Trust-Based Community Sharing and Leakage Trade-Off in Online Social Networks

In the online social networks (OSNs) and Social Internet of Things (SIOT), communities of interest (CoI) are often used to facilitate information sharing among user devices. However, the risk of information leaks across communities persists due to inadequate control over users’ sharing behavior. In this article, we propose a novel trust-based community sharing mechanism to control users who are contributing to high privacy leakage across communities of an OSN. In detail, we first formulate privacy loss in community based on the sensitivity and willingness of users in sharing. Second, we use this loss as the key determinant when updating trust to dynamically hold users accountable for privacy leakage. Third, we use an adjustable threshold to enable or disable sharing users and evaluate the amount of information shared before and after control, as well as the changes in community user trust. Finally, we propose an optimization method based on the upper confidence bound to make a tradeoff between information sharing and leakage through a payoff function over discretized thresholds. Simulations on three real OSNs datasets — BlogCatalog, Flickr, and YouTube — demonstrated that our proposed mechanism can effectively reduce community privacy loss by achieving the best payoff score of 1076.53, while the state-of-the-art baselines PDC-InfoSharing and user trust value scored 506.33 and 957.98, respectively.