JP5662600B2 - Portable storage medium adapter and data access disabling method - Google Patents

Description

  The present invention relates to a portable storage medium adapter and a data access disabling method.

  A portable storage medium such as a USB (Universal Serial Bus) memory is excellent in portability, but has a risk of information leakage due to loss or theft. For this reason, a lock function has been added to the USB memory data storage area. If the password is not authenticated, the lock cannot be released, or the data file can be deleted or locked in response to a password input error. Although there is no function, the entire data storage area is encrypted, and functions such as decryption cannot be performed unless authentication is performed with a password.

  Further, as a computer terminal storage medium that can suppress unauthorized use of data, a technique such as that disclosed in Patent Document 1 is also appearing.

JP 2006-338583 A

  However, there is a limit to the number of times data can be written in a storage unit such as a flash memory incorporated in a portable storage medium such as a USB memory, and the portable storage medium itself cannot be used when the number of data writing reaches this number. Further, when the user wants to change the storage capacity of the portable storage medium (for example, to increase the storage capacity), he or she has to replace the portable storage medium itself.

  In order to cope with these, it is conceivable to make the storage unit itself detachable / replaceable. However, if the storage unit becomes detachable, a new problem of information leakage due to loss or theft of the storage unit arises. .

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a portable storage medium adapter that can improve user convenience while suppressing information leakage. Another object of the present invention is to provide a data access disabling method capable of suppressing information leakage.

  The portable storage medium adapter described in this specification is an adapter for a portable storage medium that stores data received from the host device in a portable storage medium in a state of being connected to the interface unit of the host device. A holding unit that detachably holds the portable storage medium, a detection unit that detects a removal operation of the portable storage medium from a user, and a timing at which the removal operation is detected by the detection unit, A portable storage medium adapter comprising: a disabling execution unit that executes a disabling process for disabling external access to data stored in a portable storage medium.

  In the data access disabling method described in the present specification, a detection step of detecting a removal operation from a user with respect to a holding unit that detachably holds a portable storage medium, and the removal operation is detected in the detection step. And a disabling execution step of executing a disabling process for disabling access to data stored in the portable storage medium at a timing.

  The adapter for a portable storage medium described in the present specification has an effect that the usability of the user can be improved while suppressing information leakage. Further, the data access disabling method described in the present specification has an effect that information leakage can be suppressed.

It is a perspective view which shows the information processing apparatus which concerns on 1st Embodiment, and a USB adapter. It is a block diagram which shows the schematic structure of a USB adapter. It is a figure which shows schematic apparatus structure or arrangement | positioning of the USB adapter by another example of 1st Embodiment. 4 shows a functional configuration or arrangement of main functional units inside the microcomputer of FIGS. 2 and 3. It is a flowchart which shows the process of a USB adapter when an insertion / extraction switch is pushed. It is a flowchart which shows the specific process of step S12 of FIG. It is a flowchart which shows the specific process of step S28 of FIG. FIG. 8A is a diagram showing a format of an inaccessible policy, FIG. 8B is a diagram showing an example of values of factors that cause inaccessibility, and FIG. It is a figure which shows an example of the value of the access disabling method. It is a figure which shows the specific example of an access disable policy. The function structure or arrangement | positioning of the main function parts inside the microcomputer which concerns on 2nd Embodiment is shown. It is a flowchart which shows the process by the encryption module and insertion / extraction detection module which concern on 2nd Embodiment. It is a figure which shows the structure of FAT16 typical as a file system. It is a figure which shows the command issued with respect to a file system, when OS of information processing apparatus reads the data described in the file system, or writes it out. The function structure or arrangement | positioning of the main function parts inside the microcomputer which concerns on 3rd Embodiment is shown. It is a figure which shows a modification.

<< First Embodiment >>
Hereinafter, a first embodiment of the portable storage medium adapter and the data access disabling method will be described with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected to the same component.

