Patent ID: 6321079
Filing Date: 2001-11-20
Classification: H04W

Abstract:
A method for network operator control of locking and unlocking of a mobile telephone to selected networks, said method comprising the steps of:causing said mobile telephone to store a secret number therein by an outer-module at the time of network locking;instructing said mobile telephone to generate a random number by said outer-module at the time of network unlocking;generating a random number, transmitting said random number to said outer-module, and generating a first value using said secret number and said random number by said mobile telephone;generating a second value using said secret number and said random number transmitted from said mobile telephone by said outer-module;transmitting said second value back to the mobile telephone by said outer-module; andunlocking the network lock by said mobile telephone when said second value returned from said outer-module matches said first value.