We show that the claim of insecurity of the Y-00 (or αη) cryptosystem made by C. Ahn and K. Birnbaum in Phys. Lett. A 370 (2007) 131-135 even under ciphertextonly heterodyne attack, as well as the unfavorable security comparison between αη and an additive stream cipher for all kinds of attacks, is based on invalid extrapolations of Shannon’s random cipher analysis to two concrete ciphers. We ge...

‡ A multi-year project to identify new stream ciphers that might become suitable for widespread adoption

The main objective of this paper is to review the current status of stream cipher standardisation. The hope is that, by doing so, the algorithms and techniques that are likely to be standardised at some point during the next year or so will be subjected to rigorous scrutiny by the cryptographic community.

A new family of very fast stream ciphers called COS (for “crossing over system”) has been proposed by Filiol and Fontaine, and seems to have been adopted for at least one commercial standard. COS(2,128) Mode I and COS(2,128) Mode II are particular members of this family for which the authors proposed a cryptanalysis challenge. The ciphers accept secret keys of 256, 192 or 128 bits. In this note...

This report presents a security evaluation of the Enocoro128v2 stream cipher. Enocoro-128v2 was proposed in 2010 and is a member of the Enocoro family of stream ciphers. This evaluation examines several different attacks applied to the Enocoro-128v2 design. No attack better than exhaustive key search has been found.

Algebraic immunity of Boolean functions is a very important concept in recently introduced algebraic attacks of stream cipher. For a n-variable Boolean function f , the algebraic immunity AIn(f) takes values in {0, 1, . . . , d2 e}. For every k in this range, denote Bn,k the set of all n-variable Boolean functions with algebraic immunity k, and we know that Bn,k is always non-empty. According t...

Chaotic and classical (binary) stream ciphers are compared with respect to their cryptographical properties. Possible synchronization schemes, algebraic and analytical properties as well as design and implementation aspects are discussed. For two example classes with similar system structures it is shown that chaotic stream ciphers can achieve a higher level of complexity than classical binary ...

The shrinking generator is a keystream generator which is good for stream ciphers in wireless mobile communications, because it has simple structure and generates a keystream faster than other generators. Nevertheless, it has a serious disadvantage that its keystream is not balanced if they use primitive polynomials as their feedback polynomials. In this paper, we present a method to construct ...

An initialisation process is a key component in modern stream cipher design. A well-designed initialisation process should ensure that each key-IV pair generates a different keystream. In this paper, we analyse two ciphers, A5/1 and Mixer, for which this does not happen due to state convergence. We show how the state convergence problem occurs and estimate the effective key-space in each case.

In this paper we study relationships between the linear complexities of a sequence when treated as a sequence over two distinct fields. We obtain bounds for one linear complexity in the form of a constant multiple of the other, where the constant depends only on the fields, not on the particular sequence. key words: Linear complexity, stream cipher, finite field, pseudorandom sequence.