Group access control with blacklist for data dissemination in mobile opportunistic networks

In mobile opportunistic networks, security is a major concern in consequence of store-carry-and-forward data dissemination. To guarantee that messages can be only accessed by authorized users, access control is a necessity. Fuzzy-IBE that has been proposed can provide group access control. In addition, if a sender wants to expose his/her message only to some members of his/her group, Fuzzy-IBE can provide a whitelist mechanism to further indicate which users in the group can access the data. Because overhead linearly increases with respect to the length of the whitelist, this mechanism is not sufficiently scalable as the whitelist becomes larger. In this work, we propose a Fuzzy-IBE based negative access control scheme (NAC) that allows users to selectively exclude specific members from accessing data dynamically. NAC, which does not require intensive calculation in mobile devices, is suitable for mobile opportunistic networks.