November 1, Tuesday 12:15, Room 506, Jacobs Building
Title: Versatile algorithms for searching guess-and-determine and meet-in-the-middle attacks on byte-oriented symmetric primitives
Lecturer: Pierre-Alain Fouque
Lecturer homepage
: http://www.di.ens.fr/~fouque/
Affiliation : Ecole Normale Superieure
The AES encryption scheme is actually the target of many new
attacks. Two important classes of attacks are meet-in-the-middle attacks
and guess-and-determine attacks. Such attacks are very simple and
efficient (since a small number of plaintext/ciphertext are required) and
it is possible to automatically look for these attacks.
In this talk I will present some versatile and powerful algorithms for
searching guess-and-determine and meet-in-the-middle attacks on
byte-oriented symmetric primitives. These algorithms exploit the
algebraically simple byte-oriented structure of the AES. To demonstrate
the strengh of these tool, I will show that they allow to automatically
discover new attacks on round-reduced AES with very low data complexity,
and to find improved attacks on the AES-based MACs Alpha-MAC and
Pelican-MAC, and also on the AES-based stream cipher LEX.