Covert Ephemeral Communication in Named Data Networking

In the last decade, there has been a growing realization that the current Internet Protocol is reaching the limits of its senescence. This has prompted several research efforts that aim to design potential next-generation Internet architectures. Named Data Networking (NDN), an instantiation of the content-centric approach to networking, is one such effort. In contrast with IP, NDN routers maintain a significant amount of user-driven state. In this paper we investigate how to use this state for covert ephemeral communication (CEC). CEC allows two or more parties to covertly exchange ephemeral messages, i.e., messages that become unavailable after a certain amount of time. Our techniques rely only on network-layer, rather than application-layer, services. This makes our protocols robust, and communication difficult to uncover. We show that users can build high-bandwidth CECs exploiting features unique to NDN: in-network caches, routers' forwarding state and name matching rules. We assess feasibility and performance of proposed cover channels using a local setup and the official NDN testbed

Adult listeners’ processing of indexical versus linguistic differences in a pre-attentive discrimination paradigm

The human ability to comprehend speech regardless of variation across speakers and accents has long puzzled researchers. Human listeners appear to employ separate mechanisms to cope with speaker versus accent variation. The present study uses event-related potentials (ERP) to test whether such different mechanisms exist at a pre-attentive level of speech processing. We assessed Australian English monolinguals’ and bilinguals’ perceptual sensitivity to four types of variation in vowels: namely, variation in speaker identity, gender, accent, and vowel category. Interestingly, listeners showed similar results regardless of their linguistic background. As expected, listeners showed large sensitivity to accent changes. Rather surprisingly, however, they were more sensitive to changes in speaker gender than to changes in vowel category. These results are not in line with those of overt vowel classification but are explained by adults’ sensitivity to large differences in voice quality when discriminating speech sounds

Consistency Without Borders

Distributed consistency is a perennial research topic; in recent years it has become an urgent practical matter as well. The research literature has focused on enforcing various flavors of consistency at the I/O layer, such as linearizability of read/write registers. For practitioners, strong I/O consistency is often impractical at scale, while looser forms of I/O consistency are difficult to map to application-level concerns. Instead, it is common for developers to take matters of distributed consistency into their own hands, leading to application-specific solutions that are tricky to write, test and maintain. In this paper, we agitate for the technical community to shift its attention to approaches that lie between the extremes of I/O-level and application-level consistency. We ground our discussion in early work in the area, including our own experiences building programmer tools and languages that help developers guarantee distributed consistency at the application level. Much remains to be done, and we highlight some of the challenges that we feel deserve more attention.