Security Hazards when Law is Code.

As software continues to eat the world, there is an increasing pressure to automate every aspect of society, from self-driving cars, to algorithmic trading on the stock market. As this pressure manifests into software implementations of everything, there are security concerns to be addressed across many areas. But are there some domains and fields that are distinctly susceptible to attacks, making them difficult to secure? My dissertation argues that one domain in particular—public policy and law— is inherently difficult to automate securely using computers. This is in large part because law and policy are written in a manner that expects them to be flexibly interpreted to be fair or just. Traditionally, this interpreting is done by judges and regulators who are capable of understanding the intent of the laws they are enforcing. However, when these laws are instead written in code, and interpreted by a machine, this capability to understand goes away. Because they blindly fol- low written rules, computers can be tricked to perform actions counter to their intended behavior. This dissertation covers three case studies of law and policy being implemented in code and security vulnerabilities that they introduce in practice. The first study analyzes the security of a previously deployed Internet voting system, showing how attackers could change the outcome of elections carried out online. The second study looks at airport security, investigating how full-body scanners can be defeated in practice, allowing attackers to conceal contraband such as weapons or high explosives past airport checkpoints. Finally, this dissertation also studies how an Internet censorship system such as China’s Great Firewall can be circumvented by techniques that exploit the methods employed by the censors themselves. To address these concerns of securing software implementations of law, a hybrid human-computer approach can be used. In addition, systems should be designed to allow for attacks or mistakes to be retroactively undone or inspected by human auditors. By combining the strengths of computers (speed and cost) and humans (ability to interpret and understand), systems can be made more secure and more efficient than a method employing either alone.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120795/1/ewust_1.pd

Antigen-specific electrophoretic cell separation for immunological investigations

Preincubation of human blood lymphocytes with cell surface antigen specific antibodies under non-capping conditions reduces the electrophoretic mobility of the corresponding lymphocyte subpopulation. Antigen-positive and antigen-negative cells can be separated by free flow electrophoresis with high yield, purity and viability. The use of fluorescence-labelled second antibodies augments the induced decrease in net surface charge density, and allows rapid detection of antigen-positive cells in the fractions of electrophoresis. Carrier-free cell electrophoresis of human peripheral blood lymphocytes after reaction with anti-IgM-antibody or the monoclonal antibodies OKT4 or OKT8, and sandwich staining with tetrarhodamine isothiocyanate-labelled anti-IgG resulted in the large-scale separation of high pure human B and T lymphocyte subpopulations. Their functional integrity was shown in assays of lymphocyte transformation and of antigen-specific induction and regulation of antibody synthesis in vitro. These separate lymphocyte subpopulations are useful tools for immunological investigations. While, for instance, the effects of drugs on human lymphocytes are obscured by coincident changes in cell composition of the peripheral blood tested that do not by themselves reflect whole body immunocompetence, the cell separation and in vitro assays at a defined cell number and cell composition allow the recording of quantitative changes in the function of different cell subpopulations. We studied the influence of the anesthetic thiopental on separated human lymphocyte subsets. In both polyclonal lectin stimulation and in vitro antibody production, thiopental exhibited a noncytotoxic suppression of lymphocyte functions. B-Cells, T-helper and T-suppressor cells were equally affected and showed the same dose response.(ABSTRACT TRUNCATED AT 250 WORDS

The Effect Of Temperature On The Transdermal Absorption Of Anthracene In Healthy Individuals

The respiratory routes of exposure to hazardous chemicals such polycyclic aromatic hydrocarbons among occupational groups workers has been well studied; however, the contribution to dermal routes of exposure has remained understudied. Microdialysis (MD) is an intradermal sampling technique allowing bidirectional exchange of substances between the MD fiber and interstitial fluid, depending on concentration gradient and pressure. To determine if anthracene can be dermally absorbed and sampled via MD, multiple MD fibers were inserted into the ventral forearm and a 2.0% anthracene solution was applied over the sites. Dialysate from the MD fibers were sampled over 4 hours at a rate of 1 µL/min. The dialysate was measured using liquid chromatography and tandem mass spectrometry. Anthracene concentration in the dialysate samples was similar between the hot and thermoneutral sites (P=0.263), with values of 2.9 ± 0.4 ppm and 3.5 ± 0.4 ppm respectively. Absolute SkBF (flux) was significantly higher at the heated versus the thermoneutral site (P=0.001) with values of 35.7 ± 11.8 and 7.2 ± 1.0, respectively; however, values were not significantly different between sites when presented as a percentage of maximum cutaneous vascular conductance (%CVCmax; P= 0.057) with values of 29.2 ± 8.3 and 8.6 ± 2.3, respectively

The Proof is in the Pudding: Proofs of Work for Solving Discrete Logarithms

We propose a proof of work protocol that computes the discrete logarithm of an element in a cyclic group. Individual provers generating proofs of work perform a distributed version of the Pollard rho algorithm. Such a protocol could capture the computational power expended to construct proof-of-work-based blockchains for a more useful purpose, as well as incentivize advances in hardware, software, or algorithms for an important cryptographic problem. We describe our proposed construction and elaborate on challenges and potential trade-offs that arise in designing a practical proof of work

