This thesis focuses on the cryptanalysis and the design of block ciphers and hash functions. The thesis starts with an overview of methods for cryptanalysis of block ciphers which are based on differential cryptanalysis. We explain these concepts and also several combinations of these attacks. We propose new attacks on reduced versions of ARIA and AES. Furthermore, we analyze the strength of th...

Stochastic screen halftoning combines the speed of ordered dither and high quality of error diiusion. The general approach to stochastic screen design employs either spatial domain or frequency domain ltering to generate binary patterns with \blue noise" characteristic at each gray level, which can be summed to form a single threshold array. In this paper, we will propose a novel technique to d...

These are notes for a lecture given at Ohio University on June 3, 2006. An important topic in commutative algebra is the Rees algebra of an ideal in a commutative ring. The Rees algebra encodes a lot of information about the ideal and corresponds geometrically to a blow-up. One can represent the Rees algebra as the quotient of a polynomial ring by an ideal. This ideal is generated by the defini...

We propose a quartic function to represent a family of continuous quality loss functions. Depending on the choice of its parameters the shape of this function within the specification limits can be either symmetric or asymmetric, and it can be either similar to the ubiquitous quadratic loss function or somewhat closer to the conventional step function. We examine this family of loss functions i...

.

Using a new Bayesian Optimization algorithm to guide the design of mechanical metamaterials, we nonhomogeneous 3D structures possessing Cauchy symmetry, which dictates relationship between continuum and atomic deformations. Recent efforts merge optimization techniques with metamaterials has resulted in concentrated effort tailor their elastic post properties. Even though these properties either...