BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a security protection method and portable storage device using the method. 
         [0003]    2. General Background 
         [0004]    Portable storage devices are used to transfer data between computing devices or other devices. For example, Universal Serial Bus (USB) memory sticks, USB flash memory devices, USB flash memory cards, and other portable devices are often used to transfer data between computing devices or other devices. These portable storage devices offer great convenience to users, allowing the users to easily transfer data between devices. 
         [0005]    Often times, the data stored on a portable storage device need to be protected in some way. For example, the data may need to be protected because of privacy concerns, corporate security concerns, or copyright reasons. There is a password protection solution that has been implemented on the portable storage device for security protection. The portable storage device typically provides the user with a prompt when the user attempts to access the protected data. The user must then provide the password to unlock data access prevention software resident in the portable storage device if the password entered matches an originally provided password. 
         [0006]    Once the password verification procedure is completed successfully, the user can access to the protected data. When having entered an incorrect password, the user is denied access, thereby preventing unauthorized access to the portable storage device. However, even if a user is an owner of the portable storage device and tries to use his or her own computing device to access the portable storage device, he or she still has to enter the password every time. This practice is apparent to be time consuming and burdensome to the owner-user. 
         [0007]    What is needed, therefore, is an improved portable storage device and security protection method that can effectively protect unauthorized access to the portable storage device. 
       SUMMARY 
       [0008]    A security protection method used in a portable electronic device is provided. The portable electronic device provides an identifier table for recording IDs of external electronic devices, which are allowed to access the portable electronic device. The method includes: (a) obtaining an ID of an external electronic device when the external electronic device is connected to the portable electronic device; (b) determining whether the obtained ID exists in the ID table; and (c) allowing the connected external electronic device to access the portable electronic device when the obtained ID exists in the ID table. 
         [0009]    Other advantages and novel features will be drawn from the following detailed description with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The components of the drawings are not necessarily drawn to measuring scale, the emphasis instead being placed upon clearly illustrating the principles of the portable electronic device with a security protection function. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0011]      FIG. 1  is a block diagram of a hardware infrastructure of a portable electronic device with a security protection function according to an exemplary embodiment of the present invention. 
           [0012]      FIG. 2  is a block diagram of main function modules of an identifying module of the portable electronic device of  FIG. 1 . 
           [0013]      FIG. 3  is a flowchart of a security protection method implemented by the portable electronic device of  FIG. 1  according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0014]      FIG. 1  is a block diagram of a hardware infrastructure of a portable electronic device with a security protection function (hereinafter, “the device”) according to an exemplary embodiment of the present invention. The device  1  is typically a storage device, such as a memory card. The device  1  includes an interface  11 , a storage unit  12 , and a micro-program control unit (MCU)  13 . The interface  11  is configured for enabling the device  1  to communicate data with external electronic devices  2 . The interface  11  can be, but not limited to, a wireless interface such as BLUETOOTH or ZIGBEE interface, or a wired interface such as a universal serial bus (USB) interface, or a firewire interface. The MCU  13  is with microinstructions and is configured for executing the microinstructions to make the interface  11  performing specific functions, such as reading and writing data from/to the storage unit  12 . 
         [0015]    The storage unit  12  stores an identifier (ID) table  121 , a predetermined password  122 , an identification module  123 , and an identification program  124 . The ID table records IDs of external electronic devices  2  which are allowed to access the device  1 . The identification module  1   23  is run according to the identification program  124 . 
         [0016]    Referring to  FIG. 2 , the identification module  123  includes a program installing sub-module  1230 , an ID obtaining sub-module  1232 , an ID determining sub-module  1234 , a password determining sub-module  1236 , an access control sub-module  1237 , an ID table updating sub-module  1238 , and a program uninstalling sub-module  1239 . 
         [0017]    The program installing sub-module  1230  is configured for automatically installing the identification program  124  on the external electronic device  2  when the external electronic device  2  is connected to the device  1 . 
         [0018]    The ID obtaining sub-module  1232  is configured for obtaining the ID of the connected external electronic device  2 . 
         [0019]    The ID determining sub-module  1234  is configured for determining whether the obtained ID exists in the ID table  121 . If the obtained ID exists in the ID table  121 , the ID determining sub-module  1234  generates a first signal to the access control sub-module  1237 . If the obtained ID does not exist in the ID table  121 , the ID determining sub-module  1234  generates a second signal to the access control sub-module  1237 . 
         [0020]    The access control sub-module  1237  is configured for controlling the connected external electronic device  2  to access the device  1  according to the signal from the ID determining sub-module  1234 . Typically, when receiving the first signal, the access control sub-module  1237  allows the connected external electronic device  2  to access the device  1 . For example, the access control sub-module  1237  allows the connected external electronic device  2  to read and/or write data from/to the device  1 . When receiving the second signal, the access control sub-module  1237  prohibits the connected external electronic device  2  from accessing the device  1 . 
