Patent ID: 8032748

Claim:
Method of allocating a chip card to one network operator of a plurality of network operators using a personalisation device so as to determine a final authentication key assigned to a subscriber of the operator, comprising the following steps: loading an allocation algorithm, an allocation key, an algorithm for determining the authentication key and at least one intermediate authentication key not assigned to the operator in the card located in the personalisation device, transmitting an allocation message, including a final identity number assigned to the subscriber of the operator, a random number relative to the subscriber and an allocation signature resulting from applying the final identity number, the random number and the allocation key to the allocation algorithm, from the personalisation device to the card, authenticating the allocation message by the allocation algorithm in the card according to the allocation key and the allocation signature, determining the final authentication key assigned to the subscriber by the authentication key determination algorithm in the card according to the intermediate key and the random number, determining the final authentication key by the authentication key determination algorithm in the personalisation device according to the intermediate key and the random number, and allocating the card to the one network operator from among the plurality of network operators, responsive to selection of the one network operator after production of the card.