The Value of Traded Target Information in Security Games

Abstract

Ample evidence has confirmed the importance of information in security. While much research on security game has assumed the attackers' limited capabilities to obtain target information, few studies consider the possibility that the information can be acquired from a data broker, not to mention exploring the attackers' profit-seeking behaviors in the shrouded underground society. This paper studies the role of information in the security problem when the target information is sold by a data broker to multiple attackers. We formulate a novel multi-stage game model to characterize both the cooperative and competitive interactions of the data broker and attackers. The attackers' competition with correlated purchasing and attacking decisions is modeled as a two-stage stochastic model, and the bargaining process between the data broker and the attackers is analyzed in a Stackelberg game. The study contributes to the literature by exploring the behaviors of the attackers with labor specialization, and providing quantitative measures of information value from an economic perspective. The proposed frameworks characterize both the attackers' competitive equilibrium solutions and the data broker's pricing strategies under different market parameters. We also show how factors such as the quality of information, the heterogeneity in attackers' utilities, and their cooperative purchasing strategy would have an impact on the results.