Abstract:
An external memory access device and a method of accessing an external memory are provided. The external memory access device includes an internal memory unit for storing authentication information of at least one external memory and a control unit for extracting the authentication information from the internal memory unit, transmitting the authentication information to an installed external memory, and controlling to display accessibility of the external memory according to the result of a comparison between the stored authentication information and the authentication information of the external memory. Accordingly, a data security function is provided by setting a password to an external memory and enabling an access to the external memory in an authenticated terminal, and convenient access to the external memory is provided by managing a password and an automatic password decrypting function of the corresponding external memory in the terminal without requiring repeated input of the password.

Description:
PRIORITY 
     This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Nov. 9, 2007 and assigned Serial No. 2007-0114019, the entire disclosure of which is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device and method for accessing an external memory. More particularly, the present invention relates to a device and method for enabling security preservation of an external memory installed in a terminal and easy access to the external memory. 
     2. Description of the Related Art 
     With the advances in mobile communication technology, mobile terminals now selling in the market include additional functions such as an MP3 player, a camera, and a video player in addition to a communication function. Due to the increased number of functions, portable terminals require a high capacity memory that can store a large amount of data such as music files, image files taken by a camera, moving pictures and the like. However, providing sufficient memory space for data generated by the additional functions is difficult. Sufficient memory space is difficult to provide because an internal memory unit for the terminal is expensive. Moreover, the application programs necessary for operating the terminal already occupy a large amount of the memory capacity. In order to address the problem of memory shortage, an external memory slot for utilizing an external memory is provided in the terminal to expand the memory capacity. 
     By installing the external memory in the external memory slot of the terminal, the memory capacity of the terminal is expanded by the memory capacity of the external memory. Also, exchange of data between terminals having a compatible external memory slot becomes more convenient by simply exchanging the external memory between the terminals. If the external memory is not password protected, the external memory may be freely used in any terminal having a compatible external memory slot. That is, the external memory may be used in any terminal supporting the external memory and a user of a terminal in which the external memory is installed can read and write data to and from the external memory. Therefore, data security of the external memory is very low. 
     One proposal to address the lack of data security is found in Korean Patent Publication No. 1997-29173. There, it is disclosed that usage of an external memory could be regulated by setting a password of the external memory. However, a user must input the password each time the external memory is installed in the terminal because the password is stored in the external memory. Accordingly, if the password is lost, the external memory must be reformatted for reuse and thereby all the data in the external memory would be deleted. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an external memory access device that enables a password registration for accessing an external memory and management of the registered password in a terminal, and a method of accessing the external memory. 
     Another aspect of the present invention is to provide an external memory access device that enables an easy access to an external memory by managing a password of the corresponding external memory in a terminal, and a method of accessing the external memory. 
     In accordance with an aspect of the present invention, an external memory access device is provided. The memory access device includes an internal memory unit for storing authentication information of an external memory and a control unit for extracting the authentication information from the internal memory unit, for transmitting the authentication information to an installed external memory, and for controlling accessibility of the external memory according to the result of a comparison between the stored authentication information and the authentication information of the external memory. 
     In accordance with another aspect of the present invention, a method of accessing an external memory is provided. The method includes identifying, if an external memory set with a password is installed, whether an automatic password decrypting option corresponding to the installed external memory is set in a corresponding internal memory unit, extracting, if an automatic password decrypting option corresponding to the installed external memory is set in the internal memory unit, a password corresponding to the installed external memory from the internal memory unit and transmitting the extracted password to the external memory, comparing a password set in the installed external memory with the password extracted from the internal memory unit, and receiving, if the password set in the installed external memory is identical to the password extracted from the internal memory unit, an access permission message from the external memory, and displaying the access permission message. 
     According to the present invention, a data security function is provided by setting a password to an external memory and enabling an access to the external memory by an authenticated terminal, and a convenient access to the external memory is provided by managing a password and an automatic password decrypting function of the corresponding external memory in the terminal without requiring repeated input of the password. 
     Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram illustrating a schematic configuration of an external memory access device according to an exemplary embodiment of the present invention; and 
         FIGS. 2A and 2B  are flowcharts illustrating a method of accessing an external memory according to another exemplary embodiment of the present invention. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
     According to exemplary embodiments of the present invention, authentication information for enabling access to an external memory is stored in an internal memory unit of a terminal. If an external memory that is set with an automatic password decrypting option is installed in the terminal, and if the password of the external memory is identical to a password stored in the internal memory unit of the terminal, the terminal permits reading and writing of data in the data area of the external memory. 
     In an exemplary implementation, a serial number and a password of the external memory are stored in the internal memory unit of the terminal. Further, a flag for setting an automatic password decrypting option of the corresponding external memory may also be stored in the internal memory unit of the terminal. 
