paper
title
Algebraic Immunity of S-boxes and Augmented Functions.
authors
Simon Fischer and Willi Meier.
publication
In A. Biryukov, editor, Fast Software Encryption - FSE 2007, 14th International Workshop, Luxembourg City, Luxembourg, March 26-28, 2007. Proceedings, volume 4593 of Lecture Notes in Computer Science, pages 366-381. Springer-Verlag, 2007.
abstract
In this paper, the algebraic immunity of S-boxes and augmented functions of stream ciphers is investigated. Augmented functions are shown to have some algebraic properties that are not covered by previous measures of immunity. As a result, efficient algebraic attacks with very low data complexity on certain filter generators become possible. In a similar line, the algebraic immunity of the augmented function of the eSTREAM candidate Trivium is experimentally tested. These tests suggest that Trivium has some immunity against algebraic attacks on augmented functions.