Wireless Contact tracing has emerged as an important tool for managing the COVID19 pandemic and relies on continuous broadcasting of a person's presence using Bluetooth Low Energy beacons. The limitation of current contact tracing systems in that a reception of a single beacon is sufficient to reveal the user identity, potentially exposing users to malicious trackers installed along the roads, passageways, and other infrastructure. In this paper, we propose a method based on Shamir secret sharing algorithm, which lets mobile nodes reveal their identity only after a certain predefined contact duration, remaining invisible to trackers with short or fleeting encounters. Through data-driven evaluation, using a dataset containing 18 million BLE sightings, we show that the method drastically reduces the privacy exposure of users. Finally, we implemented the approach on Android phones to demonstrate its feasibility and measure performance for various network densities.
Privacy Preservation and Identity Tracing Prevention in AI-Driven Eye Tracking for Interactive Learning Environments
Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences, Bergen, Norway（计算机科学、电气工程与数学科学系，西挪威应用科学大学，卑尔根，挪威）
Understanding the Identity-Transformation Approach in OIDC-Compatible Privacy-Preserving SSO Services
School of Cyber Security, University of Science and Technology of China（中国科学技术大学网络空间安全学院）；Beijing Zitiao Network Technology Co., Ltd, China（北京字跳网络技术有限公司）；School of Cryptology, University of Chinese Academy of Sciences（中国科学院大学密码学学院）
Decentralized Blockchain for Privacy-Preserving Large-Scale Contact Tracing
在COVID-19大流行期间，使用短距离通信（SRC）技术的活动跟踪应用程序和基于位置的服务的需求突然增加，特别是对于自动接触跟踪。公众和政策对相关实际问题的关注不断增加，其中包括\textit{1) how to protect data security and location privacy? 2) how to efficiently and dynamically deploy SRC Internet of Thing (IoT) witnesses to monitor large areas?}为了回答这些问题，本文提出了一种分散的无许可区块链协议，名为\textit{Bychain}。具体而言，1）将交互式零知识证明协议与密钥托管机制相结合，提出了一种用于活动跟踪的隐私保护SRC协议及相应的广义块结构。因此，个人身份和链上位置信息的所有权之间的联系被解耦。同时，链上位置数据的所有者仍然可以在不向其他任何人透露私钥的情况下声称其所有权。2)提出了一种基于人工势场的激励分配机制，以激励物联网证人追求最大的监测覆盖部署。我们使用蓝牙5.0在现实世界中实现和评估了拟议的区块链协议。分析了各个过程的存储、CPU利用率、功耗、时延、安全性以及活动的性能。实验和安全性分析表明，提供了一个现实世界的性能评估。
