A Cut Principle for Information Flow

We view a distributed system as a graph of active locations with unidirectional channels between them, through which they pass messages. In this context, the graph structure of a system constrains the propagation of information through it. Suppose a set of channels is a cut set between an information source and a potential sink. We prove that, if there is no disclosure from the source to the cut set, then there can be no disclosure to the sink. We introduce a new formalization of partial disclosure, called *blur operators*, and show that the same cut property is preserved for disclosure to within a blur operator. This cut-blur property also implies a compositional principle, which ensures limited disclosure for a class of systems that differ only beyond the cut.Comment: 31 page

Description and Practical Application of the Physiologic Distribution of 3’-Deoxy-3’-[18F]Fluorothymidine in Companion Animals

Access to positron emission tomography (PET), and more recently PET combined with computed tomography (PET/CT), is increasing in veterinary medicine. This molecular imaging technology allows clinicians to map biological functions within patients based on the distribution and selective uptake of specialized positron-emitting radiopharmaceuticals. Although most clinical studies utilize 2-deoxy-2-[18F]fluoro-Dglucose (18FDG), a versatile but relatively nonspecific tracer that interrogates the energy metabolism of tissues, there is a growing need to establish reference values for alternative or adjunct tracers in veterinary species. Among these is 3’-deoxy-3’- [18F]fluorothymidine (18FLT), a thymidine analog that selectively accumulates in proliferating tissues. In the present work, 18FLT distribution in clinically healthy adult dogs and young adult cats was imaged using a state-of-the-art PET/CT scanner to define normal uptake levels within numerous tissues, including major parenchymal organs, bone marrow, and other sites of increased radiopharmaceutical uptake. The marrow signal was subsequently segmented into separate skeletal regions, and used to quantitatively define the adult marrow distribution pattern in the dog. Marrow activity is concentrated in the vertebral column (particularly within the thoracic and lumbar regions), sternum, ribs, and proximal aspects of the appendicular skeleton in the adult dog. Feline marrow distribution is similar; however, considerable uptake within more distal appendicular structures suggests that age-related marrow conversion is ongoing in 3-year-old cats. Outside the marrow compartment, physiologic uptake was observed within the urinary and biliary systems, intestinal tract, and variably within lymphoid structures. Prominent uptake within the hepatic parenchyma was also observed in cats, but not dogs, at the times imaged in this study. The details of normal canine and feline 18FLT biodistribution included in this dissertation may be used to inform lesion interpretation in dogs and cats with suspected disease. Likewise, quantitative details of adult marrow distribution in dogs may be used by clinicians to guide the selection of marrow sampling sites or inform tissue-sparing efforts during radiotherapeutic planning in canine patients

A Hybrid Analysis for Security Protocols with State

Cryptographic protocols rely on message-passing to coordinate activity among principals. Each principal maintains local state in individual local sessions only as needed to complete that session. However, in some protocols a principal also uses state to coordinate its different local sessions. Sometimes the non-local, mutable state is used as a means, for example with smart cards or Trusted Platform Modules. Sometimes it is the purpose of running the protocol, for example in commercial transactions. Many richly developed tools and techniques, based on well-understood foundations, are available for design and analysis of pure message-passing protocols. But the presence of cross-session state poses difficulties for these techniques. In this paper we provide a framework for modeling stateful protocols. We define a hybrid analysis method. It leverages theorem-proving---in this instance, the PVS prover---for reasoning about computations over state. It combines that with an "enrich-by-need" approach---embodied by CPSA---that focuses on the message-passing part. As a case study we give a full analysis of the Envelope Protocol, due to Mark Ryan

