Cryptanalysis of the Improvement of an Authentication Scheme Based on the Chinese Remainder Theorem for Multicast Communications

Abstract

Abstract.Recently, Antequera and López-Ramos have proposed an improvement on the secure multicast protocol based on the extended Euclidean algorithm in order to overcome the weaknesses and breaches detected by Peinado and Ortiz. The improvement defines a new authentication scheme based on the Chinese Remainder Theorem. However, we show in this work that the protocol is still vulnerable to impersonation attack due to the relationships between the authentication message of different multicast keys.