JP3825917B2 - Access control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an authentication system and an access control device, and more particularly to an authentication system and an access control device for protecting the storage contents of a storage device.
[0002]
[Prior art]
In recent years, a memory card equipped with a flash memory or the like has been used as a portable non-volatile storage medium, particularly a storage medium for a portable information terminal.
The memory card is usually connected to a computer or the like via, for example, a PCMCIA bus, and stores data supplied from the computer or the like in response to access of the computer or the like. Or to supply.
[0003]
[Problems to be solved by the invention]
However, there is a risk that the data stored in the memory card described above is easily leaked by being connected to another computer by a person other than the owner of the memory card, for example. This risk is particularly great in a memory card with excellent portability.
[0004]
As a technique for solving this problem, a technique for encrypting data stored in a memory card can be considered.
However, software for encrypting and decrypting data increases the execution time due to the enormous mathematical processing for encrypting and decrypting, and as a result, it is difficult to use the memory card comfortably. become. Also, software for data encryption and decryption is difficult to develop due to the complexity of the mathematical processing described above.
[0005]
In addition, when the owner of the memory card wants to give data to another person, the encrypted data must be decrypted once by a computer etc., and only the meaningless data is given to the other party. . For this reason, transfer and exchange of data become complicated.
[0006]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a simple authentication system for concealing data stored in a storage device while ensuring ease of transfer.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, an access control apparatus according to the present invention provides:
  An access control device that is connected to a storage device and a computer that accesses the storage device, and that accesses the storage device according to instructions from the computer,
  The storage device is enabled to allow access to the storage devicecommandEnable to memorize rewritablecommandArea, and a password area for storing the password for authentication in a rewritable manner,
  The computer supplies a write command and data to be written to the access control device in order to write data to the storage device in a state where the access control device accepts an access command. An access instruction means for supplying a read command to the access control device for reading data from the storage device;commandAnd an authentication instruction means for supplying a password to the access control device,
  This access control device
  At the time of initialization processing of the access control device, it is determined whether or not the stored contents of the password area match a predetermined condition for accepting an access command. Accepts an access command, enters a first state for accessing the storage device according to the access command, and enters a second state for rejecting execution of an access command supplied from the computer when it is determined that they do not match Initializing means for performing initial processing, and
  After completion of the initial processing, the computer is enabled in the second state in which execution of the access command is rejected because the stored contents of the password area do not match the predetermined condition.commandAnd if a password is supplied, the supplied enablecommandIs the enablecommandEnable stored in the areacommandAnd whether or not the supplied password matches the password stored in the password area.commandIf it is determined that at least one of the password and the password does not match, the second state in which execution of the access command is rejected is maintained, and if it is determined that both match, the third command that accepts the access command An authentication processing means for performing an authentication process of transitioning to a state;
  Access means for accessing the storage device according to the contents indicated by the supplied access command when the access command is supplied from the computer in the first or third state in which the access command is received.The
  It is characterized by that.
[0011]
  The access control device is enabled by the computer in the first or third state in which an access command is received.commandAnd if a password is supplied, the supplied enablecommandIs the enablecommandEnable stored in the areacommandAnd whether the supplied password is different from the password stored in the password area. If it is determined that the password is not, the access command is accepted. If it is determined that the relation is satisfied, it is further determined whether or not the stored content of the password area matches the predetermined condition. If it is determined that the access command is not to be executed, a means for performing a process of shifting to the second state in which execution of the access command is rejected may be provided.
[0012]
As a result, the data stored in the storage device is changed to a state that cannot be read by others even when the storage device is in use. Therefore, for example, even when the user of the storage device temporarily leaves a location where the storage device is located, the data stored in the storage device is securely concealed.
[0020]
In addition, the number attached | subjected in the parenthesis is a reference number of the corresponding structure in embodiment, should be used only for reference, and does not limit this invention.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking an authentication system including a memory card and a computer as an example.
