JP4996489B2 - Distributed backup system, distributed backup method, depositor device, administrator device - Google Patents

Description

  The present invention relates to a technique for distributing and backing up data among users.

  In order for the backup system to function as a backup system, the backup information must be managed in consideration of a hardware failure such as a hard disk failure or a software failure such as a computer virus.

  For this reason, preparing a backup system for each computer is not a good solution from the viewpoint of cost. In order to solve this disadvantage, there is a backup server (NAS (network attached storage) server) that uses NDMP (network data management protocol), and by sharing the backup software on the network, The backup system that had to be prepared in one is consolidated into one. For this reason, the management cost of backup per unit can be reduced.

However, in a configuration in which the backup system is centrally managed in one place, such as a backup system based on NDMP, damage that is difficult to recover occurs when each system is destroyed due to a large-scale disaster or the like. In order to avoid such a concern, there is a distributed backup system that distributes and backs up data, such as DIBS (Distributed Internet Backup System) shown in Non-Patent Document 1, for example.
Emin Martinian, "Distributed Internet Backup System", Internet <URL: http://www.mit.edu/~emin/source_code/dibs/index.html> [searched on January 15, 2008]

  The backup system based on NDMP is easy to manage because it is configured to centrally manage the backup system in one place, but it has a weak point in avoiding the risk of failure. On the contrary, since DIBS is configured to perform distributed management, it has excellent fault tolerance, but it takes time to manage each base.

  When trying to improve the weakness of the backup system by NDMP, it is possible to try to solve the problem by distributing the installation locations for all NAS servers under its management. May cause problems that cannot be solved without actually going to the location, which raises problems in terms of management costs.

  In view of such circumstances, an object of the present invention is to provide a distributed backup technology capable of verifying the validity of backup data.

  In order to solve the above problems, the distributed backup system of the present invention includes a depositor device and a plurality of trustee devices, and at least the depositor device and the trustee device can communicate with each other. The depositor apparatus includes predetermined data (deposit data) to be backed up, depositor identification information for identifying the depositor apparatus to which the deposit data is deposited, and a threshold T for the number of valid backup data. Storage means for storing, tag generation means for generating information (tag) that can verify the identity between the deposit data and the backup data stored in the trustee device, using the deposit data, and the depositor device with the deposit data Deposit data and backup data generated from the first pair trustee device transmitting means for sending to the trustee device using the backup data stored in the trustee device Using the tag and the verification data, the identity between the trustee device receiving means for receiving verification data, which is information that can be verified, and the deposit data and the backup data stored in the trustee device A verification unit for verifying, a determination unit for obtaining a difference t between the number of backup data successfully verified and the threshold T, and if the number of backup data successfully verified is smaller than the threshold T, the deposited data is at least t Second trustee device transmitting means for sending to each trustee device, wherein each trustee device receives depositary data transmitted from the depositor device, and depositor data receiving means, Means for storing data as backup data, verification data generation means for generating verification data using backup data stored in the storage means, and verification And a pair depositor apparatus transmitting means for transmitting over data to the depositor apparatus.

  Alternatively, the distributed backup system of the present invention includes an administrator device, a depositor device, and a plurality of trustee devices, and at least between the administrator device and the depositor device, the administrator device and the trustee device. The depositor apparatus is stored in the deposit data and the trustee apparatus using the storage means for storing predetermined data (deposit data) to be backed up, and the deposit data. Comprising: tag generation means for generating information (tag) capable of verifying the identity with backup data, and anti-administrator apparatus transmission means for transmitting deposit data and tags to the administrator apparatus. Depositor identification for identifying depositor device receiving means for receiving deposit data and tags transmitted from the depositor device, deposit data, tags, and depositor devices to which deposit data is deposited Stored in the trustee device from the trustee device, the storage means for storing the information and the threshold T of the number of valid backup data, the first pair trustee device transmitting means for sending the deposit data to the trustee device And receiving means for receiving verification data, which is information that can be used to verify the identity between the deposit data and the backup data, and is stored in the deposit data and the depositor apparatus. Verification means for verifying the identity of the backup data using the tag and the verification data, determination means for obtaining the difference t between the number of backup data successfully verified and the threshold T, and the backup successfully verified above When the number of data is smaller than the threshold value T, the second counter trustee device transmitting means for sending the deposit data to at least t trustee devices, The depositor device uses the deposit data transmitted from the administrator device to the manager device receiving means, storage means for storing the deposit data as backup data, and deposit data using the backup data stored in the storage means. Verification data generation means for generating verification data, which is information capable of verifying the identity of data and backup data, and anti-administrator apparatus transmission means for transmitting verification data to the administrator apparatus.

