Title: 50 years history of the cross correlation between m-sequences
Time： 14:30-15:30, November26 Thursday,2019
Location:   Room 1002, Science Building B 
Lecturer：Professor Tor Helleseth University of Bergen 

Abstract:
Maximum-length sequences (or m-sequences) of period 2^m-1 are generated by a linear feedback shift register of degree m. These sequences have many important applications in modern communication systems. The most well known property of m-sequences is their well-known two-level ideal autocorrelation. The first major result on the cross correlation is the determination of the cross correlation between the m-sequences used in constructing the famous Gold sequences that was published 50 years ago in January 1968. During the last 50 years the cross correlation between m-sequences of the same period has been intensively studied by many research groups. Many important results have been obtained but still many open problems remain in this area. This talk will give an updated survey of the status of the cross correlation of m-sequences as well as some consequences of these results. 

Introduction of Lectuer:
Tor Helleseth (IEEE Fellow) received his Dr. Philos. degree in mathematics from the University of Bergen, Norway, in 1979. During the academic years 1977-1978 and 1992-1993 he was on sabbatical leave at the University of Southern California, USA, and during 1979-1980 he was a Postdoctoral fellow at the Eindhoven University of Technology, The Netherlands. From 1981 to 1984 he was a researcher at the Chief Headquarters of Defense in Norway. Since 1984 has he has been Professor at the Department of Informatics, University of Bergen. He served as an Associate Editor for IEEE Transactions on Information Theory, 1991-1993 for Coding Theory and 2012-2014 for Sequences. He is on the editorial board for Designs, Codes and Cryptography (DCC), and Cryptography and Communications: Discrete Structures, Boolean Functions and Sequences (CCDS). He has published more than 350 papers in international refereed journals and conferences in coding theory, cryptography and sequence designs, including more than 100 co-authors from more than 25 countries. He was the program co-chair for Eurocrypt’93, IEEE Information Theory Workshop, ITW1997, ITW2007, Arctic Crypt 2016 and for Sequences and Their Applications, SETA’98, SETA’04, SETA’06, SETA’12 and SETA’18. Professor Helleseth was a coordinator of NISNet, a national network in information security, in Norway 2007-2011. In 1997 he was elected IEEE Fellow for his "Contributions to Coding Theory and Cryptography" and in 2004 elected member of the Norwegian Academy of Science (Det Norske Videnskaps-Akademi). He served on the Board of Governors for the IEEE IT-Society during 2007-2009. His interests include coding theory, cryptography, sequence designs, finite fields and discrete mathematics.