Thales Dis France Sas

Francis D'Souza

Michel Anslot

This invention relates to a method for updating a one-time secret key Kn maintained in a subscription module implemented in a communication apparatus, a wireless communication network maintaining an identical version of said one-time secret key Kn and configured to determine a result XRES expected from the communication apparatus when an authentication function is applied by the subscription module using a random challenge and said one-time secret key Kn as an input, the method comprising the following steps: receiving from the communication network an authentication request message containing at least a random challenge RANDn; determining by the subscription module a result RES by applying the authentication function using the random number RANDn and the one-time secret key Kn as inputs; transmitting said result RES to the communication network for it to be compared with the expected result XRES determined by the communication network using the random number RANDn and the corresponding version of the one-time secret key Kn, the subscriber being authenticated if said first and second results are matching; updating the one-time secret key Kn by replacing its current version with a new version obtained by applying a first key derivation function using the random challenge RANDn as an input, the updated version of the one-time secret key Kn being used by the subscription module for processing a subsequent authentication request, the same update being carried out by a server accessible or part of the wireless communication network in order to maintain an identical version of the one-time secret key Kn.

Growing community of inventors

Meudon, France

Francis D'Souza