Method for legitimately unlocking a sim card lock, unlocking server, and unlocking system for a sim card lock

An unlocking server to be connected to an unstructured supplementary service data (USSD) gateway for unlocking a subscriber identity module (SIM) card lock set by a telecommunications service provider to a mobile terminal of a subscriber, said unlocking server comprising:

• a USSD data port to be connected to the USSD gateway for receiving an unlocking request transmitted from the mobile terminal and through the USSD gateway, said unlocking request including subscriber data and a USSD code representing activation of said unlocking request;
• a telecommunications interface for connecting to the telecommunications service provider;
• and
• an unlocking control unit for requesting the telecommunications service provider to verify, with reference to the subscriber data, whether the subscriber has a right to unlock the SIM card lock, and, upon receiving verification from the telecommunications service provider that the subscriber has the right to unlock the SIM card lock, for initiating transmission of an unlocking program and an unlocking password to the mobile terminal such that the mobile terminal may execute said unlocking program and load said unlocking password for unlocking the SIM card lock.

An unlocking system for unlocking a subscriber identity module (SIM) card lock of a mobile terminal of a subscriber, said unlocking system comprising:

• a register for storing contract status of a phone number associated with the mobile terminal of the subscriber, an unlocking program and an unlocking password corresponding to the SIM card lock;
• an unstructured supplementary service data (USED) gateway for receiving a USSD code from the mobile terminal and for determining whether said USSD code represents activation of an unlocking request;
• and
• an unlocking server connected to said register and said USSD gateway;
• said USSD gateway transmitting said USSD code and data of the subscriber to said unlocking server when said USSD gateway determines that said USSD code represents activation of said unlocking request;
• said unlocking server searching said register to verify, with reference to the data of the subscriber, whether the subscriber has a right to unlock the SIM card lock, and initiating transmission of said unlocking program and said unlocking password to the mobile terminal upon verification that the subscriber has a right to unlock the SIM card lock, such that the mobile terminal may execute said unlocking program and load said unlocking password to unlock the SIM card lock.