Demo: LiShield: Create a Capture-Resistant Environment...
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Demo: LiShield: Create a Capture-Resistant Environment Against Photographing Shilin Zhu University of California San Diego [email protected] Chi Zhang University of Wisconsin-Madison [email protected] Xinyu Zhang University of California San Diego [email protected] ABSTRACT The ubiquity of mobile camera devices has been triggering an out- cry of privacy concerns. In this demo, we introduce LiShield, which automatically protects a physical scene against photographing, by illuminating it with smart LEDs flickering in specialized waveform. We have also designed mechanisms to unblock authorized cam- eras and enable graceful degradation under strong ambient light interference. KEYWORDS Privacy Protection; Visible Light; Camera; Computer Vision 1 INTRODUCTION Cameras are now pervasive on consumer mobile devices. The ubiq- uity of these cameras, paired with pervasive wireless access, is creating a new wave of visual sensing applications. Zooming in the photo-sharing application alone, statistics report that 350 million photos/videos are uploaded to Facebook every day, majority of which are from mobile users [2]. While these technologies bring significant convenience to individuals, they also trigger an outcry of privacy concerns. In this demo, we introduce LiShield, a system that thwarts pho- tographing of sensitive indoor physical space, and automatically enforces location-bound visual privacy protection. LiShield safe- guards the physical scenes against undesired recording without requiring user intervention, and without disrupting the human vi- sual perception. Our key idea is to illuminate the environment using smart LEDs, and design the waveform in such a way that can disrupt the image sensors on mobile devices. In addition, LiShield can tailor the waveform for two special use cases: (i.) allowing an authorized camera, which shares secrete configuration information with the LED, to recover the image or video frames it captures. (ii.) when strong ambient light interferes with the smart LED, LiShield embeds invisible “barcode” that can convey a “no distribution” message into physical environment, allowing online servers (e.g., from Facebook and Instagram) to prevent the image from being distributed. 2 WORKING PRINCIPLE AND DEMO SETUP Nearly all consumer digital cameras, pinhole cameras and smart- phones use the rolling shutter sampling mechanism [1]. When Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). S3’17, October 9–13, 2017, Snowbird, UT, USA © 2017 Copyright held by the owner/author(s). ACM ISBN 978-1-4503-5145-4/17/10. https://doi.org/10.1145/3131348.3131354 Figure 1: Experimental setup and multiple scenes we used. capturing an image frame, a rolling shutter camera exposes each row sequentially. LiShield harnesses the disparity between cameras and eyes to disrupt the camera imaging without affecting human vision. It modulates a smart LED to generate high frequency flickering patterns and aims to minimize the image capturing quality by opti- mizing the LED waveform. LiShield still maintains its protection while allowing authorized users to capture the same scene simul- taneously without distortion. The solution leverages a secure side channel (e.g., VLC [3]) between authorized users and the smart LED, which conveys secrete information such as frame timing and wave- form parameters. In case strong ambient interference may degrade LiShield’s protection, LiShield embeds barcodes in images/videos captured by the attacker to convey privacy policies and ensures they are detectable even after common post-processing. In the demo, we will show our LiShield hardware prototype (Fig. 1), and encourage the audience to take photos using their smart- phones while experiencing the corruption effects under LiShield. We will also demonstrate how an authorized camera (which we bring by ourselves) can circumvent the corruption effects. Besides the AC power and a table, no other facility is needed. The setup time is around 10 minutes. 3 CONCLUSION We implemented and evaluated LiShield under various representa- tive indoor scenarios, which demonstrates LiShield’s effectiveness and robustness in privacy protection. REFERENCES [1] QImaging. 2014. Rolling Shutter vs. Global Shutter. (2014). https://www.qimaging. com/ccdorscmos/pdfs/RollingvsGlobalShutter.pdf [2] Social Pilot. 2016. 125 Amazing Social Media Statistics You Should Know. (2016). https://socialpilot.co/blog/125-amazing-social-media-statistics-know-2016/ [3] Jialiang Zhang, Chi Zhang, Xinyu Zhang, and Suman Banerjee. 2016. Towards a Visible Light Network Architecture for Continuous Communication and Lo- calization. In Proceedings of the 3rd Workshop on Visible Light Communication Systems (VLCS).
Transcript of Demo: LiShield: Create a Capture-Resistant Environment...
