JPS6216425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Technical Field of the Invention The present invention relates to a data processing system using a volume content security protection system in which the content of a file is stored on an external storage device volume. In addition to maintaining the contents of the label in an encrypted state, a program is created on the central processing unit that encrypts and decrypts the contents of the volume label, so that even if the volume is set in another system, the contents cannot be decrypted. The present invention relates to a volume content security protection system that prevents data from being stored.

(B) Technical background and problems Various methods have been devised to protect the confidentiality of files. However, in these systems, the contents of the file could be decoded by setting the entire external storage volume containing the file in another system. In other words, even if a certain center (data processing system) imposes restrictions on the reading of files on a volume and prohibits third parties from reading them, the entire volume cannot be read under the restrictions. By going to another system that does not have the above file and setting it, it was possible for a third party to read the contents of the file.

Therefore, for security reasons, when the volume is removed from the system,
It was essential to handle the volume with care, such as storing it in a safe.

(C) Object and Structure of the Invention The present invention aims to solve the above-mentioned problems, and by encrypting the contents of the volume label on the medium, it is possible to solve the problem by encrypting the contents of the volume label on the medium. The purpose is to make it virtually impossible to decipher. Therefore, the volume content security protection method of the present invention is
It is equipped with an external storage device volume in which the addresses of a plurality of files are stored on a volume content table, and the addresses of the volume content table can be specified by the contents of the volume label on the medium, and the volume Prior to accessing the files in the medium, the central processing unit reads the contents of the volume label on the medium and maintains the contents of the volume contents table in the main storage based on the contents of the volume label on the medium. , a data processing system configured to access each of the files based on the contents of the volume content table, the processing device comprising a mask processing program for encrypting volume label contents in an unencrypted state; , at least an unmasking processing program that decrypts the contents of the volume label in the encrypted state, and the content of the volume label in the encrypted state is encrypted by the central processing unit by the mask processing program. is written to the volume label on the medium, and at the same time, in the process prior to the access, the contents of the volume label on the medium are read, decrypted by the unmasking processing program, and written in the volume contents table. The present invention is characterized in that the contents are held on the main storage device, and the external storage device volume is accessed while the contents of the volume label on the medium are held in an encrypted state. This will be explained below with reference to the drawings.

(D) Embodiment of the Invention FIG. 1 is a block diagram showing an embodiment of the security system according to the present invention, focusing on the processing mode of the external storage device and the central processing unit. A flowchart illustrating aspects of processing is shown.

In FIG. 1, 1 is a central processing unit, which is represented by a main storage device, 2 is an external storage device (or its volume),
3P, 3Q, 3R, ...... are files stored on the volume, and 4 is a volume content table that is stored on the volume and contains information necessary to decipher the contents of the files, such as the starting address of each of the above files. The item holding information, 5, is a volume label on the medium according to the present invention, which is stored on the volume and holds information necessary to access the table 4, such as the start address of the volume content table 4. It represents what you are doing. Further, 6 is a volume/label reading processing program, and is a volume/label reading processing program for reading the volume/label on the medium.
It performs processing to read the contents of label 5 onto the main memory (MEM). 7 is volume
This is a label update processing program, which is used when updating the contents of the volume label 5 on the medium. Reference numeral 8 is a volume label writing processing program, which performs processing for writing the contents of the volume label 5 on the medium.
Reference numeral 9 is a mask processing program that performs processing to encrypt the contents of a given volume label in an unencrypted state. Reference numeral 10 is an unmasking processing program that decrypts the encrypted volume label contents. Furthermore, 11 is a data buffer area, 12
is the volume label content (A) in the given unencrypted state, 13 is the volume label content M(A) encrypted by the mask processing program, 1
4 is the encrypted volume label content M(A) read from the volume label 5 on the medium;
15 is the volume label content M(B) that has been updated and encrypted, and 16 is the volume label content A that has been unencrypted by the unmasking processing program.
It represents.

In the present invention, when the central processing unit processes a volume as shown in the figure, (i) initialization of the volume and (ii) mounting of the volume are performed to protect the security of the file. That's what I do. That is, when initializing the volume, the address of the volume contents table (VTOC) 4 is written into the contents of the volume label 5 on the illustrated medium. In addition, when mounting a volume, the central processing unit reads the contents of the volume label 5 on the medium on the mounted volume, and displays the volume label 5 on the medium.
The address of the volume contents table 4 is determined based on the contents of the table 4, and the contents of the table 4 are read and held in the main memory (MEM). Then, when accessing the file 3 from now on, the retained contents are used.

Hereinafter, FIG. 1 will be explained with reference to FIGS. 2 to 4.