[0022]
FIG. 1 is a block diagram showing a physical configuration of an authentication system according to an embodiment of the present invention.
As shown in the figure, this authentication system includes a memory card 1 and a computer 2. The memory card 1 is detachably attached to the computer 2 through a slot provided in the computer 2.
The slots provided in the computer 2 include, for example, PCMCIA slots for relaying the PCMCIA bus.
[0023]
The memory card 1 includes a flash memory 11 and a controller 12.
[0024]
The flash memory 11 constitutes a storage device or storage means, and the flash memory 11 includes an EEPROM (Electrically Erasable / Programmable Read Only Memory) or the like. In response to the access performed by the controller 12, the flash memory 11 stores the data supplied from the computer 2, supplies the stored data to the computer 2, and erases the stored data.
[0025]
An address is assigned to the storage area of the flash memory 11, and the storage area for 512 bytes from the head address forms an authentication information storage area as shown in FIG.
As shown in FIG. 2, the first 510 bytes of the authentication information storage area forms a password area for storing a password to be described later, and the remaining 2 bytes of storage area has an enable command to be described later. A command code area for storing a code to be shown is formed.
The flash memory 11 stores a FAT (File Allocation Table) made up of data indicating the data structure of its own storage area.
[0026]
The controller 12 constitutes an access control device, and includes a CPU (Central Processing Unit) 121 and a ROM (Read Only Memory) 122 that stores an operation program executed by the CPU 121, as shown in FIG. Yes.
The CPU 121 is connected to the ROM 122 and the flash memory 11 and is detachably connected to the computer 2 through a PCMCIA slot provided in the computer 2. The CPU 121 includes a status register.
[0027]
The CPU 121 performs the functions of command execution means, permission means, and update means, which will be described later, by executing the above-described operation program stored in the ROM 122.
[0028]
  The CPU 121 obtains command data supplied from the computer 2 constituting the access device, and when the command data represents a predetermined command, the CPU 121 performs an operation according to the command.
  The command that the CPU 121 follows includes an enable command,This is a maintenance commandManufacturer identification command, set password command andInstructs reading and writing of storage media in compliance with ATA commandsFour types of access commands are included.
[0029]
  The enable command isPaired with passwordThis is an instruction to give the computer 2 permission to access the flash memory 11. The code indicating the enable command is stored in the command code area of the flash memory 11 as described above.
[0030]
  The CPU 121 receives an enable command from the computer 2Command data consisting of password and passwordIs supplied, it is determined whether or not an access command (described later) supplied from the computer 2 is accepted according to a process described later, and the access command is accepted and rejected according to the determination result.
[0031]
  That is, the CPU 121 determines that the command data supplied from the computer 2 is an enable command.And the password stored in the password area of the flash memory 11The CPU 121 itself is permitted to receive the access command supplied by the computer 2. Therefore, the CPU 121 performs a function as a permission unit.
[0032]
However, when the content of the data stored in the password area of the flash memory 11 meets a predetermined condition (for example, when all the bits in the password area are “1”), the CPU 121 determines that the computer 2 It is determined that the access command supplied from is unconditionally accepted.
[0033]
Further, the CPU 121 determines to accept the access command supplied from the computer 2 unconditionally even when a predetermined manufacturer identification command is supplied from the computer 2.
The manufacturer identification command is a maintenance command for the manufacturer or the like to read data stored in the flash memory 11 when the user forgets the enable command or the password. The code indicating the command is designated in advance by the manufacturer of the CPU 121 or the like.
[0034]
If the CPU 121 determines to accept an access command supplied from the computer 2, the CPU 121 accepts the access command by setting, for example, the above-described status register included in the CPU 121 and notifying the computer 2 of the status of the status register. Notify that. If it is decided to deny access, the status register is reset to notify the computer 2 of denial of access.
[0035]
The set password command is an instruction for instructing an enable command and a password change. The code indicating the set password command is designated in advance by the manufacturer of the controller 12 or the like.