  FIG. 1 shows an information processing device 40 as a host device such as a personal computer and a USB adapter 100 as a portable storage medium adapter. The USB adapter 100 is connected to the USB port 49 of the information processing apparatus 40. In FIG. 1, the information processing apparatus 40 is connected to the server 320 via a local area network (LAN) or the like. However, the present invention is not limited to this, and the information processing apparatus 40 may not be connected to the server 320.

  The information processing apparatus 40 includes a processor 42, a storage device 44 (for example, a hard disk), an input device 46 such as a keyboard, a display device 48 such as a liquid crystal display, and a USB port (connection terminal) 49.

  FIG. 2 shows a schematic configuration of the USB adapter 100. As shown in FIG. 2, the USB adapter 100 includes a USB interface (I / F) 110, a USB hub 112, a ROM 118, a microcomputer (μC) 120, a hub switch 130, and an SD card 205 as a portable storage medium. It includes a holding unit that can be inserted and removed and holds an SD card, a card slot 134 that functions as a releasing unit that releases the holding, and a display 144 such as an LED. The USB adapter 100 further includes a main power supply circuit 150, a battery and charging circuit 160, an auxiliary power supply circuit 162, a real time clock (RTC) 164 for time display or time monitoring, and a switch 166.

  The SD card 205 held (inserted) in the card slot 134 stores a user data file received from the information processing apparatus 40. Further, the card slot 134 ejects the inserted SD card 205 (releases the holding state) when the insertion / extraction switch 201 as a detection unit is pressed by the user. It is assumed that the insertion / extraction switch 201 is provided in a part of the main body 100b of the USB adapter 100 as shown in FIG.

  The USB interface 110 includes a power line or pin PL (dashed arrow) and a data line or pin DL (double-headed solid arrow). The USB hub 112 is coupled to the USB interface 110 and includes a branch power line PL (dashed arrow) and a branch data line DL (double-headed solid arrow).

  The display 144 is controlled by the microcomputer 120 (CPU 122), and displays the operating state of the USB adapter 100 and the remaining time until the first or next inaccessibility or protection processing by the microcomputer 120.

  The microcomputer 120 includes a CPU 122, a RAM 126, an internal flash memory 124, and a power supply control circuit 128. The internal flash memory 124 includes a firmware program (FW) used by the CPU 122, and data (identification information for authentication, encryption key such as a data file, inaccessibility (invalidation) policy, log, status information) Can be stored.

  A user USB memory utility program (PRG_U) used by the information processing apparatus 40 (processor 42) is stored in the ROM 118. A USB memory utility (for management, authentication, policy evaluation, etc.) program (PRG_F) used by the CPU 122 of the microcomputer 120 is stored in the flash memory 124.

  The USB adapter 100 is coupled to the USB port 49 of the information processing apparatus 40 via the USB interface 110 (DL). ROM 118 and microcomputer 120 are coupled to USB interface 110 via USB hub 112 (DL). Microcomputer 120 is coupled to card slot 134 and SD card 205 inserted into card slot 134 via hub switch 130 (DL) and coupled to battery and charging circuit 160, real-time clock 164, and display 144. Has been. The card slot 134 and the SD card 205 are coupled to the USB interface 110 or the microcomputer 120 via the hub switch 130 and the USB hub 112 (DL).

  The battery and charging circuit 160 receives power from the USB port 49 of the information processing apparatus 40 via the USB hub 112 and the USB interface 110 (PL), charges the rechargeable battery, and supplies power to the auxiliary power circuit 162. , Power is supplied to the main power supply circuit 150 via the switch 166. The battery and charging circuit 160 is coupled to the auxiliary power circuit 162. The main power supply circuit 150 also receives power from the USB port 49 of the information processing apparatus 40 via the USB hub 112 and the USB interface 110 (PL). When the USB adapter 100 is not coupled to the information processing apparatus 40, the main power supply circuit 150 is on / off controlled by the switch 166 and receives power from the battery and the charging circuit 160.

