JP5850974B2 - File distribution system, file distribution method, and program - Google Patents

Description

  The present invention relates to a file distribution system, a file distribution method, and a program for authenticating a user using a password.

  A file distribution system is known in which a file is divided into a plurality of pieces and distributed and stored in a plurality of devices. Here, a subject who distributes and stores files using the file distribution system is called a “user”. A device that divides and distributes files is called a “file distribution device”, and a device that stores fragments is called a “fragment storage device”. In order for a user to use a file distribution device to divide a file and send it to a fragment storage device, it is necessary to authenticate a plurality of fragment storage devices from the file distribution device.

  As a conventional method, there is a method in which the user remembers the passwords of a plurality of fragment storage devices and inputs the passwords of all the devices every time they are stored.

  Alternatively, there is a method of storing the fragment storage device password in the file distribution device so that the user does not have to remember a plurality of passwords.

  For example, Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3 are known as online storage services that divide and store a file into a plurality of fragments using a secret sharing algorithm.

NRI Secure Technologies, Inc., “SecureCube SecretShare”, [online], [Search April 3, 2014], Internet <URL: http://www.nri-secure.co.jp/service/cube/secretshare. html> SKY Perfect JSAT Corporation, "What is S * Plex3 technology?", [Online], [Search April 3, 2014], Internet <URL: http://www.splex3.com/service/index.html> ITOCHU Techno-Solutions Corporation, "CTC starts selling Cleversafe storage products for the first time in Japan", [online], [April 15, 2014 search], Internet <URL: http: //www.ctc- g.co.jp/news/press/20130402a.html>

  In the method in which the user remembers the passwords of a plurality of fragment storage devices and enters the passwords of all the devices every time the user stores them, the user needs to store the same number of fragment storage device passwords as the number of fragment storage devices. There is. As the number of fragment storage devices increases to three and five, the number of passwords that the user must store increases and the burden on the user increases.

  On the other hand, if the fragment storage device password is stored in the file distribution device, the user need not remember the fragment storage device password. By building a system that can automatically authenticate each fragment storage device using the fragment storage device password stored in the file distribution device, users who have already authenticated to the file distribution device are aware of the authentication of the fragment storage device. The system can be used without

  However, in the method of storing the fragment storage device passwords in the file distribution device, all the fragment storage device passwords are stored in the file distribution device, which causes a confidentiality problem. In the unlikely event that an unauthorized third party can operate the file distribution device, all fragment storage device passwords may be leaked. As a result, there is a possibility that an unauthorized third party logs in to all the fragment storage devices, and the level of confidentiality is lowered as compared with the above-described method in which the user remembers the passwords of a plurality of fragment storage devices.

  In addition to the above-mentioned method, even if there is a method that solves the above-mentioned problems and can be operated safely during normal operation, it is not necessary unless a processing flow for securely issuing a new password when reissuing the password is established. It is enough. For example, if the user forgets the password, the password may be leaked during the reissue process.

  SUMMARY An advantage of some aspects of the invention is that it provides a file distribution system that is safe and can reduce the burden of password management for a user.

  The file distribution system of the present invention includes a file distribution device that distributes a file into N pieces, restores the file from the N pieces, and N piece storage devices that store the pieces. However, N is an integer of 2 or more. Each fragment storage device transmits a temporary password determined in advance by the administrator of each fragment storage device to the file distribution device and stores it in a predetermined storage area in advance. The file distribution device includes a unique information generation unit, a fragment storage device password generation unit, and a password overwrite unit. The unique information generation unit stores N random numbers in a predetermined storage area as N unique information corresponding to each fragment storage device. The fragment storage device password generation unit outputs the file distribution device password input by the administrator of the file distribution device and the calculation result of the one-way function based on each of the N pieces of unique information as N pieces of fragment storage device passwords. . The password overwrite unit sends the temporary password to each corresponding fragment storage device, and when the write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device corresponds to each fragment storage device. Overwrite the fragment storage device password to be used. When each fragment storage device receives a temporary password from the file distribution device, it compares the temporary password stored in advance in a predetermined storage area with the received temporary password and writes it to the file distribution device based on the verification result. Send permission signal.

