JP4133215B2 - Data division method, data restoration method, and program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for managing divided data, and more particularly to a technique that enables data restoration without managing a storage location of divided data.
[0002]
[Prior art]
When important confidential data (hereinafter referred to as original data) is stored, there is a threat of loss, destruction, theft and privacy infringement. These problems cannot be solved by simply encrypting data that should be kept secret. Also, making multiple copies in preparation for loss or destruction increases the risk of theft.
[0003]
As a means for solving such a problem, there is a secret sharing method (see Non-Patent Document 1). In the threshold secret sharing method (see Non-Patent Document 2), which is one of secret sharing methods, the original data S can be obtained by encoding the original data S into n pieces of divided data and collecting any k pieces of divided data. Can be restored, but S cannot be restored with any k−1 pieces of divided data.
[0004]
Accordingly, even if up to k-1 pieces of divided data are stolen, the original data does not leak, and even if up to nk pieces of divided data are lost or destroyed, the original data S can be restored.
[0005]
In the prior art, management information used for restoring the divided data is managed in one place. When dividing the data, the divided data is read based on the management information and the original data is reconstructed. (See Patent Document 1).
[0006]
[Patent Document 1]
JP 2000-172548 A [Non-Patent Document 1]
Shamir, A "How to Share a Secret" Comm. Assoc. Comput. Mach., Vol.22, no.11, pp.612-613 (Nov.1979)
[Non-Patent Document 2]
Hiroshi Yamamoto: “(k, L, n) threshold secret sharing system” IEICE Transactions, vol.J68-A, no.9, pp.945-952 (Sep.1985)
[0007]
[Problems to be solved by the invention]
However, even if the original data is divided and stored, if the control information and control functions for the divided data are collectively managed as described above, all of the divided data is stored when the information regarding the storage location is stolen among the control information. Confidentiality is weakened by clarifying the location. Further, there is a problem that even if the divided data itself is safe, the original data cannot be recovered when the control information necessary for restoring the original data or the control function is destroyed or lost.
[0008]
The present invention has been made in view of the above points, and it is an object of the present invention to provide a data management technique capable of restoring original data from divided data without collectively managing data storage locations and the like. And
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
[0010]
The present invention relates to a data dividing method in which a data dividing device divides data, wherein an input unit in the data dividing device inputs a data dividing instruction, and a dividing unit in the data dividing device performs data by a predetermined method. And generating divided data, and the dividing unit generates a divided element including divided data for each divided data, and the divided element includes data including divided data and a keyword. And a method part including a message processing part.
[0011]
According to the present invention, since the division element having the function of performing restoration processing in an autonomous distributed manner is generated, the division element can be distributed and stored without separately managing the storage location, and security can be improved.
[0012]
The division elements are classified into a plurality of hierarchies, and the data portion of the division element belonging to a certain hierarchy is common in the hierarchy below the hierarchy when there is a common keyword in the hierarchy and a hierarchy below the hierarchy. The divided elements belonging to the highest hierarchy further include the number of divided data necessary for restoration and a divided data restoration unit.
[0013]
Further, the present invention can be configured as a program that causes a computer to execute the above method.
[0014]
Further, the present invention is a method in which a plurality of storage devices that store divided data restore the original data from the divided data, and each storage device has a division element that is a program including the divided data, The division elements in the storage device are classified into a plurality of hierarchies, the division elements belonging to a certain hierarchy have a common keyword in the hierarchy, and the storage device that stores the division elements belonging to one hierarchy has the one hierarchy. A storage device that transmits a keyword of a lower hierarchy to another division element and stores a division element belonging to the lower hierarchy having the keyword of the lower hierarchy, and stores the position information in the division element belonging to the one hierarchy. The storage device that transmits and stores the divided elements belonging to the one layer requests the divided data from the storage device that has transmitted the position information, acquires the divided data, and uses the acquired divided data. To restore the data.
[0015]
According to the present invention, data can be restored autonomously in cooperation with each storage device in this way.
