The linearcomplexity and k-error linear complexity of sequences are important measures of the strength of key-streams generated by stream ciphers. Based on the characters of the set of sequences with given linear com...
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ISBN:
(纸本)9783319500119;9783319500102
The linearcomplexity and k-error linear complexity of sequences are important measures of the strength of key-streams generated by stream ciphers. Based on the characters of the set of sequences with given linearcomplexity, people get the characterization of 2(n)-binary sequences with given k-error linear complexity for small k recently. In this paper, we put forward this study to get the distribution of linearcomplexity and k-error linear complexity of 2(n)-periodic binary sequences with fixed Hamming weight. First, we give the counting function of the number of 2(n)-periodic binary sequences with given linearcomplexity and fixed Hamming weight. Provide an asymptotic evaluation of this counting function when n gets large. Then we take a step further to study the distribution of 2(n)-periodic binary sequences with given 2-errorlinearcomplexity and fixed Hamming weight. Through an asymptotic analysis, we provide an estimate on the number of 2(n)-periodic binary sequences with given 2-errorlinearcomplexity and fixed Hamming weight.
This paper studies the stability of the linearcomplexity of l-sequences. Let (s) under bar be an I-sequence with linearcomplexity attaining the maximum per((s) under bar)/2 + 1. A tight lower bound and an upper boun...
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This paper studies the stability of the linearcomplexity of l-sequences. Let (s) under bar be an I-sequence with linearcomplexity attaining the maximum per((s) under bar)/2 + 1. A tight lower bound and an upper bound on minerror((s) under bar), i.e., the minimal value k for which the k-error linear complexity of (s) under bar is strictly less than its linearcomplexity, are given. In particular, for an I-sequence (s) under bar based on a prime number of the form 2r + 1, where r is an odd prime number with primitive root 2, it is shown that minerror((s) under bar) is very close to r, which implies that this kind of I-sequences have very stable linearcomplexity. (C) 2010 Published by Elsevier Inc.
In our previous work we transformed the optimisation problem of finding the k-error linear complexity of a sequence into an optimisation problem in the DFT (Discrete Fourier Transform) domain, using Blahut's theor...
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ISBN:
(纸本)9783642158735
In our previous work we transformed the optimisation problem of finding the k-error linear complexity of a sequence into an optimisation problem in the DFT (Discrete Fourier Transform) domain, using Blahut's theorem. We then gave an approximation algorithm of polynomial complexity for the transformed problem by restricting the search space to error sequences whose DFT have period up to k. However, when applying the inverse transformation, the error vectors obtained are in general in an extension of the original field. In the present paper we develop our previous approximation algorithm so that now it can be constrained to only obtain errors over the original field. Essentially, we give a polynomial approximation algorithm for the computation of the k-error linear complexity of a sequence. More precisely, the algorithm will find the optimum among a restricted set of errors over the original field. While this restricted search space is still exponential, the complexity of the algorithm is polynomial, O(N-2 log N log log N).
The linearcomplexity and k-error linear complexity of a sequence have been used as important measures for keystream strength, hence designing a sequence with high linearcomplexity and k-error linear complexity is a ...
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ISBN:
(纸本)9781467398343
The linearcomplexity and k-error linear complexity of a sequence have been used as important measures for keystream strength, hence designing a sequence with high linearcomplexity and k-error linear complexity is a popular research topic in cryptography. In order to study k-error linear complexity of binary sequences with period 2(n), a new tool called cube theory is developed. In this paper, we first give a general decomposition approach to decompose a binary sequence with period 2(n) into some disjoint cubes. Second, a counting formula for m-cubes with the same linearcomplexity is derived, which is equivalent to the counting formula for k-error vectors. The counting formula of 2(n)-periodic binary sequences which can be decomposed into more than one cube is also investigated, which extends an important result by Etzion et al..
The p(n)-periodic q-ary sequence with high linearcomplexity and high k-error linear complexity is defined as excellent sequence. With appropriate fitness function and parameters, this paper design a genetic algorithm...
