TC: Small: Collaborative Research: Towards a Dynamic and Composable Model of Trust

人们在做日常决定时依赖于两种类型的信任：垂直信任和水平信任。纵向信任捕获了个人和机构之间的信任关系，而横向信任代表了从其他同伴的观察和意见中推断出来的信任。虽然将水平信任机制和垂直信任机制结合起来可以实现显著的效益，但它们在计算系统中是独立发展的。该项目侧重于开发一个可组合的信任模型，该模型能够以一种既适合正式分析又可有效部署的方式紧密耦合垂直和水平信任。本研究通过一系列创新成果推动了信任管理的发展，包括设计了一个统一的框架来指定复合信任策略，以及设计和分析了有效的策略评估算法。这个项目所倡导的复合信任管理方法还使策略作者能够超越简单的合规性证明，以识别满足安全策略的“top-k”首选用户，包括主观评估。这项研究的受益者包括传统计算机系统的管理员，他们可以更好地将过去的历史纳入他们的决策过程，以及社交网络的用户，他们可以更仔细地管理他们个人数据的暴露。

People rely on two types of trust when making everyday decisions:vertical and horizontal trust. Vertical trust captures trustrelationships between individuals and institutions, while horizontaltrust represents the trust inferred from the observations and opinionsof other peers. Although significant benefit could be realized bycombining horizontal and vertical trust mechanisms, they have evolvedindependently in computing systems.This project focuses on developing a composable trust model capable oftightly coupling vertical and horizontal trust in a manner that isboth amenable to formal analysis and efficiently deployable. Thisresearch advances the state of the art in trust management through aseries of innovative results, including the design of a unifiedframework for specifying composite trust policies and the design andanalysis of efficient algorithms for policy evaluation. The compositetrust management approach championed by this project also enablespolicy authors to move beyond simple proof of compliance to identifythe "top-k" preferred users satisfying security policies includingsubjective assessments. The beneficiaries of this research range fromadministrators of traditional computing systems who can betterincorporate previous history into their decision-making processes, tousers in social networks who can more carefully manage the exposure oftheir personal data.