TC: Small: Collaborative Research: Accountability and Identifiability

万维网和其他网络信息系统提供了巨大的好处，使人们能够访问前所未有的大量信息。然而，多年来，这些系统也会产生严重的问题，这让用户感到沮丧。敏感的个人数据被泄露，机密的公司数据被窃取，版权被侵犯，一个政府机构拥有的数据库被另一个政府机构的成员在违反政府政策的情况下访问。这类事件的发生频率在不断增加，现在只有真正令人发指的事件才被认为有新闻价值。该项目认为，当发生安全违规时，应该可以以某种方式惩罚违规者。虽然“问责制”被广泛认为是重要和可取的，但关于这个问题的理论工作很少；事实上，“问责制”似乎甚至没有一个标准的定义，不同领域的研究人员用它来表示不同的东西。本项目解决了这些问题、问责制与其他目标（如用户隐私）之间的关系，以及现实世界系统中问责制的需求（如违规者和违规行为的可识别性）。对问责制这一重要概念的澄清将有助于推动用户理解和信任的下一代网络中介交互和服务。该项目的技术方法将问责制作为可信度的重要组成部分，涉及两个相互交织的研究重点。第一部分着重于定义和基础理论。直觉上，问责制存在于任何系统中，其中的行为由明确定义的规则管理，违反这些规则将受到惩罚。项目目标是识别这种直观概念中的歧义和差距，提供捕获重要的责任制所需的正式定义，并解释责任制与已充分研究的概念（如可识别性、身份验证、授权、隐私和匿名）之间的关系。第二个重点是分析、设计和抽象。该项目研究现实世界系统中的基本责任和可识别性要求，包括技术和社会。项目的一个目标是更好地理解问责制在多大程度上与隐私和其他理想的系统属性不一致，从而设计具有可证明的问责制属性的新协议。基于在设计协议过程中获得的理解和见解，该项目还解决了各种环境下关于问责制和可识别性的基本权衡和不可能结果。这项工作的更广泛影响不仅包括与学生的接触，还包括对可信赖系统中现实世界问责制的新视角。

The World Wide Web and other networked information systems provide enormous benefits by enabling access to unprecedented amounts of information. However, for many years, users have been frustrated by the fact that these systems also create significant problems. Sensitive personal data are disclosed, confidential corporate data are stolen, copyrights are infringed, and databases owned by one government organization are accessed by members of another in violation of government policy. The frequency of such incidents continues to increase, and an incident must now be truly outrageous to be considered newsworthy. This project takes the view that when security violations occur, it should be possible to punish the violators in some fashion. Although "accountability" is widely agreed to be important and desirable, there has been little theoretical work on the subject; indeed, there does not even seem to be a standard definition of "accountability," and researchers in different areas use it to mean different things. This project addresses these issues, the relationship between accountability and other goals (such as user privacy), and the requirements (such as identifiability of violators and violations) for accountability in real-world systems. This clarification of the important notion of accountability will help propel a next generation of network-mediated interaction and services that users understand and trust.The project's technical approach to accountability as an essential component of trustworthiness involves two intertwined research thrusts. The first thrust focuses on definitions and foundational theory. Intuitively, accountability is present in any system in which actions are governed by well defined rules, and violations of those rules are punished. Project goals are to identify ambiguities and gaps in this intuitive notion, provide formal definitions that capture important accountability desiderata, and explicate relationships of accountability to well studied notions such as identifiability, authentication, authorization, privacy, and anonymity. The second thrust focuses on analysis, design, and abstraction. The project studies fundamental accountability and identifiability requirements in real-world systems, both technological and social. One project goal is to use the resulting better understanding of the extent to which accountability is truly at odds with privacy and other desirable system properties to design new protocols with provable accountability properties. Building on that understanding and insights gained in designing protocols, the project also addresses fundamental trade-offs and impossibility results about accountability and identifiability in various settings. The broader impacts of the work include not only engagement with students but also a new perspective on real world accountability in trustworthy systems.