JP7384028B2 - Data storage systems, data storage devices, computer programs and data storage methods - Google Patents

Description

The present invention relates to a data storage system, a data storage device, a computer program, and a data storage method in which a plurality of devices connected via a network store data in a distributed manner.

In recent years, computer performance has improved and network communication speeds have increased, and by storing data using multiple computers connected via a network, the reliability and robustness of data storage can be improved. Various technologies are being researched and developed. For example, in a distributed ledger technology called blockchain, multiple computers store a database that is a chain of data collections called blocks, and hash technology is used to prevent tampering with the data contained in the blocks. It's getting more difficult.

Patent Document 1 proposes an electronic transaction device that stores transaction data using blockchain technology for the purpose of improving data confidentiality and transaction fairness regarding electronic data transactions. This electronic transaction device verifies the validity of electronic data between a terminal on the transmitting side and a terminal on the receiving side of the electronic data.

JP 2019-106639 Publication

Computers that store blockchains need to perform arithmetic processing such as calculating hash values, so they are required to have high computing power. Additionally, since new blocks are added to the blockchain every moment, computers need a storage device with sufficient capacity to store these blocks.

The present invention has been made in view of the above circumstances, and its purpose is to provide a data storage system that is expected to realize distributed storage of data using relatively low-performance computers. An object of the present invention is to provide a data storage device, a computer program, and a data storage method.

A data storage system according to the present invention is a data storage system in which a plurality of devices connected via a network store data in a distributed manner, and a data generation source device included in the plurality of devices is a data storage system that stores data in a distributed manner. an identification information generation unit that generates identification information that identifies data; a data division unit that divides the data into a plurality of pieces; and a restoration information that restores the plurality of data divided by the data division unit to the original data. A restoration information generation unit generates, and the data division unit adds identification information generated by the identification information generation unit and restoration information generated by the restoration information generation unit to a plurality of data divided by the data division unit, and each of the data is different from the other. A receiving side device that is included in the plurality of devices and that receives the divided data has a data transmitting unit that transmits data to the device, and a receiving device that is included in the plurality of devices and that receives the divided data. a condition determination unit; a storage unit that stores the data together with the identification information and the restoration information when the division termination condition determination unit determines that the division termination condition is satisfied; a data division unit that divides the data into a plurality of pieces when it is determined that the division end condition is not satisfied; and a restoration unit that generates restoration information for restoring the plurality of data divided by the data division unit to the original data. a data transmitting unit that attaches the identification information and the restoration information generated by the restoration information generation unit to the plurality of data divided by the data division unit and transmits them to different other devices. have

Further, in the data storage system according to the present invention, the data generating device has an encryption unit that encrypts data to be stored, and the data dividing unit of the data generating device is encrypted by the encryption unit. Split the formatted data.

Further, in the data storage system according to the present invention, the data generating device and the receiving device each include an error correction information generating unit that generates error correction information for each of the plurality of divided data, and the data generating device The data transmitting units of the source device and the receiving device each attach error correction information to the plurality of divided data and transmit them.

Further, in the data storage system according to the present invention, the data division section determines the number of data divisions according to the number of destination devices to which the data transmission section transmits data.

Further, in the data storage system according to the present invention, the data transmission section determines a destination of the data according to the number of data divided by the data division section.

Further, in the data storage system according to the present invention, the division end condition is that the size of the divided data is smaller than a threshold value, or the size of the divided data is attached to identification information and restoration information attached to the data. is smaller than the size of

Further, in the data storage system according to the present invention, when the receiving side device receives a confirmation request as to whether or not data specifying the identification information is stored, it is possible to check whether the receiving device stores data related to the identification information. and a response unit that responds to the source of the confirmation request when the storage determination unit determines that the data is stored.

Further, in the data storage system according to the present invention, a data restoration device included in the plurality of devices includes a data collection unit that collects the divided data based on a response from the receiving device; and a restoration section that restores the plurality of divided data collected by the division into original data.

Further, in the data storage system according to the present invention, the response unit of the receiving device transmits access information for accessing the own device and the restoration information stored in the storage unit to the sender of the confirmation request. The data collection unit of the data restoration device collects the data based on the access information, and the restoration unit of the data restoration device restores the data based on the restoration information.

Further, the data storage device according to the present invention is a data storage device that communicates with other devices via a network, and which divides data received from the other device to determine whether or not a division end condition is satisfied. When the division termination condition determining unit and the division termination condition determination unit determine that the division termination condition is satisfied, the data received from the other device is converted into the original data using identification information for identifying the data and the data received from the other device. a storage unit that stores the data together with restoration information for restoration; a data division unit that divides the data into a plurality of pieces when the division end condition determination unit determines that the division end condition is not satisfied; and the data division unit a restoration information generation section that generates restoration information for restoring the plurality of data divided into original data; and a restoration information generation section that generates the identification information and the restoration information generation section for the plurality of data divided by the data division section. and a data transmitting unit that attaches restoration information generated by the data transmitter and transmits the data to different other devices.

Further, the computer program according to the present invention causes a computer that communicates with another device via a network to determine whether or not a division end condition is satisfied for data received from another device, and sets the division end condition to the computer that communicates with another device via a network. If it is determined that the division termination condition is satisfied, the data received from the other device is stored together with identification information for identifying the data and restoration information for restoring the data to the original data, and the division end condition is not satisfied. If it is determined that the data is the same, the data is divided into multiple pieces of data, restoration information for restoring the divided data to the original data is generated, and the identification information and the generated restoration information are added to the multiple pieces of divided data. The information is attached and a process of transmitting to different other devices is executed.

Further, the data storage method according to the present invention is a data storage method in which data is distributed and stored in a plurality of devices connected via a network, wherein a data generation source device included in the plurality of devices is a storage device. Generate identification information for identifying target data, divide the data into multiple pieces, generate restoration information for restoring the multiple pieces of divided data to the original data, and generate identification information for the multiple pieces of divided data. Whether the receiving device that attaches information and restoration information and transmits the divided data to different other devices, and that is included in the plurality of devices and receives the divided data, satisfies the division termination condition for the received data. If it is determined that the division termination condition is satisfied, the data is stored together with the identification information and the restoration information, and if it is determined that the division termination condition is not satisfied, the data is divided into multiple pieces. and generates restoration information for restoring the divided plurality of data to the original data, attaches the identification information and the generated restoration information to the divided plurality of data, and transmits each to a different other device. .

In the present invention, a plurality of devices connected via a network store data in a distributed manner. At least one of the plurality of devices serves as a data generation source device that generates data to be stored. The data generation source device divides the data to be stored into a plurality of pieces, and generates restoration information for restoring the divided data to the original data. The data generating device attaches restoration information and identification information for identifying the original data to the divided data, and transmits the divided data to different devices.
A receiving device that receives the divided data determines whether or not the received data satisfies a predetermined division end condition, and stores the received data if the division end condition is satisfied. If the division termination condition is not met, the receiving device further divides the received data, generates restoration information, attaches the restoration information and identification information to the divided data, and transmits them to different other devices. .
As a result, in the data storage system according to the present invention, data is repeatedly divided and transmitted, and the divided data is stored in a device that has determined that the division end condition is satisfied. Each device only needs to divide and transmit data, and sophisticated processing is not required. Furthermore, since the data stored in one device is obtained by dividing the original data, there is no need for each device to have a large-capacity storage section.

