JP2006107305A - Data storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an access history from being altered at low cost by enhancing the data confidentiality of a data storage device. <P>SOLUTION: When access is given to data from the outside, a control part generates an access history and writes the access history in a storage medium. Then, a message authentication code generated from the access history by a generating key is attached to the access history. In addition, a key for authenticating an access source, a management server authentication key for allowing a change in configuration information and a message authentication code generation key are stored in a tamper-proof module in the data storage device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data storage device, and more particularly to a data storage device suitable for recording an access history of data in an information system in a form that cannot be falsified.

  As computers and networks become inseparable from our lives, the importance of protecting personal information in systems is increasing. In order to appropriately protect personal information, it is fundamental to leave an access log in a storage device of a computer system and monitor unauthorized access.

  The “data with access qualification authentication” in the following Patent Document 1 is a server that verifies a user's access qualification, and records data in a write-once type in a data storage device when the verification is successful. In particular, it has been suggested in paragraph numbers 0035, 0317, 0318, etc. that falsification can be prevented by recording the access log on a write-once recording medium.

JP 2001-117823 A Douglas R. Stinson, “Cryptography: theory and practice”, CRC Press LLC, 1995: Chapter 7 “Hash Function”

  As seen in the Personal Information Protection Law, regulations on how information is used have become stricter, and companies and public institutions are obliged to comply with laws and regulations regarding the use of information. There is a growing need to prove this to a third party.

  It is known that fraud related to the protection of personal information is often a crime by an internal human being. Conventional computer systems and recording devices have encryption and access control functions, and data access record storage functions, but these functions are used by internal persons with legitimate access rights to information. It is not possible to prevent the act of using it. For this reason, there is an increasing need for a mechanism for preventing unauthorized use of information by an internal person having system management authority.

  In the above prior art, the access log is stored in a write-once storage medium, so that tampering can be dealt with. However, when the data body is recorded on a rewritable medium such as a magnetic disk, only the access log is stored. Since the data is stored in a medium different from the data, for example, only the access log may be destroyed by physical means, and if only the access log is stored in a medium different from the data, the device The cost of will also increase.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a mechanism for enhancing the confidentiality of data and preventing falsification of the access history of the data storage device at a low cost.

  In the data storage device according to the present invention, when the data is accessed from the outside, the control unit generates an access history and writes it in the storage medium. Then, a message authentication code (MAC, Message Authentication Code) generated from the access history using the generation key is added to the access history.

  In addition, a key for authenticating the access source, a management server authentication key for the management server that permits change of configuration information, and a message authentication code generation key are stored in a tamper resistant module in the data storage device.

  It is desirable to manage the initial setting / update of these encryption keys by an external organization other than the user or system administrator.

  With the above configuration, it is possible to forcibly leave an access history on the same storage medium as that of the data body, which is difficult to falsify or erase even by using physical means or by an internal person. This makes it difficult for a user or a system administrator who has a legitimate access right to the data to modify the access history, and prevents unauthorized access. In addition, by storing various authentication keys in the tamper-resistant module, it is difficult to selectively tamper and destroy only the access history even using physical means, and it can be implemented in a storage device at low cost. Enable.

  In this data storage device, even if an external computer or the like does not have a function for recording access history by software, the control unit of the data storage device compulsorily stores the access history in a form that cannot be falsified. .

  In addition, by forcibly recording the access history in the same storage medium as the data body, it is difficult to selectively erase or destroy only the access history even if a physical method is used. The risk of loss can be reduced. In addition, the log storage process is performed by the disk unit's control unit, so it can be integrated with the access control function (for example, allowing access only to a computer with a specific ID) and the data encryption function, reducing costs. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the mechanism which raises the confidentiality of data and prevents falsification of the access history of a data storage device can be provided at low cost.

  Embodiments according to the present invention will be described below with reference to FIGS.

Embodiment 1
A first embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is an internal configuration diagram of a data storage device according to the first embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of the data structure of the access history 32.
FIG. 3 is a flowchart showing a procedure when accessing from an external computer in the first embodiment of the present invention.
FIG. 4 is a diagram for explaining the authentication of the management server 7.

