On a class of key agreement protocols which cannot be unconditionally secure

Abstract

In [5] a new key agreement protocol called CHIMERA was introduced which was supposed to be unconditionally secure. In this paper an attack against CHIMERA is described which needs little memory and computational power and is successful almost with probability 1. The bug in the security proof in [5] is explained. Further, it is shown that a whole class of CHIMERA-like key agreement protocols cannot be unconditionally secure. © Springer-Verlag Berlin Heidelberg 2003.