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In this paper, we construct four families of linear codes over finite fields from the complements of either the union of subfields or the union of cosets of a subfield, which can produce infinite families of optimal linear codes, including infinite families of (near) Griesmer codes. We also characterize the optimality of these four families of linear codes with an explicit computable criterion using the Griesmer bound and obtain many distance-optimal linear codes. In addition, by a more in-depth discussion on some special cases of these four families of linear codes, we obtain several classes of (distance-)optimal linear codes with few weights and completely determine their weight distributions. It is shown that most of our linear codes are self-orthogonal or minimal which are useful in applications. [ABSTRACT FROM AUTHOR]

The expansion complexity is a new figure of merit for cryptographic sequences. In this paper, we present an explicit formula of the (irreducible) expansion complexity of ultimately periodic sequences over finite fields. We also provide improved upper and lower bounds on the $N$ th irreducible expansion complexity when they are not explicitly determined. In addition, for some infinite sequences with given nonlinear complexity, a tighter upper bound of their $N$ th expansion complexity is given. [ABSTRACT FROM AUTHOR]

Extending previous results, we study a class of general quadrinomials over the field of size 22m with odd m and characterize conditions under which they are permutations with 4-uniform BCT, a new and important parameter related to boomerang-style attacks. These permutations are known to have the best known nonlinearity. Numerical data also show that the inverse of these functions all have large algebraic degree, making them desirable for applications. [ABSTRACT FROM AUTHOR]

In Eurocrypt’18, Cid et al. proposed a new cryptanalysis tool called Boomerang Connectivity Table (BCT), to evaluate S-boxes of block ciphers. Later, Boura and Canteaut further investigated the new parameter Boomerang uniformity for cryptographic S-boxes. It is of great interest to find new S-boxes with low Boomerang uniformity for even dimensions. In this paper, we prove that a class of permutation quadrinomials over $\mathbb {F}_{2^{2m}}$ with $m$ odd has Boomerang uniformity four, which gives the fifth class of such kind of permutation polynomials. Further, the occurrences of 0 and 4 in the BCTs of the investigated permutation polynomials are also completely determined. [ABSTRACT FROM AUTHOR]

In this paper, a class of $p$ -ary 3-weight linear codes and a class of binary 2-weight linear codes are proposed respectively by virtue of the properties of the perfect nonlinear functions over $\mathbb {F}_{p^{m}}$ and $(m,s)$ -bent functions from $\mathbb {F}_{2^{m}}$ to $\mathbb {F}_{2^{s}}$ , where $p$ is an odd prime and $m, s$ are positive integers. The weight distributions are completely determined by the sign of the Walsh transform of weakly regular bent functions and the size of the preimage of the employed $(m,s)$ -bent functions at the zero point, respectively. As a special case, a class of optimal linear codes meeting Griesmer bound is obtained from our construction. [ABSTRACT FROM AUTHOR]

An involution over finite fields is a permutation polynomial whose inverse is itself. Owing to this property, involutions over finite fields have been widely used in applications, such as cryptography and coding theory. Following the idea by Wang to characterize the involutory behavior of the generalized cyclotomic mappings, this paper gives a more concise criterion for $x^{r}h(x^{s})\in {\mathbb F} _{q}[x]$ being involutions over the finite field ${\mathbb F}_{q}$ , where $r\geq 1$ and $s\,|\, (q-1)$. By using this criterion, we propose a general method to construct involutions of the form $x^{r}h(x^{s})$ over ${\mathbb F}_{q}$ from given involutions over some subgroups of ${\mathbb F}_{q}^{*}$ by solving congruent and linear equations over finite fields. Then, many classes of explicit involutions of the form $x^{r}h(x^{s})$ over ${\mathbb F}_{q}$ are obtained. [ABSTRACT FROM AUTHOR]