Further, in the present invention, the data generating device encrypts the original data to be stored, divides the encrypted data, and transmits the divided data to another device. The receiving device that receives the divided data does not need to further encrypt the encrypted divided data. Data confidentiality can be increased by encrypting and dividing data.

Further, in the present invention, the data generating device and the receiving device generate error correction information for each of the divided data, attach the error correction information to each data, and transmit the data to another device. Thereby, the device that has received the divided data can correct and store errors in the data that occurred during transmission and reception based on the error correction information. Furthermore, even if some of the plurality of divided data are missing when restoring divided data, the missing parts can be corrected based on the error correction information and the original data can be restored.

Further, in the present invention, the number of data divisions is determined depending on the number of devices to which the data is transmitted. This allows data to be divided appropriately depending on the number of other devices that can transmit data.

Further, in the present invention, data is divided into, for example, a predetermined number of divisions, and another device to which the data is to be transmitted is determined according to the number of divided data. Thereby, it is possible to determine a data transmission destination suitable for the number of data divisions.

In addition, in the present invention, the size of divided data is smaller than a predetermined threshold, or the size of divided data is smaller than the size of identification information and restoration information attached to this data. This is the division end condition for determining whether to end data division and store this data. As a result, division is repeatedly performed until the size of the divided data is reduced to a certain extent, and the data whose size is reduced to a certain extent is stored in a plurality of devices.

Further, in the present invention, a request to confirm whether or not data with identification information specified is stored is sent from the device that restores the divided data to each device on the network. The device that receives this determines whether it has stored the data with the identification information specified in the confirmation request, and if it has stored the data, it sends the request to the device that sent the confirmation request. Make a response. Thereby, the device that restores data can grasp which of the multiple devices in the network stores the multiple pieces of divided data based on the responses from each device.

Further, in the present invention, the data restoration device collects the divided data based on a response from the device storing the data, and restores the collected plurality of divided data to the original data. This allows devices that require data to acquire, restore, and utilize data that is distributed and stored in multiple devices.

Further, in the present invention, the device that has stored the divided data, in response to a confirmation request from the device that restores the data, provides access information for accessing its own device and information for restoring the divided data. Send as a response to the device that sent the confirmation request. Thereby, the device for restoring data can communicate with the device that has stored the data based on the access information and can acquire the divided data from this device. Furthermore, the data restoration device can restore the collected data to the original data based on the restoration information.

According to the present invention, it is expected that distributed storage of data can be realized using relatively low-performance computers.

1 is a schematic diagram showing a configuration example of a data storage system according to the present embodiment. FIG. 2 is a block diagram showing the configuration of a node device according to the present embodiment. FIG. 3 is a schematic diagram for explaining data division processing performed by the node device according to the present embodiment. FIG. 3 is a schematic diagram for explaining data re-division processing performed by the node device according to the present embodiment. FIG. 3 is a schematic diagram for explaining data restoration processing performed in the data storage system according to the present embodiment. FIG. 3 is a schematic diagram for explaining data restoration processing performed in the data storage system according to the present embodiment. 1 is a block diagram showing the configuration of a data restoration device 2 according to the present embodiment. FIG. 3 is a flowchart showing the procedure of data division processing performed by the node device according to the present embodiment. 3 is a flowchart showing the procedure of data division processing performed by the node device according to the present embodiment. 3 is a flowchart showing the procedure of data restoration processing performed by the node device according to the present embodiment. 3 is a flowchart showing the procedure of data restoration processing performed by the node device according to the present embodiment. 3 is a flowchart showing the procedure of data restoration processing performed by the data restoration device according to the present embodiment.

A specific example of a privilege management system according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all changes within the meaning and scope equivalent to the scope of the claims.

<System configuration>
FIG. 1 is a schematic diagram showing a configuration example of a data storage system according to the present embodiment. In the data storage system according to this embodiment, a plurality of node devices 1 constitute a peer-to-peer type network. In this figure, the node devices 1 are shown by circular symbols, and the communication paths between the node devices 1 are shown by solid lines or broken lines. Further, in the following, when a plurality of node devices 1 are to be distinguished, they will be described with different symbols, such as node devices 1a to 1j.

In the data storage system according to the present embodiment, data to be stored is divided into a plurality of pieces, and some of the node apparatuses 1 of the plurality of node apparatuses 1 included in this system individually store the divided data. do. An overview of the data storage method performed by the data storage system according to the present embodiment will be briefly explained using the example shown in FIG. In this example, one node device 1a among the plurality of node devices 1 included in the data storage system is an issuer (generator) device of the original data to be stored. For example, the node device 1a divides the original data into three pieces of divided data 1 to 3. The node device 1a selects three node devices 1b to 1c as destinations of divided data 1 to 3, transmits divided data 1 to the node device 1b, transmits divided data 2 to the node device 1c, and sends divided data 3 to the node device 1c. is transmitted to the node device 1d.

The node devices 1b to 1d that have received the divided data 1 to 3 further divide the received divided data 1 to 3. In this example, each of the node devices 1b to 1d divides the received divided data 1 to 3 into two, and transmits the redivided new divided data to the other node devices 1. For example, the node device 1b transmits divided data to the node devices 1e and 1f, the node device 1c transmits divided data to the node devices 1g and 1h, and the node device 1d transmits divided data to the node devices 1i and 1j.

In this example, it is assumed that the node devices 1e to 1j that have received the most divided data have decided not to perform any further division. Each of the node devices 1e to 1j stores the received divided data in its own storage unit. As a result, the original data generated by the node device 1a is finally divided into six pieces, and the six pieces of divided data are stored in the storage units of the six node devices 1e to 1j. The data stored in each of the node devices 1e to 1j is different data. When the original data is needed, the node device 1a collects and restores the data divided from the six node devices 1e to 1j. Note that details of processing such as data division and restoration will be described later.

Further, in this embodiment, it is assumed that the node devices 1a to 1d that have divided data and sent it to other node devices 1 do not store the divided data or the original data thereof. However, data transmitted by the node devices 1a to 1d to other node devices 1 may be stored. As a result, the same data is stored in a plurality of node devices 1, and resistance to data loss due to failure of the node device 1 that stored divided data can be increased.

FIG. 2 is a block diagram showing the configuration of the node device 1 according to this embodiment. The node device 1 constituting the data storage system according to the present embodiment includes, for example, a high-performance information processing device such as a personal computer or a server computer, and a so-called IOT (Internet of Things) device such as a sensor device or an actuator device. A variety of information processing devices can be used, including low-function information processing devices called ``devices''. The node device 1 according to the present embodiment may be any device as long as it has a function of storing data, a function of communicating with other devices, and a function of performing calculations necessary for data division. Good too.