  The switch 166 is controlled by the microcomputer 120 and the real time clock 164.

  The main power supply circuit 150 includes a ROM 118, a microcomputer 120, a card slot 134, when the USB interface 110 is coupled to the USB port of the information processing apparatus 40 or when it is turned on by the switch 166 and supplied with power from the battery and charging circuit 160. In addition, power is supplied to the display 144. The auxiliary power circuit 162 supplies power to the real-time clock 164 and the switch 166. The display 144 may be supplied with power by the auxiliary power circuit 162 instead of by the main power circuit 150.

  The processor 42 of the information processing device 40 can operate according to programs (PRG_M, PRG_U) stored in the storage device 44 or the USB adapter 100 (ROM 118). The storage device 44 stores a utility program (PRG_M) for an administrator and / or a utility program (PRG_U) for a user.

  The user utility program (PRG_U) is read from the ROM 118 of the USB adapter 100 and stored in the storage device 44 when the USB adapter 100 is coupled to the information processing apparatus 40. The utility program for the user includes, for example, a management program for user authentication, information processing apparatus authentication, and file system construction of the USB adapter 100 (SD card 205).

  The utility program (PRG_M) for administrator includes, for example, administrator authentication, information processing device authentication, setting of information processing device that allows access (addition, change, deletion), setting of access disable policy (addition, change) ), And a management program for building a file system of the USB adapter 100 (SD card 205). The disabling policy may include rules or conditions and disabling process identification information and / or parameters. The input device 46 includes, for example, a keyboard and a pointing device.

  FIG. 3 shows another schematic device configuration or arrangement of the USB adapter 100 according to another example of the first embodiment. In the example of FIG. 3, the function of the hub switch 132 provided in the microcomputer 120 is used instead of the hub switch 130 of FIG. Other device configurations or arrangements and operations of the USB adapter 100 shown in FIG. 3 are the same as those in FIG.

  FIG. 4 shows a functional configuration or arrangement of main functional units inside the microcomputer 120 of FIGS. 2 and 3.

  As shown in FIG. 4, the microcomputer 120 includes a policy evaluation unit or determination unit 20, an authentication processing unit 22, a command processing unit 24, and an access disabling policy storage unit (setting information storage unit) 26 as functional parts or circuit parts. , A time management unit 28 and a status output unit 30. The microcomputer 120 includes a selection unit or control unit 32 that selects or controls access disabling, an access disabling processing unit (execution unit) as a disabling execution unit, or data protection processing as another functional part or circuit part. And a status information and log (record) storage unit (status information holding unit) 36. These functions are realized (implemented) by the firmware FW or the program PRG_F in the flash memory 124. The authentication processing unit 22 has an authentication information storage unit. The authentication information storage unit, the access disabling policy storage unit 26, and the status information and log storage unit 36 of the authentication processing unit 22 are areas of the flash memory 124 in the microcomputer 120. Note that the firmware FW, the program PRG_F, and the data in the flash memory 124 are not lost even if the remaining power of the battery in the battery and the charging circuit 160 is exhausted.

  The encryption key deletion in the protection process 1 of the inaccessibility processing unit 34 is a process of deleting a plurality of encryption keys stored in the flash memory 124. The plurality of encryption keys are generated and stored in the flash memory 124 when the encrypted data file is stored in the SD card 205.

  The policy evaluation unit 20 follows the respective access disabling policies (its rules or conditions and the disabling processing method) stored in the access disabling policy storage unit (rule or condition and disabling processing method storage unit) 26. Whether to protect the SD card 205 inserted in the USB adapter 100 based on the current date, log, and status information, that is, access to the data file in the SD card 205 is disabled at each protection level. Determine if it should. If it is determined that the SD card 205 should be protected, the policy evaluation unit 20 controls the selection unit 32 to select an access disabling method or a protection method, such as encryption key deletion, data deletion, function restriction, etc. Then, access to the data in the SD card 205 is disabled.

