A Relation between Self-Reciprocal Transformation and Normal Basis over Odd Characteristic Field

摘要

Let q and f(x) be an odd characteristic and an irreducible polynomial of degree m over F_q, respectively. Then, suppose that F(x) = x~m f(x+ x~(-1)) becomes irreducible over F_q. This paper shows that the conjugate zeros of F(x) with respect to F_q form a normal basis in F_q2m if and only if those of f(x) form a normal basis in F_qm and the part of conjugates given as follows are linearly independent over F_q,(r-r~(-1),(r-r~(-1))~q,···,(r-r~(-1))~q~(m-1)}, where y is a zero of F(x) and thus a proper element in F_q2m. In addition, from the viewpoint of q-polynomial, this paper proposes an efficient method for checking whether or not the conjugate zeros of F(x) satisfy the condition.