The Department of Electrical Engineering-ESAT at the Katholieke Universiteit Leuven regularly runs a course on the state of the art and evolution of computer security and industrial cryptography. The rst course took place in 1983, the second in 1989, and since then the course has been a biennial event. The course is intended for both researchers and practitioners from industry and government. It covers the basic principles as well as the most recent - velopments. Our own interests mean that the course emphasizes cryptography, but we also ensure that the most important topics in computer...

This volume comprises the proceedings of the 4th Conference on Advanced - cryption Standard, AES State of the Crypto Analysis, which was held in Bonn, Germany, during 10 12 May 2004. The conference followed a series of events organized by the US National - stitute of Standards and Technology (NIST) in order to hold an international competition to decide on an algorithm to serve as the Advanced Encryption Standard (AES). In 1998, at the ?rst AES conference (AES 1), 15 di?erent al- rithmswerepresented, discussed, reviewedandveri?ed.Asecondconferencewas organizedinApril1999,...