  According to the file distribution system of the present invention, the burden of password management for the user can be reduced safely.

1 is a block diagram illustrating an outline of a file distribution system according to a first embodiment. FIG. 3 is a diagram for explaining a preliminary operation of the file distribution system according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration of each device included in the file distribution system according to the first embodiment. 5 is a flowchart showing the operation of the file distribution apparatus according to the first embodiment. FIG. 4 is a block diagram illustrating an outline of a file distribution system according to a second embodiment. FIG. 9 is a block diagram illustrating an outline of a file distribution system according to a third embodiment. FIG. 10 is a block diagram illustrating a configuration of each device included in the file distribution system according to the third embodiment. FIG. 10 is a sequence diagram illustrating operations of devices in the file distribution system according to the third embodiment. The block diagram which shows the structure of each apparatus contained in the file distribution system of the modification 1. FIG. The sequence diagram which shows operation | movement of each apparatus of the file distribution system of the modification 1. FIG. FIG. 10 is a block diagram illustrating an outline of a file distribution system according to a fourth embodiment.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, the same number is attached | subjected to the structure part which has the same function, and duplication description is abbreviate | omitted.

[Explanation of terms]
Terms used in this specification will be described.

<File distribution system>
A system that divides a file into multiple pieces and stores them in multiple devices. It consists of a file distribution device and a plurality of fragment storage devices. In this specification, it uses as a term which shows the whole system this time.

<File distribution device>
A device that fragmentes files and restores them from files. Access to the file area for storing files is protected by authentication, and only the file distribution device administrator can access. A file distribution device is a device that has a timing to store a file raw. Therefore, in order to ensure safety, in principle, human beings in the organization that read and write files are managed and not outsourced to external administrators. Whether it is a server type use or a personal use on a notebook PC, the configuration is free.

<Distributed information management storage unit>
The basic configuration such as the first embodiment is included in the file dividing device. Specific information, information on where the fragment is stored in the fragment storage device, and the like are stored.

<Fragment storage device>
A device (server) for storing fragments. It does not matter whether it is installed in an organization or an external organization. The number of fragment storage devices is an arbitrary integer value of 2 or more. In some embodiments, for convenience, the number of fragment storage devices is two. As a simple example of the fragment storage device, for example, there is an FTP server.

<Authentication storage unit>
A fragment storage device password or temporary password for logging into the fragment storage device is stored in the fragment storage device.

<File distribution device administrator>
The administrator of the file distribution apparatus is a person who activates / stops the file distribution apparatus and initializes / resets the password.

<Shard storage device administrator>
The administrator of the fragment storage device. Since a fragment storage device manager is assigned to each fragment storage device, there are a plurality of fragment storage device managers. Since one of the fragment storage device managers does not know the other fragment storage device password, one of the fragment storage device administrators cannot collect the fragments and restore the file.

<General users>
It is a subject who does not have administrator authority and performs only the distributed file save / restore processing for the file distribution apparatus.

<User>
A file distribution system user who has the roles of a file distribution device administrator and general users. In the present specification, “user” is used in the first half of the specification when there is no need to explain the situation separately to general users and administrators.

<File distribution device password>
This is the password used for login authentication of the file splitting device.

<Fragment storage device password>
This is the password used for login authentication of the fragment storage device.

<Temporary password>
This password is used for login authentication of the fragment storage device, which is temporarily set by the fragment storage device administrator when the file distribution device password is initialized or when the file distribution device password is reissued.

<Unique information>
For example, a random number. The unique information is prepared in the same number as the number of fragment storage devices, and is associated with each fragment storage device. Used when generating a fragment store password.

<Password change processing function>
This is a function to change the password in the file distribution device at the time of initial use or password reissue.

