Dear editor,rnA polynomial f(x) ∈ Fq [x] is called a permutation polynomial (PP) over the finite field Fq if the associated mapping f : c (→) f(c) from Fq to itself is bijective.A PP f is called a complete permutation polynomial if f(x) + x is a PP.PPs over finite fields of even characteristic have wide applications, including cryptography, coding theory,and communication theory.