     The term ‘terminal’ is used in this specification for convenience of description to indicate any digital equipment installable with an external memory. Accordingly, the present invention may be applied to any telecommunication or digital equipment, and their applications, such as a mobile terminal, a mobile phone, a wired/wireless phone, a Portable Multimedia Player (PMP), a Personal Digital Assistant (PDA), a smart phone, an MP3 player, a Global Positioning System (GPS) and the like. 
       FIG. 1  is a block diagram illustrating a schematic configuration of an external memory access device according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , the external memory access device includes a display unit  10 , an input unit  20 , an external memory  30 , an external memory slot  40  into which the external memory  30  may be inserted, an internal memory unit  50 , and a control unit  60 . 
     The external memory  30  stores authentication information for determination of accessibility and permits access to data stored therein if authentication information stored in the terminal is identical to the authentication information stored in the external memory  30 . In an exemplary implementation, the external memory  30  is a micro Secure Digital (SD) memory card. However, the present invention is applicable to other and different kinds of external memory devices such as SD, miniSD, Secure Multi Media Card (SecureMMC) and the like. 
     The input unit  20  may include a keypad having a plurality of letter and number keys as well as function keys. The input unit  20  may also include a touch pad. The input unit  20  receives a user&#39;s input for operation of the terminal. In particular, the user must input authentication information corresponding to the external memory  30 , for example a password and an automatic password decrypting option, through the input unit  20  to enable access to the data stored in the external memory  30 . The password input by the user through the input unit  20  may be stored in either or both of the internal memory unit  50  of the terminal and in the external memory  30 . The password may be a combination of alphanumeric and special characters available in the input unit  20 . In an exemplary implementation, the password may include audio data such as a specific word or phrase input by the user and stored in the internal memory unit  50  as well as the external memory  30 . 
     The internal memory unit  50  stores programs and various data required for the operation of the terminal. For example, the internal memory unit  50  stores an operating system program used by the terminal for normal operation as well as programs for operating various additional functions such as an MP3 player, a camera function and the like. The internal memory unit  50  includes a data table for storing authentication information of at least one external memory  30 . The authentication information may include a serial number unique to the external memory  30 , a password, an automatic password decrypting option of the external memory  30  and the like. 
     The control unit  60  controls general operations of the terminal. The control unit  60  also controls to store a user password corresponding to the matching serial number of the external memory  30  in the internal memory unit  50 . Further, the control unit  60  may control to store a flag indicating the automatic password decrypting option in the internal memory unit  50 . 
     If an external memory  30 , set with the automatic password decrypting option, is installed in the external memory slot  40 , the control unit  60  determines the serial number of the external memory  30 . Based on the determined serial number, the control unit  60  transmits the user password matched with the serial number of the corresponding external memory  30  to the external memory  30 . If an access permission signal is then received from the external memory  30 , the control unit  60  permits reading and writing of data to and from the external memory  30 . If an access refusal signal is received due to non-matching of the user password with the password set in the external memory  30 , the control unit  60  requests the user to change the user password by entering a new password. If the user changes the user password, the control unit  60  changes the authentication information in the internal memory unit  50 , namely, a password in the internal memory unit  50 . 
     Additionally, when access to the external memory  30  is permitted by matching the user password with the password set in the external memory  30 , the control unit  60  may permit changing the password set in the memory unit  30 . In this case, the control unit  60  also changes the password stored in the internal memory unit  50 . 
       FIGS. 2A and 2B  are flowcharts illustrating a method of accessing an external memory according to an exemplary embodiment of the present invention. 
     In a method of accessing an external memory according to an exemplary embodiment of the present invention, the terminal must have authentication information of the external memory  30 . Accordingly, a process of registering authentication information of the external memory  30  in the internal memory unit  50  of the terminal must be performed. Such a process is briefly described as follows (not shown in  FIGS. 2A and 2B ). 
     If an external memory  30  is installed in the external memory slot  40  of the terminal, the control unit  60  determines a serial number of the installed external memory  30 . Using the serial number of the installed external memory  30 , the control unit  60  stores a password input by the user in the internal memory unit  50 . More specifically, the control unit  60  receives a password, input by a user and corresponding to the installed external memory  30 , and stores the password matched with the corresponding serial number in the internal memory unit  50 . In addition to setting the password, the user may set an automatic password decrypting option of the corresponding external memory  30 . The control unit  60  stores the automatic password decrypting option, matched with the serial number and the password, in the internal memory unit  50  of the terminal. 
     Hereinafter, a method of accessing an external memory according to an exemplary embodiment of the present invention is described referring to  FIG. 2A . 
     When an external memory  30  is installed in the external memory slot  40  of the terminal in step S 211 , the control unit  60  determines whether a password is set in the external memory  30  in step S 213 . That is, the control unit  60  determines if the external memory  30  is protected by a password. 
