1–4 June
Information Theory and Communications
"Highly Nonlinear Filter Boolean Functions with High Algebraic Immunity for Stream Ciphers"
by
Claude Carlet
Université Paris 8
Abstract: Boolean functions, that is, functions from the vectorspace F2n of all binary vectors of length n, to the finite field with two elements F2, play a central role in the security of symmetric (i.e. conventional) cryptography. Cryptographic transformations (pseudo-random generators in stream ciphers, S-boxes in block ciphers) can be designed by appropriate composition of nonlinear Boolean functions. We shall recall how Boolean functions can be used in the pseudo-random generators of stream ciphers. We shall describe the principle of the recent algebraic attacks on them and the related notion of algebraic immunity. A first series of constructions of infinite classes of Boolean functions with optimum algebraic immunity has been proposed. All of them give functions which do not allow resistance to another kind of cryptanalysis called fast correlation attacks. We shall describe more recent infinite classes of functions which achieve an optimum algebraic immunity and allow resistance to all other attacks on stream ciphers.
Biography: Claude Carlet is a full professor in Mathematics at the University of Paris 8 in France. He is the Editor-in-Chief of the new journal Cryptography and Communications: Discrete Structures, Boolean Functions and Sequences. He was also Associate Editor for Coding Theory for the IEEE Transactions on Information Theory from March 2002 until March 2005. Six PhD students defended their theses under his supervision and guidance.
He has written or co-written at least 42 journal papers, 47 conference papers and 7 books or parts of books. His fields of interest include coding and cryptography and also the algebraic construction for the ideas in coding and cryptography.
He has been member or chairman of numerous international conferences and workshops, amongst them the Workshop on Coding and Cryptography (WCC), International Symposium on Information Theory (ISIT), International Conference on Sequences and their Applications (SETA), Asiacrypt (an IACR conference) and Fast Software Encryption.