Patent ID: 6198823
Filing Date: 2001-03-06
Classification: H04W

Abstract:
As a part of a cellular-phone-call-initiating process, a method for authenticating a caller seeking access to a telephone network via transmission from a cellular terminal through a cellular-phone-service-provider station, each of said cellular terminal and said cellular-phone-service-provider station having a previously stored encrypted result and a unique key assigned to the caller, the method comprising the steps of:a. transmitting, from said cellular terminal, said previously-stored encrypted result to said cellular-phone-service-provider station;b. authenticating by comparison whether said encrypted result transmitted from said cellular terminal matches said encrypted result previously stored in said cellular-phone-service-provider station;c. calculating, at the cellular-phone-service-provider station, a new encrypted result by means of a first ciphering algorithm using a random number and said unique key assigned to the caller;d. transmitting said random number from said cellular-phone-service-provider station to said cellular terminal; ande. independent of said calculation in step (c), calculating, at the cellular terminal, said new encrypted result by means of a second ciphering algorithm using said transmitted random number and said unique key assigned to the caller;wherein said new encrypted result calculated in step (c) is stored in said cellular-phone-service-provider station and said new encrypted result calculated in step (e) is stored in said cellular terminal for next authentication attempt.