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ISBN:
(纸本)9781467372114
The p(n)-periodic q-ary sequence with high linearcomplexity and high k-error linear complexity is defined as excellent sequence. With appropriate fitness function and parameters, this paper design a genetic algorithm to generate the N-periodic q-ary excellent sequences, where N=27,81,., 2187, and get some laws of k-error linear complexity and linearcomplexity, here p is an odd prime and q is a primitive root modulo p(2).
Niederreiter showed that there is a class of periodic sequences which possess large linearcomplexity and large k-error linear complexity simultaneously. This result disproved the conjecture that there exists a trade-...
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Niederreiter showed that there is a class of periodic sequences which possess large linearcomplexity and large k-error linear complexity simultaneously. This result disproved the conjecture that there exists a trade-off between the linearcomplexity and the k-error linear complexity of a periodic sequence by Ding et al. By considering the orders of the divisors of x(N)-1 over F-q, we obtain three main results which hold for much larger k than those of Niederreiter et al.: a) sequences with maximal linearcomplexity and almost maximal k-error linear complexity with general periods;b) sequences with maximal linearcomplexity and maximal k-error linear complexity with special periods;c) sequences with maximal linearcomplexity and almost maximal k-error linear complexity in the asymptotic case with composite periods. Besides, we also construct some periodic sequences with low correlation and large k-error linear complexity.
In the present paper, by making use of some special properties of the Hermitian function fields, we construct multisequences with both large linearcomplexity and k-error linear complexity. Moreover, these sequences c...
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In the present paper, by making use of some special properties of the Hermitian function fields, we construct multisequences with both large linearcomplexity and k-error linear complexity. Moreover, these sequences can be explicitly constructed.
Several fast algorithms for the determination of the linearcomplexity of d-periodic sequences over a finite field F-q, i.e. sequences with characteristic polynomial f(x) = x(d) - 1, have been proposed in the literatu...
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Several fast algorithms for the determination of the linearcomplexity of d-periodic sequences over a finite field F-q, i.e. sequences with characteristic polynomial f(x) = x(d) - 1, have been proposed in the literature. In this contribution fast algorithms for determining the linearcomplexity of binary sequences with characteristic polynomial f(x) = (x - 1)(d) for an arbitrary positive integer d, and f(x) = (x(2) + x + 1)(2v) are presented. The result is then utilized to establish a fast algorithm for determining the k-error linear complexity of binary sequences with characteristic polynomial (x(2) + x + 1)(2v).
linearcomplexity is an important measure of the cryptographic strength of key streams used in stream ciphers. The linearcomplexity of a sequence can decrease drastically when a few symbols are changed. Hence there h...
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ISBN:
(纸本)9783642041587
linearcomplexity is an important measure of the cryptographic strength of key streams used in stream ciphers. The linearcomplexity of a sequence can decrease drastically when a few symbols are changed. Hence there has been considerable interest in the k-error linear complexity of sequences which measures this instability in linearcomplexity. For 2(n)-periodic sequences it is known that minimum number of changes needed per period to lower the linearcomplexity is the same for sequences with fixed linearcomplexity. In this paper we derive an expression to enumerate all possible corresponding number of 2(n)-periodic binary sequences with fixed linear equals the minimum number of changes needed to lower the linearcomplexity below L. For some of these values we derive the expression for the of 2(n)-periodic binary sequences with fixed linearcomplexity L, when k values for the k-error linear complexity binary sequences with fixed linearcomplexity and k-error linear complexity when k equals the minimum stability of linearcomplexity of 2(n)-periodic binary sequences. are of importance to compute some statistical properties concerning.
For binary sequences with period , where is an odd prime and 2 is a primitive root modulo , we present an algorithm which computes the minimum number so that the -errorlinearcomplexity is not greater than a given co...
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For binary sequences with period , where is an odd prime and 2 is a primitive root modulo , we present an algorithm which computes the minimum number so that the -errorlinearcomplexity is not greater than a given constant . An associated error sequence which gives the -errorlinearcomplexity is also obtained.
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