Cryptanalysis of multicast protocols with key refreshment based on the extended Euclidean algorithm

Abstract

Recently, Naranjo, López-Ramos and Casado have proposed a key refreshment for multicast schemes based on the extended Euclidean algorithm. We show in this paper that the key refreshment is not secure, describing several weaknesses and the algorithm to obtain the private key of any user. Hence, every system in which the key refreshment is applied will be compromised. © 2011 Springer-Verlag.