Reconstructing Social Policy and Ageing

This article draws from the work of Michel Foucault to reconstruct an understanding of social policy and ageing in contemporary Britain. In many ways, policy provides three trajectories for older people; first, as independent self-managing consumers with private means and resources; second, as people in need of some support to enable them to continue to self-manage and third, as dependent and unable to commit to self-management. Governmentality provides the theoretical framework through which to view policy and practice that is largely governed by discourses of personalisation

Concurrency Semantics for the Geiger-Paz-Pearl Axioms of Independence

Independence between two sets of random variables is a well-known relation in probability theory. Its origins trace back to Abraham de Moivre\u27s work in the 18th century. The propositional theory of this relation was axiomatized by Geiger, Paz, and Pearl. Sutherland introduced a relation in information flow theory that later became known as "nondeducibility." Subsequently, the first two authors generalized this relation from a relation between two arguments to a relation between two sets of arguments and proved that it is completely described by essentially the same axioms as independence in probability theory. This paper considers a non-interference relation between two groups of concurrent processes sharing common resources. Two such groups are called non-interfering if, when executed concurrently, the only way for them to reach deadlock is for one of the groups to deadlock internally. The paper shows that a complete axiomatization of this relation is given by the same Geiger-Paz-Pearl axioms

Information Leakage Games

We consider a game-theoretic setting to model the interplay between attacker and defender in the context of information flow, and to reason about their optimal strategies. In contrast with standard game theory, in our games the utility of a mixed strategy is a convex function of the distribution on the defender's pure actions, rather than the expected value of their utilities. Nevertheless, the important properties of game theory, notably the existence of a Nash equilibrium, still hold for our (zero-sum) leakage games, and we provide algorithms to compute the corresponding optimal strategies. As typical in (simultaneous) game theory, the optimal strategy is usually mixed, i.e., probabilistic, for both the attacker and the defender. From the point of view of information flow, this was to be expected in the case of the defender, since it is well known that randomization at the level of the system design may help to reduce information leaks. Regarding the attacker, however, this seems the first work (w.r.t. the literature in information flow) proving formally that in certain cases the optimal attack strategy is necessarily probabilistic

Our Very Privileged Executive: Why the Judiciary Can (and Should) Fix the State Secrets Privilege

This paper was first presented at the Temple Law Review Symposium on Executive Power. In Reynolds v. United States, the Supreme Court shaped the state secrets privilege (the Privilege) as one akin to that against self-incrimination. In recent litigation, the government has asserted the Privilege in motions for pre-discovery dismissal, thus transforming the Privilege into a form of executive immunity. This Paper argues that courts must step in to return the Privilege to a scope more in keeping with its status as a form of evidentiary privilege. After reviewing the doctrinal origins of the Privilege, the Paper explores three types of issues implicated by the government\u27s invocation of the Privilege. The government, in calling for judicial deference to executive assertions of the Privilege, often realies on (1) separation of powers arguments or on (2) arguments sounding in institutional competence. Courts are often swayed by such arguments and thus give relatively little consideration to the (3) conflict of interest inherent in the government\u27s assertion of the Privilege and the impact of the successful invocation of the Privilege on the rights of individual litigants. The Paper then proceeds to address arguments that Congress can provide a check on executive abuse of the Privilege. The Paper argues that, assuming that Congress has constitutional authority, it lacks the will or the institutional competence to provide a proper solution to the problems raised by the Privilege. Instead, the Paper contends that, since courts created the Privilege, courts are best positioned to rein it in. The final section of the Paper provides examples drawn from case law illustrating mechanisms whereby courts can protect state secrets while also giving litigants adverse to the government their day in court

A Machine-Checked Formalization of the Generic Model and the Random Oracle Model

Most approaches to the formal analyses of cryptographic protocols make the perfect cryptography assumption, i.e. the hypothese that there is no way to obtain knowledge about the plaintext pertaining to a ciphertext without knowing the key. Ideally, one would prefer to rely on a weaker hypothesis on the computational cost of gaining information about the plaintext pertaining to a ciphertext without knowing the key. Such a view is permitted by the Generic Model and the Random Oracle Model which provide non-standard computational models in which one may reason about the computational cost of breaking a cryptographic scheme. Using the proof assistant Coq, we provide a machine-checked account of the Generic Model and the Random Oracle Mode