SenShield: Preserving User Privacy Against Passive WiFi Sensing

SenShield：保护用户隐私免受被动 WiFi 感应的影响

• 批准号: 447586980
• 负责人: Professor Dr.-Ing. Matthias Hollick, since 4/2024
• 金额: --
• 依托单位: Fachgebiet Sichere Mobile Netze
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/447586980?language=en
• 关键词: SenShield; Preserving; User; Privacy; Against

Within the past decade, researchers have shown that WiFi signals can be used for a variety of sensing applications ranging from human motions to emotions. Lately, device-free WiFi sensing has gained traction since it does not require the target to carry a device. Although device-free, these solutions proved highly accurate in tracking movement and trajectory of the users on decimeter-level as well as recognizing their activities (e.g., running, walking) and fine- grained gestures (lips, fingers). Indeed, WiFi sensing is a convenient method for such tasks, given the abundance of WiFi- enabled devices around us. From a technical point of view, WiFi sensing boils down to extracting the impact of human body motion on the signal propagation, which is conceptually similar to bistatic radar. Recently, a few startups (e.g., Totemic, Emerald) ventured into this area, branding their products as non-invasive and privacy-preserving health monitoring devices, as opposed to video and on-body sensors. However, the maturity of the technology, its practicality, and the abundance of WiFi devices pose significant risks to user privacy. In its simplest form, a burglar can identify empty houses or profile them based on the number of occupants and even the health of the occupants through monitoring their moving speed or heartbeat. The more significant privacy risk is that, unlike radars, the adversary can leverage WiFi sensing techniques passively (i.e., without transmitting any signal), hence going undetected. Furthermore, WiFi device manufacturers and government agencies can potentially conduct mass surveillance with unnoticeable firmware manipulation. Unfortunately, even in the presence of such risks, we cannot defy the use of WiFi devices since they are already an integral part of our lives at home and work. Although WiFi sensing is conceptually similar to radar, we cannot leverage classic radar jamming techniques because they interfere with legitimate communication over WiFi. In SenShield, we devise fundamental solutions to minimize the concerns raised by the recent advent of WiFi sensing techniques. More specifically, we aim at thwarting passive WiFi sensing possibilities where the adversary does not transmit any signal and tries to obtain all necessary information via eavesdropping on ongoing legitimate WiFi communication.

在过去的十年里，研究人员已经证明，WiFi信号可以用于从人体运动到情感的各种传感应用。最近，免设备WiFi传感获得了吸引力，因为它不需要目标携带设备。虽然无需设备，但事实证明，这些解决方案在分米级跟踪用户的运动和轨迹以及识别他们的活动(例如，跑步、行走)和细粒度手势(嘴唇、手指)方面非常准确。事实上，考虑到我们周围有大量支持WiFi的设备，WiFi传感是执行此类任务的一种便捷方法。从技术角度来看，WiFi传感归结为提取人体运动对信号传播的影响，这在概念上类似于双基地雷达。最近，一些初创公司(如图腾、Emerald)冒险进入这一领域，将他们的产品标榜为非侵入性和保护隐私的健康监测设备，而不是视频和身体传感器。然而，这项技术的成熟度、实用性和WiFi设备的丰富对用户隐私构成了巨大的风险。在最简单的形式下，窃贼可以识别空房子或根据居住者的数量，甚至通过监测居住者的移动速度或心跳来分析他们的健康状况。更大的隐私风险是，与雷达不同，攻击者可以被动地利用WiFi传感技术(即，不传输任何信号)，因此不会被发现。此外，WiFi设备制造商和政府机构可能会通过不引人注目的固件操作进行大规模监控。不幸的是，即使存在这样的风险，我们也不能无视WiFi设备的使用，因为它们已经是我们家庭和工作生活中不可或缺的一部分。尽管WiFi侦听在概念上类似于雷达，但我们不能利用经典的雷达干扰技术，因为它们会干扰WiFi上的合法通信。在SenShield，我们设计了基本的解决方案，以最大限度地减少最近出现的WiFi传感技术带来的担忧。更具体地说，我们的目标是挫败被动WiFi侦听可能性，即对手不传输任何信号，并试图通过窃听正在进行的合法WiFi通信来获取所有必要的信息。