  The authentication processing unit 22 sets identification information for authentication, and based on the identification information for authentication set by the administrator, authentication of an information processing apparatus permitted to access, authentication of the administrator, user authentication, etc. I do. As a result, the connection of the USB adapter 100 to the authorized information processing apparatus and the use of the USB adapter 100 by the authorized user or administrator are detected (detected). The authentication processing unit 22 uses the current date and time, the date and time when an event such as authentication occurs, the date and time connected to the server 320 via the information processing apparatus, and the USB adapter 100 as opened or closed as log or status information ( Cap opening / closing or strap attachment / detachment) Date / time, number of consecutive user authentication failures, number of continuous administrator (privileged user) authentication failures, number of continuous authentication failures of information processing device 40, remaining battery power, status information, etc. Is recorded in the state information and log storage unit 36.

  The command processing unit 24 executes the command received from the information processing apparatus 40. The command processing unit 24 stores the access disabling policy (identification information and / or parameter indicating the rule or condition and the disabling processing method) set by the administrator in the access disabling policy storage unit 26 according to the command. The command processing unit 24 controls the hub switch 130 or 132 according to the command. The command processing unit 24 causes the state output unit or the state transfer unit 30 to transfer state information or a log to the information processing apparatus 40 via the USB interface 110 and the USB hub 112 according to the command.

  The time management unit 28 manages, sets, and controls the real-time clock 164 according to the request or evaluation result of the policy evaluation unit 20.

  When the insertion / extraction switch 201 is pressed by the user, the insertion / extraction switch 201 notifies the policy evaluation unit 20 to that effect. In addition, after the access disable processing is performed by the access disable processing unit 34 under the instruction of the policy evaluation unit 20, an instruction from the policy evaluation unit 20 is received so that the user can take out the SD card 205. The SD card 205 is ejected from the card slot 134 (the holding state is released).

  Next, processing in the USB adapter 100 when the insertion / extraction switch 201 is pushed will be described with reference to FIGS. FIG. 5 is a flowchart showing processing of the USB adapter 100 when the insertion / extraction switch 201 is pressed.

  When the user presses the insertion / extraction switch 201 in step S10 of FIG. 5 and notifies the policy evaluation unit 20 to that effect, a state evaluation subroutine is executed in step S12.

  In step S12, the policy evaluation unit 20 executes a state evaluation subroutine. Specifically, the policy evaluation unit 20 confirms the access disabling policy registered in the access disabling policy storage unit 26 and determines whether there is an access disabling process to be executed when the SD card 205 is removed. Execute the subroutine to check. In the subroutine of step S12, the process of FIG. 6 is executed.

  In step S <b> 20 of FIG. 6, the policy evaluation unit 20 reads one access disable policy from the access disable policy storage unit 26. Here, the access disabling policy has a format as shown in FIG. However, this format is also an example. Further, as an example, the value of the factor causing the inaccessibility is defined as shown in FIG. 8B, and the value of the inaccessibility method is defined as shown in FIG. 8C as an example. .

  Here, the format of FIG. 8A includes, for example, a factor (2 bytes) that causes the data to become inaccessible, an access disable method (1 byte), and a threshold value (4 bytes). The threshold means a threshold related to a factor that causes inaccessibility. Also, in FIG. 8B, as factors that cause inaccessibility, for example, the elapsed time from the last legitimate access, the remaining battery level of the battery, the number of authentication failures of the information processing apparatus, the number of user authentication failures Administrator (privileged user) authentication failure count, time from the start of connection of the USB memory 100 to the information processing apparatus 40 to the completion of authentication of the information processing apparatus 40 (success), user access disable command, SD card 205 Includes items such as removal.

  From FIG. 8A to FIG. 8C, the access disabling policy is as shown in FIG. 9 as an example. Therefore, in step S20, the policy evaluation unit 20 reads out the access disabling policies in FIG. 9 in order from the top.

