Abstract:
Internet is today’s buzz. It brings with it, many advantages and disadvantages.
One such disadvantage is security. The communication done through the Internet
must be secure so that no third party could read the information being shared by
the two communicating parties. Lot of research is being done in the field of cryptology
to find such functions which can have high nonlinearity so that they cannot
be approximated to linear functions. In this report, some major transforms are
discussed which classify the boolean functions into bent and negabent functions.
An introduction on Boolean function and its use in cryptology is described. Then,
the different types of transforms are explained along with their algorithms and its
complexity. We have used the HN-Spectra to find the quadratic approximation
for the S-Boxes. At the end, the report is summarized stating the further work
still being done in this field.