The node device 1 according to the present embodiment includes a processing section (processor) 11, a storage section (storage) 12, a communication section (transceiver) 13, and the like. The processing unit 11 is configured using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The processing unit 11 reads and executes the program 12a stored in the storage unit 12 to perform various processes related to data storage, such as data division processing and data restoration processing.

The storage unit 12 is configured using, for example, a magnetic storage device such as a hard disk, or a memory element such as a flash memory or an EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 12 is preferably non-volatile, but may be configured using a volatile memory element such as SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). The storage unit 12 stores various programs executed by the processing unit 11 and various data necessary for processing by the processing unit 11. In this embodiment, the storage unit 12 stores a program 12a executed by the processing unit 11, and an encryption key 12b and a destination table 12c as data necessary for processing. The storage unit 12 is also provided with a divided data storage unit 12d that stores divided data.

In this embodiment, the program 12a is provided in a form recorded on a recording medium 99 such as a memory card or an optical disk, and the node device 1 reads the program 12a from the recording medium 99 and stores it in the storage unit 12. However, the program 12a may be written into the storage unit 12, for example, during the manufacturing stage of the node device 1. Further, for example, the program 12a may be distributed by a remote server device or the like, and the node device 1 may acquire it through communication and store it in the storage unit 12. For example, the program 12a may be recorded on the recording medium 99 and read by a writing device and written into the storage unit 12 of the node device 1. The program 12a may be provided in the form of distribution via a network, or may be provided in the form of being recorded on the recording medium 99.

The encryption key 12b is information used to encrypt and decrypt data. When the node device 1 according to the present embodiment performs processing as a device that generates original data to be stored (node device 1a of the original data issuer in FIG. 1), the node device 1 performs encryption on the original data before division. Encryption processing is performed using the key 12b, and the encrypted original data is divided. From this point on, the node devices 1 (node devices 1b to 1d in FIG. 1) that receive divided data and re-divide the data, and the node devices 1 that receive and store divided data (node devices 1e in FIG. 1) ~1j), encryption and decryption processing is not performed. Therefore, the node device 1 that has no possibility of becoming the original data issuer does not need to store the encryption key 12b in the storage unit 12, and does not need to have the function of performing encryption and decryption processing.

The destination table 12c is a table that stores information regarding other node devices 1 that can be selected as destinations of divided data. The destination table 12c is a table in which, for example, a device ID for identifying the node device 1 is associated with network address information for accessing the node device 1. However, the destination table 12c does not need to store information about all the node devices 1 that make up the data storage system, but only needs to store information about at least one node device 1. For example, in FIG. 1, the node device 1a only needs to store at least information regarding the node devices 1b to 1d in the destination table 12c, and information regarding the node devices 1e to 1j does not need to be stored in the destination table 12c. .

The divided data storage unit 12d is a storage area for storing divided data received from other node devices 1. However, it is not necessary to provide a dedicated area for storing divided data in the storage unit 12, and an empty area of the storage unit 12 may be used as the divided data storage unit 12d.

The communication unit 13 communicates with other node devices 1 via a network N including the Internet, a wireless LAN, a mobile phone communication network, and the like. The communication unit 13 transmits data given from the processing unit 11 to other node devices 1, and also provides data received from other node devices 1 to the processing unit 11.

Note that the storage unit 12 may be an external storage device connected to the node device 1. Further, the node device 1 may be a multicomputer including a plurality of computers, or may be a virtual machine virtually constructed by software. Further, the node device 1 is not limited to the above configuration, and may include, for example, a reading unit that reads information stored in a portable storage medium, an input unit that accepts operation input, a display unit that displays an image, etc. .

Furthermore, the processing unit 11 of the node device 1 according to the present embodiment has a data division processing unit 11a, a data restoration processing unit 11b, and a program 12a stored in the storage unit 12. The response processing unit 11c and the like are realized as software-like functional units. Note that these functional units are functional units related to processes such as data division, storage, and restoration, and illustrations and explanations of functional units related to processes other than these will be omitted.

The data division processing unit 11a performs a process of dividing original data to be stored that is generated by the own device or data received from another node device 1. The data division processing unit 11a transmits a plurality of divided data with various additional information attached thereto to other node devices 1.

The data restoration processing unit 11b performs a process of restoring divided data stored in a plurality of other node devices 1 to original data. The data restoration processing unit 11b first inquires of the other node devices 1 included in the data storage system to find out which node device 1 stores the divided data. The data restoration processing unit 11b performs restoration to the original data by acquiring and combining the divided data from the node device 1 that stores the divided data.

When the response processing unit 11c receives an inquiry from another node device 1 as to whether divided data is stored, the response processing unit 11c performs a process of transmitting a response to this inquiry. The response processing unit 11c determines whether the divided data related to the inquiry is stored in the divided data storage unit 12d of the storage unit 22, and if it is determined that the divided data is stored, the response processing unit 11c A response to the effect that the divided data is stored is sent to No. 1. In the present embodiment, the response processing unit 11c does not transmit a response indicating that the divided data is not stored to the node device 1 that is the inquiry source.

<Data division processing>
FIG. 3 is a schematic diagram for explaining data division processing performed by the node device 1 according to the present embodiment. The process shown in FIG. 3 is a process performed by the node device 1 (node device 1a in FIG. 1) of the original data issuer. The node device 1 of the original data issuer performs processing for generating a data ID for uniquely identifying the data in the system, for the original data stored in the data storage system according to the present embodiment. The node device 1 generates a data ID by combining, for example, a device ID predetermined for the node device itself and date and time information at that time. The device ID is stored in the storage unit 12 in advance, for example. Further, for example, the node device 1 has a function of measuring time, year, month, day, etc. based on the clock signal generated by the clock signal generation circuit, and acquires date and time information using this function. In this example, an ID of "XYZ" is generated as the data ID.

Further, the node device 1 uses the encryption key 12b stored in the storage unit 12 to encrypt the original data. As the encryption algorithm performed by the node device 1, various algorithms such as DES (Data Encryption Standard) or AES (Advanced Encryption Standard) using a common key, or RSA or elliptic curve cryptography using a public key can be adopted. . Note that, as described above, the node device 1 that has no possibility of becoming the original data issuer does not need to have the function of performing encryption and decryption processing.

After encrypting the original data, the node device 1 performs a process of dividing the original data into a plurality of pieces of data. In the illustrated example, the node device 1 divides the original data into three parts: "data 1", "data 2", and "data 3". Although the data is divided into three parts in this example, the present invention is not limited to this, and the number of data divisions may be two or less or four or more. The number of divisions of data by the node device 1 may be a predetermined fixed number, or may be variable depending on the communication status and the like. When the number of data divisions is made variable, the node device 1 performs processing to determine the number of data divisions before dividing the data. Whether the number of data divisions is fixed or variable may be different for each node device 1 of the data storage system.

