Courtois and Pieprzyk have done significant progress in new class of XSL attacks on block and stream ciphers, resulting in cracking of Japan Toycrypt algorithm, with big perspectives on both fields. ,,Cryptanalysis of Block Ciphers using Overdefined Systems of Equations'' Nicolas Courtois and Josef Pieprzyk http://eprint.iacr.org/2002/044/ ,,Higher Order Correlation Attacks, XL Algorithm and Cryptanalysis of Toycrypt'' Nicolas Courtois and Josef Pieprzyk http://eprint.iacr.org/2002/087/ WARNING: please note that my email address is modified to avoid harvesting from list archives. -- Pawe3 Krawczyk * http://echelon.pl/kravietz/ Krakow, Poland * http://ipsec.pl/