Optimal Secret Protections in Discrete-Event Systems
Optimal Secret Protections in Discrete-Event Systems
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DOI：
10.1109/tac.2021.3091438
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发表时间：
2021-06
影响因子：
6.8
通讯作者：
Ziyue Ma;Kai Cai
中科院分区：
文献类型：
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作者：
Ziyue Ma;Kai Cai
在本文中，我们研究了由确定性有限自动机建模的离散事件系统中保护秘密的安全问题。在系统中，一些状态被定义为秘密，每个状态都与一个安全级别相关联。问题是设计一个事件保护策略，使得从初始状态到秘密状态的任何事件序列都包含不少于所需安全级别的受保护事件。为了解决这个秘密保护问题，我们首先开发一种称为安全自动机的分层结构。然后，我们证明该问题转化为安全自动机中的监督控制问题。我们考虑保护策略的两个最优标准：1）破坏性，即保护策略对合法用户正常操作的干扰程度最小； 2）成本，即以最小的成本保护保单。对于破坏性的最优性，我们证明了在安全自动机中使用经典的监督控制理论可以得到最小破坏性的保护策略。为了实现成本最优，我们开发了一种通过在安全自动机中寻找最小切割来以最小成本获得保护策略的方法。
In this article, we study a security problem of protecting secrets in discrete-event systems modeled by deterministic finite automata. In the system, some states are defined as secrets, each of which is associated with a security level. The problem is to design an event-protecting policy such that any event sequence from the initial state that reaches a secret state contains a number of protected events no less than the required level of security. To solve this secret securing problem, we first develop a layered structure called the security automaton. Then, we show that the problem is transformed to a supervisory control problem in the security automaton. We consider two criteria of optimality on protecting policies: 1) disruptiveness, i.e., protecting policies with a minimum degree of disturbance to legal users’ normal operations; and 2) cost, i.e., protecting policies with a minimal cost. For the optimality on disruptiveness, we prove that a minimally disruptive protecting policy is obtained by using the classical supervisory control theory in the security automaton. For the optimality on cost, we develop a method to obtain a protecting policy with minimal cost by finding a min-cut in the security automaton.