Algebraic Analysis of LEX

Z'aba, Muhammad Reza, Raddum, Havard, Simpson, Leonie, Dawson, Ed, Henricksen, Matt, & Wong, Kenneth (2009) Algebraic Analysis of LEX. In Brankovic, Ljiljana & Susilo, Willy (Eds.) Australasian Information Security Conference (AISC2009), 20-23 January 2009, Wellington, New Zealand.


LEX is a stream cipher that progressed to Phase 3 of the eSTREAM stream cipher project. In this paper, we show that the security of LEX against algebraic attacks relies on a small equation system not being solvable faster than exhaustive search. We use the byte leakage in LEX to construct a system of 21 equa- tions in 17 variables. This is very close to the require- ment for an efficient attack, i.e. a system containing 16 variables. The system requires only 36 bytes of keystream, which is very low.

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2 citations in Scopus
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ID Code: 27517
Item Type: Conference Paper
Refereed: Yes
Keywords: LEX, Advanced Encryption Standard, Stream Cipher
Subjects: Australian and New Zealand Standard Research Classification > INFORMATION AND COMPUTING SCIENCES (080000) > DATA FORMAT (080400) > Data Encryption (080402)
Divisions: Past > Institutes > Information Security Institute
Deposited On: 24 Sep 2009 05:30
Last Modified: 29 Feb 2012 13:55

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