[0016]
Further, the present invention is a program for causing a computer to execute a process of restoring original data from divided data classified into a plurality of hierarchies, and the program is common to the hierarchy below the hierarchy to which the divided data belongs. The program has a keyword, and the program requests the divided data from the computer having the keyword based on the procedure for transmitting the keyword to the computer storing other divided data and the position information received from the computer having the keyword. And causing the computer to execute a procedure for restoring the original data using the divided data received from the computer having the keyword.
[0017]
The above program can be realized as an object in object-oriented technology, for example, and if such an object including divided data is distributed to each storage device, highly confidential distributed data management can be performed. Become.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0019]
FIG. 1 is a diagram illustrating an example of a system configuration in the present embodiment. As shown in the figure, this system has a terminal 1 and a storage center 2 for storing divided data, and these are connected to a network 3.
[0020]
The terminal 1 includes a dividing unit 11, an authentication unit 12, and a message processing unit 13. Each storage center stores division elements including division data.
[0021]
Next, processing from the terminal 1 until the original data is divided and the divided elements are stored in the storage center 2 will be described with reference to the flowchart of FIG.
[0022]
First, the user instructs the dividing unit 11 to divide and store the original data via the input unit such as a keyboard or a mouse of the terminal 1 (step 1). Next, the dividing unit 11 divides the original data into a plurality of pieces (step 2). In this embodiment, it is divided into six. The division is performed using, for example, a threshold secret sharing method, and the divided data is generated so that the original data can be restored from a certain number among the divided numbers, and the original data is unknown from the smaller number.
[0023]
Subsequently, the dividing unit generates a dividing element including divided data as shown in FIG. Dividing elements are divided into a plurality of hierarchies. In the present embodiment, it is divided into two layers of level 1 and level 2, and two level 1 division elements and four level 2 division elements are generated. In general, a level i division element instructs processing to a level (i + 1) division element.
[0024]
Each division element includes data portions 4 and 6 and method portions 5 and 7. The data part has a keyword at its own hierarchy level and a keyword at the next lower hierarchy level, and the keyword at each hierarchy level is a keyword common to the division elements of the hierarchy. In the example shown in FIG. 3, the level 1 keyword is a keyword common to the level 1 division elements, and the level 2 keyword is a keyword common to the level 2 division elements. These keywords are set so as to be unique throughout the network in which the present invention is implemented.
[0025]
Each division element has two levels of level 1 and level 2 in this embodiment, and no level 3 division element is generated. Therefore, the level 2 division element does not have a level 3 keyword. When generating level 3 division elements, level 3 keywords are set in the level 2 division elements. The same applies when the number of hierarchies is further increased.
[0026]
The data section 4 in the level 1 division element holds the number of divided data necessary for restoration, and this number is referred to when the data is restored.
[0027]
The method units 5 and 7 in each division element are a collection of various processing functions. In the present embodiment, the method unit includes a message processing unit and an authentication unit. Further, the level 1 division element has a division data restoration unit. The function of each part is as follows.
[0028]
The message processing unit has a function of exchanging information with other division elements or terminals. The authentication unit has a function of performing mutual authentication with other division elements or with the authentication unit of the terminal. The divided data restoration unit has a function of restoring original data from the divided data. In this example, since the restoration of the original data is performed by collecting the divided data that requires the level 1 division element, the level 2 division element does not have a division data restoration unit.
[0029]
When the division unit 11 in the terminal finishes the generation of the above-described division elements, each division element is transmitted to the storage center (step 4 in FIG. 2), and the server stores each division element. In this example, six division elements are stored in different storage centers so that the original data can be restored even if some of the division elements are destroyed due to a disaster or the like. In the present invention, the storage location of each divided element is not managed. Finally, the terminal 1 notifies the user of the level 1 keyword (step 5). This level 1 keyword is used when obtaining stored data.
