Patent ID: 7023994

Claim:
A method for personalizing GSM chips, wherein at the manufacturer for pre-personalizing the chip a subscriber identification number (IMSI), a card number (ICCID) and an additional secret key Ki comprising the steps of: a) performing the personalization of the chip when the subscriber logs on to the subscriber network for the first time; b) obtaining the (ICCID) card number and the (IMSI) subscriber identification number from a number pool, the chip itself derives an initial secret key Ki — 1 from the secret key Ki which is known and entered into the chip, while PIN and PUK are set to a default value; c) making an entry in an authentication center (AC) and a home location register (HLR) as soon as the subscriber has entered into a contract with a network operator; d) deriving at the authentication center (AC) the initial secret key Ki — 1; e) setting the conditions of the network so that during logon to the network, a connection is established from the chip to the security center (SC) of the network operator; f) routing the connection from the chip to the security center (SC) during the first logon; g) negotiating between the chip and the security center (SC) a new second secret key Ki — 2 for the chip; h) unconditionally disabling the conditions of step e).