Linearity in decimation-based generators: an improved cryptanalysis on the shrinking generator

Decimation-based sequence generators are a class of non-linear cryptographic generators designed to be used in hardware implementations. An inherent characteristic of such generators is that their output sequences are interleaved sequences. This profitable characteristic can be used in the cryptanal...

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Bibliographic Details
Main Authors: Cardell Sara D., Fúster-Sabater Amparo, Ranea Adrián H.
Format: Article
Language:English
Published: De Gruyter 2018-06-01
Series:Open Mathematics
Subjects:
Online Access:https://doi.org/10.1515/math-2018-0058
Description
Summary:Decimation-based sequence generators are a class of non-linear cryptographic generators designed to be used in hardware implementations. An inherent characteristic of such generators is that their output sequences are interleaved sequences. This profitable characteristic can be used in the cryptanalysis of those generators. In this work, emphasis is on the most representative decimation-based generator, the shrinking generator, which has been cryptanalyzed just by solving linear equation systems. Compared with previous cryptanalysis, computational complexity and intercepted sequence requirements are dramatically reduced. Although irregularly decimated generators have been conceived and designed as non-linear sequence generators, in practice they can be easily analyzed in terms of simple linear structures.
ISSN:2391-5455