Linear Complexity Profile Research Articles

Perfect linear complexity profile and apwenian sequences

Sequences with perfect linear complexity profile were defined more than thirty years ago in the study of measures of randomness for binary sequences. More recently apwenian sequences, first with values ±1, then with values in {0,1}, were introduced in the study of Hankel determinants of automatic sequences. We explain that these two families of sequences are the same up to indexing, and give consequences and questions that this implies. We hope that this will help gathering two distinct communities of researchers.

On the arithmetic autocorrelation of the Legendre sequence

The Legendre sequence possesses several desirable features of pseudorandomness in view of different applications such as a high linear complexity (profile) for cryptography and a small (aperiodic) autocorrelation for radar, gps, or sonar. Here we prove the first nontrivial bound on its arithmetic autocorrelation, another figure of merit introduced by Mandelbaum for errorcorrecting codes.

Long Period Sequences Generated by the Logistic Map over Finite Fields with Control Parameter Four

Pseudorandom number generators have been widely used in Monte Carlo methods, communication systems, cryptography and so on. For cryptographic applications, pseudorandom number generators are required to generate sequences which have good statistical properties, long period and unpredictability. A Dickson generator is a nonlinear congruential generator whose recurrence function is the Dickson polynomial. Aly and Winterhof obtained a lower bound on the linear complexity profile of a Dickson generator. Moreover Vasiga and Shallit studied the state diagram given by the Dickson polynomial of degree two. However, they do not specify sets of initial values which generate a long period sequence. In this paper, we show conditions for parameters and initial values to generate long period sequences, and asymptotic properties for periods by numerical experiments. We specify sets of initial values which generate a long period sequence. For suitable parameters, every element of this set occurs exactly once as a component of generating sequence in one period. In order to obtain sets of initial values, we consider a logistic generator proposed by Miyazaki, Araki, Uehara and Nogami, which is obtained from a Dickson generator of degree two with a linear transformation. Moreover, we remark on the linear complexity profile of the logistic generator. The sets of initial values are described by values of the Legendre symbol. The main idea is to introduce a structure of a hyperbola to the sets of initial values. Our results ensure that generating sequences of Dickson generator of degree two have long period. As a consequence, the Dickson generator of degree two has some good properties for cryptographic applications.

Cube Theory and k-error Linear Complexity Profile

Cube Theory and k-error Linear Complexity Profile

On the Pseudorandomness of the Liouville Function of Polynomials over a Finite Field

Abstract We study several pseudorandom properties of the Liouville function and the Möbius function of polynomials over a finite field. More precisely, we obtain bounds on their balancedness as well as their well-distribution measure, correlation measure, and linear complexity profile.

On the linear complexity profile of some sequences derived from elliptic curves

For a given elliptic curve $$\mathbf {E}$$ over a finite field of odd characteristic and a rational function f on $$\mathbf {E}$$ we first study the linear complexity profiles of the sequences f(nG), $$n=1,2,\dots $$ which complements earlier results of Hess and Shparlinski. We use Edwards coordinates to be able to deal with many f where Hess and Shparlinski’s result does not apply. Moreover, we study the linear complexities of the (generalized) elliptic curve power generators $$f(e^nG)$$ , $$n=1,2,\dots $$ We present large families of functions f such that the linear complexity profiles of these sequences are large.

Linear complexity profile and correlation measure of interleaved sequences

Let m be a positive integer. We study the linear complexity profile and correlation measure of two interleaved m-ary sequences of length s and t, respectively. In the case that s ? 2t or s = t and m is prime we estimate the correlation measure in terms of the correlation measure of the first base sequence and the length of the second base sequence. In this case a relation by Brandstatter and Winterhof immediately implies a lower bound on the linear complexity profile of the interleaved sequence. If m is not a prime, under the same restrictions on s and t, the power correlation measure introduced by Chen and Winterhof takes the role of the correlation measure to obtain lower bounds on the linear complexity profile. Moreover, we show that these restrictions on s and t are necessary, and otherwise the (power) correlation measure can be close to st. However, introducing and estimating the (power) correlation measure with bounded lags we are able to get a lower bound on the linear complexity profile of the interleaved sequence.

Linear Complexity Profile as a Means of Measuring the Quality of Random Sequences

Linear Complexity Profile as a Means of Measuring the Quality of Random Sequences

On lattice profile of the elliptic curve linear congruential generators

Lattice tests are quality measures for assessing the intrinsic structure of pseudorandom number generators. Recently a new lattice test has been introduced by Niederreiter and Winterhof. In this paper, we present a general inequality that is satisfied by any periodic sequence. Then, we analyze the behavior of the linear congruential generators on elliptic curves (EC-LCG) under this new lattice test and prove that the EC-LCG passes it up to very high dimensions. We also use a result of Brandstatter and Winterhof on the linear complexity profile related to the correlation measure of order \(k\) to present lower bounds on the linear complexity profile of some binary sequences derived from the EC-LCG.

On the use of expansion series for stream ciphers

AbstractFrom power series expansions of functions on curves over finite fields, one can obtain sequences with perfect or almost perfect linear complexity profile. It has been suggested by various authors to use such sequences as key streams for stream ciphers. In this work, we show how long parts of such sequences can be computed efficiently from short ones. Such sequences should therefore be considered to be cryptographically weak. Our attack leads in a natural way to a new measure of the complexity of sequences which we call expansion complexity.

