利用相對定位系統來增進無線區域網路之位置隱私

Abstract

目前使用者的位置隱私在不同的環境中都有遭受威脅的可能。在無線區域網路的環境中，攻擊者可以透過使用者不會改變的網路卡實體位置來達到追蹤的目的。雖然目前有很多相關的研究被提出來克服這個問題，由於這些相關研究並未把附近移動裝置的移動行為列入考量，因此這些目前的解決方案會錯過許多可以改善使用者位置隱私的理想時機，也就是這些現行方案對於找到理想的網卡位置更新時機是有困難的；此外，這些現行方案會有頻繁的無用網卡位置更新動作發生。因此，在這篇論文中，我們提出一個以相對定位技術為基礎的方案，透過分析每位使用者的移動行為來提高位置隱私。我們的方案藉由讓每個移動裝置去蒐集彼此的訊號強度，並週期地將這些資訊送到特定的伺服器作移動行為分析並決定哪些移動裝置需要更新網卡實體位置。由實驗結果，我們的方案確實有效地減少使用者被追蹤的時間。

A user’s location privacy can be threatened in many different environments. In WLAN, an adversary can track a user through his/her unchanged MAC address. Although previous schemes were proposed to combat this issue, they do not take the mobile behavior of neighboring nodes into account. Therefore, these schemes may miss the opportune moment to update MAC address, i.e. they have difficulty determining the ideal time to change MAC addresses. Furthermore, they suffer from unnecessary MAC address updates. In this thesis, we propose a relative-positioning based scheme to enhance user’s location privacy by analyzing the mobile behavior of each user. This scheme requires the mobile station associated with the same access point to collect the signal strength of others, and then periodically send to a centralized server for determining the stations to update MAC addresses. The experiment results showed that our scheme effectively reduces the duration of time that a user can be tracked in comparison to prior works.