Kloosterman sums over finite Frobenius rings

Abstract

We study Kloosterman sums in a generalized ring-theoretic context, that of finite commutative Frobenius rings. We prove a number of identities for twisted Kloosterman sums, loosely clustered around moment computations. Our main result is the computation of the fourth moment of twisted Kloosterman sums, for non-primitive twists.