  The present invention focuses on the password change processing function that is a part of the file distribution system. The password change processing function is a function in which a user changes a password at the time of initial use or password reissue. In the password change processing function of the present invention, if the user completes the initial setting by inputting the file distribution device password and the temporary password at the initial use, then only the file distribution device password is input, Will be available.

  Hereinafter, the file distribution system 100 according to the first embodiment will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 1 is a block diagram illustrating an outline of a file distribution system 100 according to the present embodiment. FIG. 2 is a diagram for explaining the preliminary operation of the file distribution system 100 according to the present embodiment. FIG. 3 is a block diagram illustrating a configuration of each device included in the file distribution system 100 according to the present embodiment. FIG. 4 is a flowchart showing the operation of the file distribution apparatus 10 of this embodiment.

  As shown in FIG. 1, the file distribution system 100 of this embodiment distributes a file 8-1 into N pieces of fragments 7-1,..., 7-N, and N pieces of fragments 7-1,. .., 7 -N, and N pieces of fragment storage devices 20-1,... 20-N included. However, N is an integer of 2 or more.

  As shown in FIG. 2, each of the fragment storage devices 20-1,..., 20-N is determined in advance by the managers 6-1 of the fragment storage devices 20-1,. The provisional passwords 5-1,..., 5-N are transmitted to the file distribution apparatus 10 and stored in advance in a predetermined storage area (authentication storage unit 21). This operation is assumed to be executed in advance before the password initial setting or update operation described later is executed. The fragment storage device managers 6-1,..., 6-N send the set temporary password to the file distribution device manager 9, for example, by e-mail and notification by phone, etc. It can also be notified by the method. Even in this case, the temporary password is stored in advance in a predetermined storage area (authentication storage unit 21).

<File distribution device password setting procedure for initial use>
Hereinafter, the file distribution device password setting procedure at the initial use will be described assuming that N = 2, that is, there are two fragment storage devices. As shown in FIG. 3, the file distribution device 10 includes a distributed information management storage unit 11 for storing unique information 3-1, 3-2 and the like described later, a unique information generation unit 12, and a fragment storage device password generation. Part 13 and password overwriting part 14. The distributed information management storage unit 11 may be called a distributed information management database 11. The N pieces, that is, the two fragment storage devices 20-1 and 20-2 are configured to include an authentication storage unit 21 for storing a temporary password and the like to be described later. The authentication storage unit 21 may be called an authentication database 21.

  The file distribution device administrator 9 sets a temporary password 5-1, 5-2 for each fragment storage device and a new file distribution device administrator 9 on the password setting screen displayed on the file distribution device 10 when setting the password. The file distribution device password 4-1 is entered.

  The unique information generation unit 12 generates N, that is, two random numbers, and generates the two random numbers corresponding to the two pieces of unique information 3-1, 2-1 corresponding to the fragment storage devices 20-1, 20-2, respectively. 3-2 is stored in a predetermined storage area (distributed information management storage unit 11) (S12). Note that step S12 may be performed at any timing as long as it is before step S13 described later.

  The fragment storage device password generation unit 13 is a one-way function based on the file distribution device password 4-1 input by the administrator 9 of the file distribution device 10 and each of the two pieces of unique information 3-1, 3-2. The calculation result is output as two fragment storage device passwords 2-1 and 2-2 (S13). As a one-way function, for example, a hash function can be considered. For example, the fragment storage device password generation unit 13 combines the file distribution device password 4-1 input by the administrator 9 of the file distribution device 10 with each of the two pieces of unique information 3-1, 3-2. Two combined values are generated, and hash values of the two combined values are output as two fragment storage device passwords 2-1 and 2-2 (S13).