FIG. 2 shows the processing at the time of volume initialization. Upon initialization, the central processing unit 1 stores the standard volume label contents (A) 1 in a non-encrypted state.
2 is prepared and written on the volume label 5 on the medium, but in the case of the present invention, the processing shown in the shaded area in FIG. 2 is added. That is, the mask processing program 9 transforms the standard volume label content (A) 12 into the encrypted volume label content (M(A)) 13. Then, the encrypted volume label contents 13 are written to the volume label 5 on the medium by the volume label writing processing program 8.

FIG. 3 shows the process when updating the volume label. When updating, the central processing unit 1
The contents of the volume label 5 on the medium on the volume 2 are read by a volume label reading processing program 6. If this content is in an encrypted state, the volume/label update processing program 7 calls the unmasking processing program 10 and requests the content 14 to be unencrypted. - Update the content of the label to, for example, content B, and then call the mask processing program 9 to encrypt content B to create encrypted volume label content (M(B)) 15. Then, the content (M(B)) 15 is written to the volume label 5 on the medium by the volume label writing processing program 8.

In this way, the volume label 5 on the medium
If the content of is encrypted,
The contents of the volume label 5 on the medium are updated in encrypted form.

FIG. 4 shows the processing at the time of mounting. When a volume is newly mounted on the system, the central processing unit 1 activates the volume label reading processing program 6 to mount the volume 1 on the system.
The contents of the volume label 5 on the medium are read.
If this content is encrypted,
The contents 14 are unencrypted by the unmasking program 10 to obtain the volume label contents 16 in an unencrypted state. Then, based on the volume label contents 16, the central processing unit 1 reads and holds the contents of the volume contents table 4 on the main storage device, and when accessing the file 3 from now on, the central processing unit 1 reads the contents of the volume contents table 4 and stores it in the main storage device. Extracts information such as whether to do so or not from the content.

As mentioned above, in the case of the present invention, the volume 2
The contents of the volume label 5 on the medium are written in an encrypted state. For this reason, even if a third party attempts to decrypt the contents of the file and sets the volume 2 itself in another system, the contents of the file cannot be decrypted. That is, the above-described mounting process is performed in the other system as well, and the contents of the volume label 5 on the medium of the volume are read into the main storage device. At this time, the other system cannot decipher the content (M(A)) of the volume label on the medium, and therefore cannot read or decipher the content of the volume content table 4. For this purpose, files 3P, 3Q,...
...etc. cannot be read. Of course, the central processing unit 1 shown in FIG. 1 is a system in which the contents of the volume label 5 on the medium are generated by the mask processing program 9, so the contents of the volume label 5 on the medium read at the time of mounting are can be unencrypted and the files can be accessed as described above. However, in this system, a third party may access the file 3 in an undesired manner.
The data is protected so that it cannot be read, so no secrets will be leaked through this line. Further, the volume label contents 16 shown in FIG. 1 will not be undesirably dumped to the outside by a third party.

(E) Effects of the Invention As explained above, according to the present invention, even if a third party steals the entire volume, mounts it on another system, and attempts to read it, the volume content table 4 cannot be grasped after all. The file cannot be decrypted. Of course, it is possible for a third party to copy the entire contents of volume 2 or print out the contents on a printout, for example, under another system. However, even if this is done, the volume content table 4 cannot be grasped unless the encryption processing key is known.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a security protection system according to an embodiment of the present invention, focusing on the processing mode between an external storage device and a central processing unit, and FIGS. 2 to 4 are flowcharts for explaining the above processing mode. Show chart. In the figure, 1 is the central processing unit, 2 is the external storage device (or its volume), 3 is the file, 4 is the volume content table, 5 is the volume label on the medium, 9 is the mask processing program, and 10 is the unmask processing program. It represents.

Claims (1)

[Claims] 1 An external storage device is provided with an external storage device volume configured such that addresses of a plurality of files are stored on a volume content table and the address of the volume content table can be specified by the contents of a volume label on the medium, Prior to accessing a file in a volume, the central processing unit reads the contents of the volume label on the medium and maintains the contents of the volume contents table in the main storage based on the contents of the volume label on the medium. In a data processing system configured to access each of the files based on the contents of the volume content table, the processing device includes a mask processing program that encrypts the volume label contents that are in an unencrypted state. and an unmasking processing program that decrypts the contents of the volume label in the encrypted state, and the central processing unit is configured to unmask the volume label in the encrypted state that has been encrypted by the mask processing program. The content is written to the volume label on the medium, and the volume label on the medium is written in the process prior to the access.
The contents of the label are read and decrypted by the unmasking processing program, and the contents of the volume contents table are held on the main storage device, and the contents of the volume label on the medium are held in an encrypted state. A volume content security protection method characterized in that the volume of the external storage device is accessed in the process.