Leakage-Resilient Lattice-Based Partially Blind Signatures

Blind signature schemes (BSS) play a pivotal role in privacy-oriented cryptography. However, with blind signature schemes, the signed message remains unintelligible to the signer, giving them no guarantee that the blinded message he signed actually contained valid information. Partially-blind signature schemes (PBSS) were introduced to address precisely this problem. In this paper we present the first leakage-resilient, lattice-based partially-blind signature scheme in the literature. Our construction is provably secure in the random oracle model (ROM) and offers quasilinear complexity w.r.t. key/signature sizes and signing speed. In addition, it offers statistical partial blindness and its unforgeability is based on the computational hardness of worst-case ideal lattice problems for approximation factors in $˜ O(n^4)$ in dimension $n$. Our scheme benefits from the subexponential hardness of ideal lattice problems and remains secure even if a (1-o(1)) fraction of the signer’s secret key leaks to an adversary via arbitrary side-channels. Several extensions of the security model, such as honest-user unforgeability and selective failure blindness, are also considered and concrete parameters for instantiation are proposed

Evidence for Nonlinear Asymmetric Causality in US Inflation, Metal, and Stock Returns

The purpose of this paper is to propose a version of causality testing that focuses on how the sign of the returns affects the causality results. We replace the traditional VAR specification used in the Granger causality test by a discrete-time bivariate noisy Mackey glass model. Our test reveals interesting and previously unexplored relationships in US economic series, including inflation, metal, and stock returns

Research Article Evidence for Nonlinear Asymmetric Causality in US Inflation, Metal, and Stock Returns

purpose of this paper is to propose a version of causality testing that focuses on how the sign of the returns affects the causality results. We replace the traditional VAR specification used in the Granger causality test by a discrete-time bivariate noisy Mackey glass model. Our test reveals interesting and previously unexplored relationships in US economic series, including inflation, metal, and stock returns. Copyright q 2008 D. Hristu-Varsakelis and C. Kyrtsou. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1

Optimizing production with energy and GHG emission constraints in Greece: An input-output analysis

Under its Kyoto and EU obligations, Greece has committed to a greenhouse gas (GHG) emissions increase of at most 25% compared to 1990 levels, to be achieved during the period 2008-2012. Although this restriction was initially regarded as being realistic, information derived from GHG emissions inventories shows that an increase of approximately 28% has already taken place between 1990 and 2005, highlighting the need for immediate action. This paper explores the reallocation of production in Greece, on a sector-by-sector basis, in order to meet overall demand constraints and GHG emissions targets. We pose a constrained optimization problem, taking into account the Greek environmental input-output matrix for 2005, the amount of utilized energy and pollution reduction options. We examine two scenarios, limiting fluctuations in sectoral production to at most 10% and 15%, respectively, compared to baseline (2005) values. Our results indicate that (i) GHG emissions can be reduced significantly with relatively limited effects on GVP growth rates, and that (ii) greater cutbacks in GHG emissions can be achieved as more flexible production scenarios are allowed.GHG emissions Input-output analysis Greek economy