We propose a new method for evaluating the security of block ciphers against di erential cryptanalysis and propose new structures for block ciphers. To this end, we de ne the word-wise Markov (Feistel) cipher and random output-di erential (Feistel) cipher and clarify the relations among the di erential, the truncated di erential and the impossible di erential cryptanalyses of the random output-...

it is known that a stochastic dierential equation (sde) induces two probabilisticobjects, namely a diusion process and a stochastic ow. while the diusion process isdetermined by the innitesimal mean and variance given by the coecients of the sde,this is not the case for the stochastic ow induced by the sde. in order to characterize thestochastic ow uniquely the innitesimal covariance give...

Oberwolfach Tagungsbericht 26/1999 Partial Di erential Equations 13.06.1999 { 19.06.1999 This meeting was organized by L. C. Evans (Berkeley), S. M uller (MPI Leipzig) and E. Kuwert (Freiburg). The 22 delivered talks addressed a broad spectrum of questions for nonlinear partial di erential equations. Most of the considered problems arise in geometry or in physics, as for example submanifolds w...

It is proven that an initial value problem of an autonomous system verifying some conditions has exactly one open continuously di€erentiable trajectory on R, whose limit set is not one point. The proof of the result is based upon continuation methods. 1. Preliminaries Di€erential equations play a key role in nature and technology because they control their processes. In time-dependent processes...

This article presents a numerical method for solving nonlinear two-dimensional fractional Volterra integral equation. We derive the Hat basis functions operational matrix of order integration and use it to solve integro-di?erential equations. The is described illustrated with examples. Also, we give error analysis.

Higher-order intergrid transfer operators used within cell-centered multigrid can improve the convergence properties of the multigrid method compared to low-order operators. In this thesis those operators are analyzed and incorporated into the LSE (linear systems of equation) module of the waLBerla software framework. The aim is to provide a solver for Poisson and Poisson-Boltzmann partial di e...

In this paper we present an estimate of accuracy for a piecewise polynomial approximation of a classical numerical solution to a non linear di erential problem. We suppose the numerical solution u is computed using a grid with a small linear step and interval time Tu, while the polynomial approximation v is an interpolation of the values of a numerical solution on a less ne grid and interval ti...

We investigate the D-optimal design problem in the common trigonometric regression model, where the design space is a partial circle. The task of maximizing the criterion function is transformed into the problem of determining an eigenvalue of a certain matrix via a di erential equation approach. Since this eigenvalue is an analytic function of the length of the design space, we can make use of...

Steady, inviscid, axisymmetric vortex ows past a sphere are obtained numerically as solutions of a partial di erential equation for the stream function. The solutions found include vortex rings, bounded vortices attached to the sphere and in nite vortex tubes. Four families of attached vortices are described: vortex wakes behind the sphere, spherically annular vortices surrounding the spherical...

We consider optimal control of nonlinear partial di erential equations involving potentially singular solution-dependent terms. Singularity can be prevented by either restricting controls to a closed admissible set for which well-posedness of the equation can be guaranteed, or by explicitly enforcing pointwise bounds on the state. Bymeans of an elliptic model problem, we contrast the requiremen...