報告人：  Tor Helleseth

報告題目：Stream Ciphers and Coding Theory

          (流密碼和編碼理論)

  時間：2014年10月28日星期四下午3:30-4:30

  地點：kaiyun開云官方網(wǎng)站學(xué)術(shù)報告廳X2511

主講人簡介：Tor Helleseth教授現(xiàn)任挪威Bergen大學(xué)教授，是信息科學(xué)領(lǐng)域的國際著名學(xué)者，一直致力于基礎(chǔ)理論和應(yīng)用研究，在編碼理論、信息安全、組合數(shù)學(xué)等領(lǐng)域都做出了多項開創(chuàng)性和奠基性的工作和獨特的貢獻，取得舉世矚目的成就。迄今他已發(fā)表論文300余篇，其中包括國際信息論旗艦刊物IEEE T. IT論文90余篇，研究深度和廣度在國際信息科學(xué)領(lǐng)域都是極為罕見的。

Tor Helleseth教授在學(xué)術(shù)上的卓越成就贏得了國際信息科學(xué)界的普遍尊重和崇高的學(xué)術(shù)聲譽，被公認為大師級學(xué)者。他1997年當選IEEE Fellow，2004年當選挪威科學(xué)院院士，2007-2009任IEEE信息論分會管理委員會理事。

報告內(nèi)容簡介：

Stream ciphers have many applications in modern communication systems.  In recent years stream ciphers have received a lot of attention in the eSTREAM project organized by ECRYPT, a European network of Excellence  in cryptography.
　　Important building blocks in many constructions of stream ciphers are the filter generator and the nonlinear combiner generator. These constructions consist of one of more linear feedback shift registers combined with a Boolean function. Based on the content of the involved shift registers the Boolean function provides a keystream.
　　This talk will survey some attacks on the filter generator and nonlinear combiner generator including the R?njom-Helleseth attack and some recent generalizations considering the Boolean function as a univariate polynomial. Furthermore a discussion of some connections to coding theory will be provided. The concept of algebraic immunity of Boolean function is shown to be less natural than the new concept of spectral immunity that is determined by coding theoretic properties of a code defined by the Boolean function.