UC-15 Malware Analysis Using Reverse Engineering

The motivation for this project is driven by evaluation of the different tools on the market that allow for breaking down executables or binary files, and understanding what the malware is doing. By reverse-engineering the malware, we can understand its impact and how to protect against it. Our focus is to understand where different tools are stronger than others, as well as understand the evolving landscape of malware and security overall. For this capstone project, we utilized two different tools and many sample malware files. The methods used to debug the malware are detailed in our milestone two report and will be expanded upon in our final presentation. At this point, we\u27ve found the tool WinDbg to be the most versatile for binary and executable debugging. We also evaluated IDA Pro, and understand the many ways in which its graphical display of data and relationships, equips a researcher with the necessary tools and information to walk through an executable. Our focus in milestone 3 is to expand our documentation and guide on malware debugging to the point that it provides a user the full breadth of information and steps needed to start from scratch and end with a broken apart piece of malware. We provided much of this as part of the milestone 2 presentation and report, but we will continue to build on it so it\u27s a useful how-to guide for anyone trying to debug a piece of malicious code.Advisors(s): Dr. Ying Xie [email protected](s): SecurityIT 498

The Transit Light Curve Project. VIII. Six Occultations of the Exoplanet TrES-3

We present photometry of the exoplanet host star TrES-3 spanning six occultations (secondary eclipses) of its giant planet. No flux decrements were detected, leading to 99%-confidence upper limits on the planet-to-star flux ratio of 0.00024, 0.0005, and 0.00086 in the i, z, and R bands respectively. The corresponding upper limits on the planet's geometric albedo are 0.30, 0.62, and 1.07. The upper limit in the i band rules out the presence of highly reflective clouds, and is only a factor of 2-3 above the predicted level of thermal radiation from the planet.Comment: To appear in AJ [14 pages

A security perspective on Unikernels

Cloud-based infrastructures have grown in popularity over the last decade leveraging virtualisation, server, storage, compute power and network components to develop flexible applications. The requirements for instantaneous deployment and reduced costs have led the shift from virtual machine deployment to containerisation, increasing the overall flexibility of applications and increasing performances. However, containers require a fully fleshed operating system to execute, increasing the attack surface of an application. Unikernels, on the other hand, provide a lightweight memory footprint, ease of application packaging and reduced start-up times. Moreover, Unikernels reduce the attack surface due to the self-contained environment only enabling low-level features. In this work, we provide an exhaustive description of the unikernel ecosystem; we demonstrate unikernel vulnerabilities and further discuss the security implications of Unikernel-enabled environments through different use-cases

A Third Hot White Dwarf Companion Detected by Kepler

We have found a system listed in the Kepler Binary Catalog (3.273 day period; Prsa et al. 2010) that we have determined is comprised of a low-mass, thermally-bloated, hot white dwarf orbiting an A star of about 2.3 solar masses. In this work we designate the object, KIC 10657664, simply as KHWD3. We use the transit depth of ~0.66%, the eclipse depth of ~1.9%, and regular smooth periodic variations at the orbital frequency and twice the orbital frequency to analyze the system parameters. The smooth periodic variations are identified with the classical ellipsoidal light variation and illumination effects, and the newly utilized Doppler boosting effect. Given the measured values of R/a and inclination angle of the binary, both the ELV and DB effects are mostly sensitive to the mass ratio, q = M_2/M_1, of the binary. The two effects yield values of q which are somewhat inconsistent - presumably due to unidentified systematic effects - but which nonetheless provide a quite useful set of possibilities for the mass of the white dwarf (either 0.18 +/- 0.03 M_Sun or 0.37 +/- 0.08 M_Sun). All of the other system parameters are determined fairly robustly. In particular, we show that the white dwarf has a radius of 0.15 +/- 0.01 R_Sun which is extremely bloated over the radius it would have as a fully degenerate object, and an effective temperature T_eff = 14,100 +/- 350 K. Binary evolution scenarios and models for this system are discussed. We suggest that the progenitor binary was comprised of a primary of mass ~2.2 M_Sun (the progenitor of the current hot white dwarf) and a secondary of mass ~1.4 M_Sun (the progenitor of the current A star in the system). We compare this new system with three other white dwarfs in binaries that likely were formed via stable Roche-lobe overflow (KOI-74, KOI-81, and Regulus).Comment: Accepted for publication in Ap