An example of a method for determining the number of divisions when the number of divisions of data is made variable will be described. However, the method for determining the number of data divisions is not limited to this, and any method may be adopted. For example, in this embodiment, the maximum number of data divisions is preset to, for example, "5". The node device 1 periodically exchanges information with other node devices 1 registered in the destination table 12c, and updates the free space of the storage unit 12 of the other node device 1 and the other node device 1. Investigate the communication speed etc. between Based on this investigation result, the node device 1 determines which other node device 1 is suitable as the destination of the divided data. The node device 1 determines the number of data divisions to be "5" when the number of other node devices 1 suitable for transmission destinations of the divided data is greater than or equal to the maximum value of the number of divisions "5". If the number of other node devices 1 suitable for the transmission destination of the divided data is less than the maximum value "5", the node device 1 divides the data by the number of other node devices 1 determined to be suitable for the transmission destination. Decide on the number. However, the maximum value of the number of divisions does not have to be set.

When the number of data divisions is a fixed number, there is a possibility that the number of other node devices 1 suitable for transmission destinations of the divided data is less than this number of divisions. In such a case, the node device 1 may transmit two or more pieces of divided data to one node device 1, or may reduce the number of divided data. Further, instead of setting the number of data divisions to be a fixed number, the size of the data after division may be fixed, and the node device 1 may determine the number of divisions so that the data after division has a fixed size. Note that in this embodiment, the number of data divisions may include "1". That is, the node device 1 may transmit data to another node device 1 without dividing the data.

Further, in the illustrated example, the node device 1 divides the encrypted original data into pieces of predetermined size in order from the beginning, and creates three pieces of divided data, data 1 to 3. In this case, after determining the number of data divisions, the node device 1 determines the size of each piece of data after division by dividing the size of the data to be divided by the number of divisions, and starts from the beginning of the data to be divided. Divide the data by dividing the data by size. However, any method may be adopted for the data division method by the node device 1. For example, when dividing data to be divided into two, the node device 1 may divide the data into even bits and odd bits.

Next, the node device 1 generates restoration information for restoring the divided data to the original data. The restoration information includes, for example, information indicating how many times the divided data was generated from the original original data, and which part of the data immediately before division the divided data corresponds to. information indicating. In the illustrated example, information expressed as a fraction indicates which part of the data immediately before the division the divided data corresponds to. In other words, the restoration information for data 1 = 1/3 indicates that the data immediately before division is divided into three parts using the denominator in fractional notation, and corresponds to the first part from the beginning of the three divisions. The numerator is expressed as a fraction. In addition, as will be described later with reference to FIG. 4, in this example, the number of times the divided data is generated from the first original data is indicated by the above-mentioned fraction notation. For example, when the data 1 in FIG. 3 is further divided into two, the restoration information of the divided data is expressed as 1/3 and 1/2.

The node device 1 assigns a common data ID and individual restoration information to each piece of divided data, for example, as header information. Further, the node device 1 performs a process of adding an error correction code for correcting these errors to the data ID, restoration information, and divided data. As a method for generating an error correction code by the node device 1, various code generation methods such as a Hamming code, a cyclic code, or a convolutional code may be adopted. Since the error correction code generation method is an existing technology, detailed explanation will be omitted. Note that in this embodiment, the data ID, the restoration information, and the divided data are subject to error correction, but the present invention is not limited to this, and it is sufficient that at least the divided data is subject to error correction.

The node device 1 divides the original data into a plurality of pieces of data according to the above-described procedure, and sends each piece of divided data with a data ID, restoration information, and error correction code to different other node devices 1. After the data transmission is completed, the node device 1 may erase the original data, divided data, etc. from its own register, memory, storage unit 12, etc. The data transmitted by the node device 1 is received by a plurality of other node devices 1, and the data is re-divided or stored in the other node devices 1.

FIG. 4 is a schematic diagram for explaining data re-division processing performed by the node device 1 according to the present embodiment. The process shown in FIG. 4 is a process performed by the node device 1 (node devices 1b to 1d in FIG. 1) that has received the divided data. Further, the received data shown in FIG. 4 is the data divided as data 1 in FIG. The node device 1 that has received the data divided by another node device 1 first determines whether to re-divide or store the data. In the present embodiment, in the node device 1, division termination conditions for terminating data division are determined in advance and stored in the storage unit 12. The node device 1 determines whether to end the division and store the data or to perform further division by determining whether the division end condition is satisfied for the received data.

In this embodiment, the division termination condition is that the data size of the divided data (received data excluding data ID, restoration information, and error correction code) included in received data is smaller than a predetermined threshold. do. If the node device 1 determines that the data size of the divided data is smaller than the threshold and satisfies the division end condition, it stores the received data in the divided data storage section 12d of the storage section 12. If the node device 1 determines that the data size of the divided data is equal to or larger than the threshold and the division end condition is not satisfied, the node device 1 further divides the received data. The example shown in FIG. 4 is a case where the received data is further divided.

The node device 1 that has decided to perform re-segmentation regards the divided data excluding the data ID and restoration information included in the received data and the error correction code portion as the original data to be re-segmented. The node device 1 divides the data, generates restoration information, adds a data ID and restoration information, and adds an error correction code to this original data using the same procedure as described above. Here, the node device 1 assigns the same data ID as the data ID assigned to the received data to each piece of divided data. Further, the node device 1 generates new restoration information by adding information regarding the current division to the restoration information attached to the received data.

In the illustrated example, the node device 1 divides the original data into two parts, "data 1-1" and "data 1-2." The ID assigned to each divided data is the same ID=XYZ as the received data. The restoration information attached to each divided data is such that 1/2 or 2/2 information regarding the current division is added to the restoration information = 1/3 attached to the received data. The node device 1 generates and attaches error correction codes to the data ID, new restoration information, and new divided data, and transmits them to other node devices 1, respectively.

In this way, the divided data is propagated through the network and re-divided by each node device 1, and finally the divided data is distributed to the plurality of node devices 1 that have been determined to satisfy the division end condition. is memorized.

<Data restoration process>
5 and 6 are schematic diagrams for explaining data restoration processing performed in the data storage system according to this embodiment. In the data storage system according to the present embodiment, the restoration process of divided data is carried out through cooperation between the node device 1a of the original data issuer and the data restoration device 2, which is different from the node device 1 of the data storage system. It will be done. However, the data restoration process may be performed solely by the node device 1a of the original data issuer. The data restoration device 2 according to the present embodiment is configured using, for example, an information processing device such as a server computer. The data restoration device 2 is preferably a computer with higher performance than the node device 1, but is not limited to this.

