Title of lecture:
 First - Divide, Then - Attack

 Abstract:

 Since differential and linear cryptanalysis were introduced, ciphers have
 been devised to withstand this attacks. One popular method used by cipher
 designers is to bound the maximal differential and linear probabilities
 after several rounds to a small enough value, which is low enough so
 that these attacks are impractical.
 In order to attack this kind of ciphers new techniques have been devised,
 some of them are basedon treating the cipher as a cascade of
 sub-cipher. Each of this sub-ciphers is extremely vulnerable to
 differential and/or linear cryptanalysis. Using specific constructions, we
 can exploit this weakness for attacking the whole cipher.

 In the talk we shall cover the basic ideas behind this methodology, and
 present various attacks which use it (boomerang, rectangle,
 differential-linear).