A Survey on Interdependent Privacy <s> Access Control <s> Recent years have seen a significant increase in the popularity of social networking services. These online services enable users to construct groups of contacts, referred to as friends, with which they can share digital content and communicate. This sharing is actively encouraged by the social networking services, with users’ privacy often seen as a secondary concern. In this paper we first propose a privacy-aware social networking service and then introduce a collaborative approach to authoring privacy policies for the service. In addressing user privacy, our approach takes into account the needs of all parties affected by the disclosure of information and digital content. <s> BIB001 </s> A Survey on Interdependent Privacy <s> Access Control <s> Online Social Network (OSN) has become a popular and de facto portal for digital information sharing. Preserving information privacy is indispensable in such applications, as the shared information would be sensitive. The issue becomes more challenging due to participation of multiple parties on the shared resources or data. In this paper, we propose an effective access control technique to allow or disallow the shared resources considering authorization requirements of all the multiple parties. A logical representation of the proposed access control technique is prepared to analyse the privacy risk. <s> BIB002 </s> A Survey on Interdependent Privacy <s> Access Control <s> The collaborative nature of content development has given rise to the novel problem of multiple ownership in access control, such that a shared resource is administrated simultaneously by co-owners who may have conflicting privacy preferences and/or sharing needs. Prior work has focused on the design of unsupervised conflict resolution mechanisms. Driven by the need for human consent in organizational settings, this paper explores interactive policy negotiation, an approach complementary to that of prior work. Specifically, we propose an extension of Relationship-Based Access Control (ReBAC) to support multiple ownership, in which a policy negotiation protocol is in place for co-owners to come up with and give consent to an access control policy in a structured manner. During negotiation, the draft policy is assessed by formally defined availability criteria: to the second level of the polynomial hierarchy. We devised two algorithms for verifying policy satisfiability, both employing a modern SAT solver for solving subproblems. The performance is found to be adequate for mid-sized organizations. <s> BIB003 </s> A Survey on Interdependent Privacy <s> Access Control <s> Photo sharing is an attractive feature which popularizes online social networks (OSNs). Unfortunately, it may leak users’ privacy if they are allowed to post, comment, and tag a photo freely. In this paper, we attempt to address this issue and study the scenario when a user shares a photo containing individuals other than himself/herself (termed co-photo for short). To prevent possible privacy leakage of a photo, we design a mechanism to enable each individual in a photo be aware of the posting activity and participate in the decision making on the photo posting. For this purpose, we need an efficient facial recognition (FR) system that can recognize everyone in the photo. However, more demanding privacy setting may limit the number of the photos publicly available to train the FR system. To deal with this dilemma, our mechanism attempts to utilize users’ private photos to design a personalized FR system specifically trained to differentiate possible photo co-owners without leaking their privacy. We also develop a distributed consensus-based method to reduce the computational complexity and protect the private training set. We show that our system is superior to other possible approaches in terms of recognition ratio and efficiency. Our mechanism is implemented as a proof of concept Android application on Facebook’s platform. <s> BIB004
Access control (AC) techniques control the access to some resources by some entities (e.g., a user) via a mechanism (e.g., a reference monitor) that decides, based on a set of rules also called policies, to grant or deny access to the resources. In the context of privacy protection, the resource to which access is controlled is typically sensitive data. Users can be authenticated by: something they know (e.g., a password), something they have (e.g., a smart-card), and something they are (e.g., fingerprint). Several models exist to define access based on the identity or on the role of users, such as mandatory access control (MAC), discretionary access control (DAC), and role-based access control (RBAC). Relationship-based access control (ReBAC) improves upon the RBAC model by adding granularity and context in the definition of roles [Fong 2011]. ReBAC relies on social network data to determine the type of relationship (if any) between two users. The most common AC policies when sharing new content on OSNs are: select specific users, select specific groups of users/friends, or select pre-defined categories of users (e.g., friends of friends and public). In the cases where the data can be divided into sub-resources (e.g., faces in a group picture), access control rules are determined for each sub-resource. An important challenge, in collaborative systems, is to combine the access control rules of the shared resource based on the individual rules and preferences of the involved users. 9 Typical combination strategies include voting (e.g., majority voting and veto voting). Application to interdependent privacy. Access-control techniques are particularly useful in interdependent privacy situations as they help determine the audience of co-owned data, typically shared online. Such techniques have been used in several works BIB002 BIB001 BIB004 ]. ReBAC has also been successfully used in the case of OSNs where social relationship information is available (e.g., BIB003 ) (see Section 5.2 and more specifically Table 4 on page 32).