  The password overwrite unit 14 transmits the previously acquired temporary passwords 5-1 and 5-2 to the corresponding fragment storage devices 20-1 and 20-2, respectively. When the fragment storage devices 20-1 and 20-2 receive the temporary passwords 5-1 and 5-2 from the file distribution device 10, the temporary passwords stored in advance in a predetermined storage area (authentication storage unit 21). 5-1, 5-2 and the received temporary password are collated, and a write permission signal is transmitted to the file distribution apparatus 10 based on the collation result. When the password overwriting unit 14 receives a write permission signal from each of the fragment storage devices 20-1 and 20-2, the temporary password 5-1 and 5-5 stored in each of the fragment storage devices 20-1 and 20-2. 2 is overwritten on the fragment storage device passwords 2-1 and 2-2 corresponding to the fragment storage devices 20-1 and 20-2 (S14). In other words, the password overwrite unit 14 accesses the fragment storage devices 20-1 and 20-2 using the temporary passwords 5-1 and 5-2, and the fragment storage devices 20-1 and 20-2. And the temporary passwords 5-1 and 5-2 in the authentication storage unit 21 are overwritten with the fragment storage device passwords 2-1 and 2-2. Note that the same procedure is performed when the file distribution device password 4-1 is reset, such as when the file distribution device administrator 9 forgets the file distribution device password 4-1.

  As described above, in order to perform inter-machine authentication between the file distribution device 10 and each of the fragment storage devices 20-1,..., 20-N, conventionally, the user has to use the fragment storage device passwords 2-1,. I had to remember all 2-N. Alternatively, it is necessary to take measures such that the fragment storage device passwords 2-1,..., 2-N are retained on the file distribution device 10 by the number of the fragment storage devices 20-1,.

  Therefore, in the file distribution system 100 according to the present embodiment, a one-way function (for example, a hash) based on a password (file distribution device password 4-1) known only by the user and random numbers (unique information 3-1,..., 3-N). Function) is set as the fragment storage device passwords 2-1,..., 2-N, so that the number of passwords that the file distribution device administrator 9 has to manage is reduced, and important information such as passwords is stored in the file. A configuration that does not need to be stored in the distribution apparatus 10 is realized.

  According to the file distribution system 100 of the present embodiment, the user can use the file distribution system 100 only by inputting the file distribution device password 4-1 which is the only password designated by the user.

  Further, according to the file distribution system 100 of the present embodiment, since the fragment storage device passwords 2-1,..., 2-N are not stored in the file distribution device 100, the confidentiality of the password is high. It can be said. Since the fragment storage device passwords 2-1,..., 2-N are not stored, the distributed information management storage unit (database) 11 can also be outsourced to the outside. This merit will be described in more detail in the third embodiment.

  Further, according to the file distribution system 100 of the present embodiment, the procedure is set so that the password can be safely reissued even if the user forgets the password.

  According to the file distribution system 100 of the present embodiment, it is possible to satisfy both merits such as improvement of user convenience and improvement of password confidentiality.

  Next, the file distribution system 200 according to the second embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing an outline of the file distribution system 200 of this embodiment. As shown in FIG. 5, the file distribution system 200 includes a file distribution device 30 and N pieces of fragment storage devices 40-1,..., 40-N. The difference between the present embodiment and the first embodiment is that in this embodiment, the file distribution apparatus 30 executes file distribution and restoration using a secret distribution algorithm. Therefore, the file distribution device 30 distributes the file 8-1 to N pieces of secret-distributed fragments 7a-1,..., 7a-N, and N pieces of secret-distributed pieces 7a-1,. Restore file 8-1 from -N.

  The file distribution system 200 of the present embodiment has a configuration using a secret sharing algorithm as an algorithm for distributing and combining files. The secret sharing algorithm has the property that the file information cannot be known at all from one secret-distributed fragment, but the file can be restored when a certain number of fragments are available. Therefore, confidentiality is enhanced by combining the present invention and the secret sharing algorithm.

  However, when the secret sharing algorithm is used, the secret-distributed fragment needs to be 3 or more (N ≧ 3). When combined with the secret sharing algorithm, the fragment storage devices 40-1,..., 40-N are more preferably distributed and arranged in different regions in order to cope with a catastrophic disaster.

