Dynamic tags for security protocol

The design and verification of cryptographic protocols is a notoriously difficult task, even in symbolic models which take an abstract view of cryptography. This is mainly due to the fact that protocols may interact with an arbitrary attacker which yields a verification problem that has several sources of unboundedness (size of messages, number of sessions, etc. In this paper, we characterize a class of protocols for which deciding security for an unbounded number of sessions is decidable. More precisely, we present a simple transformation which maps a protocol that is secure for a bounded number of protocol sessions (a decidable problem) to a protocol that is secure for an unbounded number of sessions. The precise number of sessions that need to be considered is a function of the security property and we show that for several classical security properties a single session is sufficient. Therefore, in many cases our results yields a design strategy for security protocols: (i) design a protocol intended to be secure for a {single session}; and (ii) apply our transformation to obtain a protocol which is secure for an unbounded number of sessions.Comment: 50 pages with 30 reference

Studying Abroad, Toilet Paper, and Other Exercises in Missing the Point

I have been in Ghana only for a few days, and I can already tell I am going to love the place­—the people, the food, the environment, all remind me of my home country, Sierra Leone. However, I don’t think I can adjust to the constant uttering by some of my peers about how this experience “makes them appreciate how much they have.” In the past four days, I have heard that same phrase over and over again. [excerpt

The role of regional surveillance networks in enhancing global outbreak reporting

BACKGROUND: The Program for Monitoring Emerging Diseases (ProMED) is a moderated electronic reporting system dedicated to the rapid, global dissemination of outbreak reports. Its moderators are globally diverse, carefully selected, highly trained specialists. To improve cross-border communication and rapidly identify regional health threats, ProMED created regional networks where locally-based moderators use their access to local and regional medical and public health networks and media sources to obtain information not readily available outside of their region. In this analysis, we assess the impact of the establishment of ProMED's Middle East/North Africa (MENA) and South Asia (SoAs) regional networks in April 2014 on ProMED's outbreak reports for these regions. METHODS & MATERIALS: Outbreak reports in countries within the two regions were extracted from ProMED's database, and included country, disease name, species type, spatial coordinates, and report issue date. Data analysis included visualizing spatial information, identifying unique reports, and reporting trends per country and region. Data processing and analysis were conducted using R 3.4.0 statistical software. Rates of outbreak events per total number of ProMED reports per year were calculated to adjust for temporal trends in the total number of reports posted on ProMED. Rate comparison used a two-sided t-test; P < 0.05 was considered statistically significant. RESULTS: The mean monthly incidence of ProMED reports concerning outbreaks in the MENA region increased from 28 reports (May 2012 - April 2014) to 83 reports after the establishment of the networks (May 2014 - April 2016), and from 29 reports to 101 reports concerning outbreaks in the SoAs region over the same time period. The number of reports per total number of ProMED reports increased by 259% for MENA, and 289% for SoAs (P < 0.01). MENA reports most often addressed MERS (32.3%), foot-and-mouth disease (7.0%), avian influenza (6.7%), and measles (3.8%); whereas SoAs most often addressed dengue (14.9%), anthrax (7.3%), Japanese encephalitis (7.0%), CCHF (4.9%), and rabies (4.8%). CONCLUSION: The establishment of MENA and SoAs regional networks with locally-based, expert moderators resulted in a significant increase in ProMED's outbreak reports from these regions and an increased flow of disease information across regional borders and to the global public health community

Analysis of School Shootings: December 15, 2012 - December 9, 2014

Regardless of the individuals involved in a shooting or the circumstances that gave rise to it, gunfire in our schools shatters the sense of security that these institutions are meant to foster. Everyone should agree that even one school shooting is one too many.In this report, incidents were classified as school shootings when a firearm was discharged inside a school building or on school or campus grounds, as documented by the press or confirmed through further inquiries with law enforcement. Incidents in which guns were brought into schools but not fired, or were fired off school grounds after having been possessed in schools, were not included.Over the course of two years, we identified a total of three incidents in which a private citizen discharged a firearm at a school that was ultimately determined to be self-defense -- February 4, 2013 at Martin Luther King, Jr., High School in Detroit, MI, January 30, 2014 at Eastern Florida State College, and April 7, 2014 at Eastern New Mexico University. These three incidents were not included in the analysis

Nonlinearity and nonclassicality in a nanomechanical resonator

We address quantitatively the relationship between the nonlinearity of a mechanical resonator and the nonclassicality of its ground state. In particular, we analyze the nonclassical properties of the nonlinear Duffing oscillator (being driven or not) as a paradigmatic example of a nonlinear nanomechanical resonator. We first discuss how to quantify the nonlinearity of this system and then show that the nonclassicality of the ground state, as measured by the volume occupied by the negative part of the Wigner function, monotonically increases with the nonlinearity in all the working regimes addressed in our study. Our results show quantitatively that nonlinearity is a resource to create nonclassical states in mechanical systems.Comment: 6 pages; 7 figures; RevTeX4-