In this embodiment, a process for reading data that is divided and stored in a plurality of node devices 1 included in the data storage system is started from the node device 1 (1a) that is the generation source of this data. The node device 1a transmits a confirmation request message specifying the data ID assigned to the required data to the other node device 1. For example, the confirmation request message is a message that includes information such as a command instructing to send a response when data with a specified data ID is stored, and a data ID specifying the target data. . In this example, the node device 1a sends a confirmation request message to three node devices 1b to 1d with which it can communicate.

The node device 1 that has received the confirmation request message determines whether or not it stores the data with the data ID specified in the confirmation request message, and if it determines that it has stored the data, it transmits the confirmation request message. A response message is sent to the original node device 1 notifying that the specified data is stored. The response message includes restoration information attached to the data with the designated data ID and address information indicating the location of the device itself in the network. For example, the response message is a message that includes information indicating that it is a response to the confirmation request message, and the above-mentioned restoration information and address information.

Further, the node device 1 that has received the confirmation request message further transfers this confirmation request message to another node device 1. As a result, a confirmation request message sent from one node device 1 to several node devices 1 is forwarded by the node device 1 that received it, and more node devices 1 included in the data storage system are forwarded. transmitted to. By repeating the transfer, the confirmation request message is received by the node device 1 that stores the divided data. In response to receiving the confirmation request message, the node device 1 storing the divided data transmits a response message including restoration information and address information.

In the example shown in FIG. 5, six node devices 1e to 1j store divided data, and each of these node devices 1e to 1j sends a response message to the node device 1a, which is the source of the confirmation request message. There is. As a result, the node device 1a that is the sender of the confirmation request message, that is, the node device 1a of the original data issuer, receives restoration information regarding the divided data of the original data and the addresses of the node devices 1e to 1j that store the divided data. Information can be collected. Note that the response message may be directly transmitted from the source node devices 1e to 1j to the destination node device 1a, or from the node devices 1e to 1j to the other node devices 1b to 1d. may be sent via.

In the data storage system according to this embodiment, an error correction code is assigned to the divided data. Therefore, even if some of the plurality of divided data obtained by dividing the original data are missing and all the divided data are not collected, the original data can be restored as long as a certain amount of divided data is collected. The node device 1 that sent the confirmation request message receives a response message from another node device 1 that stores the divided data, and collects restoration information and address information regarding the number of divided data that can be restored. Once completed, the collected restoration information and address information are transmitted to the data restoration device 2, and a data restoration process using these information is requested.

How many pieces of divided data are needed to restore the original data depends on the bit length of the error correction code, algorithm, etc. When the node device 1 is able to collect restoration information and address information for a predetermined number (for example, 85% of the total) of divided data, it requests the data restoration device 2 to perform data restoration processing. However, since the information collected at this point may not be able to be restored, the node device 1 may transmit information that can be additionally collected after this point to the data restoration device 2 as additional information.

The data restoration device 2 that has been requested to perform data restoration processing determines whether the original data can be restored using the divided data whose location is known at that time, based on the restoration information from the node device 1. Determine whether The data restoration device 2 examines the plural pieces of restoration information obtained from the node device 1, and checks how much of the data divided at the final stage of division is complete, thereby reducing the divided data at this final stage into one piece. Determine whether the divided data at the previous stage can be restored. Next, the data restoration device 2 examines the restoration information regarding the divided data that has been determined to be able to be restored to the previous stage, and checks how much of the data that was divided at this stage is complete. It is determined whether the data can be restored to the divided data of the previous stage. The data restoration device 2 sequentially determines whether restoration is possible starting from the final stage, and finally determines whether restoration to the original data is possible. If it is determined that restoration to the original data is not possible, the data restoration device 2 waits until it receives additional information from the node device 1.

If it is determined that restoration to the original data is possible, the data restoration device 2 sends the divided data to the node device 1 storing the divided data based on the address information given together with the restoration information. Request transmission. At this time, the data restoration device 2 transmits a divided data transmission request message specifying the data ID to the node device 1. This transmission request message may be directly transmitted from the data restoration device 2 to each node device 1, or may be transmitted indirectly via another node device 1.

The node device 1 storing the divided data receives the transmission request message from the data restoration device 2, and stores the divided data of the data ID specified in the received transmission request message from the divided data storage section 12d of the storage section 12. The data is read and transmitted to the requesting data restoration device 2. In the example shown in FIG. 6, divided data is transmitted to the data restoration device 2 from six node devices 1e to 1j. This divided data may be directly transmitted from each node device 1e to 1j to the data restoration device 2, or may be transmitted indirectly via another node device 1.

The data restoration device 2 that has received the divided data from the plurality of node devices 1 restores the divided data to the original data based on the restoration information. Data restoration is performed by sequentially restoring from the final stage divided data to the previous divided data, and finally restoring to the original single data, in the same way as determining whether restoration is possible as described above. It will be done. In each stage of restoration, the data restoration device 2 combines a plurality of pieces of divided data in the order indicated in the restoration information, and performs error correction using an error correction code as necessary to restore the data before division. Restore. The data restoration device 2 finally transmits the restored piece of original data to the node device 1 that requested the restoration.

The restored original data sent from the data restoration device 2 to the node device 1 is the original data in an encrypted state. The node device 1 that has received the restored original data from the data restoration device 2 uses the encryption key 12b stored in the storage unit 12 to decrypt the original data. This allows the node device 1 to obtain unencrypted original data.

FIG. 7 is a block diagram showing the configuration of the data restoration device 2 according to this embodiment. The data restoration device 2 according to the present embodiment includes a processing section (processor) 21, a storage section (storage) 22, a communication section (transceiver) 23, and the like. The processing unit 21 is configured using an arithmetic processing device such as a CPU or an MPU. The processing unit 21 reads and executes a program 22a stored in the storage unit 22 to perform various processes related to data restoration.

The storage unit 22 is configured using, for example, a magnetic storage device such as a hard disk. The storage unit 22 stores various programs executed by the processing unit 21 and various data necessary for processing by the processing unit 21. In this embodiment, the storage unit 22 stores a program 22a executed by the processing unit 21. In this embodiment, the program 22a is provided in a form recorded on a recording medium 98 such as a memory card or an optical disk, and the data restoration device 2 reads the program 22a from the recording medium 98 and stores it in the storage unit 22. However, the program 22a may be written into the storage unit 22, for example, during the manufacturing stage of the data restoration device 2. Further, for example, the program 22a may be distributed by a remote server device or the like, and the data restoration device 2 may acquire it through communication and store it in the storage unit 22. For example, the program 22a may be recorded on the recording medium 98 and read by a writing device and written into the storage unit 22 of the data restoration device 2. The program 22a may be provided in the form of distribution via a network, or may be provided in the form of being recorded on the recording medium 98.

The communication unit 23 communicates with the node device 1 via a network N including the Internet, a wireless LAN, a mobile phone communication network, and the like. The communication unit 23 transmits data provided from the processing unit 21 to the node device 1 and also provides data received from the node device 1 to the processing unit 21.