Correlation Measure of Order <i>k</i> and Linear Complexity Profile of Legendre-Sidelnikov Sequences

Correlation Measure of Order <i>k</i> and Linear Complexity Profile of Legendre-Sidelnikov Sequences

The independence of two randomness properties of sequences over finite fields

We prove the logical independence of a complexity-theoretic and a statistical randomness property of sequences over a finite field. The two properties relate to the linear complexity profile and to the ∞-distribution of sequences, respectively. The proofs are given by constructing counterexamples to the presumed logical implications between these two properties.

Correlation of the two-prime Sidel’nikov sequence

Motivated by the concepts of Sidel'nikov sequences and two-prime generator (or Jacobi sequences) we introduce and analyze some new binary sequences called two-prime Sidel'nikov sequences. In the cases of twin primes and cousin primes equivalent 3 modulo 4 we show that these sequences are balanced. In the general case, besides balancedness we also study the autocorrelation, the correlation measure of order k and the linear complexity profile of these sequences showing that they have many nice pseudorandom features.

On the generalized joint linear complexity profile of a class of nonlinear pseudorandom multisequences

Recently, multisequences have gained increasing interest for applications in cryptography and quasi-Monte Carlo methods. We study the (generalized) joint linear complexity of a class of nonlinear pseudorandom multisequences introduced by the first two authors as well as the linear complexity of its coordinate sequences. We prove lower bounds which are much stronger than in the case of single sequences since the multidimensional case brings in new and favourable effects.

Linear complexity profile of m-ary pseudorandom sequences with small correlation measure

We estimate the linear complexity profile of m-ary sequences in terms of their correlation measure, which was introduced by Mauduit and Sárközy. For prime m this is a direct extension of a result of Brandstätter and the second author. For composite m, we define a new correlation measure for m-ary sequences, relate it to the linear complexity profile and estimate it in terms of the original correlation measure. We apply our results to sequences of discrete logarithms modulo m and to quaternary sequences derived from two Legendre sequences.

Cryptographic pseudo-random sequences from the chaotic Hénon map

A scheme for pseudo-random binary sequence generation based on the two-dimensional discrete-time Hénon map is proposed. Properties of the proposed sequences pertaining to linear complexity, linear complexity profile, correlation and auto-correlation are investigated. All these properties of the sequences suggest a strong resemblance to random sequences. Results of statistical testing of the sequences are found encouraging. An estimate of the keyspace size is presented.

The Pagoda Sequence: a Ramble through Linear Complexity, Number Walls, D0L Sequences, Finite State Automata, and Aperiodic Tilings

We review the concept of the number wall as an alternative to the traditional linear complexity profile (LCP), and sketch the relationship to other topics such as linear feedback shift-register (LFSR) and context-free Lindenmayer (D0L) sequences. A remarkable ternary analogue of the Thue-Morse sequence is introduced having deficiency 2 modulo 3, and this property verified via the re-interpretation of the number wall as an aperiodic plane tiling.

Determining the complexity of FH/SS sequence by approximate entropy

High complexity of frequency-hopping (FH)/spreadspectrum (SS) sequence is of great importance to high-security multiple-access communication systems, for it makes FH/SS sequence difficult to be analyzed. With the growing development in the design of FH/SS sequence in much wider fields, the wellknown complexity measuresiquestthe linear complexity (LC), the linear complexity profile (LCP) and the k-error linear complexity (k-error LC)iquestare widely used but not sufficient to evaluate the complexities of the sequences available, such as the cryptographical sequence and the chaotic sequence families. In this paper, a new complexity metric to evaluate the unpredictability of FH/SS sequence based on the approximate entropy (ApEn) is proposed in the view of the maximal randomness of the sequences with arbitrary length. And the theoretical bounds of the ApEn are derived from a probabilistic point of view. Simulations and analysis results show that, the proposed ApEn works effectively to discern the changing complexities of the FH/SS sequences with small number of samples, which provide superior performance over its candidates.

A New Randomness Test Based on Linear Complexity Profile

Linear complexity can be used to detect predictable nonrandom sequences, and hence it is included in the NIST randomness test suite. But, as shown in this paper, the NIST test suite cannot detect nonrandom sequences that are generated, for instance, by concatenating two different M-sequences with low linear complexity. This defect comes from the fact that the NIST linear complexity test uses deviation from the ideal value only in the last part of the whole linear complexity profile. In this paper, a new faithful linear complexity test is proposed, which uses deviations in all parts of the linear complexity profile and hence can detect even the above nonrandom sequences. An efficient formula is derived to compute the exact area distribution needed for the proposed test. Furthermore, a simple procedure is given to compute the proposed test statistic from linear complexity profile, which requires only O(M) time complexity for a sequence of length M.

A Construction of Binary Cyclotomic Sequences Using Extension Fields

Based on the cyclotomy classes of extension fields, a family of binary cyclotomic sequences are constructed and their pseudorandom measures (i.e., the well-distribution measure and the correlation measure of order k) are estimated using certain exponential sums. A lower bound on the linear complexity profile is also presented in terms of the correlation measure.