Delivering Live Multimedia Streams to Mobile Hosts in a Wireless Internet with Multiple Content Aggregators

We consider the distribution of channels of live multimedia content (e.g., radio or TV broadcasts) via multiple content aggregators. In our work, an aggregator receives channels from content sources and redistributes them to a potentially large number of mobile hosts. Each aggregator can offer a channel in various configurations to cater for different wireless links, mobile hosts, and user preferences. As a result, a mobile host can generally choose from different configurations of the same channel offered by multiple alternative aggregators, which may be available through different interfaces (e.g., in a hotspot). A mobile host may need to handoff to another aggregator once it receives a channel. To prevent service disruption, a mobile host may for instance need to handoff to another aggregator when it leaves the subnets that make up its current aggregator�s service area (e.g., a hotspot or a cellular network).\ud In this paper, we present the design of a system that enables (multi-homed) mobile hosts to seamlessly handoff from one aggregator to another so that they can continue to receive a channel wherever they go. We concentrate on handoffs between aggregators as a result of a mobile host crossing a subnet boundary. As part of the system, we discuss a lightweight application-level protocol that enables mobile hosts to select the aggregator that provides the �best� configuration of a channel. The protocol comes into play when a mobile host begins to receive a channel and when it crosses a subnet boundary while receiving the channel. We show how our protocol can be implemented using the standard IETF session control and description protocols SIP and SDP. The implementation combines SIP and SDP�s offer-answer model in a novel way

Prochlo: Strong Privacy for Analytics in the Crowd

The large-scale monitoring of computer users' software activities has become commonplace, e.g., for application telemetry, error reporting, or demographic profiling. This paper describes a principled systems architecture---Encode, Shuffle, Analyze (ESA)---for performing such monitoring with high utility while also protecting user privacy. The ESA design, and its Prochlo implementation, are informed by our practical experiences with an existing, large deployment of privacy-preserving software monitoring. (cont.; see the paper

Finding and Resolving Security Misusability with Misusability Cases

Although widely used for both security and usability concerns, scenarios used in security design may not necessarily inform the design of usability, and vice- versa. One way of using scenarios to bridge security and usability involves explicitly describing how design deci- sions can lead to users inadvertently exploiting vulnera- bilities to carry out their production tasks. This paper describes how misusability cases, scenarios that describe how design decisions may lead to usability problems sub- sequently leading to system misuse, address this problem. We describe the related work upon which misusability cases are based before presenting the approach, and illus- trating its application using a case study example. Finally, we describe some findings from this approach that further inform the design of usable and secure systems

High-rate quantum cryptography in untrusted networks

We extend the field of continuous-variable quantum cryptography to a network formulation where two honest parties connect to an untrusted relay by insecure quantum links. To generate secret correlations, they transmit coherent states to the relay where a continuous-variable Bell detection is performed and the outcome broadcast. Even though the detection could be fully corrupted and the links subject to optimal coherent attacks, the honest parties can still extract a secret key, achieving high rates when the relay is proximal to one party, as typical in public networks with access points or proxy servers. Our theory is confirmed by an experiment generating key-rates which are orders of magnitude higher than those achievable with discrete-variable protocols. Thus, using the cheapest possible quantum resources, we experimentally show the possibility of high-rate quantum key distribution in network topologies where direct links are missing between end-users and intermediate relays cannot be trusted.Comment: Theory and Experiment. Main article (6 pages) plus Supplementary Information (additional 13 pages

Teaching as a Collaborative Practice:Reframing Security Practitioners as Navigators

The need is growing for a workforce with both technical skills and the ability to navigate existing and emerging information security challenges. Practitioners can no longer depend upon process-driven approaches to people, processes and IT systems to manage information security. They need to be navigators of the entire environment to effectively integrate controls to protect information and technology. The research presented in this paper trialed an innovative tactile learning activity developed through the European Technology-supported Risk Estimation by Predictive Assessment of Socio-technical Security (TREsPASS) project with tertiary education students, designed to provide students with experience in real-world modelling of complex information security scenarios. The outcomes demonstrate that constructing such models in an educational setting are a means of encouraging exploration of the multiple dimensions of security. Such teaching may be a means of teaching social, organization and technical navigation skills necessary to integrate security controls in complex settings