  Next, in step S22, the policy evaluation unit 20 determines whether one line of the inaccessible policy has been read. If the determination here is affirmed, in the next step S24, it is confirmed whether or not the read access disable policy factor and threshold value match (applies) the situation at the time when the insertion / extraction switch 201 is pressed. To do. If the result of step S24 is not the same, the determination in step S26 is denied and the process returns to step S20. However, if the result is the same and the determination is affirmed, the process proceeds to step S28.

  In this embodiment, since the insertion / extraction switch 201 is pressed in step S10 in FIG. 5, the determination in step S26 is always made when the disabling factor of the access disabling policy is “removal of SD card 205”. It will be affirmed. In addition, there is a case where the determination in step S26 is affirmed due to the disabling factor of another rule before determining the rule that the disabling factor is “removal of SD card 205”.

  When the process proceeds to step S <b> 28, the policy evaluation unit 20 executes a read subroutine for the access disable process. Specifically, the policy evaluation unit 20 executes the process of FIG.

  In FIG. 7, in step S30, the policy evaluation unit 20 determines whether or not the access disable method of the read access disable policy is encryption key deletion. If the determination here is affirmed, an encryption key deletion flag is set in step S32. The policy evaluation unit 20 has a 2-byte variable as a flag. For this reason, in step S32, a bit corresponding to encryption key erasure is set in the 2-byte variable.

  Next, in step S34, the policy evaluation unit 20 determines whether or not the access disabling method is overwrite erasure, and if affirmative, sets an overwrite erasure flag (step S36). In step S38, the policy evaluation unit 20 determines whether or not the access disabling method is partial erasure. If the determination is affirmative, the policy evaluation unit 20 sets a partial erasure flag (step S40). In step S42, the policy evaluation unit 20 determines whether or not the access disabling method is lock. If the method is affirmed, the policy evaluation unit 20 sets a lock flag (step S44). Further, in step S46, the policy evaluation unit 20 determines whether or not the access disabling method is function restriction. If the policy evaluation part 20 is affirmed, it sets a function restriction flag (step S48).

  Thereafter, when the process proceeds to step S50, the policy evaluation unit 20 sets a variable n indicating a spare number to 1. In step S52, the policy evaluation unit 20 determines whether or not the access disabling method is backup n (backup 1). If the method is affirmed, the policy evaluation unit 20 sets a backup 1 flag (step S54). In step S56, the policy evaluation unit 20 determines whether n is the maximum value N of n. If the determination here is negative, in step S58, after incrementing n by 1, Return to S52. Thereafter, steps S52 to S58 are repeated until n becomes N. When the determination in step S56 is affirmed, step S28 in FIG. 6 is terminated, and the process returns to step S20. Thereafter, the processing and determination in FIG. 6 are repeated until the determination in step S22 is denied, that is, until all the access disabling policies have been read. Then, when the determination in step S22 is negative, the process proceeds to step S14 in FIG.

  In step S14 of FIG. 5, the policy evaluation unit 20 determines whether or not to protect, that is, whether or not a flag is set in any bit of the 2-byte variable in the process of FIG. If the determination here is negative, the entire process of FIG. 5 is terminated. If the determination here is positive, the process proceeds to step S16.

  In step S <b> 16, the policy evaluation unit 20 selects, for example, the bits having the flag set in the 2-byte variable through the inaccessible processing unit 34 in order from the largest bit, and corresponds to the bit. The disabling process is sequentially executed. This disabling process makes it difficult or impossible to access the file (data) in the SD card 205. Depending on the order, there may be a disabling process that does not make sense even if it is executed. In this case, the disabling process is skipped.

  In step S16, after the disabling process is executed, the process proceeds to step S18, and the policy evaluation unit 20 notifies the insertion / extraction switch 201 of removal permission. Then, with the insertion / extraction switch 201, an operation of taking out (ejecting) the SD card 205 in the card slot 134 is executed. Thus, all the processes in FIGS. 5 to 7 are completed. When the processing is completed in this way, the data stored in the SD card 205 is difficult or impossible to read thereafter.