Captura do Sistema Fluvial Camaquã pelo Sistema Fluvial Jacuí - São Gabriel, RS, Brasil

The analysis of LANDSAT-MSS images and aerial photographs show a capture of headwaters of Camaquã river by Jacui river, at about 54ºW longitude and 31º latitude. This capture occurred 15 km northwest of Lavras do Sul. The area of capture has dimensions of about 30 km2. Elbows of capture and barbed tributaries of the Jacui river provide this evidence and indicate that the Camaquã river was shortened about 6 km. This capture probably has occurred in the Neogene, when erosion is belived to have started in peripheric depression of Rio Grande do Sul. Field work is needed to identify deposits that should provide more clues to the nature and timing of this capture

Estágio de docência orientada na Escola Estadual de Ensino Médio Professora Maria Rocha, Santa Maria/RS

This paper presents the report of the activities developed in the teaching stage linked to the Teacher Education Program for Professional and Technological Education (PEG / UFSM), which was held at the State High School Professor Maria Rocha, in the courses Technical of Accounting and Secretariat, in the disciplines of Organization and Commercial Techniques and Psychology. The teaching stage was the first exercise of professional practice in which there were moments of anxiety in the preparation of classes, a study about the contents that should be worked with the students and the constant concern to propose innovative methodologies in the teaching process. We highlight reflections about teaching practice, especially related to the positive and negative points, difficulties, challenges and contributions of the experience of professional insertion.Key-word: teaching stage; teacher training; teaching methodologies.Por meio deste texto apresenta-se o relato das atividades desenvolvidas no estágio de docência vinculado ao Programa de Formação de Professores para Educação Profissional e Tecnológica - PEG/UFSM -, o qual foi realizado na Escola Estadual de Ensino Médio Professora Maria Rocha, nos cursos técnicos de Contabilidade e Secretariado, nas disciplinas de Organização e Técnicas Comerciais e Psicologia. O estágio de docência foi o primeiro exercício da prática profissional em que houve momentos de ansiedade na preparação das aulas, estudo sobre os conteúdos que deveriam ser trabalhados com os alunos e a constante preocupação em propor metodologias inovadoras no processo de ensino. Destacam-se reflexões acerca da prática docente, em especial relacionadas com os pontos positivos e negativos, dificuldades, desafios e contribuições da experiência de inserção profissional

Stretched Non-negative Matrix Factorization

An algorithm is described and tested that carries out a non negative matrix factorization (NMF) ignoring any stretching of the signal along the axis of the independent variable. This extended NMF model is called StretchedNMF. Variability in a set of signals due to this stretching is then ignored in the decomposition. This can be used, for example, to study sets of powder diffraction data collected at different temperatures where the materials are undergoing thermal expansion. It gives a more meaningful decomposition in this case where the component signals resemble signals from chemical components in the sample. The StretchedNMF model introduces a new variable, the stretching factor, to describe any expansion of the signal. To solve StretchedNMF, we discretize it and employ Block Coordinate Descent framework algorithms. The initial experimental results indicate that StretchedNMF model outperforms the conventional NMF for sets of data with such an expansion. A further enhancement to StretchedNMF for the case of powder diffraction data from crystalline materials called Sparse-StretchedNMF, which makes use of the sparsity of the powder diffraction signals, allows correct extractions even for very small stretches where StretchedNMF struggles. As well as demonstrating the model performance on simulated PXRD patterns and atomic pair distribution functions (PDFs), it also proved successful when applied to real data taken from an in situ chemical reaction experiment.Comment: 39 pages, 16 figure

Elliptic Curve Cryptography in Practice

In this paper, we perform a review of elliptic curve cryptography (ECC), as it is used in practice today, in order to reveal unique mistakes and vulnerabilities that arise in implementations of ECC. We study four popular protocols that make use of this type of public-key cryptography: Bitcoin, secure shell (SSH), transport layer security (TLS), and the Austrian e-ID card. We are pleased to observe that about 1 in 10 systems support ECC across the TLS and SSH protocols. However, we find that despite the high stakes of money, access and resources protected by ECC, implementations suffer from vulnerabilities similar to those that plague previous cryptographic systems

Securing the Wireless Emergency Alerts System

Modern cell phones are required to receive and display alerts via the Wireless Emergency Alert (WEA) program, under the mandate of the Warning, Alert, and Response Act of 2006. These alerts include AMBER alerts, severe weather alerts, and (unblockable) Presidential Alerts, intended to inform the public of imminent threats. Recently, a test Presidential Alert was sent to all capable phones in the U.S., prompting concerns about how the underlying WEA protocol could be misused or attacked. In this paper, we investigate the details of this system and develop and demonstrate the first practical spoofing attack on Presidential Alerts, using commercially available hardware and modified open source software. Our attack can be performed using a commercially available software-defined radio, and our modifications to the open source software libraries. We find that with only four malicious portable base stations of a single Watt of transmit power each, almost all of a 50,000-seat stadium can be attacked with a 90% success rate. The real impact of such an attack would, of course, depend on the density of cellphones in range; fake alerts in crowded cities or stadiums could potentially result in cascades of panic. Fixing this problem will require a large collaborative effort between carriers, government stakeholders, and cellphone manufacturers. To seed this effort, we also propose three mitigation solutions to address this threat