  The file distribution system 200 according to the present embodiment is capable of restoring a file from a fragment in another fragment storage device even if a certain fragment storage device cannot be used at all due to, for example, a catastrophic disaster. It is valid. In addition, since one secret-distributed fragment has the property of not knowing any file, it is safe to entrust the management of each of the fragment storage devices 40-1,..., 40-N to each external organization.

  Hereinafter, the file distribution system according to the third embodiment in which a part of the file distribution system according to the first embodiment is changed will be described with reference to FIGS. 6, 7, and 8. FIG. 6 is a block diagram showing an outline of the file distribution system 300 of this embodiment. FIG. 7 is a block diagram showing the configuration of each device included in the file distribution system 300 of this embodiment. FIG. 8 is a sequence diagram showing the operation of each device of the file distribution system 300 of this embodiment. As shown in FIG. 6, the file distribution system 300 of this embodiment includes a file distribution device 50 and N fragment storage devices 60-1,..., 60-N. In the present embodiment, the distributed information management storage unit 11 included in the file distribution apparatus 10 in the first embodiment is moved to each of the N fragment storage apparatuses 60-1,..., 60-N. Accordingly, the operations performed by the file distribution device 50 and the N fragment storage devices 60-1,..., 60-N are different from those in the first embodiment.

  Hereinafter, N = 2. As shown in FIG. 7, the file distribution device 50 of this embodiment includes a unique information generation unit 52, a fragment storage device password generation unit 13, and a password overwrite unit 14. The N pieces, that is, the two pieces of fragment storage devices 60-1 and 60-2 are for storing the authentication storage unit 21 for storing a temporary password and the like, the unique information 3-1 and 3-2, and the like. The distributed information management storage unit 11 and the unique information transmission unit 61 are included. The difference between the first embodiment and the present embodiment is that the file distribution apparatus 50 of the present embodiment does not include the distributed information management storage unit 11 included in the file distribution apparatus 10 of the first embodiment. 60-1 and 60-2 include the distributed information management storage unit 11, the specific information generation unit 12 of the first embodiment is changed to the specific information generation unit 52 in the present embodiment, The fragment storage devices 60-1 and 60-2 include the unique information transmission unit 61 that is not included in the fragment storage devices 20-1 and 20-2 of the first embodiment.

  As described above, the fragment storage devices 60-1 and 60-2 transmit the temporary password to the file distribution device 50 and store it in a predetermined storage area in advance.

  Next, the unique information generation unit 52 sets N pieces, that is, two random numbers as two pieces of unique information 3-1 and 3-2 corresponding to the fragment storage devices 60-1 and 60-2. Information 3-1 and 3-2 are stored in a predetermined storage area (distributed information management storage unit 11) of each fragment storage device 60-1 and 60-2 (S52). The unique information transmission unit 61 of each of the fragment storage devices 60-1 and 60-2 transmits the unique information 3-1 and 3-2 stored in the distributed information management storage unit 11 to the file distribution device 50 (S61). . Thereafter, the fragment storage device password generation unit 13 and the password overwrite unit 14 of the file distribution device 50 execute steps S13 and S14, respectively, as in the first and second embodiments.

  For example, in the configuration of the file distribution systems 100 and 200 according to the first and second embodiments, a case where the file distribution apparatuses 10 and 30 cannot be used due to a severe disaster in an area where the file distribution apparatuses 10 and 30 exist is considered. In this case, since the fragment itself is not in the file distribution devices 10 and 30, the contents of the file are not lost. However, the fragment storage device 20-, such as the unique information 3-1,. Since the information used when using 1,..., 20-N (40-1,..., 40-N) is lost, it becomes difficult to return to a file.

