SBE TWC: Small: Collaborative: Privacy Protection in Social Networks: Bridging the Gap Between User Perception and Privacy Enforcement

Facebook、Twitter和谷歌等在线社交网络已经变得非常流行。它们极大地改变了我们分享信息和社交的行为，尤其是在年轻一代中。然而，这种在线社交网络的极度流行已经成为一把双刃剑--在促进在线社交的同时，这些系统也带来了隐私问题。为了在不影响社交功能的情况下保护用户隐私，该项目阐明了一个统一的框架，该框架弥合了以人为本和以技术为中心的观点之间的差距。具体地说，该项目正在开发方法来(1)检测用户的信息共享期望与实际信息披露之间的差异；(2)设计一个以用户为中心但计算效率高的社交网络中用户隐私的形式化模型；(3)在所提出的模型中开发一种有效执行隐私策略的机制。潜在的长期社会效益是显著的，因为这种意识可能会逐渐改变人们的隐私认知，并影响他们在以隐私为中心的场景中的行为。该项目开发了“社交圈”的概念，在受限访问和受限控制框架内模拟社交网络访问。正在开发从社交网络内的各种类型的现有信息派生社交圈的方法；这些方法用于确定适当的访问控制设置。在这种情况下，该项目正在评估信息流和泄漏风险，包括系统的异质性带来的问题。除了对各种敌方模型的潜在信息流进行理论分析外，该项目正在进行用户研究，以确定这种方法是否减少了感知隐私和实际隐私之间的差距。

Online social networks, such as Facebook, Twitter, and Google+, have become extremely popular. They have significantly changed our behaviors for sharing information and socializing, especially among the younger generation. However, the extreme popularity of such online social networks has become a double-edged sword -- while promoting online socialization, these systems also raise privacy issues. To protect user privacy without compromising socialization functions, this project articulates a unifying framework that bridges the gap between the human-oriented and technology-centered perspectives. In particular, this project is developing methods to (1) detect the discrepancies between users' information sharing expectations and actual information disclosure; (2) design a user-centered yet computationally-efficient formal model of user privacy in social networks; and (3) develop a mechanism to effectively enforce privacy policies in the proposed model. The potential long-term social benefits are significant, since such awareness may gradually change people's privacy perceptions and affect their behavior in privacy-centric scenarios. This project develops a concept of "Social Circles" to model social network access within a Restricted Access and Limited Control framework. Methods are being developed to derive social circles from a variety of types of existing information within the social network; these are used to determine appropriate access control settings. The project is assessing information flow and risk of leakage given such settings, including the issues raised by heterogeneity of systems. In addition to theoretical analysis of potential information flows with respect to a variety of adversary models, the project is conducting user studies to determine if this approach reduces the gap between perceived and actual privacy.