharing scheme among interdependent
defenders; each defender wishes to (locally) maximize her own total fair share
to the attackers extinguished due to her involvement (and possibly due to those
of others). What is the maximum amount of protection achievable by a number of
such defenders against a number of attackers while the system is in a Nash equilibrium?
As a measure of system protection, we adopt the Defense-Ratio (Mavronicolas et
al., 2008)[20], which provides the expected (inverse) proportion of attackers
caught by the defenders. In a Defense-Optimal Nash equilibrium, the Defense-Ratio
matches a simple lower bound.We discover that the existence of Defense-Optimal
Nash equilibria depends in a subtle way on how the number of defenders compares
to two natural graph-theoretic thresholds we identify. In this vein, we obtain,
through a combinatorial analysis of Nash equilibria, a collection of trade-off
results:• When the number of defenders is either sufficiently small or sufficiently
large, Defense-Optimal Nash equilibria may exist. The corresponding decision problem
is computationally tractable for a large number of defenders; the problem becomes
NPNP-complete for a small number of defenders and the intractability is inherited
from a previously unconsidered combinatorial problem in Fractional Graph Theory.•
Perhaps paradoxically, there is a middle range of values for the number of defenders
where Defense-Optimal Nash equilibria do not exist.@eng
bibo_authorlist:
- foaf_Person:
foaf_givenName: Marios
foaf_name: Mavronicolas, Marios
foaf_surname: Mavronicolas
- foaf_Person:
foaf_givenName: Burkhard
foaf_name: Monien, Burkhard
foaf_surname: Monien
- foaf_Person:
foaf_givenName: Vicky
foaf_name: Papadopoulou Lesta, Vicky
foaf_surname: Papadopoulou Lesta
bibo_doi: 10.1016/j.dam.2013.05.022
bibo_issue: 16-17
bibo_volume: 161
dct_date: 2013^xs_gYear
dct_language: eng
dct_publisher: Elsevier@
dct_title: How many attackers can selfish defenders catch?@
...