Patent ID: 7899440

Claim:
A mobile terminal, comprising: a transceiver configured to transmit and receive signals to and from at least one other mobile terminal; an input unit configured to input an address of said at least one other mobile terminal and to input a message to be transmitted to said at least one other mobile terminal; a security parameter module included on the mobile terminal and configured to set a security option when predetermined information is included in the message and to set a security parameter in data of the message to be transmitted to said at least one other mobile terminal; and a checking module included on the mobile terminal and configured to check whether or not an address of the at least one other mobile terminal, which transmits the signals to the mobile terminal, is included in an address list of the mobile terminal that receives the signals when the security option is turned on, wherein when the mobile terminal transmits the data to said at least one other mobile terminal, the security parameter module determines whether or not the security option is turned on, and sets the security parameter in the data to be transmitted when the security option is on and does not set the security parameter in the data to be transmitted when the security option is not on, and wherein after the security parameter module determines the security option is on, the checking module included on the mobile terminal prevents the message from being transmitted to said at least one other mobile terminal when the input address of the at least one other mobile terminal is not included in the address list of the mobile terminal.