When the CPU 121 is supplied with a set password command from the computer 2 while receiving an access command, the CPU 121 updates the code and password of the enable command stored in the authentication information storage area of the flash memory 11 according to the processing described later. . That is, the CPU 121 performs a function of an update unit.
[0036]
The access command is an instruction for instructing the CPU 121 to access the flash memory 11. The access command is designated in advance by a manufacturer or the like in accordance with an existing command set such as an ATA command.
[0037]
When the access command is supplied from the computer 2 while the access command is being received, the CPU 121 accesses the flash memory 11 in accordance with the contents indicated by the supplied access command.
Specifically, the CPU 121 stores data to be written to the flash memory 11 supplied from the computer 2 in the flash memory 11, reads out data stored in the flash memory 11, and supplies the data to the computer 2. To do. That is, the CPU 121 functions as a command execution unit when performing an operation according to the access command supplied from the computer 2.
[0038]
The CPU 121 supplies attribute information for identifying the memory card 1 to which the CPU 121 belongs to the computer 2 in response to a request from the computer 2.
[0039]
The computer 2 constitutes an access device or access means, and includes an input means and a command supply means.
The computer 2 is a personal computer or the like, has a PCMCIA slot, and stores an operating system (OS), a driver, and an authentication program.
[0040]
The computer 2 executes the OS, detects that the memory card 1 is inserted in the PCMCIA slot, and starts the driver according to the processing of the OS. On the other hand, the computer 2 starts an authentication program in accordance with a user operation under the control of the OS, and requests the controller 12 to accept an access command supplied by itself as described later according to the processing of the authentication program.
[0041]
In a state where the access command is received, the computer 2 supplies the CPU 121 with the access command and the data to be written to the flash memory 11 according to the driver processing, thereby allowing the CPU 121 to access the flash memory 11. To do. Then, the CPU 121 acquires from the CPU 121 data read from the flash memory 11 and supplied to the CPU 121 in accordance with the access command supplied by itself.
[0042]
(Operation)
Next, the operation of this authentication system will be described with reference to FIGS.
4A and 4B are flowcharts showing the initial process.
5A and 5B are flowcharts showing the authentication process.
FIGS. 6A and 6B are flowcharts showing a process for applying a password lock.
[0043]
(Initial processing)
When the computer 2 is turned on, the computer 2 performs the initial processing shown in FIG. 4A, while the memory card 1 performs the initial processing shown in FIG. 4B.
[0044]
That is, when the computer 2 is first turned on, the computer 2 executes an OS process (step S001), and detects whether the memory card 1 is installed in the PCMCIA slot according to the OS process.
[0045]
When the memory card 1 is inserted into the PCMCIA slot, the computer 2 detects the insertion of hardware (step S002), and accesses the controller 12 of the memory card 1 to request supply of attribute information. The CPU 121 of the controller 12 supplies the attribute information to the computer 2, and the computer 2 acquires the attribute information (step S003).
[0046]
Next, the computer 2 determines whether or not the acquired attribute information represents the memory card 1 (step S004). Specifically, for example, it is determined whether or not the acquired attribute information matches the attribute information assigned in advance to the memory card that matches a predetermined standard by the manufacturer.
[0047]
If the computer 2 determines that it does not represent the memory card 1, the process returns to step S002. However, if the attribute information represents another available device, it is recognized that the device is mounted, and a predetermined process to be performed to use the device is performed.
[0048]
If it is determined in step S004 that the attribute information represents the memory card 1, the computer 2 activates the driver (step S005).
[0049]
On the other hand, when the memory card 1 is inserted into the PCMCIA slot, the CPU 121 of the controller 12 of the memory card 1 reads the contents of the password area of the flash memory 1 and the contents are predetermined for accepting an access command unconditionally. It is determined whether or not the condition is met (step S011).
[0050]
If it is determined that they match, the CPU 121 shifts to a state of accepting an access command supplied from the computer 2 (step S012), ends the initial processing on the memory card 1 side, and receives data such as an access command from the computer 2. Wait for it to be supplied.