  As described above, according to the first embodiment, the access disable processing unit 34 stores the SD card 205 at the timing when the insertion / extraction switch 201 accepts the user's removal operation of the SD card 205. Execute disabling processing that disables external access to data. As a result, when the SD card 205 is removed, access to the data stored in the SD card 205 is disabled, so that leakage of information in the SD card 205 can be suppressed. In addition, since the SD card 205 can be exchanged as necessary, it is possible to improve the usability of the user as compared with a conventional USB memory. In other words, while maintaining (or improving) the security function of a USB memory (with built-in flash memory, etc.), the SD card already owned by the user can be used, or the life of the SD card can be limited by limiting the number of writes. Even if this happens, it is possible to extend the product life by replacing only the SD card.

  In the first embodiment, since the SD card 205 is not ejected from the card slot 134 until the access disable processing unit 34 finishes executing the access disable processing, information leakage is more reliably suppressed. Can do.

  In the first embodiment, the case where the access disable processing unit 34 executes the access disable processing such as erasing the data of the SD card 205 has been described. However, the present invention is not limited to this. For example, when the SD card 205 itself has a high-speed data erasing function, the access disabling processing unit 34 may only issue a command for causing the SD card 205 itself to erase data.

<< Second Embodiment >>
Next, a second embodiment will be described in detail based on FIGS. In the following, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. In the second embodiment, as shown in FIG. 10, instead of the insertion / extraction switch 201 of the first embodiment (see FIG. 4), an encryption module 211 as an encryption key generation unit and a disablement execution unit, And a detection module 213. Note that the card slot 134 can be manually inserted and removed. However, the present invention is not limited to this, and the card slot 134 may be capable of automatic insertion / extraction (insertion / extraction using an insertion / extraction button), as in the first embodiment.

  The encryption module 211 encrypts data to be written to the SD card 205 connected to the card slot 134 with an encryption key stored inside. When data is read, it is decrypted with the encryption key stored inside. The encryption module 211 also performs encryption generation and encryption deletion.

  The insertion / removal detection module 213 detects a state in which the SD card 205 is inserted (attached) into the card slot 134 and a state in which the SD card 205 is removed (removed). Note that the insertion / removal detection module 213 detects insertion / removal of the SD card 205 using, for example, an optical sensor or a contact sensor. When the SD card 205 is inserted, the insertion / extraction detection module 213 requests the encryption module 211 to generate an encryption key. When the SD card 205 is removed, the insertion / removal detection module 213 requests the encryption module 211 to delete the encryption key stored therein.

  FIG. 11 is a flowchart showing processing by the encryption module 211 and the insertion / extraction detection module 213. As shown in FIG. 11, in step S60, when the insertion / extraction detection module 213 detects that the SD card 205 has been inserted into the card slot 134 (step S60: Yes), in step S62, the insertion / extraction detection module 213 An encryption key generation command is issued to the encryption module 211. The encryption module 211 generates and stores an encryption key based on the encryption key generation command.

  Next, in step S64, the SD card 205 is formatted. Here, the user confirms from the information processing apparatus 40 (on the OS) the data obtained by decrypting the data stored in the SD card 205 by the encryption module 211. However, since the data originally stored in the SD card 205 is not data encrypted using the encryption key stored in the encryption module 211, the data string that has an unknown meaning even if decrypted by the encryption module 211 Become. Therefore, in order to read the data in the SD card 205 correctly, it is necessary to format the SD card 205 in step S64.

  Next, in step S66, in response to a request from the information processing apparatus 40, data recording using an encryption key to the SD card 205 is started. Here, the encryption method in the present embodiment will be described with reference to FIGS. FIG. 12 shows the structure of a typical FAT 16 as a file system. In this structure, data is written to the file system in units of sectors. In the information processing apparatus 40, the OS reads and writes data described in the file system using commands as shown in FIG. 13 with respect to the file system. In the present embodiment, when the command is “write” in FIG. 13, the encryption module 211 writes the encrypted data into the read / write data area shown in FIG. If the command is “read”, the cryptographic module 211 decrypts and reads the data in the read / write data area.

