Security as a Systems Property

How do we protect systems? The answer is straightforward: each component must be evaluated independently and protected as necessary. Beware the easy answers, such as deploying stronger encryption while ignoring vulnerable end points; that's too much like looking under the streetlamp for lost keys, not because they're likely to be there but because it's an easy place to search. Remember, too, that people and processes are system components as well, and often the weakest ones ”think about phishing, but also about legitimate emails that are structurally indistinguishable from phishing attacks. I'm not saying you should ignore one weakness because you can't afford to address another serious one” but in general, your defenses should be balanced. After that, of course, you have to evaluate the security of the entire system. Components interact, not always in benign ways, and there may be gaps you haven't filled

Water rights for variable supplies

The relative merits of different systems of property rights to allocate water among different extractive uses are evaluated for the case where variability of supply is important. Three systems of property rights are considered. In the first, variable supply is dealt with through the use of water entitlements defined as shares of the total quantity available. In the second, there are two types of water entitlements, one for water with a high security of supply and the other a lower security right for the residual supply. The third is a system of entitlements specified as state-contingent claims. With zero transaction costs, all systems are efficient. In the realistic situation where transaction costs matter, the system based on state-contingent claims is globally optimal, and the system with high-security and lower security entitlements is preferable to the system with share entitlements.property rights, state-contingent claims, water, Resource /Energy Economics and Policy,

A UML-based static verification framework for security

Secure software engineering is a new research area that has been proposed to address security issues during the development of software systems. This new area of research advocates that security characteristics should be considered from the early stages of the software development life cycle and should not be added as another layer in the system on an ad-hoc basis after the system is built. In this paper, we describe a UML-based Static Verification Framework (USVF) to support the design and verification of secure software systems in early stages of the software development life-cycle taking into consideration security and general requirements of the software system. USVF performs static verification on UML models consisting of UML class and state machine diagrams extended by an action language. We present an operational semantics of UML models, define a property specification language designed to reason about temporal and general properties of UML state machines using the semantic domains of the former, and implement the model checking process by translating models and properties into Promela, the input language of the SPIN model checker. We show that the methodology can be applied to the verification of security properties by representing the main aspects of security, namely availability, integrity and confidentiality, in the USVF property specification language

Designing and Operating Safe and Secure Transit Systems: Assessing Current Practices in the United States and Abroad, MTI Report 04-05

Public transit systems around the world have for decades served as a principal venue for terrorist acts. Today, transit security is widely viewed as an important public policy issue and is a high priority at most large transit systems and at smaller systems operating in large metropolitan areas. Research on transit security in the United States has mushroomed since 9/11; this study is part of that new wave of research. This study contributes to our understanding of transit security by (1) reviewing and synthesizing nearly all previously published research on transit terrorism; (2) conducting detailed case studies of transit systems in London, Madrid, New York, Paris, Tokyo, and Washington, D.C.; (3) interviewing federal officials here in the United States responsible for overseeing transit security and transit industry representatives both here and abroad to learn about efforts to coordinate and finance transit security planning; and (4) surveying 113 of the largest transit operators in the United States. Our major findings include: (1) the threat of transit terrorism is probably not universal—most major attacks in the developed world have been on the largest systems in the largest cities; (2) this asymmetry of risk does not square with fiscal politics that seek to spread security funding among many jurisdictions; (3) transit managers are struggling to balance the costs and (uncertain) benefits of increased security against the costs and (certain) benefits of attracting passengers; (4) coordination and cooperation between security and transit agencies is improving, but far from complete; (5) enlisting passengers in surveillance has benefits, but fearful passengers may stop using public transit; (6) the role of crime prevention through environmental design in security planning is waxing; and (7) given the uncertain effectiveness of antitransit terrorism efforts, the most tangible benefits of increased attention to and spending on transit security may be a reduction in transit-related person and property crimes

Does Social Security Affect Retirement and Labor Supply? Using the Chilean Experience as an Experiment

The paper explores the effects of the social security system over retirement and labor supply decision of individuals aged 55 to 65 in Chile. We use the 1998 CASEN survey elaborated by the Chilean government. Due to regulations established by the current social security law, two social security systems coexist on 1998: the .Pay-as-you-go. and the individual account system. This property of the dataset, allows us to disentangle the effects of those two systems over retirement and labor supply. The results show that social security may significantly affect retirement and labor supply decisions. The effects are mainly twofold. First, larger benefits may induce earlier retirement and lower labor supply and second, larger variance of benefits may induce later retirement and larger labor supply, due to a precautionary motive. This last effect seems to be important when analyzing the path of the Chilean retirement rates on the nineties.

Water Rights for Variable Supplies Creation_Date: 2004-02 Revision_Date: 2005-05

The relative merits of different property right systems to allocate water among different extractive uses where variability of supply is important are evaluated. Three systems of property rights are considered. In the first, variable supply is dealt with through the use of water rights defined as shares of the total quantity available. In the second, there are two types of water rights, one for water with a high security of supply and the other a low-security right for the residual supply. The third is a system of state-contingent claims. With zero transaction costs, all systems are efficient. In the realistic situation where transaction costs matter, the state-contingent claims system is globally optimal, and the system with high-security and low-security rights is preferable to the system with share allocations.Uncertainty, property rights, Murray-Darling