If it is determined that they do not match, the process proceeds to a state in which the access command supplied from the computer 2 is rejected (step S013), and the initial processing on the memory card 1 side is terminated.
[0051]
In step S012, when the CPU 121 shifts to a state of accepting an access command, the computer 2 supplies the CPU 121 with an access command that instructs reading of the contents of the FAT. The CPU 121 reads the contents of the FAT stored in the flash memory 11 in response to the supplied access command, and supplies it to the computer 2. The computer 2 acquires the contents of the FAT supplied from the CPU 121 and grasps the data structure of the storage area of the flash memory 11 (step S006).
[0052]
Then, the computer 2 displays an icon indicating that the flash memory 11 has been accessed according to the access command supplied from the computer 2 (step S007), and ends the initial processing on the computer 2 side. To do.
[0053]
After displaying the icon, the computer 2 provides the controller 12 with access to the flash memory 11 by supplying an access command or the like to the controller 12 in accordance with a user operation or processing of an application program executed by the computer 2. It becomes a state that can be performed.
[0054]
(Authentication process)
On the other hand, after the driver is activated, the computer 2 activates the authentication program in accordance with a user operation. In the following, while the CPU 121 of the controller 12 of the memory card 1 rejects the access command supplied from the computer 2, the processing of the authentication program (authentication processing) and while the computer 2 executes the processing of the authentication program The operation of the memory card 1 will be described with reference to FIGS. 5 (a) and 5 (b).
[0055]
When starting the processing of the authentication program, the computer 2 prompts the user to input the enable command and password by displaying a text box for writing the enable command and password, for example (step S101).
[0056]
When the data representing the enable command and the password are input, the computer 2 supplies the data input as the enable command and the password to the controller 12 of the memory card 1 in accordance with the driver processing (step S102), and the processing ends.
[0057]
The memory card 1 waits for data to be supplied from the computer 2 (step S201). When the data is supplied, the CPU 121 of the controller 12 of the memory card 1 determines whether the portion representing the enable command in the data matches the code of the enable command stored in the command code area of the flash memory 11. It is determined whether or not (step S202).
If it is determined that they do not match, the supplied data is ignored and the process returns to step S201.
[0058]
If it is determined in step S202 that the supplied data matches the enable command, the CPU 121 matches the password stored in the password area of the flash memory 11 in the portion of the data supplied from the computer 2 that represents the password. It is determined whether or not to perform (step S203).
[0059]
When determining that the data does not match the password, the CPU 121 ignores the data and returns the process to step S201. As a result, the CPU 121 remains rejecting the access command supplied from the computer 2.
[0060]
On the other hand, if it is determined that they match, the CPU 121 moves to a state of accepting an access command supplied from the computer 2 (step S204), ends the authentication process, and waits for data such as an access command to be supplied from the computer 2. To do.
[0061]
When the CPU 121 shifts to a state where it accepts an access command in step S204, the computer 2 performs substantially the same processing as steps S006 and S007. That is, the FAT contents are acquired to grasp the data structure of the storage area of the flash memory 11, and an icon indicating that the flash memory 11 has been accessed according to the access command supplied from the computer 2 is displayed. .
As described above, the computer 2 is in a state in which the CPU 121 can access the flash memory 11.
[0062]
(Process to change enable command and password)
The computer 2 instructs the controller 12 to change the enable command and the password by supplying a set password command to the controller 12 according to the processing of the authentication program, for example, in a state where the CPU 121 of the controller 12 receives the access command. The CPU 121 of the controller 12 changes the enable command and password according to the instruction.
[0063]
Specifically, the computer 2 that executes processing such as an authentication program displays a text box for writing a new enable command and a password, and inputs a new enable command and a new password to the user. Prompt.
When the user inputs a new enable command and a new password, the computer 2 supplies the controller 12 with a set password command, a new enable command, and a new password.
