Open AccessGuess and determine cryptanalysis with variable sampling and its applications
Author(s) -
Hodžić Samir,
Pasalic Enes,
Wei Yongzhuang
Publication year - 2019
Publication title -
iet information security
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.308
H-Index - 34
eISSN - 1751-8717
pISSN - 1751-8709
DOI - 10.1049/iet-ifs.2018.5233
Subject(s) - keystream , stream cipher , cryptanalysis , correlation attack , linear cryptanalysis , algorithm , computer science , shift register , mathematics , higher order differential cryptanalysis , cipher , binary number , cryptography , filter (signal processing) , theoretical computer science , arithmetic , encryption , computer vision , telecommunications , chip , operating system
Non‐linear filtering generators, as a well‐known family of stream ciphers, employ a filtering function F : GF ( 2 )n → GF ( 2 )m to process the secret state bits and thus outputs binary keystream blocks of length m . In this study, the authors extend the framework of a generic cryptanalytic method applicable to non‐linear filtering generators called generalised filter state guessing attacks (GFSGA), introduced as a generalisation of the filter state guessing attack method, by applying a variable sampling of the keystream bits in order to retrieve as much information about the secret state bits as possible. Two different modes that use a variable sampling of keystream blocks are presented and it is shown that in many cases these modes may outperform the standard GFSGA mode. They also demonstrate the possibility of employing GFSGA‐like attacks to other design strategies such as non‐linear feedback shift register‐based ciphers (Grain family for instance). It is also indicated that the tap positions of Grain‐128 are not chosen optimally with respect to this generic cryptanalytic method and provide a better selection of taps that gives higher resistance to GFSGA‐like attacks.