  In order to avoid the above problem, in the file distribution system 300 of this embodiment, the distributed information management storage unit 11 is moved to each of the fragment storage devices 60-1,..., 60-N. Management of the distributed information management storage unit 11 may be performed by each of the fragment storage device managers 6-1,. Since the distributed information management storage unit 11 does not contain information necessary for authentication of each of the fragment storage device managers 6-1,..., 6-N, in the unlikely event, a certain fragment storage device administrator 6-n ( There is an internal crime (n is an integer satisfying 2 ≦ n ≦ N), and even if the contents of the distributed information management storage unit 11 are read, the file is not restored.

  In the file distribution system 300 according to the present embodiment, with the above-described configuration, information with sequential changes is not stored in the file distribution apparatus 50. Even if there is, it is possible to construct and install a new file distribution device 50 relatively easily because there is no need to perform processing such as reconstructing information with successive changes. That is, there is an advantage that the entire system can be easily restored.

[Modification 1]
Hereinafter, a file distribution system according to the first modification example in which the file distribution system according to the third embodiment is modified will be described with reference to FIGS. 9 and 10. FIG. 9 is a block diagram showing the configuration of each device included in the file distribution system 300a of this modification. FIG. 8 is a sequence diagram showing the operation of each device of the file distribution system 300a of this modification. As shown in FIG. 9, the file distribution system 300a of this modification includes a file distribution device 50a and N pieces of fragment storage devices 60a-1, ..., 60a-N. This modification is characterized in that in addition to the distributed information management storage unit 11, the unique information generation unit is moved to the fragment storage device. As shown in FIG. 9, the file distribution device 50a of the file distribution system 300a of this modification includes a fragment storage device password generation unit 13 and a password overwrite unit 14. The two fragment storage devices 60a-1 and 60a-2 include an authentication storage unit 21 for storing temporary passwords and a distributed information management storage unit for storing unique information 3-1, 3-2, etc. 11, a unique information transmission unit 61, and a unique information generation unit 62. The difference between the second embodiment and this modification is that the file distribution device 50a of this modification does not include the unique information generation unit 52 included in the file distribution device 50 of the third embodiment, but instead a fragment storage device 60a- 1, 60a-2 is only a point including the unique information generating unit 62.

  As illustrated in FIG. 10, the unique information generation unit 62 of each fragment storage device 60a-1 or 60a-2 generates a random number as the unique information (3-1 or 3) of each fragment storage device (60a-1 or 60a-2). -2) is stored in a predetermined storage area (distributed information management storage unit 11) (S62). Next, the unique information transmission unit 61 of each of the fragment storage devices 60a-1 and 60a-2 sends the unique information (3-1 or 3-2) stored in the distributed information management storage unit 11 to the file distribution device 50a. Transmit (S61). Thereafter, the fragment storage device password generation unit 13 and the password overwrite unit 14 of the file distribution device 50a execute steps S13 and S14, respectively, as in the first, second, and third embodiments.

  According to the file distribution system 300a of this modification, the same advantages as those of the third embodiment can be obtained.

  The file distribution apparatus according to the fourth embodiment will be described below with reference to FIG. FIG. 11 is a block diagram showing an outline of the file distribution system 400 of this embodiment. As shown in FIG. 11, the file distribution system 400 of the present embodiment includes a file distribution device 70 and N fragment storage devices 80-1,..., 80-N. In the configuration of the file distribution system of the above-described embodiment, the person who can use the file distribution apparatus is limited to one file distribution apparatus administrator. Therefore, in this embodiment, in order to solve this problem, the file storage area on the file distribution device 70 to which authority can be given is assigned to a plurality of general users (for example, the general user 1-1 and the general user 1 in FIG. 11). -2), and a configuration that allows multiple people to store and restore files.

  According to the file sharing system 400 of the present embodiment, for example, all the related members in the company can use the shared file server such as using the secret sharing apparatus.

  The various processes described above are not only executed in time series according to the description, but may also be executed in parallel or individually as required by the processing capability of the apparatus that executes the processes. Needless to say, other modifications are possible without departing from the spirit of the present invention.