Note that the storage unit 22 may be an external storage device connected to the data restoration device 2. Further, the data restoration device 2 may be a multi-computer including a plurality of computers, or may be a virtual machine virtually constructed by software. Furthermore, the data restoration device 2 is not limited to the above configuration, and may include, for example, a reading unit that reads information stored in a portable storage medium, an input unit that accepts operation input, a display unit that displays images, etc. good.

In addition, the processing unit 21 of the data restoration device 2 according to the present embodiment has a software-like function such as the data restoration processing unit 21a by the processing unit 21 reading out and executing the program 22a stored in the storage unit 22. realized as a division. In response to a request from the node device 1, the data restoration processing unit 21a collects divided data stored in a distributed manner in a plurality of node devices 1, and performs a process of restoring the collected plurality of divided data to the original data. conduct.

<Flowchart>
FIG. 8 is a flowchart showing the procedure of data division processing performed by the node device 1 according to the present embodiment. Note that the process shown in this figure is a process performed by the node device 1 of the original data issuer. The data division processing unit 11a of the processing unit 11 of the node device 1 according to the present embodiment searches for another node device 1 suitable as a destination of the divided data (step S1). At this time, the data division processing unit 11a communicates with other node devices 1 registered in the destination table 12c stored in the storage unit 12, and determines the free capacity of the other node devices 1 and other nodes. Information such as the communication speed with the node device 1 is collected, and the node device 1 that has a free capacity equal to or higher than a predetermined capacity and is capable of communicating at a predetermined speed or higher is divided data. It is assumed that the node device 1 is suitable for the transmission destination.

The data division processing unit 11a determines the number of divisions of the original data based on the search result in step S1 (step S2). The data division processing unit 11a generates a data ID that uniquely identifies the original data (step S3). For example, the data division processing unit 11a generates a data ID by combining a device ID predetermined for its own device and date and time information at that time. The data division processing unit 11a encrypts the original data using the encryption key 12b stored in advance in the storage unit 12 (step S4).

The data division processing unit 11a divides the original data encrypted in step S4 into the number of divisions determined in step S2 (step S5). The data division processing unit 11a generates restoration information for each divided data (step S6). The data division processing unit 11a assigns the common data ID generated in step S3 and the individual restoration information generated in step S6 to the divided data divided in step S5 (step S7 ).

The data division processing unit 11a assigns error correction codes for correcting errors in the divided data, data ID, and restoration information, respectively (step S8). The data division processing unit 11a transmits a plurality of divided data to which a data ID, restoration information, and an error correction code are respectively added to a plurality of different node devices 1 (step S9), and ends the process.

FIG. 9 is a flowchart showing the procedure of data division processing performed by the node device 1 according to the present embodiment. Note that the process shown in this figure is a process performed by the node device 1 that has received data divided and transmitted by another node device 1. The data division processing unit 11a of the processing unit 11 of the node device 1 according to the present embodiment determines whether divided data has been received from another node device 1 through the communication unit 13 (step S21). If divided data has not been received (S21: NO), the data division processing unit 11a waits until it receives divided data from another node device 1.

If divided data is received from another node device 1 (S21: YES), the data division processing unit 11a determines whether the received divided data satisfies the division end condition (Step S22). The data division processing unit 11a can make a determination, for example, using the fact that the size of the received divided data is smaller than a predetermined threshold as a division end condition. If the division end condition is satisfied (S22: YES), the data division processing section 11a stores the received data in the divided data storage section 12d of the storage section 12 (step S23), and ends the process.

If the division condition is not satisfied (S22: NO), the data division processing unit 11a searches for another node device 1 suitable as a transmission destination of the divided data (Step S24). The data division processing unit 11a determines the number of divisions of the original data based on the search result in step S24 (step S25). The data division processing unit 11a divides the divided data received from another node device 1 into the number of divisions determined in step S25 (step S26). The data division processing unit 11a generates restoration information for each divided data (step S27). The data division processing unit 11a updates the divided data divided in step S26 with the data ID assigned to the divided data received from another node device 1 and the individual restoration information generated in step S27. (Step S28).

The data division processing unit 11a assigns error correction codes for correcting errors in the divided data, data ID, and restoration information, respectively (step S29). The data division processing unit 11a transmits a plurality of divided data to which a data ID, restoration information, and error correction code have been respectively added to a plurality of different node devices 1 (step S30), and ends the process.

FIG. 10 is a flowchart showing the procedure of data restoration processing performed by the node device 1 according to the present embodiment. Note that the process shown in this figure is a process performed by the node device 1 of the original data issuer. The data restoration processing unit 11b of the processing unit 11 of the node device 1 according to the present embodiment sends a confirmation request message to the communication unit 13 for checking whether divided data obtained by dividing the data to be restored is stored. and transmits it to other node devices 1 (step S41). The confirmation request message includes information on the data ID assigned to the data to be restored. The data restoration processing unit 11b transmits a confirmation request message to one or more node devices 1 stored as destinations in the destination table 12c of the storage unit 12.

The data restoration processing unit 11b determines whether or not a response message to the confirmation request message has been received (step S42). If the response message has not been received (S42: NO), the data restoration processing unit 11b waits until it receives the response message. When the response message is received (S42: YES), the data restoration processing unit 11b stores the restoration information and the address information of the node device 1 included in the received response message in the storage unit 12 (Step S43). The data restoration processing unit 11b determines whether the number of pieces of divided data whose location has been determined by the response messages received so far exceeds a predetermined threshold (step S44). If the number of data does not exceed the threshold (S44: NO), the data restoration processing unit 11b returns the process to step S42 and continues to receive response messages.

If the number of data exceeds the threshold (S44: YES), the data restoration processing unit 11b transmits the restoration information and address information received and stored so far to the data restoration device 2 through the communication unit 13 ( Step S45). Although not shown in this flowchart, when the data restoration processing unit 11b receives a new response message after transmitting the information in step S45, the data restoration processing unit 11b additionally stores the restoration information and address information included in this response message as data. Send it to the restoration device 2.

The data restoration processing unit 11b determines whether or not the restored original data has been received from the data restoration device 2 (step S46). If the original data has not been received (S46: NO), the data restoration processing unit 11b waits until the original data is received from the data restoration device 2. When the original data is received (S46: YES), the data restoration processing unit 11b performs a decryption process on the received original data using the encryption key 12b stored in the storage unit 12 (step S47), and restores the data. Finish the process.

FIG. 11 is a flowchart showing the procedure of data restoration processing performed by the node device 1 according to the present embodiment. Note that the process shown in this figure is a process performed by a node device 1 other than the node device 1 of the original data issuer. The response processing unit 11c of the processing unit 11 of the node device 1 according to the present embodiment determines whether the confirmation request message sent by the node device 1 of the original data issuer has been received (step S61). If the confirmation request message has not been received (S61: NO), the response processing unit 11c waits until it receives the confirmation request message. If the confirmation request message is received (S61: YES), the response processing unit 11c transmits (transfers) the received confirmation request message to another node device 1 (step S62). At this time, the response processing unit 11c transfers the confirmation request message to one or more node devices 1 stored as destinations in the destination table 12c of the storage unit 12.

