Automatic generation of private authentication key for wireless communication systems

Method of generating a private authentication key in a mobile cellular station having a unique electronic serial number associated therewith and a user selected value, said electronic serial number and said user selected value being transmitted to a cellular service provider and said cellular service provider transmitting a system selected value to said mobile cellular station, said method comprising the steps of:

• receiving a random challenge number on a broadcast forward control channel transmitted to said mobile cellular station by a base station;
• receiving a unique random number included in a unique challenge authentication order transmitted to said mobile cellular station by said base station;
• loading mixing registers at said mobile cellular station with said electronic serial number, said user selected value, said system selected value, said random challenge number and said unique random number;
• loading a linear feedback shift register with a value which is a function of the values in said mixing registers;
• setting a first offset index for a predetermined algorithm to a value which is a function of said user selected value and said unique random number;
• setting a second offset index for said predetermined algorithm to a value which is a function of said system selected value and said unique random number;
• running said predetermined algorithm a preselected number of rounds to modify the values in said mixing registers;
• and
• setting said authentication key to a value which is a function of the modified values in said mixing registers.