         [0021]    In addition, in another exemplary embodiment of the present invention, if the obtained ID does not exist in the ID table  121 , the ID determining sub-module  1234  generates the second signal to the password determining sub-module  1236 . 
         [0022]    The password determining sub-module  1236  is configured for generating a password dialogue diagram for receiving a password input from a user, and determining whether the input password matches the predetermined password  122 . If the input password matches the predetermined password  122 , the password determining sub-module  1236  generates a third signal to the access control sub-module  1237 . The access control sub-module  1237  allows the connected external electronic device  2  to access the device  1  according to the third signal. If the input password does not match the predetermined password  122 , the password determining sub-module  1236  generates a fourth signal to the access control sub-module  1237 . The access control sub-module  1237  prohibits the connected external electronic device  2  from accessing the device  1  according to the fourth signal. 
         [0023]    In addition, if the input password matches the predetermined password  122 , the password determining sub-module  1236  further sends the third signal to the ID table updating sub-module  1238 . 
         [0024]    The ID table updating sub-module  1238  is configured for generating an ID dialogue diagram for inquiring the user whether to add the obtained ID of the current connected external electronic device  2  to the ID table  121  according to the third signal. For example, the ID dialogue diagram provides a “YES” item and a “NO” item for selection. If receiving an input on the “YES” item, the ID table updating sub-module  1238  adds the obtained ID to the ID table  121 . If receiving an input on the “NO” item, the ID table updating sub-module  1238  does not add the obtained ID to the ID table  121 . 
         [0025]    The program uninstalling sub-module  1239  is configured for automatically uninstalling the identification program  124  from the connected external electronic device  2  when the external electronic device  2  is being disconnected with the device  2 . 
         [0026]    In addition, in another embodiment, the identification module  123  does not include the program uninstalling sub-module  1239 . In such situation, the program installing sub-module  1230  does not need to install the identification program  124  again in the external electronic device  2  when the external electronic device  2  is, not for the first time, connected to the device  1 . 
         [0027]      FIG. 3  is a flowchart of a security protection method implemented by the device  1  according to an exemplary embodiment of the present invention. In step S 301 , the program installing sub-module  1230  installs the identification program  124  on the connected external electronic device  2  when external electronic device  2  is connected to the device  1 . 
         [0028]    In step S 302 , the ID obtaining sub-module  1232  obtains the ID of the connected external electronic device  2 . 
         [0029]    In step S 303 , the ID determining sub-module  1234  determines whether the obtained ID exists in the ID table  121 . 
         [0030]    If the obtained ID exists in the ID table  121 , in step S 304 , the access control sub-module  1237  allows the connected external electronic device  2  to access the device  1 . 
         [0031]    If the obtained ID does not exist in the ID table  121 , in step S 305 , the password determining sub-module  1236  generates the password dialogue diagram to receive the password from the user. 
         [0032]    In step S 306 , the password determining sub-module  1236  determines whether the input password matches the predetermined password  122 . 
         [0033]    If the input password does not match the predetermined password  122 , in step S 307 , the access control sub-module  1238  prohibits the connected external electronic device  2  from accessing the device  1 , and the procedure goes to step S 310  described later. 
         [0034]    If the input password matches the predetermined password  122 , in step S 308 , the ID table updating sub-module  1238  generates the ID dialogue diagram for inquiring the user whether to add the obtained ID of the current connected external electronic device  2  to the ID table  121 . If receiving the input on the “NO” item, namely where the user does not want to add the ID to the ID table  121 , the procedure goes to step S 304  described above. 
         [0035]    If receiving the input on the “YES” item, namely where the user wants to add the ID to the ID table  121 , in step S 309 , the ID table updating sub-module  1238  adds the obtained ID to the ID table  121 . 
         [0036]    In step S 310 , the program uninstalling sub-module  1239  uninstalls the identification program  124  from the external electronic device  2  when the external electronic device  2  is being disconnected with the device  1 . 
         [0037]    Although the present invention has been specifically described on the basis of exemplary embodiments, the invention is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiments without departing from the scope and spirit of the invention.
A security protection method used in a portable electronic device is provided. The portable electronic device provides an ID table for recording IDs of external electronic devices that are allowed to access the portable electronic device. The method includes: obtaining an ID of an external electronic device when the external electronic device is connected to the portable electronic device; determining whether the obtained ID exists in the ID table; and allowing the connected external electronic device to access the portable electronic device when the obtained ID exists in the ID table. A portable electronic device used the method is also provided.