  The data storage device of the present embodiment will be described by taking a magnetic disk device as an example, but the present invention is applicable to other storage devices such as flash memory sticks, memory cards of various standards, IC cards, and the like.

  The data storage device 1 according to the present embodiment includes a control unit 2 and a storage medium 3. The control unit 2 includes a network interface 201, a CPU 202, a disk head control unit 203, a RAM (anytime read / write memory) 204, a ROM (read only memory) 205, and an EEPROM (electrically erasable memory) 206. Here, the case of the network interface 201 has been described as an interface with the outside, but other interfaces such as a port interface such as a USB, a bus interface, and the like may be used.

  The EEPROM 206 stores a client authentication key 601, a management server authentication key 602, a MAC generation key 603, a data encryption key 604, and access history format information 605.

  The client authentication key 601 is a key for authenticating a client that is an access source computer that accesses the data storage device 1. A client authentication method using the client authentication key 601 will be described later.

  The management server authentication key 602 is a key for authenticating the management server 602 that can change the configuration information of the data storage device 1. The configuration information of the data storage device 1 and the management server 602 will be described later.

  The MAC generation key 603 is a key for generating a message authentication code (MAC) 33.

  The data encryption key 604 is a key for encrypting external data and writing it to the storage medium 3.

  The storage medium 3 stores data 31, access history 32, and access record message authentication code (MAC) 33.

  The format of the access history 32 will be described next.

The message authentication code 33 is stored by encrypting a part of the record of the access history 32 or data extracted by a hash function or the like with the message authentication code generation key 603 stored in the EEPROM. Code. (This technology is described in Non-Patent Document 1 above.)
Therefore, when the access history 32 is tampered with, the message authentication code 33 is different from the result of re-encryption with the message authentication code generation key 603, so that unauthorized tampering can be found.

  When the access history 32 or the like is to be audited, the audit command is transmitted to this storage device, so that the result can be output and checked.

  Next, the data structure of the access history 32 will be described with reference to FIG.

  Each time an access to a file recorded on the storage medium occurs, one record is added to the access history 32. Each record of the access history 32 includes fields of transaction ID 321, access source ID 322, access source application 323, access source user name 324, file name 325, access time 326, and access type 327.

  The transaction ID 321 is a time-sequential number assigned to the data access processing accepted by the disk device.

  The access source ID 322 is the ID of the access source computer.

  The application 323 is the name and code of the access source application software.

  The user 324 is a user ID or a user name of a user who is using the access source computer and application software.

  The file name 325 is the name of the file to be accessed, and the time 326 is the time when the transaction occurred or ended.

  The access type 327 records the type of access such as reading, writing, creating, and erasing the file.

  Next, the operation of the data storage device 1 when an access to a file stored in the data storage device 1 occurs from the access source computer will be described with reference to FIGS. 1 and 3. It is assumed that the data 31 stored in the storage medium 3 is encrypted with the data encryption key 604.

  When the data storage device 1 receives an access request via the network interface 201 (501), it authenticates the access request source. Authentication of the access request source is performed by, for example, confirming that the access request source has a common encryption key distributed in advance. In this method, for example, the data storage device 1 sends a secret random number to the access request source, and the access request source computer encrypts this random number using the encryption key shared with the disk device and returns it to the disk device. The disk device is realized by decrypting it using the same encryption key and confirming that it matches the original random number.

  If authentication of the access request source fails, the data storage device 1 makes a non-permission response (510). If the authentication of the access request source is successful, the data storage device 1 subsequently verifies the access right (503). The access right verification 503 compares the type of access request with the authority of the access request source, and checks whether the computer, application, and user of the access request source have an appropriate access right. Types of access rights include data read permission, data read / write permission, and configuration information read permission.

  If the access right verification fails, the data storage device 1 makes a non-permission response (510).

  When the access right verification is successful, the disk control unit 2 generates an access record (504), further generates a message authentication code 33 for the access record (505), and stores the access history 32 and the message authentication code 33. Write to the access history recording area and the message authentication code recording area 33 of the medium 3.