  Further, when the above-described configuration is realized by a computer, processing contents of functions that each device should have are described by a program. The processing functions are realized on the computer by executing the program on the computer.

  The program describing the processing contents can be recorded on a computer-readable recording medium. As the computer-readable recording medium, for example, any recording medium such as a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory may be used.

  The program is distributed by selling, transferring, or lending a portable recording medium such as a DVD or CD-ROM in which the program is recorded. Furthermore, the program may be distributed by storing the program in a storage device of the server computer and transferring the program from the server computer to another computer via a network.

  A computer that executes such a program first stores, for example, a program recorded on a portable recording medium or a program transferred from a server computer in its own storage device. When executing the process, the computer reads a program stored in its own recording medium and executes a process according to the read program. As another execution form of the program, the computer may directly read the program from a portable recording medium and execute processing according to the program, and the program is transferred from the server computer to the computer. Each time, the processing according to the received program may be executed sequentially. Also, the program is not transferred from the server computer to the computer, and the above-described processing is executed by a so-called ASP (Application Service Provider) type service that realizes the processing function only by the execution instruction and result acquisition. It is good. Note that the program in this embodiment includes information that is used for processing by an electronic computer and that conforms to the program (data that is not a direct command to the computer but has a property that defines the processing of the computer).

  In this embodiment, the present apparatus is configured by executing a predetermined program on a computer. However, at least a part of these processing contents may be realized by hardware.

Claims (8)

