Most Online Social Networks allow users to set their privacy settings concerning posting information, but current implementations do not allow a fine grained enforcement in case the posted item concerns other users. In this paper we propose a new collaborative access control framework that takes into account the relation of multiple users for viewing as well as for sharing items, eventually solving conflicts in the privacy settings of the users involved. Our solution relies on two algorithms, one for viewing and another one for sharing items. We provide an evaluation of these algorithms where we demonstrate how varying some of the parameters directly influences the decision of viewing or sharing an item. Last but not least, we present a proof-of-concept implementation of our approach in an open source social network called Diaspora.

大多数在线社交网络允许用户设置有关发布信息的隐私设置，但是当前的实现方式不允许细粒度的实施，以防发布的项目涉及其他用户。在本文中，我们提出了一种新的协作式访问控制框架，该框架考虑了多个用户的查看和共享项目之间的关系，最终解决了所涉及用户的隐私设置中的冲突。我们的解决方案依靠两种算法，一种用于查看，另一种用于共享项目。我们提供了对这些算法的评估，其中我们演示了如何改变某些参数直接影响查看或共享项目的决定。最后但并非最不重要的一点是，我们在称为Diaspora的开源社交网络中提出了我们方法的概念验证实施。