SaTC: CORE: Small: Customizable Geo-Obfuscation to Protect Users' Location Privacy in Mobile Crowdsourcing

地理混淆是一种隐私保护技术，允许用户在基于位置的应用程序（如移动众包）中报告混淆的位置，而不是他们的精确位置。虽然地理混淆提供了强大的隐私保证，但由于混淆而产生的位置错误可能会影响服务质量。目前对该主题的研究主要集中在通过优化技术最小化质量损失，但由于计算开销高，仅限于少数位置。因此，现有的工作将地理混淆的范围限制在大范围内的低粒度或小范围内的高粒度，使用户能够根据其特定需求定制地理混淆的空间很小。该项目的新颖之处在于设计了一个以用户为中心的多粒度、多尺度的地理混淆，可以根据用户的不同需求进行定制。所提出的研究显著提高了现有地理混淆技术的灵活性和可扩展性，从而推进了它们在各种移动环境中的应用。该项目更广泛的意义和重要性是在确保个人隐私的同时，积极影响许多先进众包应用程序的广泛采用。此外，该项目的教育工作还包括课程开发、K-12外展活动，以及让代表性不足的学生参与研究。该项目包括三个研究任务。首先，该项目设计了具有时间效率的算法，能够在大范围的位置粒度和尺度下计算地理混淆，覆盖数百万个位置，包括县、城市、街道、建筑物和房间。其次，在开发的地理混淆算法的基础上，根据大量移动用户的需求，考虑他们不同的移动特征和不同场景的上下文信息，定制地理混淆。最后，该项目确定了在不同粒度级别上对可定制地理混淆的潜在威胁。根据从威胁模型中获得的见解，该项目设计对策，以更好地保护用户的位置隐私免受新的威胁。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Geo-obfuscation is a privacy protection technique that allows users to report obfuscated locations instead of their precise locations in location-based applications such as mobile crowdsourcing. While geo-obfuscation offers strong privacy guarantees, the location errors that arise due to obfuscation can affect the quality of the service. Current research on this topic focuses on minimizing quality loss through optimization techniques, but due to the high computation overhead, it is limited to a small number of locations. Consequently, existing works restrict the scope of geo-obfuscation to either low granularity in a large-scale region or high granularity in a small-scale region, leaving little room for users to customize geo-obfuscation to their specific requirements. The project's novelties are to design a user-centric geo-obfuscation in multi-granularity and multi-scale, which can be customized based on users' diverse demands. The proposed research significantly enhances the flexibility and scalability of existing geo-obfuscation techniques, thereby advancing their application in various mobile contexts. The project's broader significance and importance are to positively impact the wide adoption of many advanced crowdsourcing applications while ensuring individual privacy. In addition, the educational efforts of this project encompass curriculum development, K-12 outreach activities, and the engagement of underrepresented students in research.The project comprises three research tasks. Firstly, the project designs time-efficient algorithms capable of calculating geo-obfuscation for a wide range of location granularity and scales, covering millions of locations in a hierarchy that includes counties, cities, streets, buildings, and rooms. Secondly, based on the developed geo-obfuscation algorithms, the project aims to customize geo-obfuscation according to the demands of a large group of mobile users, taking into account their diverse mobility features and contextual information across different scenarios. Finally, the project identifies potential threats to customizable geo-obfuscation at various granularity levels. On the basis of the insights gained from the threat models, the project designs countermeasures to better protect users' location privacy against the new threats.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.