论文标题
关于传感器攻击下控制器状态的机密性
On the confidentiality of controller states under sensor attacks
论文作者
论文摘要
随着网络攻击在控制系统上的出现，很明显，改善控制系统的安全是当今社会的重要任务。我们调查了可以访问从工厂传输到控制器的攻击者如何完美估计控制器的内部状态。一方面，对控制循环的敏感信息的攻击是违反隐私的行为，另一方面，如果在较大的攻击方案中使用了所获得的估计，则违反了闭环系统的安全性。当前有关传感器攻击的文献通常假定攻击者已经访问了控制器的状态。但是，这并非总是可能的。我们得出了攻击者能够完美估计控制器状态的条件。这些条件表明，如果控制器具有不稳定的极点，则无法对控制器状态进行完美的估计。此外，我们提出了一种防御机制，以使袭击变得不可行。该防御是基于为控制器动态增加不确定性。我们还讨论了为什么不稳定的控制器只是某些植物的良好防御能力。最后，使用三坦克系统的模拟验证了我们的结果。
With the emergence of cyber-attacks on control systems it has become clear that improving the security of control systems is an important task in today's society. We investigate how an attacker that has access to the measurements transmitted from the plant to the controller can perfectly estimate the internal state of the controller. This attack on sensitive information of the control loop is, on the one hand, a violation of the privacy, and, on the other hand, a violation of the security of the closed-loop system if the obtained estimate is used in a larger attack scheme. Current literature on sensor attacks often assumes that the attacker has already access to the controller's state. However, this is not always possible. We derive conditions for when the attacker is able to perfectly estimate the controller's state. These conditions show that if the controller has unstable poles a perfect estimate of the controller state is not possible. Moreover, we propose a defence mechanism to render the attack infeasible. This defence is based on adding uncertainty to the controller dynamics. We also discuss why an unstable controller is only a good defence for certain plants. Finally, simulations with a three-tank system verify our results.
