無線網狀網路中考量惡意與多重干擾器攻擊下最大化系統存活度之高效網路規劃與防禦策略

Abstract

由於無線網路的便利性，近十幾年來快速發展出許多服務與應用，例如：行動電話網路、Wi-Fi、WiMAX等，為我們的生活帶來很多便利。然而，有部分的無線網路服務是應用於所謂safe-critical或是life-critical的系統，例如病患的追縱、交通監視、以及緊急救援等等，一旦系統無法使用將會造成嚴重的問題。因此，資訊安全，特別是持續性(continuity)在無線網路裡是一項重要的議題。 但在無線網路裡，有一種攻擊形式對於無線網路服務的持續性會有極大威脅，這種攻擊形式稱為「阻斷式攻擊」(Jamming Attack)。這種攻擊的目標是阻斷特定或是一定範圍的無線通訊頻道，使其無法進行通訊。由於無線傳輸媒介的開放特性，任何只要有無線通訊能力的網路裝置都能發起這樣的攻擊。而當網路中存在多個阻斷器時，情況又更加複雜。然而，目前對於防禦者應如何規劃網路或是分配資源以最小化由惡意攻擊者使用發起的阻斷式攻擊對網路的影響之研究仍尚付闕如，更不用提具有多重阻斷器的情境。 因此，在本論文中提出一個數學模型來描述這個問題的攻防情境。該問題的解法是藉由一連串的評估與策略強化的「評估流程」，逐步提升解的品質。最終為防禦者找出一個高效的網路規劃以及防禦策略。藉著模擬的優勢，我們可以考量「不完全資訊」(imcomplete information)的概念，使這個問題情境更貼近於真實情況。

Owing to the convenience of wireless networks, there are many mature applications which have been developed in recent years, for example, cellular telephone systems, Wi-Fi and WiMAX. However, some wireless applications are safe-critical or life-critical, such as patient tracking, traffic monitoring and emergency rescue. Therefore, security, especially continuity, of wireless networks is a critical issue in wireless networks. Unfortunately, there is a category of attacks that seriously threatens the continuity of wireless networks, which is called jamming attack. The objective of such attacks focuses on interdiction of any communication on the targeted channels or a range of frequency. The open nature of wireless mediums makes it vulnerable to any wireless capable devices. Worst of all, the wireless environment become more sophisticated when there are multiple jammers in one single channel. However, there have not been any researches address the issue of how the service providers should deploy its topology or allocate its resources to minimize the impact of jamming attacks of multiple jammers launched by malicious attackers. Therefore, in this thesis, we proposed a mathematical model to formulate an attack-defense scenario of the problem. The solution is derived by evaluation process which applies a series of evaluations and policy enhancements to improve the quality of solution. Finally, obtain an effect solution of topology planning and defending strategies for the defenders. With the advantage of simulations, we can take the concept of incomplete information into consideration which makes the problem closer to reality.