On the number of unsuitable Boolean functions in constructions of filter and combining models of stream ciphers
It is well known that every stream cipher is based on a good pseudorandom generator. For cryptographic purposes, we are interested in generation of pseudorandom sequences of the maximal possible period. A feedback register is one of the most known cryptographic primitives that is used in construction of stream generators. We analyze periodic properties of pseudorandom sequences produced by filter and combiner generators equipped with nonlinear Boolean functions. We determine which nonlinear functions in these schemes lead to pseudorandom sequences of not maximal possible period. We call such functions unsuitable and count the exact number of them for an arbitrary n.
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Keywords
stream cipher, filter generator, combiner generator, gamma, Boolean function, потоковый шифр, фильтрующий генератор, комбинирующий генераторAuthors
| Name | Organization | |
| Bonich T. A. | Novosibirsk State University; Crypto Labs JetBrains Research | t.bonich@g.nsu.ru |
| Panferov M. A. | Novosibirsk State University; Crypto Labs JetBrains Research | m.panferov@g.nsu.ru |
| Tokareva N. N. | S. L. Sobolev Institute of Mathematics SB RAS; Novosibirsk State University | tokareva@math.nsc.ru |
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On the number of unsuitable Boolean functions in constructions of filter and combining models of stream ciphers | Applied Discrete Mathematics. Supplement. 2020. № 13. DOI: 10.17223/2226308X/13/23
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