National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
APN functions with non-classical Walsh spectra
Maršálek, Michal ; Göloglu, Faruk (advisor) ; Drápal, Aleš (referee)
An interesting class of Boolean functions are APN functions - these func- tions are "as far" from linear functions as possible. Most of the quadratic APN functions have the same (=classical) Walsh spectrum - a sort of footprint of the function. The aim of this thesis is to describe a method which might lead to a generalisation of a sporadic example of a quadratic APN function with non-classical Walsh spectrum. Up until recently, it was believed that no such function exists. This was proven to be false in 2009, as an example of such func- tion in dimension 6 was introduced. In this thesis, we describe the construction and then deduce necessary conditions for some free coefficients in order to reduce the search space to a level which enables a computer search. 1
Cryptographic criteria for Boolean functions
Luňáčková, Radka ; Hojsík, Michal (advisor) ; Tůma, Jiří (referee)
The work is focused on Boolean functions. At first, it describes the ways Boolean functions are represented. Besides the representation using truth- table, vector of values and algebraic normal form which are usually shown we also show some other representations like univariate representation and trace repre- sentation. Moreover, we explain the relations among these representations. Then summary of the theory of Boolean functions is given, in order to understand important properties of Boolean functions corectly. Finally, these properties are studied, their interconnection is explained and the following cryptographic cri- teria of Boolean functions are describe: the algebraic degree, the nonlinearity, balancedness, resiliency and correlation immunity. 1

Interested in being notified about new results for this query?
Subscribe to the RSS feed.