Nowadays we are faced with an increasing popularity of social software including wikis, blogs, micro-blogs and online social networks such as Facebook and MySpace. Unfortunately, the mostly used social services are centralized and personal information is stored at a single vendor. This results in potential privacy problems as users do not have much control over how their private data is disseminated. To overcome this limitation, some recent approaches envisioned replacing the single authority centralization of services by a peer-to-peer trust-based approach where users can decide with whom they want to share their private data. In this peer-to-peer collaboration it is very difficult to ensure that after data is shared with other peers, these peers will not misbehave and violate data privacy. In this paper we propose a mechanism that addresses the issue of data privacy violation due to data disclosure to malicious peers. In our approach trust values between users are adjusted according to their previous activities on the shared data. Users share their private data by specifying some obligations the receivers must follow. We log modifications done by users on the shared data as well as the obligations that must be followed when data is shared. By a log-auditing mechanism we detect users that misbehaved and we adjust their associated trust values by using any existing decentralized trust model.
In order to return data ownership to users rather than to a third party central authority, some recent works @cite_3 @cite_15 explore the coupling between social networks and peer-to-peer systems. In this context privacy protection is understood as allowing users to encrypt their data and control access by appropriate key sharing and distribution. Our approach is complementary to this work and refers to what happens to data after it has been shared.
@cite_15 @cite_3
2122048208 1984599464
Online social networking has quickly become one of the most common Internet activities. As social networks evolve, they encourage users to share more information, requiring the users, in turn, to place more trust into social networks. In centralized systems, this means trusting a third-party commercial entity, like Facebook or MySpace. Peer-to-peer (P2P) systems can enable the creation of online social networks extending trust to friends only. In this paper, we present a novel approach to constructing completely decentralized social networks through P2P overlays, OverSoc. Our approach relies on a common directory overlay, which facilitates friend discovery and bootstraps connectivity to individualized profile overlays. Each user has their own individual profile overlay managed transparently using a public key infrastructure (PKI). We define necessary interfaces for constructing the system and describe some examples of user interactions with the system. To address privacy concerns over Online Social Networks (OSNs), we propose a distributed, peer-to-peer approach coupled with encryption. Moreover, extending this distributed approach by direct data exchange between user devices removes the strict Internet-connectivity requirements of web-based OSNs. In order to verify the feasibility of this approach, we designed a two-tiered architecture and protocols that recreate the core features of OSNs in a decentralized way. This paper focuses on the description of the prototype built for the P2P infrastructure for social networks, as a first step without the encryption part, and shares early experiences from the prototype and insights gained since first outlining the challenges and possibilities of decentralized alternatives to OSNs.