N is an integer greater than or equal to 2,
A file distribution system including a file distribution device that distributes a file into N pieces, restores the file from the N pieces, and N piece storage devices that store the pieces;
Each of the fragment storage devices transmits a temporary password determined in advance by an administrator of each of the fragment storage devices to the file distribution device and stores it in a predetermined storage area in advance.
The file distribution device includes:
A unique information generating unit for storing N random numbers in a predetermined storage area as N unique information corresponding to each of the fragment storage devices;
Fragment storage device password generation unit that outputs a file distribution device password input by an administrator of the file distribution device and a calculation result of a one-way function based on each of the N pieces of unique information as N piece storage device passwords When,
When the temporary password is transmitted to each corresponding fragment storage device and a write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device is transmitted to each fragment storage device. includes a password override portion to overwrite in said corresponding fragment storage device password, and
Each said fragment storage device
When the temporary password is received from the file distribution device, the temporary password stored in advance in the predetermined storage area is compared with the received temporary password, and the write to the file distribution device is performed based on the verification result A file distribution system that sends permission signals. The file distribution system according to claim 1,
A file distribution system in which the file distribution apparatus executes the file distribution and the restoration using a secret sharing algorithm. N is an integer greater than or equal to 2,
A file distribution system including a file distribution device that distributes a file into N pieces, restores the file from the N pieces, and N piece storage devices that store the pieces;
Each of the fragment storage devices transmits a temporary password determined in advance by an administrator of each of the fragment storage devices to the file distribution device and stores it in a predetermined storage area in advance.
The file distribution device includes:
A unique information generating unit for storing N pieces of random numbers as N pieces of unique information corresponding to each of the fragment storage devices, and storing the corresponding unique information in a predetermined storage area of each of the fragment storage devices;
A calculation result of a one-way function based on each of the N pieces of unique information received from each of the fragment storage devices and the file distribution device password input by the administrator of the file distribution device and each of the N pieces of unique information A fragment storage device password generation unit that outputs N pieces of fragment storage device passwords,
When the temporary password is transmitted to each corresponding fragment storage device and a write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device is transmitted to each fragment storage device. includes a password override portion to overwrite in said corresponding fragment storage device password, and
Each said fragment storage device
A unique information transmission unit that transmits the unique information stored in the predetermined storage area to the file distribution device;
When the temporary password is received from the file distribution device, the temporary password stored in advance in the predetermined storage area is compared with the received temporary password, and the write to the file distribution device is performed based on the verification result A file distribution system that sends permission signals. N is an integer greater than or equal to 2,
A file distribution system including a file distribution device that distributes a file into N pieces, restores the file from the N pieces, and N piece storage devices that store the pieces;
Each of the fragment storage devices transmits a temporary password determined in advance by an administrator of each of the fragment storage devices to the file distribution device and stores it in a predetermined storage area in advance.
The file distribution device includes:
N pieces of unique information are received from each of the fragment storage devices, and a file distribution device password input by an administrator of the file distribution device and a calculation result of a one-way function based on each of the N pieces of unique information A fragment storage device password generation unit that outputs N fragment storage device passwords;
When the temporary password is transmitted to each corresponding fragment storage device and a write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device is transmitted to each fragment storage device. includes a password override portion to overwrite in said corresponding fragment storage device password, and
Each said fragment storage device
A unique information generating unit that stores a random number as unique information of each fragment storage device in a predetermined storage area;
A unique information transmission unit that transmits the unique information stored in the predetermined storage area to the file distribution device;
When the temporary password is received from the file distribution device, the temporary password stored in advance in the predetermined storage area is compared with the received temporary password, and the write to the file distribution device is performed based on the verification result A file distribution system that sends permission signals. N is an integer greater than or equal to 2,
A file distribution method for distributing a file into N pieces, restoring the file from the N pieces, and a file distribution method executed by N pieces of piece storage devices for storing the pieces,
Each of the fragment storage devices transmits a temporary password determined in advance by an administrator of each of the fragment storage devices to the file distribution device and stores it in a predetermined storage area in advance.
The file distribution device includes:
A unique information generating step of storing N random numbers in a predetermined storage area as N unique information corresponding to each of the fragment storage devices;
Fragment storage device password generation step for outputting, as N fragment storage device passwords, a file distribution device password input by an administrator of the file distribution device and a calculation result of a one-way function based on each of the N pieces of unique information When,
When the temporary password is transmitted to each corresponding fragment storage device and a write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device is transmitted to each fragment storage device. run password overwriting step of overwrite in said corresponding fragment storage device password, and
Each said fragment storage device
When the temporary password is received from the file distribution device, the temporary password stored in advance in the predetermined storage area is compared with the received temporary password, and the write to the file distribution device is performed based on the verification result A file distribution method for executing a step of transmitting a permission signal. The file distribution method according to claim 5,
A file distribution method in which the file distribution apparatus performs the file distribution and the restoration using a secret distribution algorithm. N is an integer greater than or equal to 2,
A file distribution method for distributing a file into N pieces, restoring the file from the N pieces, and a file distribution method executed by N pieces of piece storage devices for storing the pieces,
Each of the fragment storage devices transmits a temporary password determined in advance by an administrator of each of the fragment storage devices to the file distribution device and stores it in a predetermined storage area in advance.
The file distribution device includes:
A unique information generating step of storing N random numbers as N pieces of unique information corresponding to each of the fragment storage devices, and storing the corresponding unique information in a predetermined storage area of each of the fragment storage devices;
A calculation result of a one-way function based on each of the N pieces of unique information received from each of the fragment storage devices and the file distribution device password input by the administrator of the file distribution device and each of the N pieces of unique information A fragment storage device password generation step for outputting N pieces of fragment storage device passwords;
When the temporary password is transmitted to each corresponding fragment storage device and a write permission signal is received from each fragment storage device, the temporary password stored in each fragment storage device is transmitted to each fragment storage device. run password overwriting step of overwrite in said corresponding fragment storage device password, and
Each said fragment storage device
A unique information transmission step of transmitting the unique information stored in the predetermined storage area to the file distribution device;
When the temporary password is received from the file distribution device, the temporary password stored in advance in the predetermined storage area is compared with the received temporary password, and the write to the file distribution device is performed based on the verification result A file distribution method for executing a step of transmitting a permission signal.   A program for causing a computer to function as a file distribution apparatus included in the file distribution system according to any one of claims 1 to 4.

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