  In the distributed backup method of the present invention, the storage means of the depositor device has the depositor identification information for identifying the predetermined data (deposit data) to be backed up and the depositor device as the deposit destination of the deposit data. And the threshold value T of the number of legitimate backup data stored therein, the tag generation means of the depositor device generates the deposit data and the backup data stored in the trustee device using the deposit data. Generating step for generating information (tag) that can verify the identity of the depositing device, and a first paired trustee device transmitting step in which the first paired trustee device transmitting means of the depositor device transmits the deposit data to the trustee device The depositor device receiving means of the trustee device receives the deposit data transmitted from the depositor device; and the storage device of the trustee device stores the deposit data. The step of storing as backup data and the verification data generation means of the trustee device can verify the identity of the deposit data and the backup data using the backup data stored in the storage means of the trustee device. A verification data generation step for generating verification data that is information; a depositor device transmission means for the depositor device; a counter depositor device transmission step for transmitting verification data to the depositor device; and a depositor device The trustee device receiving means receives the verification data from the trustee device, and the depositor device verification means uses the same data between the deposit data and the backup data stored in the trustee device. Verifying using a tag and verification data, and the determination means of the depositor device, the number of backup data successfully verified If the determination step for obtaining the difference t from the value T and the second pair trustee device transmission means of the depositor device has a number of backup data that has been successfully verified is smaller than the threshold value T, the deposit data is determined to be at least t And a second pair trustee device transmission step for sending to the trustee device.

  Alternatively, in the distributed backup method of the present invention, predetermined data (deposited data) to be backed up is stored in the storage means of the depositor apparatus, and valid backup data is stored in the storage means of the administrator apparatus. Assuming that the threshold value T is stored, the tag generation means of the depositor apparatus can use the deposit data to verify the identity between the deposit data and the backup data stored in the trustee apparatus (tag ) Generating step, the depositor device's counter-administrator device transmitting means transmits the deposit data and tag to the manager device, and the administrator device's counter-collector device receiving means. The depositor device receiving step for receiving the deposit data and the tag transmitted from the depositor device, and the storage means of the manager device include the deposit data, the tag, and the deposit data. A storage step for storing trustee identification information for identifying a trustee device that is a deposit destination, and a first pair of trustee devices in which the first pair of trustee device transmitting means of the manager device transmits the deposit data to the trustee device. A device sending step, a manager device receiving means of the trustee device receiving the deposit data transmitted from the manager device, and a storage means of the trustee device storing the deposit data as backup data And the verification data generation means of the trustee device using the backup data stored in the storage means, the verification data that is information that can verify the identity of the deposit data and the backup data A verification data generation step to generate, and a counter device transmission means for the trustee device to transmit the verification data to the administrator device; The trustee device receiving means of the administrator device receives the verification data from the trustee device, and the backup device stored in the depositor data and the trustee device is the verification device of the administrator device. A verification step for verifying the identity with the verification data using a tag and verification data, and a determination step for determining a difference t between the number of backup data and the threshold T by the determination means of the administrator device, When the second pair trustee device transmitting means of the manager device has less than the threshold value T for the backup data successfully verified, the second pair trustee device transmits the deposit data to at least t trustee devices. A transmission step.

  According to the present invention, by using the tag generated using the deposit data and the verification data generated using the backup data that the trustee device wants to store, the identity of the two is verified, and the backup is performed. Data validity can be verified. Further, since the validity of the backup data can be verified by mutual communication between the trustee device and the depositor device / manager device, the management cost can be reduced.

Embodiment 1
The distributed backup system according to the first embodiment includes an administrator device that is a computer of an administrator who manages the system, a depositor device that is a computer of a user who is a depositor of data (hereinafter referred to as “deposit data”), It consists of a trustee device, which is a trustee's computer that will hold the deposited data as backup data in the storage. Note that the terms “depositor device” and “trustor device” are words used from the standpoint of certain deposit data X, and the device (computer) used by the user is also the depositor device. It must be noted that it can also be.

  Therefore, after describing the administrator device, the depositor device, and the trustee device, the system configuration of the distributed backup system in the first embodiment will be described. Then, the processing procedure of the distributed backup method in the system will be described descriptively.

[Distributed backup system]
<Depositor Device>
The depositor apparatus according to the first embodiment will be described.
FIG. 1 is a configuration block diagram illustrating the hardware configuration of the depositor apparatus (2) according to the first embodiment.

  As illustrated in FIG. 1, the depositor apparatus (2) includes an input unit (21) to which an input device such as a keyboard and a pointing device can be connected, an output unit (22) to which an output device such as a liquid crystal display can be connected, Depositor apparatus (2) A communication unit (23) to which a communication apparatus (for example, a communication cable) that can communicate with the outside can be connected, and a CPU (Central Processing Unit) (24) [may include a cache memory or the like. ] RAM (25) and ROM (26), which are memories, an external storage device (27), which is a hard disk, and their input unit (21), output unit (22), communication unit (23), CPU (24), The bus (28) is connected so that data can be exchanged between the RAM (25), the ROM (26), and the external storage device (27). If necessary, the depositor apparatus (2) may be provided with a device (drive) that can read and write a storage medium such as a CD-ROM. A physical entity having such hardware resources includes a general-purpose computer.

