网络安全投资外部性及博弈策略

在企业投资成本和投资利润不同的情况下,应用博弈论理论计算了网络安全投资过程中,由于病毒传染所带来的投资负外部性,提出了信息安全的投资博弈模型.确定了相互依赖前提下企业的投资成本临界点及其影响因素,以及多个企业进行信息安全投资的多个纳什均衡解.同时将问题扩展到风险内生的条件下,阐明该条件下企业投资成本临界点的变化不仅取决于相互传染的可能性大小,还取决于内生外部性的正负及其绝对值大小.该方法为信息安全的风险管理提供了新的思路,为企业确定自身的投资策略以及国家确定相应的政策指导提供依据. 

Investment externality and game strategies of network security

An investment game theoretic model was presented to study the externality in firms′ network security investment with different investment costs and profits.Taking virus contagion as an example, the negative investment externality exerted by the contagion between firms in the network was investigated. Under such an environment, the investment threshold and factors concerned such as contagion probability and the number of investing firms were computed to determine several Nash equilibrium solutions with externality representing the risk. The model was analyzed further when the risk was endogenous and the invest threshold was much more complicated than that in exogenous environment. This endogenous threshold is determined not only by the probability of contagion between firms but also by the sign and absolute value of externalities. This method provides a novel viewpoint to information security risk management and advices for firms′ decision on security investment and government policies to induce investment under externality.