The response processing unit 11c determines whether the divided data to which the data ID included in the confirmation request message is attached is stored in the divided data storage unit 12d of the storage unit 12 (step S63). If the divided data is stored (S63: YES), the response processing unit 11c sends a response message including restoration information related to the divided data and its own address information to the node device that is the source of the confirmation request message. 1 (step S64), and the process ends. If the divided data is not stored (S63: NO), the response processing unit 11c ends the process without transmitting the response message.

FIG. 12 is a flowchart showing the procedure of data restoration processing performed by the data restoration device 2 according to the present embodiment. The data restoration processing unit 21a of the processing unit 21 of the data restoration device 2 determines whether or not the restoration information and address information regarding the data to be restored transmitted from the node device 1 have been received (step S71). If the restoration information and address information have not been received (S71: NO), the data restoration processing unit 21a waits until it receives these information from the node device 1. When the restoration information and address information are received (S71: YES), the data restoration processing unit 21a determines whether it is possible to restore the divided data to the original data based on the received restoration information and address information. is determined (step S72). If it is determined that restoration is not possible (S72: NO), the data restoration processing unit 21a returns the process to step S71 and waits until additional restoration information and address information are received from the node device 1.

If it is determined that restoration to the original data is possible (S72: YES), the data restoration processing unit 21a collects the divided data stored in the node device 1 based on the address information received so far. Processing is performed (step S73). At this time, the data restoration processing unit 21a requests the node device 1 to transmit the divided data according to the given address information, and receives the divided data transmitted from the node device 1 in response to this request. Collect. The data restoration processing unit 21a restores the collected divided data to the original data based on the restoration information (step S74). The data restoration processing unit 21a transmits the restored original data to the node device 1 corresponding to the original data issuer of this data (step S75), and ends the process.

<Summary>
In the data storage system according to this embodiment having the above configuration, the plurality of node devices 1 connected via the network N store data in a distributed manner. At least one node device 1 among these plurality of node devices 1 becomes a data generation source device that generates data to be stored. The data generation source node device 1 divides the data to be stored into a plurality of pieces, and generates restoration information for restoring the divided data to the original data. The node device 1 attaches restoration information and a data ID for identifying the original data to the divided data, and transmits the plurality of divided data to different other node devices 1, respectively.

The receiving side node device 1 that receives the divided data determines whether or not the received data satisfies a predetermined division end condition, and if the division end condition is satisfied, the received data is stored in the storage unit 12. The data is stored in the divided data storage section 12d. If the division termination condition is not satisfied, the node device 1 further divides the received data, generates restoration information, and attaches the restoration information and the same data ID as the original data to the divided data to create different data. Send to other node devices 1.

As a result, in the data storage system according to the present embodiment, division and transmission of data are repeatedly performed, and the divided data is stored in the node device 1 that has determined that the division end condition is satisfied. Each node device 1 only needs to divide and transmit data, and sophisticated processing is not required. Furthermore, since the data stored in one node device 1 is obtained by dividing the original data, there is no need for each node device 1 to include a large-capacity storage unit 12.

Further, in the data storage system according to this embodiment, the node device 1 that is the data generation source encrypts the original data to be stored, divides the encrypted data, and transmits the divided data to other node devices 1. The node device 1 that receives the divided data does not need to further encrypt the encrypted divided data. By encrypting and dividing data, the confidentiality of the original data can be increased.

Furthermore, in the data storage system according to the present embodiment, each node device 1 assigns an error correction code to each divided data and transmits it to other node devices 1. Thereby, the node device 1 that has received the divided data can correct and store errors in the data that occurred during transmission and reception based on the error correction code. Furthermore, when restoring divided data, even if some of the plurality of divided data are missing, the missing parts can be corrected based on the error correction code and the original data can be restored.

Further, in the data storage system according to the present embodiment, a message requesting confirmation as to whether or not divided data specifying the data ID is stored is transmitted from the node device 1 that restores the divided data to another node device 1. The node device 1 that has received the confirmation request message determines whether or not the divided data to which the data ID specified in the confirmation request message is attached is stored in its own storage unit 12, and stores the divided data. If so, send a response message. Thereby, the node device 1 attempting to restore data can grasp which node device 1 in the network stores the plurality of divided data, based on the response message from each node device 1.

Furthermore, in the data storage system according to the present embodiment, the data restoration device 2 collects the divided data based on the address information included in the response message from the node device 1 that stores the divided data. , restore the collected plurality of divided data to the original data based on the restoration information. As a result, the data restoration device 2 can acquire and restore data distributed and stored in multiple node devices 1, and the node device 1 that requires the original data can be restored by the data restoration device 2. Data can be used.

In addition, in the data storage system according to the present embodiment, the node device 1 storing the divided data receives the address information for accessing its own device and the restoration of the divided data in response to receiving the confirmation request message. information is included in the response message, and the response message is sent to the node device 1 that is the source of the confirmation request message. Thereby, the data restoration device 2 can communicate with the node device 1 that has stored the divided data based on the address information, and can acquire the divided data from this node device 1. Furthermore, the data restoration device 2 can restore the collected data to the original data based on the restoration information.

In this embodiment, when the node device 1 divides the original data into a plurality of pieces of data, an example is shown in which the original data is divided into pieces of equal size. However, the present invention is not limited to this. The data may have different data sizes. For example, the node device 1 can determine the size of divided data depending on the performance of the node device 1 to which the divided data is to be transmitted. Further, when dividing the original data into a plurality of pieces of data, the node device 1 may perform the division so that some of the data overlaps. For example, when dividing the original data into two, the node device 1 may divide the original data into two-thirds of the data at the beginning and two-thirds of the data at the end, and the overlapping portion is divided into two parts of the divided data. may be included.

Further, in this embodiment, the node device 1 that is the data generation source encrypts the data, and the subsequent node devices 1 do not encrypt the data, but the present invention is not limited to this. The node device 1 that has received the divided data may encrypt this data before re-dividing it. However, in this case, in order to restore the divided data to the original data, it is necessary to reverse the transmission path of the data that passed through the plurality of node devices 1 during data division and restore and decode the data in order. be.

Further, in the present embodiment, the node device 1 that has determined that the division end condition is satisfied stores the data, but the present invention is not limited to this. For example, each node device 1 may store the data before division even if it determines that the division end condition is not satisfied and divides and transmits the data. This allows multiple node devices 1 to store data redundantly, increasing the possibility of restoring the original data even if a failure occurs in the node device 1 that stored divided data. be able to.

Further, in this embodiment, the restoration information shown in FIGS. 3, 4, etc. is an example, and the information is not limited to this. The restoration information may be any information as long as it can restore a plurality of divided data.

