In this paper new binary sequence families $\mathcal{F}^k$ of period $2^n-1$ are constructed for even $n$ and any $k$ with ${\rm gcd}(k,n)=2$ if $n/2$ is odd or ${\rm gcd}(k,n)=1$ if $n/2$ is even. The distribution of their correlation values is completely determined. These families have maximum correlation $2^{n/2+1}+1$ and family size $2^{3n/2}+2^{n/2}$ for odd $n/2$ or $2^{3n/2}+2^{n/2}-1$ for even $n/2$. The construction of the large set of Kasami sequences which is exactly the $\mathcal{F}^{k}$ with $k=n/2+1$ is generalized.
On the absolute irreducibility of hyperplane sections of generalized Fermat varieties in $\Bbb{P}^3$ and the conjecture on exceptional APN functions: the Kasami-Welch degree case
设$f$是有限域$F$上的函数。由多元次数多项式$n$,$ϕ(x,y,z)=f(x)+f(y)+f(z)$ in $\Bbb{P}^3(\overline{\mathbb{F}}_2)$定义的广义Fermat簇$X$的分解在几乎完美非线性(APN)函数和例外APN函数的研究中起着至关重要的作用.它们的结构基本上取决于对应于例外度$n=2^k+1$和$n=2^{2k}-2^k+1$(分别为Gold数和Kasami-Welch数)的单项函数的费马簇。Janwa,McGuire和Wilson在[12,13]中得到了非常重要的结果。本文研究了与Kasami-Welch度单项式有关的PDMATHAMO及其分解成绝对不可约分支的问题。我们表明,在这个分解,组件相交横向在一个奇异点。这一结构性事实意味着与Kasami-Welch次数多项式族相关的相应广义Fermat超曲面是绝对不可约的。特别地,我们证明了若$f(x)=x^{2^{2k}-2^k+1}+h(x)$,其中${\rm deg}(h)\equiv 3{\pmod 4}$,则对应的APN多元超曲面是绝对不可约的,因此$f(x)$不是例外APN函数.我们还证明了当${\rm deg}(h)\equiv 5{\pmod 8}$ .由于对于奇数度$f(x)$,该猜想只需要解决黄金度和Kasami-Welch度的情况下,我们的结果大大有助于证明的…
Further results on the 2-adic complexity of a class of balanced generalized cyclotomic sequences
本文研究了周期为$pq$的平衡Whiteman广义割圆序列的2-adic复杂度。通过计算其中一个序列所构造的循环矩阵的行列式,得到了相应序列的2-adic复杂度的一个下界,进一步扩展了我们以前的工作(Zhao C,Sun Y and Yan T.一类平衡广义分圆序列的2-adic复杂度研究。Journal of Cryptologic Research,6(4):455-462,2019)。结果表明,这类序列的2-adic复杂度足以抵抗带有进位移位寄存器(FCSR)的反馈有理近似算法(RAA)的攻击,即,它实际上是由$pq-p-q-1$下界的,$pq-p-q-1$远大于序列周期的一半。特别地,如果选择合适的参数,2-adic复杂度是最大的。