CAREER: Moderation and Accountability on Private Communication Platforms

为用户提供强大隐私的消息传递应用程序可能会产生意想不到的副作用，使用户更难报告滥用行为。当平台看不到用户消息的内容，或者不知道哪些用户在相互交谈时，它永远无法知道关于辱骂内容的举报是真是假。该项目的创新之处在于设计私人消息应用程序的新加密方法，允许用户以可验证的方式向平台报告辱骂内容，而不会损害未报告消息或对话的隐私。该项目更广泛的意义和重要性是为私人交流平台上的温和提供新的可能性。该项目通过采用共同设计方法设计端到端加密或隐藏元数据的消息传递应用程序的滥用报告功能，实现了比以前的工作多个数量级的性能改进。它利用这些系统的现有结构，通过以前工作中更通用的方法来改进可能的功能和性能。例如，该项目不是只假设现有平台隐藏了消息元数据，而是为隐藏元数据的平台设计了解决方案，这些平台专门依赖广泛的技术类别，如秘密共享或混合网络。该项目还开发了新的教育材料，让大学本科生和初中生及早接触到安全和隐私主题。该项目的影响将是促进研究和行业社区设计和部署新的消息传递系统的能力，以确保用户的安全和保护他们的隐私。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Messaging applications that provide strong privacy for their users can have the unintended side effect of making it harder for users to report abuse. When the platform cannot see the contents of users' messages, or does not know which users are talking to each other, it can never know if a report of abusive content is real or not. This project's novelties are in new cryptographic approaches to design private messaging applications that allow users to verifiably report abusive content to the platform without compromising the privacy of unreported messages or conversations. The project's broader significance and importance is to enable new possibilities for moderation on private communication platforms. This project achieves multiple order of magnitude performance improvements over prior work by taking a co-design approach to the design of abuse reporting features for end-to-end encrypted or metadata-hiding messaging applications. It takes advantage of the existing structure of these systems to improve on both the functionality and performance possible via the more generic approaches of prior work. For example, instead of only assuming that an existing platform hides message metadata, the project designs solutions for metadata-hiding platforms that specifically rely on broad classes of techniques like secret sharing or mixnets. The project also develops new educational materials to allow both college undergraduates and middle/high school students to gain early exposure to security and privacy topics. The project's impact will be to advance the research and industry communities' ability to design and deploy new messaging systems that keep users safe and protect their privacy.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.