Research On Attacks About LEX Algorithm

The stream cipher with a wide range of applications in wireless mobile communication hasattracted huge attention in cryptography researching once again. However, design and analysis ofstream cipher is put into the test. Europe launched formally a research project of the ECRYPTprogram in2004. eSTREAM is a project of ECRYPY in order to promote development of streamcipher. The goal of this project is to establish a new and widespread adoption stream cipherstandard by calling for the design and analysis of stream cipher algorithms throughout the wholeworld publicly．eSTREAM Project has already been finished, but the received thirty five streamcipher algorithms may be used for reference.Differential fault attack combined integrating difference analysis is a cryptographic attackto aim at hardware implement structure for cryptographic algorithm. Sliding attack is one ofattack methods, which is proposed for iterative cipher algorithm. The basic ideas of sliding attackis using the weakness that cryptographic algorithms use the same round function (or some roundfunction is cycle) to obtain partial information of the key.Based on the summarizing the eSTREAM program, we analyze and research the designidea and principle，various attacks (Differential fault analysis, Differential related-cipher attack,Alide attack) for the LEX algorithm that is candidate cipher algorithm into the third phase in thispaper. Because every round encryption of AES uses the same key in LEX algorithm, it leads tobe attacked by slide attack easily. In this paper, we improve the key selection of LEX algorithmby using AES key extension algorithm. The improved LEX algorithm can resist slide attackeffectively.