Raziskovalni matematični seminar - Arhiv

Title: On quasi-thin association schemes (joint with M.Muzychuk)

Abstract: An association scheme is called quasi-thin if the valency of each its basic relation is one or two. A quasi-thin scheme is Kleinian if its thin residue is the Klein four-group with respect to relational product.
It turns out that any Kleinian scheme arises from near-pencil on 3 points, or affine or projective plane of order 2. The main esult is that any non-Kleinian quasi-thin scheme is the two-orbit scheme of a suitable permutation group.

Title:Linear Cryptanalysis

Abstract: In this talk we present the details of linear cryptanalysis, one of the most significant attack applicable to symmetric-key block cipher. The  topic  is based on  the analysis of a simple,  yet  realistically  structured,  basic  Substitution-Permutation  Network  cipher. Understanding the attacks as they apply to this structure is useful, as the Rijndael cipher, recently  selected  for  the Advanced Encryption Standard  (AES),  has  been  derived  from the basic SPN architecture.