  In the external storage device (27) of the depositor apparatus (2), a program for generating information used by the administrator apparatus (1) for verification relating to the identity between the deposit data and the backup data from the deposit data, and this program Data necessary for the above processing is stored (not limited to an external storage device, but a program or data may be stored in a ROM that is a read-only storage device, for example). Further, data obtained by the processing of this program is appropriately stored in a RAM, an external storage device, or the like. Hereinafter, a storage device such as a RAM or a register for storing an operation result, an address of a storage area thereof, or the like is simply referred to as a “storage unit”.

  More specifically, the deposit data X is stored in the external storage device (27) of the depositor apparatus (2) in the external storage device (27) [or ROM, etc.] of the depositor apparatus (2). To do. In addition, a program for generating information (tag) that can verify the identity of the deposit data X and the backup data stored in the trustee device using the deposit data X is stored. In addition, a control program for controlling processing based on this program is also stored as appropriate.

  In this specification, the deposit data X is made up of a bit string for convenience of explanation. In particular, when the administrator device, depositor device, and trustee device are realized by a computer, any information (for example, information in a text format that can be understood by humans) is expressed in binary. Needless to say, it is stored in an external storage device (or ROM or the like) as a bit string. The deposit data X may be data encrypted by a publicly known method as necessary.

  In the depositor device (2), each program stored in the external storage device (27) [or ROM, etc.] and data necessary for processing each program are read into the RAM (25) as necessary, and the CPU Interpretation is executed and processed in (24). As a result, the CPU (24) realizes a predetermined function (tag generation unit, control unit).

<Administrator device>
An administrator device according to the first embodiment will be described.
FIG. 2 is a configuration block diagram illustrating the hardware configuration of the administrator device (1) according to the first embodiment.

  As illustrated in FIG. 2, the administrator device (1) includes an input unit (11) to which an input device such as a keyboard and a pointing device can be connected, an output unit (12) to which an output device such as a liquid crystal display can be connected, Administrator device (1) A communication unit (13) to which a communication device (for example, a communication cable) that can communicate with the outside can be connected, and a CPU (Central Processing Unit) (14) [may include a cache memory. ] RAM (15) and ROM (16), which are memories, an external storage device (17), which is a hard disk, and their input unit (11), output unit (12), communication unit (13), CPU (14), The bus (18) is connected so that data can be exchanged between the RAM (15), the ROM (16), and the external storage device (17). If necessary, the administrator device (1) may be provided with a device (drive) that can read and write a storage medium such as a CD-ROM. A physical entity having such hardware resources includes a general-purpose computer.

  The external storage device (17) of the administrator device (1) stores a program necessary for verifying that the trustee device holds deposit data, data necessary for processing of this program, and the like. (Not limited to an external storage device, for example, a program or data may be stored in a ROM which is a read-only storage device.) Further, data obtained by the processing of this program is appropriately stored in a RAM, an external storage device, or the like. Hereinafter, a storage device such as a RAM or a register for storing the calculation result and the address of the storage area is simply referred to as a “storage unit”.

  More specifically, in the external storage device (17) of the administrator device (1), the tag received from the depositor device (2) and the deposit data and backup generated by the trustee device using the backup data. A program for verifying using verification data, which is information that can verify the identity of the data, a program for determining the difference t between the number of backup data successfully verified and the threshold T, and the like are stored. Yes. In addition, a control program for controlling processing based on these programs is also stored as appropriate.

  In the administrator device (1), each program stored in the external storage device (17) [or ROM, etc.] and data necessary for processing each program are read into the RAM (15) as necessary, and the CPU Interpretation is executed and processed in (14). As a result, the CPU (14) realizes predetermined functions (verification unit, determination unit, control unit).

<Trustee device>
The trustee apparatus in the first embodiment will be described.
FIG. 3 is a configuration block diagram illustrating the hardware configuration of the trustee apparatus (3) according to the first embodiment.

  As illustrated in FIG. 3, the trustee device (3) includes an input unit (31) to which an input device such as a keyboard and a pointing device can be connected, an output unit (32) to which an output device such as a liquid crystal display can be connected, Trustee device (3) A communication unit (33) to which a communication device (for example, a communication cable) that can communicate with the outside can be connected, and a CPU (Central Processing Unit) (34) [may include a cache memory. ] RAM (35) and ROM (36) as a memory, an external storage device (37) as a hard disk, and an input unit (31), an output unit (32), a communication unit (33), a CPU (34), The bus (38) is connected so that data can be exchanged between the RAM (35), the ROM (36), and the external storage device (37). If necessary, the trustee device (3) may be provided with a device (drive) that can read and write a storage medium such as a CD-ROM. A physical entity having such hardware resources includes a general-purpose computer.