  Subsequently, the control unit 2 of the data storage device 1 reads access target data from the storage medium 3 (507), decrypts the data with the data encryption key 604 (508), and transmits the data to the access request source. (509).

  It should be noted that the access history can be generated and recorded in the same manner even when the access right verification fails. In this case, information indicating access right mismatch is recorded in the access type 327.

  Next, the authentication of the management server 7 and the change of the configuration information of the data storage device 1 will be described with reference to FIG.

  The management server 7 is a server that can change the configuration information of the data storage device 1.

  Here, the configuration information of the data storage device 1 is information for assuring the validity of data input / output and the validity of the access history. Specifically, the access history format 605, the client authentication method ( Whether or not the client authentication key 601 is used, the format, etc.), the management server authentication method (whether the management server authentication key 602 is used, the format, etc.), the data encryption method (the use of the data encryption key 604, Format), a message authentication method of the access history (format of the message generation key 603, etc.), etc.

  The management server 7 has a management server authentication key 701, and setting or changing the access history recording method of the disk device 2 by the management server 7 is performed by rewriting the control information related to the above in the disk device 2.

  At this time, the data storage device 1 authenticates the management server 7 using the management server authentication key 602 and permits the change of the configuration information only to the management server registered in advance in the disk device.

  In the example shown in FIG. 4, the change of the configuration information is permitted only when the authentication by the management server authentication key 602 and the authentication of the management server ID 604 are performed in the data storage device 1 and both are recognized. I have decided.

  Thereby, it is possible to prevent an attack that illegally manipulates the configuration information to change the stored content of the access record or stop the storage of the access record.

  Authentication of the management server ID 604 is performed by transmitting its own ID from the management server 7 and confirming whether or not it matches.

  When authentication using the management server authentication key is performed by a secret key encryption method, the management server authentication key 701 included in the management server 7 and the management server authentication key 602 included in the data storage device 1 use a common encryption key.

  Authentication using the management server authentication key can also be performed using a public key cryptosystem. At this time, the management server authentication key 603 of the data storage device 1 may be a public key encryption public key, and the management server authentication key 702 of the management server 7 may be a corresponding private key. For example, the data storage device 1 transmits random number data to the management server 7. The management server 7 encrypts the data with the management server authentication key 702 that is a secret key, and sends it back to the data storage device 1. The data storage device 1 only has to verify whether it matches the original random number data by decrypting it with the management server authentication key 603 that is a public key.

  This method has an advantage that the key management of the data storage device 1 becomes easy.

[Embodiment 2]
Hereinafter, a second embodiment according to the present invention will be described with reference to FIGS. 5 and 6.
FIG. 5 is an internal block diagram of the data storage device according to the second embodiment of the present invention.
FIG. 6 is a flowchart showing a procedure when accessing from an external computer in the second embodiment of the present invention.

  The control unit 2 of the disk device includes a tamper resistant module 207. The tamper resistant module 207 includes a microcontroller 208, a random number generation period 209, a RAM 210, a ROM 212, and an EEPROM 212. The EEPROM 212 includes a client authentication key 601, a management server authentication key 602, a MAC generation key 603, a data encryption key 604, and an access. History format information 605 is stored. The tamper resistant module 207 is a security module such as an LSI for an IC card, for example, and can read internal data even by using a physical method such as reading a current value or electromagnetic wave and measuring it. It is a device that has been tamper-resistant, such as the inside being encrypted so that it is difficult.

  Next, the operation of the data storage device 1 when an access to a file stored in the data storage device 1 occurs from the access source computer will be described with reference to FIG.

  When receiving an access request via the network interface 201 (521), the data storage device 1 authenticates the access request source (522). The access request source is authenticated by, for example, confirming that the access request source has a common encryption key distributed in advance. For example, the tamper resistant module 207 generates a random number using the random number generator 209, and the CPU 202 of the control unit reads the generated random number data and sends it to the access request source. The access request source computer encrypts this random number using the encryption key shared with the disk device and returns it to the disk device. The CPU 202 of the control unit sends this to the tamper resistant module 207, and the tamper resistant module 207 is realized by decrypting it using the same encryption key and confirming that it matches the original random number. When the authentication is successful, the tamper resistant module 207 notifies the CPU 202 of the control unit.

