探讨t(t≥1)个不同的多项式商之和定义的序列H(u)≡t ∑ i=t ai u^wi - u^wip/ p (modp)的线性复杂度.一方面,给出了作为p元序列的(H(u))u≥0的线性复杂度准确值;另一方面,结合有限域Zp上的d阶乘法特征χ,定义d元序列(su)u≥0: 0≤su<d,exp(2πis u/d)=χ(H(u)),χ(0)=1证明了当d为素数且dmodp^2为本原元时,序列(su)u≥0具有“高”的线性复杂度.同时,应用指数和估计,给出了(su)u≥0(此时d可以为合数)的线性复杂度轮廓的一个下界.
We discuss the linear complexity of the sequences H(u)≡t ∑ i=t ai u^wi - u^wip/ p (modp)defined by the summation of t(t≥1)different polynomial quotients.On one hand,we get the exact values of linear complexity of the pary sequences(H(u))u≥0.On the other hand,combining with the multiplicative characterχof order dof the finite field Zp,we define the d-ary sequences(su)u≥0: 0≤su d,exp(2πisu)d=χ(H(u)),χ(0)=1 If dis prime and dis a primitive element modulo p2,we prove that(su)u≥0has"high"linear complexity.Moreover,using certain exponential sum estimate,we give a lower bound on the linear complexity profile of(su)u≥0for any prime or composite d.