Visible to the public Biblio

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Fitwi, Alem, Chen, Yu, Zhu, Sencun.  2019.  A Lightweight Blockchain-Based Privacy Protection for Smart Surveillance at the Edge. 2019 IEEE International Conference on Blockchain (Blockchain). :552—555.

Witnessing the increasingly pervasive deployment of security video surveillance systems(VSS), more and more individuals have become concerned with the issues of privacy violations. While the majority of the public have a favorable view of surveillance in terms of crime deterrence, individuals do not accept the invasive monitoring of their private life. To date, however, there is not a lightweight and secure privacy-preserving solution for video surveillance systems. The recent success of blockchain (BC) technologies and their applications in the Internet of Things (IoT) shed a light on this challenging issue. In this paper, we propose a Lightweight, Blockchain-based Privacy protection (Lib-Pri) scheme for surveillance cameras at the edge. It enables the VSS to perform surveillance without compromising the privacy of people captured in the videos. The Lib-Pri system transforms the deployed VSS into a system that functions as a federated blockchain network capable of carrying out integrity checking, blurring keys management, feature sharing, and video access sanctioning. The policy-based enforcement of privacy measures is carried out at the edge devices for real-time video analytics without cluttering the network.

Guan, Le, Cao, Chen, Zhu, Sencun, Lin, Jingqiang, Liu, Peng, Xia, Yubin, Luo, Bo.  2019.  Protecting mobile devices from physical memory attacks with targeted encryption. Proceedings of the 12th Conference on Security and Privacy in Wireless and Mobile Networks. :34–44.
Sensitive data in a process could be scattered over the memory of a computer system for a prolonged period of time. Unfortunately, DRAM chips were proven insecure in previous studies. The problem becomes worse in the mobile environment, in which users' smartphones are easily lost or stolen. The powered-on phones may contain sensitive data in the vulnerable DRAM chips. In this paper, we propose MemVault, a mechanism to protect sensitive data in Android devices against physical memory attacks. MemVault keeps track of the propagation of well-marked sensitive data sources, and selectively encrypts tainted sensitive memory contents in the DRAM chip. When a tainted object is accessed, MemVault redirects the access to the internal RAM (iRAM), where the cipher-text object is decrypted transparently. iRAM is a system-on-chip (SoC) component which is by nature immune to physical memory exploits. We have implemented a MemVault prototype system, and have evaluated it with extensive experiments. Our results validate that MemVault effectively eliminates the occurrences of clear-text sensitive objects in DRAM chips, and imposes acceptable overheads.
Chen, Xin, Huang, Heqing, Zhu, Sencun, Li, Qing, Guan, Quanlong.  2017.  SweetDroid: Toward a Context-Sensitive Privacy Policy Enforcement Framework for Android OS. Proceedings of the 2017 on Workshop on Privacy in the Electronic Society. :75–86.

Android privacy control is an important but difficult problem to solve. Previously, there was much research effort either focusing on extending the Android permission model with better policies or modifying the Android framework for fine-grained access control. In this work, we take an integral approach by designing and implementing SweetDroid, a calling-context-sensitive privacy policy enforcement framework. SweetDroid combines automated policy generation with automated policy enforcement. The automatically generated policies in SweetDroid are based on the calling contexts of privacy sensitive APIs; hence, SweetDroid is able to tell whether a particular API (e.g., getLastKnownLocation) under a certain execution path is leaking private information. The policy enforcement in SweetDroid is also fine-grained - it is at the individual API level, not at the permission level. We implement and evaluate the system based on thousands of Android apps, including those from a third-party market and malicious apps from VirusTotal. Our experiment results show that SweetDroid can successfully distinguish and enforce different privacy policies based on calling contexts, and the current design is both developer hassle-free and user transparent. SweetDroid is also efficient because it only introduces small storage and computational overhead.