  Returning to FIG. 11, after step S66 is performed, recording using the encryption key is continued until the SD card 205 is removed from the card slot 134. When the determination in step S68 is affirmed, the process proceeds to step S70. To do.

  In step S 70, the insertion / extraction detection module 213 issues an encryption key deletion command to the encryption module 211. Then, the cryptographic module 211 executes an erase process (deletion) of the encryption key stored inside based on the erase command.

  In the second embodiment, in addition to the suppression of information leakage due to the generation and deletion of the encryption key by the encryption module 211 described above, the access disable processing similar to the first embodiment described above is appropriately performed (access disable). It may be done when the policy threshold is exceeded. This makes it possible to perform the access disabling process at an appropriate timing other than when the SD card 205 is removed.

  As described above, according to the second embodiment, the data written to the SD card 205 is data encrypted with the encryption key, and when the SD card 205 is removed from the card slot 134 of the USB adapter 100. Since the encryption key is erased, data in the SD card 205 cannot be read after the SD card 205 is removed. As a result, as in the first embodiment, it is possible to improve user convenience by making it possible to remove the SD card 205 from the USB adapter 100 while suppressing leakage of information.

  In the second embodiment, the encryption key is generated when the SD card 205 is inserted and the encryption key is deleted when the SD card 205 is removed. However, the present invention is not limited to this. is not. For example, when the SD card 205 is removed, a new encryption key may be generated, and the encryption key stored inside may be overwritten with the new encryption key. Even if it does in this way, the effect similar to the said 2nd Embodiment can be acquired.

  Moreover, although the case where the insertion / extraction detection module 213 was provided was demonstrated in the said 2nd Embodiment, it does not need to provide not only this but the insertion / extraction detection module 213. In this case, for example, the cryptographic module 211 detects whether or not the access to the SD card 205 in the card slot 134 is normally performed, and the state is changed from the state where the access is normally performed to the state where the access is not performed. It may be considered that the SD card 205 is removed from the card slot 134 (when an access error occurs). Even if it does in this way, the effect similar to the said 2nd Embodiment can be acquired. Note that whether or not access is normally performed may be monitored by another configuration (component) other than the cryptographic module 211.

  In the second embodiment, the case where the format process of the SD card 205 is automatically executed in step S64 has been described. However, the present invention is not limited to this. For example, the user may only be notified that format processing should be performed.

<< Third Embodiment >>
Next, a third embodiment will be described with reference to FIG. In the following description, the same components as those in the second embodiment described above are denoted by the same reference numerals and description thereof is omitted. In the third embodiment, as shown in FIG. 14, in addition to the configuration of the second embodiment, a volatile memory 215 is provided.

  Volatile memory 215 receives power from the battery and charging circuit 160. The volatile memory 215 stores the encryption key generated by the encryption module 211. In the volatile memory 215, when power is not supplied from the battery and the charging circuit 160, the contents of the volatile memory 215 become invalid and the stored encryption key is erased.

  In this way, in the third embodiment, the same effect as in the second embodiment can be obtained, and the battery and the battery of the charging circuit 160 can be removed illegally, so that the access disable processing unit 34 can be obtained. Even if it is attempted to make the access inaccessibility process impossible due to this, the data stored in the SD card 205 cannot be read by deleting the encryption key. Thereby, leakage of information is suppressed.