     If no password is set in the external memory  30 , the control unit  60  permits access to the external memory  30  for reading and writing data to and from the external memory  30  in step S 221 . 
     If it is determined in step S 213  that a password is set in the external memory  30 , the control unit  60  determines whether an automatic password decrypting option is set in the external memory  30  in step S 215 . In an exemplary implementation, the control unit  60  determines if an automatic password decrypting option is set by determining the serial number of the installed external memory  30 . Using the serial number of the installed external memory  30 , the control unit  60  searches for a flag, indicating that the automatic password decrypting option is set, matched with the corresponding serial number from a data table of the internal memory unit  50 . 
     If an automatic password decrypting option is set in the external memory  30 , the control unit  60  extracts a password matched to the serial number of the external memory  30  from the data table of the internal memory unit  50  and transmits the extracted password to the external memory  30  in step S 217 . The external memory  30  determines whether the password received from the terminal is identical to the password of the external memory  30  in step S 219 . 
     If the password received from the terminal is identical to the password of the external memory  30 , the external memory  30  permits access by transmitting an access permission message to the terminal, and the control unit  60  enables data reading and writing to and from the external memory  30  in step S 221 . The case that the password received from the terminal is not identical to the password of the external memory  30  at step S 219  is described later referring to  FIG. 2B . 
     If it is determined that an automatic password decrypting option is not set in the external memory  30  at step S 215 , the control unit  60  requests the user to input a password. The control unit  60  transmits the password input by the user to the external memory  30  in step S 231 . 
     The external memory  30  determines whether the password received from the terminal is identical to the password of the external memory  30  in step S 233 . If the password received from the terminal is identical to the password of the external memory  30 , the external memory  30  permits access by transmitting an access permission message to the terminal, and the control unit  60  enables data reading and writing to and from the external memory  30  in step S 221 . 
     However, if the password received from the terminal is not identical to the password of the external memory at step S 233 , the external memory  30  transmits an access refusal message to the terminal, and the control unit  60  requests the user to input another password in step S 235 . If the user inputs another password, steps S 231  and S 233  are repeated to transmit the password to the external memory  30  and to compare the passwords. If the user does not input another password at step S 235 , the control unit  60  informs the user of refusal of access to the external memory  30  in step S 237 , and terminates the process of accessing the external memory  30 . 
     Hereinafter, the case that the password received from the terminal is not identical to the password of the external memory  30  is described referring to  FIG. 2B . That is, the case resulting from step S 219  if the password extracted from the internal memory unit  50  is not identical to the password of the external memory  30 . 
     If it is determined that the password received from the control unit  60  is not identical to the password of the external memory  30  at step S 219 , the external memory  30  transmits an access refusal message to the terminal. The control unit  60  receives the access refusal message and determines that the password of the external memory  30  has been changed or otherwise does not match the password stored in the internal memory  50 . Because the passwords do not match, the control unit  60  determines if the user desires to change the password corresponding to the external memory  30  stored in the internal memory unit  50  in step S 241 . 
     If the user determines not to change the password, the control unit  60  informs the user that access to the external memory  30  is not permitted in step S 237 , and terminates the process of accessing the external memory  30 . However, if the user decides to change the password at step S 241 , the control unit  60  requests the user to input a new password, and transmits the new password input by the user to the external memory  30  in step S 243 . 
     The external memory  30  determines whether the received new password is identical to the password set in the external memory  30  in step S 245 . If the received password is not identical to the password set in the external memory  30 , the external memory  30  transmits an access refusal message to the terminal. The control unit  60  receives the access refusal message, returns to step S 241  and again determines if the user desires to change the password corresponding to the external memory  30  stored in the internal memory unit  50 . 
     Alternatively, if it is determined in step S 245  that the received new password is identical to the password set in the external memory  30 , the external memory  30  transmits an access permission message to the terminal and permits the terminal to read and write data stored in the external memory  30 . The control unit  60  then controls to store the new password input by the user in the internal memory unit  50  in step S 247 . 
     As described above, a password identical to a password set in an installed external memory is stored in the internal memory unit. Thereby, a user may easily gain access to the external memory without having to repeatedly input the password corresponding to the external memory. 
     If a password input by the user is identical to the password set in the external memory, the user can access the external memory installed in the terminal, and thereby the user may perform various operations through the terminal, such as changing the password set in the external memory. If the user changes the password set in the external memory, the control unit also changes authentication information corresponding to the external memory stored in the internal memory unit. 
     Although exemplary embodiments of the present invention have been described hereinabove, it should be understood that many variations and modifications of the basic inventive concept herein described, which may appear to those skilled in the art, will still fall within the spirit and scope the exemplary embodiments of the present invention as defined in the appended claims and their equivalents.