A New Related Message Attack on RSA

Abstract. Coppersmith, Franklin, Patarin, and Reiter show that given two RSA cryptograms x e mod N and (ax + b) e mod N for known constants a, b ∈ ZN, one can compute x in O(e log 2 e) ZN-operations with some positive error probability. We show that given e cryptograms ci ≡ (aix + bi) e mod N, i = 0, 1,...e − 1, for any known constants ai, bi ∈ ZN, one can deterministically compute x in O(e) ZN-operations that depend on the cryptograms, after a pre-processing that depends only on the constants. The complexity of the pre-processing is O(e log 2 e) ZNoperations, and can be amortized over many instances. We also consider a special case where the overall cost of the attack is O(e) ZN-operations. Our tools are borrowed from numerical-analysis and adapted to handle formal polynomials over finite-rings. To the best of our knowledge their use in cryptanalysis is novel.

Tachyon condensation on brane sphalerons

We consider a sphaleron solution in field theory that provides a toy model for unstable D-branes of string theory. We investigate the tachyon condensation on a Dp-brane. The localized modes, including a tachyon, arise in the spectrum of a sphaleron solution of a \phi^4 field theory on M^{p+1}\times S^1. We use these modes to find a multiscalar tachyon potential living on the sphaleron world-volume. A complete cancelation between brane tension and the minimum of the tachyon potential is found as the size of the circle becomes small.Comment: To appear in JHEP, 13 pages, 2 eps figures, minor changes and references adde

Noise induced transitions in semiclassical cosmology

A semiclassical cosmological model is considered which consists of a closed Friedmann-Robertson-Walker in the presence of a cosmological constant, which mimics the effect of an inflaton field, and a massless, non-conformally coupled quantum scalar field. We show that the back-reaction of the quantum field, which consists basically of a non local term due to gravitational particle creation and a noise term induced by the quantum fluctuations of the field, are able to drive the cosmological scale factor over the barrier of the classical potential so that if the universe starts near zero scale factor (initial singularity) it can make the transition to an exponentially expanding de Sitter phase. We compute the probability of this transition and it turns out to be comparable with the probability that the universe tunnels from "nothing" into an inflationary stage in quantum cosmology. This suggests that in the presence of matter fields the back-reaction on the spacetime should not be neglected in quantum cosmology.Comment: LaTex, 33.tex pages, no figure

Neo-Newtonian cosmology: An intermediate step towards General Relativity

Cosmology is a field of physics in which the use of General Relativity theory is indispensable. However, a cosmology based on Newtonian gravity theory for gravity is possible in certain circumstances. The applicability of Newtonian theory can be substantially extended if it is modified in such way that pressure has a more active role as source of the gravitational field. This was done in the neo-Newtonian cosmology. The limitation on the construction of a Newtonian cosmology, and the need for a relativistic theory in cosmology are reviewed. The neo-Newtonian proposal is presented, and its consequences for cosmology are discussed.Comment: 10 pages. Portuguese version submitted to RBE

Causal Relationship between Obesity and Vitamin D Status: Bi-Directional Mendelian Randomization Analysis of Multiple Cohorts

M.-L. Lokki työryhmän Genetic Invest Anthropometric Trai jäsen.Peer reviewe

KiDS and Euclid: Cosmological implications of a pseudo angular power spectrum analysis of KiDS-1000 cosmic shear tomography

Large scale structure and cosmolog