Further, the data storage system according to the present embodiment has a configuration in which the data generating node device 1 requests the data restoration device 2 to restore data, and the data restoration device 2 restores the data, but the configuration is not limited to this. It's not a thing. Data restoration may be performed by the node device 1 that is the data generation source. In this case, the node device 1 that has received the confirmation request message may include the restoration information and the divided data in the response message and send it.

Furthermore, in this embodiment, the configuration is such that the node device 1 as the data generation source transmits the confirmation request message, but the configuration is not limited to this. The data restoration device 2 may send the confirmation request message. In this case, the data generation source node device 1 requests the data restoration device 2 for restoration specifying the data ID. Also in this case, the node device 1 that has received the confirmation request message may include the restoration information and the divided data in a response message and transmit it to the data restoration device 2.

The embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is indicated by the claims rather than the above-mentioned meaning, and is intended to include meanings equivalent to the claims and all changes within the scope.

1 Node device (device, data storage device)
1a Node device (data generation source device)
1b to 1j Node device (receiving side device)
2 Data restoration device 11 Processing unit 11a Data division processing unit (identification information generation unit, data division unit, restoration information generation unit, data transmission unit, division end condition determination unit, encryption unit, correction information generation unit)
11b Data restoration processing unit 11c Response processing unit (memory determination unit, response unit)
12 Storage unit 12a Program (computer program)
12b Encryption key 12c Destination table 12d Divided data storage unit 13 Communication unit 21 Processing unit 21a Data restoration processing unit (data collection unit, restoration unit)
22 Storage unit 22a Program 23 Communication unit N Network

Claims (12)

A data storage system in which multiple devices connected via a network store data in a distributed manner,
The data generating device included in the plurality of devices is:
an identification information generation unit that generates identification information for identifying data to be stored;
a data division unit that divides the data into a plurality of parts;
a restoration information generation unit that generates restoration information for restoring the plurality of data divided by the data division unit to the original data;
a data transmitting unit that attaches identification information generated by the identification information generating unit and restoration information generated by the restoring information generating unit to the plurality of data divided by the data dividing unit, and transmits the data to different other devices; has
A receiving device included in the plurality of devices and receiving the divided data,
a division end condition determination unit that determines whether the received data satisfies the division end condition;
a storage unit that stores the data together with the identification information and the restoration information when the division termination condition determining unit determines that the division termination condition is satisfied;
a data division unit that divides the data into a plurality of pieces when the division termination condition determination unit determines that the division termination condition is not satisfied;
a restoration information generation unit that generates restoration information for restoring the plurality of data divided by the data division unit to the original data;
A data storage system, comprising: a data transmission unit that attaches the identification information and the restoration information generated by the restoration information generation unit to the plurality of data divided by the data division unit, and transmits the data to different other devices. The data generation source device includes an encryption unit that encrypts data to be stored,
The data division unit of the data generation source device divides the data encrypted by the encryption unit.
A data storage system according to claim 1. The data generation source device and the receiving device each include an error correction information generation unit that generates error correction information for each of the plurality of divided data,
The data transmitting units of the data generating device and the receiving device transmit error correction information to each of the plurality of divided data.
A data storage system according to claim 1 or claim 2. The data storage according to any one of claims 1 to 3, wherein the data dividing unit determines the number of data divisions according to the number of destination devices to which the data transmitting unit transmits data. system. 4. The data storage system according to claim 1, wherein the data transmitter determines a destination of the data according to the number of pieces of data divided by the data divider. Claim 1, wherein the division end condition is that the size of the divided data is smaller than a threshold value, or that the size of the divided data is smaller than the size of identification information and restoration information attached to the data. A data storage system according to any one of claims 5 to 6. The receiving device includes:
a storage determination unit that determines whether or not data related to the identification information is stored when receiving a request to confirm whether or not data specifying the identification information is stored;
and a response unit that responds to the transmission source of the confirmation request when the storage determination unit determines that the data is stored. Data storage system. The data restoration device included in the plurality of devices is
a data collection unit that collects the divided data based on a response from the receiving device;
8. The data storage system according to claim 7, further comprising: a restoration section that restores the plurality of divided data collected by the data collection section to original data. The response unit of the receiving device transmits access information for accessing the own device and the restoration information stored in the storage unit to the source of the confirmation request,
The data collection unit of the data restoration device collects the data based on the access information,
The restoration unit of the data restoration device restores data based on the restoration information.
9. A data storage system according to claim 8. A data storage device that communicates with other devices via a network,
an identification information generation unit that generates identification information for identifying data to be stored;
a first data division unit that divides the data into a plurality of parts;
a first restoration information generation unit that generates restoration information for restoring the plurality of data divided by the first data division unit to the original data;
The identification information generated by the identification information generation unit and the restoration information generated by the first restoration information generation unit are attached to the plurality of data divided by the first data division unit, and the data are transmitted to different other devices. a first data transmitter that transmits;
a division end condition determination unit that determines whether the division end condition is satisfied for data received from another device;
When the division end condition determining unit determines that the division end condition is satisfied, the data received from the other device is provided with identification information for identifying the data and restoration information for restoring the data to the original data. a storage unit that stores information together with the information;
a second data division unit that divides the data into a plurality of pieces when the division termination condition determination unit determines that the division termination condition is not satisfied;
a second restoration information generation unit that generates restoration information for restoring the plurality of data divided by the second data division unit to the original data;
Second data that is attached with the identification information and restoration information generated by the second restoration information generation unit to the plurality of data divided by the second data division unit, and transmitted to different other devices. A data storage device comprising a transmitter and a transmitter. A computer that communicates with other devices via a network,
Generate identification information that identifies data to be stored,
Divide the data into multiple parts,
Generates restoration information to restore multiple pieces of divided data to the original data,
Attach generated identification information and restoration information to multiple pieces of divided data, and send each to different other devices,
Determine whether the data received from another device satisfies the division end condition,
If it is determined that the division end condition is met, storing the data received from the other device together with identification information for identifying the data and restoration information for restoring the data to the original data;
If it is determined that the division end condition is not satisfied, divide the data into multiple parts,
Generates restoration information to restore multiple pieces of divided data to the original data,
A computer program that executes a process of attaching the identification information and generated restoration information to a plurality of divided pieces of data and transmitting the pieces of data to different devices. A data storage method in which data is distributed and stored in multiple devices connected via a network,
A data generating device included in the plurality of devices generates identification information for identifying data to be stored, divides the data into a plurality of pieces, and restores the divided pieces of data to the original data. Generate information, attach generated identification information and restoration information to multiple pieces of divided data, and send each to different other devices,
A receiving device included in the plurality of devices that receives the divided data determines whether or not the received data satisfies the division termination condition, and if it determines that the division termination condition is satisfied, the reception side device receives the divided data. is stored together with the identification information and the restoration information, and when it is determined that the division end condition is not satisfied, the data is divided into a plurality of parts, and the data is restored to restore the divided data to the original data. generating information, attaching the identification information and the generated restoration information to a plurality of divided data, and transmitting each to a different other device;
Data storage method.

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