  In each of the above embodiments, as shown in FIG. 15, an open / close sensor including a magnetic detector, a current detector, a proximity switch, or the like in the vicinity of the coupling portion or engagement portion between the main body 100 b and the cap 102 or the strap 104. 142 may be provided. The open / close sensor 142 detects that the cap 102 or the strap 104 is removed from the USB adapter 100, and detects that the cap 102 or the strap 104 is coupled or engaged with the USB adapter 100. The switch 166 is directly turned on / off by the detection of the open / close sensor 142. The cap 102 or the strap 104 may be provided with a permanent magnet that is detected by the magnetic detector, a resistor that can be coupled to the current detector, or a proximity member that can be detected by the proximity switch. Good. The microcomputer 120 (CPU 122) may monitor and control the detection output of the open / close sensor 142. In this case, the switch 166 is turned on / off via the microcomputer 120 (CPU 122). In this case, an elapsed time after the cap 102 or the strap 104 detected by the opening / closing sensor 142 is closed may be used as a factor causing the inaccessibility. By using the elapsed time from the physical opening / closing detected by the opening / closing sensor 142, the elapsed time from the time when the user last opened or closed the cap 102 or strap 104 of the USB memory 100 is made inaccessible. Factor.

  In each of the above embodiments, the case where an SD card is adopted as a portable storage medium has been described. However, the present invention is not limited to this. Examples of portable storage media include memory stick-related products such as Memory Stick (registered trademark), Memory Stick Duo (registered trademark), and Memory Stick Micro (registered trademark), MiniSD card (registered trademark), MicroSD card (registered trademark), and xD. Various memory cards such as a card (registered trademark) can also be adopted. The card slot 134 can be a card slot corresponding to one or a plurality of types of portable storage media. In addition, as a portable storage medium, a USB memory and a USB-HDD can also be adopted. In this case, the card slot in each of the embodiments is a USB connection interface.

  Each embodiment mentioned above is an example of suitable implementation of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

34 Access disable processing part (Disabling execution part)
40 Information processing device (host device)
100 USB adapter (Adapter for portable storage media)
205 Card slot (holding section, release section)
201 Insertion / extraction switch (detection unit)
211 Cryptographic module (encryption key generation unit, disablement execution unit)
215 volatile memory

Claims (10)

A portable storage medium adapter that stores data received from the host device in a portable storage medium in a state connected to the interface unit of the host device,
A holding unit for detachably holding the portable storage medium;
A detection unit for detecting a removal operation of the portable storage medium from a user;
A portable storage device comprising: a disabling execution unit that executes a disabling process for disabling external access to data stored in the portable storage medium at a timing when the removal operation is detected in the detection unit. Media adapter.   The portable storage medium adapter according to claim 1, further comprising: a release unit that releases the holding of the portable storage medium by the holding unit after the disabling process by the disabling execution unit.   The detection unit monitors an access state from the host device to the portable storage medium, and the removal operation is performed when the access state is changed from a normal state to a normal state. The portable storage medium adapter according to claim 1, wherein the adapter is detected as having occurred. An encryption key generation unit for generating an encryption key used when accessing the portable storage medium from the host device;
The portable storage according to any one of claims 1 to 3, wherein the disabling process executed by the disabling execution unit is an erasing process of an encryption key generated by the encryption key generation unit. Media adapter.   5. The portable storage medium adapter according to claim 4, wherein the disabling process executed by the disabling execution unit is a process of overwriting the encryption key with a new encryption key.   The portable storage medium adapter according to claim 4, further comprising a volatile memory for storing the encryption key. A detection step of detecting a removal operation from a user with respect to a holding unit that detachably holds a portable storage medium;
And a disabling execution step of executing a disabling process for disabling access to data stored in the portable storage medium at a timing when the removal operation is detected in the detecting step. An encryption key generation step of generating an encryption key used when accessing the portable storage medium from the outside;
8. The data access disabling method according to claim 7, wherein the disabling process executed in the disabling execution step is an erasing process of the encryption key generated in the encryption key generation step.   9. The data access disabling method according to claim 8, wherein the disabling process executed in the disabling execution step is a process of overwriting the encryption key with a new encryption key.   The data access disabling method according to claim 8 or 9, further comprising an initialization step of initializing the portable storage medium after the encryption key is generated in the encryption key generation step.

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