METHOD FOR UPDATING SHARE KEY SUITABLE FOR DIGITAL MOBILE COMMUNICATION SYSTEM

摘要

PURPOSE: A method for updating a share key is provided to share a key safely and efficiently and update a group common key contiguously and efficiently by updating a common key with an attack method based on a common modular value and an euclidean algorithm. CONSTITUTION: Information and a common modular value related to a to-be-excluded terminal is broadcast to all terminals in a group from a key management center(301) to a base station. The information and the common modular value related to the to-be-excluded terminal and information related to each terminal which receives the same are used to update a share key by an attack method based on the common modular value and an Euclidean algorithm.