[0064]
When the CPU 121 of the controller 12 is supplied with the set password command, the new enable command, and the new password, the CPU 121 writes the new enable command to the command code area of the flash memory 11 and writes the new password to the password area of the flash memory 11. Write to.
Through the process described above, the enable command and the password are updated.
[0065]
If the password is updated by the above-described processing so that the access command supplied from the computer 2 is unconditionally accepted, the data stored in the flash memory 11 does not require user authentication. It will be in a state where it can be read out.
Therefore, even if the memory card 1 is handed over to another person who does not know the enable command, the person can read the data stored in the flash memory 11 using not only the computer 2 but also another computer or the like. .
[0066]
(Process to lock password)
Even if the CPU 121 of the controller 12 receives an access command, the computer 2 can supply an enable command and a password to the CPU 121 according to the processing of the authentication program.
In this case, the user can cause the CPU 121 to reject the access command supplied from the computer 2 by operating the computer 2 and intentionally inputting a correct enable command and an incorrect password. Therefore, to enable the CPU 121 to accept the access command again, it is necessary to input a correct enable command and password (that is, a password lock is applied).
This prevents a situation in which the data stored in the flash memory 11 is acquired by another person when the user temporarily leaves the installation location of the computer 2, and data confidentiality is performed.
In the following, a password lock process for applying a password lock to the flash memory 11 will be described with reference to FIGS. 6 (a) and 6 (b).
[0067]
First, the computer 2 performs substantially the same processing as steps S101 and S102 described above, and supplies data including an enable command and a password input by the user to the controller 12 of the memory card 1 (step S301).
[0068]
When the data is supplied from the computer 2, the CPU 121 of the controller 12 performs substantially the same processing as step S <b> 202, and whether or not the enable command indicated by the data matches that stored in the flash memory 11. Is determined (step S401).
If it is determined that they do not match, the CPU 121 ignores the data and ends the process, and waits for other data to be supplied from the computer 2.
[0069]
If it is determined that they match, the memory card 1 performs substantially the same processing as in step S203, and whether or not the password indicated by the data supplied from the computer 2 matches that stored in the flash memory 11. Is determined (step S402).
[0070]
If it is determined that they match, the processing is terminated by ignoring the data supplied from the computer 2 and waits for other data to be supplied from the computer 2.
On the other hand, if it is determined that they do not match, the CPU 121 determines whether or not the password stored in the flash memory 11 matches a condition for unconditionally receiving an access command supplied from the computer 2 ( Step S403)
[0071]
If it is determined that the condition is met, the CPU 121 ignores the data supplied from the computer 2 and ends the process, and waits for other data to be supplied from the computer 2.
[0072]
If it is determined that the condition is not met, the CPU 121 shifts to a state of rejecting the access command supplied from the computer 2 (step S404), ends the process, and waits for other data to be supplied from the computer 2. To do.
[0073]
By the processing described above, a password lock is applied to the flash memory 11, and a situation in which data stored in the flash memory 11 is acquired by another person is prevented.
[0074]
Note that the configuration of the authentication system does not have to be as described above.
For example, the flash memory 11 need not be an EEPROM, as long as it can store data in a rewritable manner in response to access from the CPU 121 or any other device, or output the stored contents. Any storage device may be used.
In addition, if the memory card 1 has a so-called tamper-free structure in which data stored in the flash memory 11 is lost when it is physically destroyed, data confidentiality is more reliably performed. Is called.
[0075]
The enable command and password may be stored at a position corresponding to an arbitrary address in the storage area of the flash memory. In this case, for example, the controller 12 sets the address of the position where the enable command and the password are stored. Just remember.
Further, the data lengths of the enable command and password are both arbitrary.
[0076]
Further, it is not necessary for the flash memory 11 to store one enable command and one password. For example, a plurality of enable command and password pairs may be stored. In this case, in the authentication process described above, the enable command and password that match the enable command and password input by the user are supplied from the computer 2 only when they are stored in the flash memory 11 in the above-mentioned pair. It may be determined that the access command to be received is accepted.
