Portable digital data storage device

A portable digital data storage device comprising:

• a connector attachable to a digital data processor to provide electric connection with said digital data processor;
• a non-volatile memory module including a first logic unit for storing data and a second logic unit for storing therein an application program, said application program being automatically executed when said connector is electrically connected to said digital data processor to provide a user's operation interface;
• a verifying unit for executing a verifying procedure for information entered via said user's operation interface;
• and
• a control unit electrically connected to said connector, said non-volatile memory module and said verifying unit, and disallowing said digital data processor to access to said first logic unit through said connector until the correctness of said information entered via said user's operation interface is verified by said verifying unit.