Patent ID: 8031871

Claim:
Method of updating an authentication algorithm used by a device (CARD) to authenticate with a data processing device (SERV) wherein the device (CARD) has a memory element for storing a subscriber identity (IMSI) which is associated with an authentication algorithm, comprising: a first preliminary step of storing an active first authentication algorithm (Algo 1 ) in a non-volatile memory element of the device (CARD) associated with a first subscriber identity (IMSI 1 ); a second preliminary step of storing an inactive second inactive authentication algorithm (Algo 2 ) in a non-volatile memory element of the device (CARD) associated with a second subscriber identity (IMS 12 ); and a step for switching from the first authentication algorithm (Algo 1 ) to the second authentication algorithm (Algo 2 ) including inhibiting the first authentication algorithm (Algo 1 ) and activate activating the second authentication algorithm (Algo 2 ) used by the device (CARD).