Privacy Protection for Audio Sensing Against Multi-Microphone Adversaries
Privacy Protection for Audio Sensing Against Multi-Microphone Adversaries
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DOI：
10.2478/popets-2019-0024
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发表时间：
2019-04
影响因子：
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通讯作者：
Chuhan Gao;Kassem Fawaz;Sanjib Sur;Suman Banerjee
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文献类型：
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作者：
Chuhan Gao;Kassem Fawaz;Sanjib Sur;Suman Banerjee
摘要 基于音频的传感可以实现细粒度的人体活动检测，例如传感手势和非接触式呼吸速率估计。配备麦克风的被动对手可以利用持续的传感来推断有关个人的私人信息。此外，利用多个麦克风，具有波束成形能力的对手可以击败之前提出的隐私保护混淆技术。这样的对手可以隔离混淆信号并将其取消，即使位于墙后也是如此。 AudioSentry 是第一个通过保护用户免受多麦克风攻击来解决音频传感中的隐私问题的产品。它利用用户环境中已有的商品和支持音频的设备来形成分布式混淆器阵列。 AudioSentry 采用了一种新技术，可以在不同方向上仔细生成混淆光束，防止多麦克风对手取消混淆信号。 AudioSentry 采用动态信道估计方案来在混淆情况下保留授权传感。 AudioSentry 具有部署实用、能够有效对抗拥有大量麦克风的对手等优点。我们对商用设备进行的广泛评估表明，无论对手的位置如何，它都可以保护用户的隐私，抵御只有 4 个商用混淆器的 16 个麦克风的对手。 AudioSentry 提供隐私保护功能，对授权传感器的开销很小。
Abstract Audio-based sensing enables fine-grained human activity detection, such as sensing hand gestures and contact-free estimation of the breathing rate. A passive adversary, equipped with microphones, can leverage the ongoing sensing to infer private information about individuals. Further, with multiple microphones, a beamforming-capable adversary can defeat the previously-proposed privacy protection obfuscation techniques. Such an adversary can isolate the obfuscation signal and cancel it, even when situated behind a wall. AudioSentry is the first to address the privacy problem in audio sensing by protecting the users against a multi-microphone adversary. It utilizes the commodity and audio-capable devices, already available in the user’s environment, to form a distributed obfuscator array. AudioSentry packs a novel technique to carefully generate obfuscation beams in different directions, preventing the multi-microphone adversary from canceling the obfuscation signal. AudioSentry follows by a dynamic channel estimation scheme to preserve authorized sensing under obfuscation. AudioSentry offers the advantages of being practical to deploy and effective against an adversary with a large number of microphones. Our extensive evaluations with commodity devices show that protects the user’s privacy against a 16-microphone adversary with only four commodity obfuscators, regardless of the adversary’s position. AudioSentry provides its privacy-preserving features with little overhead on the authorized sensor.