[0030]
Next, a procedure when the terminal 1 acquires stored data will be described with reference to a flowchart shown in FIG.
[0031]
First, the user presents the level 1 keyword to the message processing unit 13 of the terminal and instructs “restoration of original data” (step 11). Upon receiving the instruction, the message processing unit 13 of the terminal simultaneously transmits the level 1 keyword to all the division elements of all the storage centers (step 12).
[0032]
The message processing unit of each division element matches the received keyword with the keyword of the same level as its own level (level 1 keyword for level 1 division element, level 2 keyword for level 2 division element) In this case, its own position information is returned to the message transmission source (step 13).
[0033]
The location information means information that can uniquely identify the storage location of each division element as data on a computer network. For example, an IP address can be used as location information, and a plurality of division elements are stored in the same server. Can specify the division element using the IP address and the port number. In this example, there are two division elements with the same keyword, level 1 division element 1 and level 1 division element 2. If these division elements are not destroyed by a disaster or the like, level 1 division element 1 and level 1 division element 2 returns its position information to the message processing unit 13 of the terminal.
[0034]
When the message processing unit 13 of the terminal receives a plurality of pieces of position information, the message processing unit 13 selects one of them and instructs the restoration of the original data (step 14). In this example, the level 1 division element 1 is selected, and “original data restoration” is instructed.
[0035]
The message processing unit of the level 1 division element 1 first authenticates with the terminal by the authentication unit of the level 1 division element 1 to prevent illegal division data acquisition and restoration. Thereafter, the message processing unit of the level 1 division element 1 simultaneously transmits the level 2 keyword to all the division elements of all the storage centers (step 15).
[0036]
The message processing unit of each division element matches the received keyword with the keyword of the same level as its own level (level 1 keyword for level 1 division element, level 2 keyword for level 2 division element) In this case, its own position information is returned to the level 1 division element 1 that is the message transmission source (step 16).
[0037]
In this example, there are four division elements (level 2 division element 1, level 2 division element 2, level 2 division element 3 and level 2 division element 4) that match the keywords, and if the division elements are not destroyed by a disaster or the like. The four division elements return their position information to the level 1 division element 1.
[0038]
In this example, there are two layers, but in the case of three layers, the level 2 division element acquires the position information of the level 3 division element using the level 3 keyword in the same manner as described above, The position information is combined and returned to the level 1 division element 1. The same applies to four or more layers.
[0039]
The message processing unit of the level 1 division element 1 adds 1 to the number of received position information because it itself has one piece of divided data, and the number of pieces of divided data necessary for restoration of the data portion. If the number is equal to or greater than the “number of divided data necessary for restoration”, “divided data transmission” is instructed to each divided element that has returned position information (step 17).
[0040]
Each division element (level 2 division element 1, level 2 division element 2, level 2 division element 3, level 2 division element 4) that has received the instruction first communicates with level 1 division element 1 using the authentication unit. Authenticate each other to prevent illegal division data acquisition and restoration. Thereafter, the divided data held by itself is transmitted to the level 1 division element 1 (step 18).
[0041]
In this example, 2 hierarchies are used, but in the case of 3 hierarchies, the level 2 subdivision element instructs “partition data transmission” to the level 3 subdivision element that returned position information to the level 2 subdivision element To do. Receiving the instruction, the level 3 division element first authenticates with the level 2 division element to prevent acquisition or restoration of illegal division data. Thereafter, the divided data held by itself is transmitted to the level 2 divided element. The level 2 division element that has acquired the division data of the level 3 division element combines it with its own division data and transmits it to the level 1 division element 1. The same applies to four or more layers.
[0042]
In the level 1 division element 1, the division data restoration unit of the level 1 division element 1 restores the original data using the division data transmitted from each division element and the division data held by itself (step 19). This restoration process is performed in a tamper-resistant area (a protected area where internal data cannot be referenced or altered, usually implemented with special hardware) to prevent unauthorized access to data during or after restoration. can do. Finally, the level 1 division element 1 returns the restored original data to the terminal 1 (step 20).
