To NACK or not to NACK? Negative Acknowledgments in Information-Centric Networking

Information-Centric Networking (ICN) is an internetworking paradigm that offers an alternative to the current IP\nobreakdash-based Internet architecture. ICN's most distinguishing feature is its emphasis on information (content) instead of communication endpoints. One important open issue in ICN is whether negative acknowledgments (NACKs) at the network layer are useful for notifying downstream nodes about forwarding failures, or requests for incorrect or non-existent information. In benign settings, NACKs are beneficial for ICN architectures, such as CCNx and NDN, since they flush state in routers and notify consumers. In terms of security, NACKs seem useful as they can help mitigating so-called Interest Flooding attacks. However, as we show in this paper, network-layer NACKs also have some unpleasant security implications. We consider several types of NACKs and discuss their security design requirements and implications. We also demonstrate that providing secure NACKs triggers the threat of producer-bound flooding attacks. Although we discuss some potential countermeasures to these attacks, the main conclusion of this paper is that network-layer NACKs are best avoided, at least for security reasons.Comment: 10 pages, 7 figure

Empirical Study of Privacy Issues Among Social Networking Sites.

Social media networks are increasing their types of services and the numbers of users are rapidly growing. However, online consumers have expressed concerns about their personal privacy protection and recent news articles have shown many privacy breaches and unannounced changes to privacy policies. These events could adversely affect data protection and compromise user trust, thus it is vital that social sites contain explicit privacy policies stating a comprehensive list of protection methods. This study analyzes 60 worldwide social sites and finds that even if sites contain a privacy policy, the site pages may also possess technical elements that could be used to serendipitously collect personal information. The results show specific technical collection methods most common within several social network categories. Methods for improving online privacy practices are suggested