We present a new cryptanalytic attack on PN-generators filtered by a Boolean function. The key-idea is to jointly combine the knowledge of the Boolean function and the LFSR structure so as to introduce a new iterative decoding technique. The results we obtained prove to be very good: indeed, even in the case of systems for which classical iterative algorithms appear powerless, our scheme enable...

A new hybrid BIST scheme is proposed which is based on using an “incrementally guided LFSR.” It very efficiently combines external deterministic data from the tester with on-chip pseudo-random BIST. The hardware overhead is very small as a conventional STUMPS architecture [1] is used with only a small modification to the feedback of the LFSR which allows the tester to incrementally guide the LF...

This paper describes new methods for fast correlation attacks, based on the theory of convolutional codes. They can be applied to arbitrary LFSR feedback polynomials, in opposite to the previous methods, which mainly focus on feedback polynomials of low weight. The results improve significantly the few previous results for this general case, and are in many cases comparable with corresponding r...

Algebraic attacks on stream ciphers apply (at least theoretically) to all LFSR-based stream ciphers that are clocked in a simple and/or easily predictable way. One interesting approach to help resist such attacks is to add a component that de-synchronizes the output bits of the cipher from the clock of the LFSR. The Bit-search generator, recently proposed by Gouget and Sibert, is inspired by th...

Our contributions are applying distinguishing attack on Linearly Filtered NLFSR as a primitive or associated with filter generators. We extend the attack on linear combinations of Linearly Filtered NLFSRs as well. Generally, these structures can be examined by the proposed techniques and the criteria will be achieved to design secure primitive. The attacks allow attacker to mount linear attack ...

Two forms of nonlinear-feedback shift-registers are considered. In the Type-I register, the feedback output is added to the shift-register contents at an arbitrary number of stages. In the type-11 register, the feedback is input to the first stage only. It is shown that for every Type-I register there is an equivalent Type-II register in the sense that the autonomous state diagrams differ only ...

The purpose of this paper is to evaluate the security of the Gollmann m-sequence cascades of k stages. We give some theoretical results, which can be utilized to construct the transition matrix T, of the conditional probabilities between the input and output strings of a stage. And then, we describe an attack algorithm for guessing the initial state of the first LFSR with desired reliability, u...

Due to ongoing improvements in high-speed communications, the speed of data encryption must also increase. Accordingly, this paper proposes an PS-LFSR with an m(¿ 2)-times faster shifting during one clock interval and a parallel stream cipher that is faster by paralleling many similar keystream generators using the PS-LFSRs. Finally, an m-parallel SUM-BSG with 8-parallel for detail is proposed ...

In this paper, we investigate matrices acting on finite commutative groups and rings. In fact, we study modules on ring of matrices over ZN and also modules over the ring (F2 , ⨁,∧); these new algebraic constructions are a generalization of some of the constructions which were previously presented by the authors of this paper. We present new linearized and nonlinear MDS diffusion layers, based ...