[0043]
Now, the “simultaneous transmission” of step 12 in the above procedure can be specifically realized as follows.
[0044]
In a TCP / IP network, using a broadcast function of an IP packet, a specific lP address is broadcast to all terminals connected to the LAN, and a terminal that matches the IP address assigned to itself is ARP (address resolution protocol) that returns the MAC address (unique physical address assigned to a network device) is known, and this technique can also be used in this embodiment.
[0045]
However, the simultaneous transmission performed as described above cannot be applied to a large-scale network connected by many routers such as the Internet because data is not transmitted across networks connected by routers.
[0046]
Therefore, as an example of a method for realizing simultaneous transmission between the terminal and each storage center via the Internet, there is the following.
(I) The terminal and each storage center are connected via the Internet via the IP-VPN device.
[0047]
The function of the IP-VPN device allows communication as if the terminal and each storage center are connected by a LAN. Therefore, the above-mentioned IP packet broadcast function allows the communication between the target terminal and each storage center. Simultaneous transmission is possible.
(Ii) By setting destination information which is a transmission destination of simultaneous transmission in a router on the Internet, simultaneous transmission between a target terminal and each storage center is enabled (multicast technology).
(Iii) Software having a function of performing simultaneous transmission to the target terminal and each storage center server is added to the terminal and each storage center server. This software manages destination information that is a transmission destination of simultaneous transmission, thereby enabling simultaneous transmission between the target terminal and the server of each storage center.
[0048]
The terminal and storage center in the present embodiment can be realized by using a computer in which a program for executing the above processing procedure is installed. Further, the program can be stored and distributed in a recording medium such as a CD-ROM, or can be distributed via a network.
[0049]
Each division element in the present invention has a data processing function. Such a function can be realized by using, for example, an object-oriented technique. In this case, the division element can be realized as an object including a data part and a method part. In this specification, an object in the object-oriented software technique is also referred to as a program.
[0050]
When the object-oriented technology is used, software that interprets the object-oriented program in the division element is installed in the terminal and the computer of the storage center.
[0051]
Further, it is possible to adopt a configuration in which the functions in the terminal shown in FIG. 1 are placed on a server in a separate processing center and the processing center requests the division and restoration processing from the terminal. Further, in the configuration of FIG. 1, it is possible to provide a configuration in which only the terminal division unit 11 is provided in another server or the like, only the division is requested to the server, and restoration is performed by the terminal.
[0052]
The present invention is not limited to the above-described embodiments, and various modifications and applications can be made within the scope of the claims.
[0053]
【The invention's effect】
As described above, in the present invention, control information and control function for restoring data in an autonomous and distributed manner are distributed and stored as divided elements together with the divided data, and the storage location of the divided data is not managed. Therefore, it is possible to solve the conventional problems in the case where the storage locations of the divided data are collectively managed, and to improve the confidentiality of the data. Further, since there is no information regarding the storage location of the divided data, even if the divided data is stolen illegally, the storage location of the other divided data cannot be known.
[0054]
In the above embodiment, the data division is performed using the secret sharing method, but the data may be divided without using the secret sharing method. In such a case, all the divided data can be acquired. In this case, the data can be completely restored, but since the divided data and the control function are distributed, the conventional problem in the case of collectively managing the storage location of the divided data can be solved.
[0055]
Furthermore, according to the present invention, in order to manage the control function for each divided data, a restoration function for a specific division method is provided for each divided storage of the original data, and additional functions such as a search function and a data processing function are provided. It can be added and held.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a system configuration in the present embodiment.
FIG. 2 is a flowchart showing processing until original data is divided and divided elements are stored in a storage center.
FIG. 3 is a diagram illustrating an example of a division element.
FIG. 4 is a diagram illustrating a procedure when a terminal acquires stored data.
