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A Game Theoretic Study of Attack and Defense in Cyber-Physical Systems. Chris Y. T. Ma, Nageswara S. V. Rao, David K. Y. Yau. Agenda. Motivation System model Boolean attack and defense System with robustness Conclusion. Motivation. Cyber-physical systems
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A Game Theoretic Study of Attack and Defense in Cyber-Physical Systems Chris Y. T. Ma, Nageswara S. V. Rao, David K. Y. Yau
Agenda Motivation System model Boolean attack and defense System with robustness Conclusion
Motivation • Cyber-physical systems • Model a number of engineering infrastructure systems • Physical – hardware components • Cyber – computations, communications • Susceptible to attacks
Motivation • Our objectives • Use of game theoretic formulations to capture the attack and defense of cyber-physical systems • Study the survival of the cyber-physical systems using different utility functions
Motivation • Our observations • Pure strategy Nash Equilibrium (NE) may not exist • Cost boundaries (budgets) may determine the NE outcome • The presence of NE does not mean the system survives
Boolean Attack and Defense Special case of attacks where the cyber and physical parts can be attacked or defended as whole units Successful attack on either cyber or physical part will disrupt the whole system
System with Robustness General case when resources are not represented as one whole unit Consider different benefit functions
System with Robustness The players’ best response functions
General Benefit and Cost FunctionsOne-space cases • Observation • Pure strategy Nash Equilibrium is rare, most likely to exist when the attacker has tight budget
General Benefit and Cost FunctionsTwo-space cases • Observations • Resource allocation is non-trivial even without an attacker, and greedy approach may be sub-optimal, e.g., the S-shaped benefit function • The NE results are sensitive to the parameters of the payoff functions in the two spaces
General Benefit and Cost FunctionsTwo-space cases System A Cyber space: Ba Physical space: Ba NE: X System C Cyber space: Ba Physical space: Bb NE: ? System B Cyber space: Bb Physical space: Bb NE: X Observations
Conclusions Presented a game theoretic formulation of the interplay between a rational attacker and a rational defender in cyber-physical system security Studied the presence (or absence) of pure strategy Nash Equilibrium using different payoff functions