Near-Field Communication (NFC) is an emerging wireless technology that expects to revolutionize a range of mobile applications. However, the widespread use of NFC is hindered by the fact that only a limited number of platforms have built-in NFC support. Moreover, while NFC’s short communication range offers some degree of physical protection, recent findings have revealed NFC’s vulnerability to malicious eavesdropping.

This project develops alternative NFC technologies that are secure and compatible with legacy mobile devices and existing infrastructure (e.g., POS terminals). The key novelty of this approach is to leverage visible light and acoustic channels to realize NFC systems with robust performance and security assurance. Due to the high directionality of narrow light beams, visible light can enable secure and interference-free wireless links. Similarly, acoustic signal can be modulated for NFC communication in close proximity. This approach offers several key advantages over the existing NFC technology. Both visual and acoustic communication channels can be implemented using prevalent components such as LCD displays, microphones, and speakers, which lead to purely software-based solutions that can easily retrofit existing infrastructure with NFC functionality. Second, in contrast to RF channels, the direction and distance of screen-camera link are controllable, preserving the communication privacy and security. Similarly, integrated with physical self-jamming techniques, the acoustic link can achieve information-theoretic security without the need for pre-shared secrets.

In this project, a new form of Visible Light Communication (VLC) is employed to implement NFC, where 2D barcodes are streamed between LCD display and camera. A new barcode design and several techniques are used to optimize the throughput of screen-camera link, which include code block adaptation and re-ordering to mitigate the impact of image blur in mobile environments, and lightweight image processing algorithms for real-time decoding of barcode stream. A systematic security study is conducted on barcode-based communication based on geometric analysis and a new acoustics-based NFC system is developed for smartphones without the need of a priori knowledge of security secrets. The emerging friendly jamming techniques are utilized for establishing an information-theoretically secure communication channel for NFC. This project also explores advanced coding techniques, high-level modulation schemes and other physical layer techniques for further improving the data transmission rates and ensuring confidentiality guarantee.

This project is a multi-disciplinary research effort that integrates novel technologies from visual/acoustic communication, adaptive self-jamming, image processing, and cryptography. The results have impacts on a range of mobile applications such as payment, access control, and smart device paring. The PIs will integrate research results into several courses, and leverage the intriguing nature of the project for reaching out to pre-college students.

Our first research module is: Real-time acoustics-based hidden data communication. We investigate and design acoustics-based NFC system for smartphones, which aims at providing a software-based solution for the communication between off-the-shelf smartphones. The developed technique utilizes a speaker and the microphones on off-the-shelf smartphones to achieve concurrent audible and hidden communication. By leveraging masking effects of the human auditory system and readily available audio signals in the daily lives, it ensures real-time unobtrusive speaker-microphone data communication without affecting the primary audio-hearing experience for human users. Meanwhile, this approach also overcomes the main limitations of existing screen-camera links. We also evaluated it extensively under various environments and practical considerations. The proposed technique shows its own superiorities and can be adopted as a complementary or joint dual-mode communication strategy with existing unobtrusive screen-to-camera communication systems to enhance the system performance under various practical settings.

Our sencond research module is: Dependable visual-stimuli-based approach for smartphone user authentication. We investigate and design a novel visual-stimuli-based user authentication framework for smartphone security protection. Specifically, the proposed technique tracks human eye movement through the built-in from camera and applies the signal processing and pattern matching techniques to explore volitional and non-volitional gaze patterns for access authentication. Four visual stimuli are introduced and discussed in the design and the experiment phases. Through a comprehensive user study, the prototype shows a promising result of applying non-volitional eye response as a biometrics and indicates that it is a secure and usable approach for smartphone user authentication.

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• M. Zhou, Q. Wang, T. Lei, Z. Wang, K. Ren, "Enabling Online Robust Barcode-based Visible Light Communication with Realtime Feedback" in IEEE Transactions on Wireless Communications, 2018. [cite]

• Z. Ba, K. Ren, "Addressing Smartphone-Based Multi-factor Authentication via Hardware-Rooted Technologies," in Distributed Computing Systems (ICDCS), 2017 IEEE 37th International Conference on, 2017. [cite]

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• Q. Wang, K. Ren, M. Zhou, T. Lei, D. Koutsonikolas, and L. Su, "Messages behind the sound: Real-time hidden acoustic signal capture with smartphones," in Proceedings of The 22nd Annual International Conference on Mobile Computing and Networking (MobiCom 16), 2016. [cite]

• C. Song, A. Wang, W. Xu, and K. Ren, "Eyeveri: A secure and usable approach for smart-phone user authentication," in Proceedings of IEEE International Conference on Computer Communications (INFOCOM'16), 2016. [cite]

• Wang, Qian and Ren, Kui and Li, Guangcheng and Xia, Chenbo and Chen, Xiaobing and Wang, Zhibo and Zou, Qin "Walls Have Ears! Opportunistically Communicating Secret Messages Over the Wiretap Channel: from Theory to Practice", Proceedings of the 2015 ACM SIGSAC Conference on Computer and Communications Security (CCS'15), 2015 [cite]

• S. Chen and M. Li and K. Ren and X. Fu and C. Qiao "Rise of the Indoor Crowd: Reconstruction of Building Interior View via Mobile Crowdsourcing", Embedded Networked Sensor Systems (SenSys 2015), 2015 The 13th ACM Conference on , 2015 [cite]

• S. Chen and M. Li and K. Ren and C. Qiao, "CrowdMap: Accurate Reconstruction of Indoor Floor Plans from Crowdsourced Sensor-Rich Videos", Distributed Computing Systems (ICDCS), 2015 the 35th IEEE International Conference on, 2015 [cite]

• Wang, Qian and Zhou, Man and Ren, Kui and Lei, Tao and Li, Jikun and Wang, Zhibo "Rain Bar: Robust Application-Driven Visual Communication Using Color Barcodes", Distributed Computing Systems (ICDCS), 2015 IEEE 35th International Conference on, 2015[cite]

• Ren, K. and Wang, Q. and Ma, D. and Jia, X. "Securing emerging short range wireless communications: the state of the art", Wireless Communications, IEEE, 2014[cite]

• B. Zhang and Q. Zhan and J. Wang and K. Ren and C. Wang and D. Ma, "PriWhisper: Enabling Keyless Secure Acoustic Communication for Smartphones.", IEEE Internet of Things, 2014 [cite]

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• B. Zhang and K. Ren and G. Xing and X. Fu and C. Wang, "SBVLC: Secure Barcode-based Visible Light Communication for Smartphones", Proc. of IEEE International Conference on Computer Communications (INFOCOM'14), 2014 [cite]

• Li, Muyuan and Zhu, Haojin and Gao, Zhaoyu and Chen, Si and Yu, Le and Hu, Shangqian and Ren, Kui, "All Your Location Are Belong to Us: Breaking Mobile Social Networks for Automated User Location Tracking", Proceedings of the 15th ACM International Symposium on Mobile Ad Hoc Networking and Computing, 2014 [cite]

• Q. Yue and Z. Ling and X. Fu and B. Liu and K. Ren and W. Zhao, "Blind Recognition of Touched Keys on Mobile Devices", Proceedings of the 2014 ACM SIGSAC Conference on Computer and Communications Security (CCS'14), 2014 [cite]

• Q. Sun and Q. Wang and K. Ren and X. Jia, "Fair Pricing in the Sky: Truthful Frequency Allocation with Dynamic Spectrum Supply", Network Protocols (ICNP), 2014 IEEE 22nd International Conference on, 2014 [cite]