  If the authentication of the access request source fails, the data storage device 1 makes a non-permission response.

  If the authentication of the access request source is successful, the data storage device 1 subsequently verifies the access right. The access right collation 503 collates the type of access request with the authority of the access request source, and checks whether the access request source computer, application, or user has an appropriate access right. This inspection method is exactly the same as in the first embodiment. If the access right verification fails, the data storage device 1 makes a non-permission response. When the access right verification is successful, the disk control unit 2 generates an access record (524), sends the access record to the tamper resistant module 207, and the tamper resistant module 207 uses the MAC generation key 604 to send the message of the access record. An authentication code 33 is generated. The control unit 2 writes the access history 32 and the message authentication code 33 in the access history recording area and the message authentication code recording area 33 of the storage medium 3.

  It is also possible to configure so that an access history is generated and recorded in the same manner when access source authentication fails.

  Next, the control unit 2 of the data storage device 1 reads the access target data from the storage medium 3 (507), performs decryption with the data encryption key (508), and transmits the data to the access request source (509). .

  When the configuration information of the data storage device 1 is changed by the management server, the disk device 2 authenticates the management server. In the second embodiment, this authentication process is performed by the tamper resistant module 207. It is.

  According to this embodiment, the client authentication key 601, management server authentication key 603, MAC generation key 603, data encryption key 604, and access history format information 605 are all stored in the tamper resistant module 207. Further, the access source authentication process, the management server authentication process, and the access record message authentication code generation process are executed inside the tamper resistant module 207. This makes it even more difficult to read these keys using physical methods.

It is an internal block diagram of the data storage device which concerns on 1st embodiment of this invention. 6 is a diagram illustrating an example of a data structure of an access history 32. FIG. It is a flowchart which shows the procedure at the time of accessing from the external computer in 1st embodiment of this invention. It is a figure explaining the authentication of the management server. It is an internal block diagram of the data storage device which concerns on 2nd embodiment of this invention. It is a flowchart which shows the procedure when accessing from an external computer in 2nd embodiment of this invention.

Claims (11)

In a data storage device having an input / output interface with the outside, a storage medium for reading and writing data, and a control unit for controlling input / output to the storage medium,
The data storage device, wherein the control unit generates an input / output access history via the external input / output interface, and records the access history in the storage medium.   The data storage device according to claim 1, wherein the control unit generates additional information for guaranteeing the validity of the access history and records the additional information on the storage medium.   The additional information for guaranteeing the legitimacy of the access history is a message authentication code attached to each access history, and has a storage unit for storing key data for generating the message authentication code. The data storage device according to claim 2.   2. The data storage device according to claim 1, wherein a computer that changes the configuration information for guaranteeing the validity of the external data access and the validity of the access history is authenticated.   5. The computer authentication for changing the configuration information for guaranteeing the validity of the external data access and the validity of the access history is performed by using the identification number of the registered computer. The data storage device described.   The data storage device and the computer that changes the configuration information have a common encryption key, and the data storage device authenticates the computer that changes the configuration information by using the encryption key. Item 5. A data storage device according to item 4. The computer that changes the configuration information for ensuring the validity of the external data access and the validity of the access history has a secret key for public key cryptography,
A data storage device having a public key corresponding to the secret key, and a computer that changes the configuration information by checking the validity of the secret key of the computer that changes the configuration information using the public key 5. The data storage device according to claim 4, wherein authentication is performed.   4. The data storage device according to claim 3, further comprising a tamper resistant module, wherein key data for generating the message authentication code is stored in the tamper resistant module.   5. The data storage device according to claim 4, further comprising a tamper-resistant module, wherein a computer that changes the configuration information is authenticated in the tamper-resistant module.   The data storage device according to claim 1, further comprising a tamper resistant module, wherein the validity of data access from the outside is determined in the tamper resistant module. The tamper resistant module has a random number generation device and an authentication key, and the randomness data generated by the random number generation device and the authentication key are used to determine the validity of a computer that accesses the data storage device. The data storage device according to claim 10.

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