[Explanation of symbols]
1 Terminal 2 Storage center 3 Network 4 6 Data part 5 7 Method part

Claims (9)

A data dividing method in which a data dividing device divides data,
An input unit in the data dividing device, inputting a data dividing instruction;
A dividing unit in the data dividing device, dividing the data by a predetermined method, and generating divided data;
The division unit includes a step of generating a division element including division data for each division data,
The dividing element, possess a data portion including the division data and keywords, and methods section including a message processing unit, and
The division elements are classified into a plurality of hierarchies, and the division elements belonging to a certain hierarchy include a common keyword in the hierarchy and, if there is a hierarchy below the hierarchy, a common keyword in the hierarchy below the hierarchy. Have
The division element belonging to the highest hierarchy is stored in the computer that stores the division element.
Sending the keywords in the hierarchy below the top hierarchy to a plurality of divided data storage computers storing other divided elements;
A procedure for requesting divided data from the divided data storage computer having the keyword based on the position information received from the divided data storage computer having the keyword;
A data division method, comprising: a program for executing a procedure for restoring original data using divided data received from a divided data storage computer having the keyword . The data division method according to claim 1 , wherein the division element belonging to the highest hierarchy further includes a number of division data necessary for restoration and a division data restoration unit. The data division method according to claim 1 or 2 , wherein the predetermined method is a secret sharing method. A data division processing program for causing a computer to execute data division processing ,
A procedure for inputting data division instructions;
A procedure of dividing the data by a predetermined method and generating divided data;
A data division processing program for causing a computer to execute a procedure for generating a divided element including divided data for each piece of divided data,
The dividing element, possess a data portion including the division data and keywords, and methods section including a message processing unit, and
The division elements are classified into a plurality of hierarchies, and the division elements belonging to a certain hierarchy include a common keyword in the hierarchy and, if there is a hierarchy below the hierarchy, a common keyword in the hierarchy below the hierarchy. Have
The division element belonging to the highest hierarchy is sent to the division data storage computer that stores the division element.
Sending the keywords in the hierarchy below the top hierarchy to a plurality of divided data storage computers storing other divided elements;
A procedure for requesting divided data from the divided data storage computer having the keyword based on the position information received from the divided data storage computer having the keyword;
A data division processing program for executing a procedure for restoring original data using divided data received from a divided data storage computer having the keyword . The data division processing program according to claim 4 , wherein the division element belonging to the highest hierarchy further includes a number of division data necessary for restoration and a division data restoration unit. The data division processing program according to claim 4 or 5 , wherein the predetermined method is a secret sharing method. A plurality of storage devices for storing divided data is a method for restoring original data from divided data,
Each storage device has a division element that is a program including divided data. The division elements in a plurality of storage devices are classified into a plurality of hierarchies, and the division elements belonging to a certain hierarchy have a common keyword in the hierarchy. ,
A storage device that stores a division element belonging to one hierarchy sends a keyword of a hierarchy below the one hierarchy to another division element,
A storage device that stores the division element belonging to the lower hierarchy having the keyword of the lower hierarchy transmits the position information to the division element belonging to the one hierarchy,
The storage device that stores the divided elements belonging to the one hierarchy requests the divided data from the storage device that has transmitted the position information, acquires the divided data, and restores the original data using the acquired divided data. A data restoration method characterized by the above. A program for causing a computer to execute processing for restoring original data from divided data classified into a plurality of layers,
The program has a keyword common to the hierarchy below the hierarchy to which the divided data belongs,
The program
A procedure for transmitting the keyword to a computer storing other divided data, a procedure for requesting the divided data from the computer having the keyword based on the positional information received from the computer having the keyword,
A program for causing a computer to execute a procedure for restoring original data using divided data received from a computer having the keyword. The divided data is data divided by a secret sharing method,
The program has a procedure for requesting divided data when the number of divided data necessary for restoration is included, and the number of position information received from the computer having the keyword plus 1 is equal to or greater than the number of divided data. The program according to claim 8 , which is executed by a computer.

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