[0077]
Further, the slot provided in the computer 2 may be detachably attached to the computer 2.
[0078]
Although the embodiment of the present invention has been described above, the authentication system of the present invention can be realized using a normal computer system, not a dedicated system. For example, an authentication system that executes the above-described processing is configured by installing the program from a medium (floppy disk, CD-ROM, etc.) that stores the program for executing the above-described operation in a computer having an external storage device can do.
[0079]
The medium for supplying the program to the computer may be a communication medium (a medium that temporarily and fluidly holds the program, such as a communication line, a communication network, or a communication system). For example, the program may be posted on a bulletin board (BBS) of a communication network and distributed via the network.
The above-described processing can be executed by starting this program and executing it under the control of the OS in the same manner as other application programs.
[0080]
When the OS shares a part of processing, or when the OS constitutes a part of one component of the present invention, a program excluding the part is stored in the recording medium. May be. Also in this case, in the present invention, it is assumed that the recording medium stores a program for executing each function or step executed by the computer.
[0081]
【The invention's effect】
As described above, according to the present invention, a simple authentication system for concealing data stored in a storage device while ensuring ease of transfer is realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an authentication system according to an embodiment of the present invention.
FIG. 2 is a diagram schematically showing a data structure of a flash memory.
FIG. 3 is a block diagram illustrating a configuration of a controller.
FIG. 4A is a flowchart showing initial processing on the computer side, and FIG. 4B is a flowchart showing initial processing on the memory card side.
5A is a flowchart showing authentication processing on the computer side, and FIG. 5B is a flowchart showing authentication processing on the memory card side.
6A is a flowchart showing a process for applying a password lock on the computer side, and FIG. 6B is a flowchart showing a process for applying a password lock on the memory card side.
[Explanation of symbols]
1 Memory card
11 Flash memory
12 Controller
121 CPU
122 ROM
2 Computer

Claims (2)

An access control device that is connected to a storage device and a computer that accesses the storage device, and that accesses the storage device in accordance with instructions from the computer,
The storage device may enable command area for rewritably storing enable command for enabling access to the storage device, and includes a password area for rewritably storing password for authentication,
The computer supplies a write command and data to be written to the access control device in order to write data to the storage device in a state where the access control device accepts an access command. An access instruction means for supplying a read command to the access control device, and an authentication instruction means for supplying an enable command and a password to the access control device in order to read data from the storage device;
This access control device
At the time of initialization processing of the access control device, it is determined whether or not the stored contents of the password area match a predetermined condition for accepting an access command. Accepts an access command, enters a first state for accessing the storage device according to the access command, and enters a second state for rejecting execution of an access command supplied from the computer when it is determined that they do not match Initializing means for performing initial processing, and
After completion of the initial processing, an enable command and a password are supplied from the computer in the second state in which execution of an access command is rejected because the stored contents of the password area do not match the predetermined condition. that when, conform to enable command is supplied enabled commands stored in the enable command area, and, to determine whether the supplied password matches the password stored in the password area, When it is determined that at least one of the enable command and the password does not match, the second state where the execution of the access command is rejected is maintained, and when it is determined that both match, the access command is received. Authentication process that performs the authentication process of moving to state 3 And means,
When the supplied access commands from the computer in the first or third state is accepting access command, in accordance with content indicated by the supplied access command, and accessing means for accessing said storage device, Ru provided with,
An access control device. In the first or third state is accepting access command, the enable command and password from the computer is supplied, conform to enable command is supplied enabled commands stored in the enable command area, In addition, it is determined whether or not the supplied password is different from the password stored in the password area. If it is determined that the supplied password is not related, the state in which the access command is received is maintained and the relationship is maintained. In addition, it is determined whether or not the stored contents of the password area match the predetermined condition. If it is determined that the password area matches, the state where the access command is accepted is determined to be not matched. When the second state refuses to execute the access command Turning to, provided with a means for performing a process of,
The access control apparatus according to claim 1.

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