Let p be a prime, n=2m and d=3p^m-2 with m\geq 2 , and \gcd (d,p^n-1)=1 . In this paper, the correlation distribution between a p -ary m -sequence of period p^n-1 and its d -decimation sequence is investigated in a unified approach. Some results for the binary case are extended to the general case. It is shown that the problem of determining the correlation distribution for d can be reduced to that of solving two combinatorial problems related to the unit circle of the finite field \mathbb {F}_{p^{n}} . For an arbitrary odd prime p , it seems difficult to solve these two problems. However, for p=3 , by studying the weight distribution of the ternary Zetterberg code and counting the numbers of solutions of some equations over \mathbb {F}_{3^{n}} , the two problems are solved, and thus, the corresponding correlation distribution for d$ is completely determined. It is noteworthy that this is the first time that the correlation distribution for a non-binary Niho decimation has been determined since 1976. [ABSTRACT FROM PUBLISHER]

The nonlinear complexity of a periodic sequence s is the length of the shortest feedback shift register that can generate s, and its value is upper bounded by the least period of s minus 1. In this paper, a recursive approach that generates all periodic sequences with maximum nonlinear complexity is presented, and the total number of such sequences is determined. The randomness properties of these sequences are also examined. [ABSTRACT FROM PUBLISHER]

In this paper, let n=2k and d=3\cdot 2^{k}-2 with k\geq 3 and \gcd (d,2^n-1)=1 . Based on some analysis of certain equations over finite fields and the number of codewords with Hamming weight five in Zetterberg code, the correlation distribution between a binary m -sequence of period 2^n-1 and its $d$ -decimation sequence is completely determined. This solves a ten-year-old open problem proposed by Dobbertin et al. [ABSTRACT FROM PUBLISHER]

In this paper, a family of new de Bruijn sequences is proposed through the construction of maximum-length nonlinear feedback shift registers (NFSRs). Let k be a positive integer and p_{0}(x), p_{1}(x), \ldots , p_{k}(x) be the primitive polynomials in \mathbb {F}_{2}[x] with their degrees strictly increasing and pairwise coprime. We determine the cycle structure and adjacency graphs of linear feedback shift registers (LFSRs) with characteristic polynomial q(x)=\prod \nolimits i=0^{k}pi(x) . In the case that p0(x)=1+x , an algorithm is proposed to produce maximum-length NFSRs from these LFSRs, and it is shown that the algorithm can generate O(2^(2^k-1)n)~n -stage maximum-length NFSRs with memory complexity O(2^kkn) and time complexity O(2^n-dkkn) , where n and d_{k} are the degrees of q(x) and pk(x) , respectively. Finally, we illustrate the proposed algorithm in the case of k=2 . In this case, we prove that for any integer $n\geq 8$ , the algorithm can produce $n$ -stage maximum-length NFSRs with time complexity as low as $O(n^{{\rm {log}{log}}(n)}$ ). [ABSTRACT FROM AUTHOR]

We show that all $k$-dimensional $q$-ary linear quasi-constant-weight codes are equivalent to the first-order RM code or its copies for $k\geq 4$, and the same result holds also for the case $k=3$ and $q$ being a prime number. [ABSTRACT FROM PUBLISHER]

In this paper, a class of linear feedback shift registers (LFSRs) with characteristic polynomial (1+x^3)p(x) is discussed, where $p(x)$ is a primitive polynomial of degree $n>2$ . The cycle structure and adjacency graphs of the LFSRs are determined. A new class of de Bruijn sequences is constructed from these LFSRs, and the number of de Bruijn sequences in the class is also considered. To illustrate the efficiency of constructing de Bruijn sequences from these LFSRs, an algorithm for producing some corresponding maximum-length nonlinear feedback shift registers with time and memory complexity $O(n)$ is also proposed. [ABSTRACT FROM AUTHOR]