Demo: LiShield: Create a Capture-Resistant EnvironmentAgainst Photographing
Shilin ZhuUniversity of California San Diego
Chi ZhangUniversity of Wisconsin-Madison
Xinyu ZhangUniversity of California San Diego
ABSTRACTThe ubiquity of mobile camera devices has been triggering an out-cry of privacy concerns. In this demo, we introduce LiShield, whichautomatically protects a physical scene against photographing, byilluminating it with smart LEDs flickering in specialized waveform.We have also designed mechanisms to unblock authorized cam-eras and enable graceful degradation under strong ambient lightinterference.
KEYWORDSPrivacy Protection; Visible Light; Camera; Computer Vision
1 INTRODUCTIONCameras are now pervasive on consumer mobile devices. The ubiq-uity of these cameras, paired with pervasive wireless access, iscreating a new wave of visual sensing applications. Zooming in thephoto-sharing application alone, statistics report that 350 millionphotos/videos are uploaded to Facebook every day, majority ofwhich are from mobile users [2]. While these technologies bringsignificant convenience to individuals, they also trigger an outcryof privacy concerns.
In this demo, we introduce LiShield, a system that thwarts pho-tographing of sensitive indoor physical space, and automaticallyenforces location-bound visual privacy protection. LiShield safe-guards the physical scenes against undesired recording withoutrequiring user intervention, and without disrupting the human vi-sual perception. Our key idea is to illuminate the environment usingsmart LEDs, and design the waveform in such a way that can disruptthe image sensors on mobile devices. In addition, LiShield can tailorthe waveform for two special use cases: (i.) allowing an authorizedcamera, which shares secrete configuration information with theLED, to recover the image or video frames it captures. (ii.) whenstrong ambient light interferes with the smart LED, LiShield embedsinvisible “barcode” that can convey a “no distribution” message intophysical environment, allowing online servers (e.g., from Facebookand Instagram) to prevent the image from being distributed.
2 WORKING PRINCIPLE AND DEMO SETUPNearly all consumer digital cameras, pinhole cameras and smart-phones use the rolling shutter sampling mechanism [1]. When
Permission to make digital or hard copies of part or all of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor profit or commercial advantage and that copies bear this notice and the full citationon the first page. Copyrights for third-party components of this work must be honored.For all other uses, contact the owner/author(s).S3’17, October 9–13, 2017, Snowbird, UT, USA© 2017 Copyright held by the owner/author(s).ACM ISBN 978-1-4503-5145-4/17/10.https://doi.org/10.1145/3131348.3131354
Figure 1: Experimental setup and multiple scenes we used.
capturing an image frame, a rolling shutter camera exposes each rowsequentially. LiShield harnesses the disparity between cameras andeyes to disrupt the camera imaging without affecting human vision.It modulates a smart LED to generate high frequency flickeringpatterns and aims to minimize the image capturing quality by opti-mizing the LED waveform. LiShield still maintains its protectionwhile allowing authorized users to capture the same scene simul-taneously without distortion. The solution leverages a secure sidechannel (e.g., VLC [3]) between authorized users and the smart LED,which conveys secrete information such as frame timing and wave-form parameters. In case strong ambient interference may degradeLiShield’s protection, LiShield embeds barcodes in images/videoscaptured by the attacker to convey privacy policies and ensuresthey are detectable even after common post-processing.
In the demo, we will show our LiShield hardware prototype(Fig. 1), and encourage the audience to take photos using their smart-phones while experiencing the corruption effects under LiShield.We will also demonstrate how an authorized camera (which webring by ourselves) can circumvent the corruption effects. Besidesthe AC power and a table, no other facility is needed. The setuptime is around 10 minutes.
3 CONCLUSIONWe implemented and evaluated LiShield under various representa-tive indoor scenarios, which demonstrates LiShield’s effectivenessand robustness in privacy protection.
REFERENCES[1] QImaging. 2014. Rolling Shutter vs. Global Shutter. (2014). https://www.qimaging.
com/ccdorscmos/pdfs/RollingvsGlobalShutter.pdf[2] Social Pilot. 2016. 125 Amazing Social Media Statistics You Should Know. (2016).
https://socialpilot.co/blog/125-amazing-social-media-statistics-know-2016/[3] Jialiang Zhang, Chi Zhang, Xinyu Zhang, and Suman Banerjee. 2016. Towards
a Visible Light Network Architecture for Continuous Communication and Lo-calization. In Proceedings of the 3rd Workshop on Visible Light CommunicationSystems (VLCS).