For an odd prime \(p\) and two positive integers \(m\) , \(k\) such that \(m/\gcd (k,m)\geq 3\) is odd, let \(d\) be a positive integer satisfying \(d(p^{k}+1)\equiv 2\,({\rm mod}\,p^{m}-1)\) . In this paper, the cross-correlation between a \(p\) -ary \(m\) -sequence and its \(d\) -decimated sequences is investigated, and the cross correlation distribution is completely determined. The relationship between the decimations \(d\) considered in this paper and some known ones is also studied. This paper generalizes some previous results, and also gives new decimations, which lead to low cross correlation. [ABSTRACT FROM PUBLISHER]

In this paper, the cycle structure and adjacency graphs of a class of linear feedback shift registers (LFSRs) are determined. By recursively applying the $D$ -morphism to the maximum-length LFSRs and representing the cycles by generating functions, a new family of maximum-length nonlinear feedback shift registers (NFSRs) are proposed based on the properties of these LFSRs. The number of NFSRs in the proposed family is also considered. [ABSTRACT FROM AUTHOR]

In this paper, a new construction of zero-difference balanced functions defined on \BBZv is given, where v is an odd positive integer. Based on the generic constructions proposed by Ding, optimal constant composition codes and perfect difference systems of sets with new parameters can be generated from the zero-difference balanced functions constructed in this paper. [ABSTRACT FROM AUTHOR]

In this paper, a new generalized cyclotomy with respect to a positive odd integer is introduced, and a construction of frequency hopping sequence sets and two constructions of frequency hopping sequences are proposed as its applications. The frequency hopping sequence sets and frequency hopping sequences obtained in this paper can be optimal with respect to the Peng–Fan bound and Lempel–Greenberger bound, respectively. Further, the length of sequences in the optimal frequency hopping sequence sets can be any odd integer larger than 3. Some of them have new parameters. [ABSTRACT FROM PUBLISHER]

In this letter, we present a family of 16-QAM periodic complementary sequences (PCSs), including three constructions. Our basic idea is to transform the known quaternary PCSs/GCSs (Golay complementary sequences) into the required ones. In order to guarantee that such transformation of every construction is successful, the own sufficient conditions of three constructions are derived, respectively. Our methods can provide quite rich 16-QAM periodic PCSs, whose main parameters up to period 50 and number 12 of sub-sequences are given in Table 1, from a large number of available quaternary PCSs/GCSs, which can potentially satisfy the requirements of communication systems making use of 16-QAM constellation. [ABSTRACT FROM PUBLISHER]

This paper studies a class of binomial functions over the finite fields of odd characteristic and characterizes their bentness in terms of the Kloosterman sums. Numerical results show that the proposed class contains bent functions that are affinely inequivalent to all known monomial and binomial ones. [ABSTRACT FROM AUTHOR]

In this paper, we propose an interleaving construction of new sets of frequency hopping sequences from the known ones. By choosing suitable known optimal frequency hopping sequences and sets of frequency hopping sequences and then recursively applying the proposed construction, optimal frequency hopping sequences and sets of frequency hopping sequences with new parameters can be obtained. [ABSTRACT FROM PUBLISHER]

In this paper, three constructions of balanced Boolean functions with optimal algebraic immunity are proposed. It is checked that, at least for small numbers of input variables, these functions have good behavior against fast algebraic attacks as well. Other cryptographic properties such as algebraic degree and nonlinearity of the constructed functions are also analyzed. Lower bounds on the nonlinearity are proved, which are similar to the best bounds obtained for known Boolean functions resisting algebraic attacks and fast algebraic attacks. Moreover, it is checked that for the number n of variables with 5\leq n\leq 19, the proposed n-variable Boolean functions have in fact very good nonlinearity. [ABSTRACT FROM AUTHOR]

Recently, new optimal Families \cal S and \cal U of quaternary sequences have been presented, and the optimal binary sequence Family \cal V obtained from Family \cal S under Gray map has been investigated as well. The two sequence Families \cal U and \cal V are optimal with respect to the well-known Sidelnikov bound and Welch bound, but their exact correlation distributions are not known until now. In this paper, their exact correlation distributions are completely determined in some cases by making use of exponential sums and the theory of \bf Z_4-valued quadratic forms. [ABSTRACT FROM AUTHOR]