  The external storage device (37) of the trustee device (3) stores a program for generating information used by the administrator device (1) for verification, data necessary for processing of this program, and the like ( Not only the external storage device but also a program or data may be stored in a ROM which is a read-only storage device, for example. Further, data obtained by the processing of this program is appropriately stored in a RAM, an external storage device, or the like. Hereinafter, a storage device such as a RAM or a register for storing the calculation result and the address of the storage area is simply referred to as a “storage unit”.

  More specifically, the external storage device (37) [or ROM, etc.] of the trustee device (3) has backup data as verification data, which is information that can verify the identity of the deposit data and the backup data. A program and the like for use and generation are stored. In addition, a control program for controlling processing based on this program is also stored as appropriate.

  In the trustee device (3), each program stored in the external storage device (37) [or ROM, etc.] and data necessary for processing each program are read into the RAM (35) as necessary, and the CPU Interpretation is executed and processed in (34). As a result, the CPU (34) realizes a predetermined function (verification data generation unit, control unit).

<System configuration>
A system configuration of the distributed backup system (5) in the first embodiment will be described.
FIG. 4 is a diagram showing a system configuration of the distributed backup system (5).

  In the first embodiment, one administrator device (1), a plurality of depositor devices (2), and a plurality of trustee devices (3) are mutually connected via a communication network (6) such as the Internet. It is connected so that it can communicate.

  In the present invention, there may be a plurality of depositor apparatuses (2) due to the nature of the distributed backup. However, for convenience of explanation, the number of depositor apparatuses (2) is one [FIG. 4 shows this case. Yes. ]. In other words, from the standpoint of certain deposit data X, there is only one depositor device that is the original owner, and in this sense, the depositor device (2) will be described as one.

  In the following description, in order to distinguish a plurality of trustee devices, f trustee devices are denoted by hyphened symbols (3-1), (3-2), ..., (3-f ). Similarly, the functional units of each device are also distinguished by applying a hyphenated code.

[Distributed backup method processing procedure]
Next, the processing procedure of the distributed backup method in the distributed backup system (5) will be described descriptively.
The first embodiment shows one basic embodiment, and can be extended to various embodiments without departing from the gist of the present invention. Hereinafter, a description will be given with reference to FIGS. 5 and 6. In addition, in the figure which shows the functional block diagram of each apparatus, although the function part to which the same code | symbol was given is shown, it does not show each different thing and is only shown separately for convenience of explanation. . The same applies to the drawings in the embodiments.

<Preparation>
An ID that is information for identifying the depositor device (2) and a corresponding authenticator (information such as a password and password, or physical ownership such as a hardware token or IC card, or biological information such as a fingerprint or an iris , Etc. can be exemplified)) is previously registered in the storage unit of the administrator device (1).

<Deposit procedure>
The tag generation unit (201) of the depositor device (2) is stored in the deposit data X and the depositor devices (3-1, 3-2,..., 3-f) using the deposit data X. Information (tag) Y capable of verifying the identity with the backup data is generated (step S1).

  Here, the tag Y can uniquely identify the deposit data X with high probability. The tag Y is preferably data having a smaller data amount than the deposit data X.

Although there is no limitation in the generation algorithm of the tag Y, an example is demonstrated here.
[Tag generation algorithm]
<1> Prime numbers such that (p-1) / 2 and (q-1) / 2 are also prime numbers are randomly selected as p and q.
<2> N = p × q is calculated.
<3> gε {(Z / NZ) ^* | (a / N) = 1, a ≠ 1, a and N are mutually prime} (g = 2 may be used). (Z / NZ) ^* is a remainder ring. The symbol (•) is a Legendre symbol.
<4> W = X (mod LCM (p-1, q-1)) is calculated.
<5> Y = g ^W (mod N) is calculated.

  The prime number selection of the tag generation algorithm <1> may be performed for each deposit data or may be performed for each user.

The calculation of the modulus N of the tag generation algorithm <2> will be described.
In this algorithm, the modulo N is a natural number excluding a number that can be determined to be a prime number, and may be a number that is difficult to be prime factorized. When N is a prime number, the order of multiplication of the remainder ring (Z / NZ) ^* modulo N can be easily obtained by calculating N-1. Therefore, it is desirable that the number that can be determined to be a prime number is not the constant N. Further, when N is a composite number (where N = p · q, and p and q are sufficiently large prime numbers), the remainder ring (Z / NZ) ^* modulo N is the order p · It becomes a cyclic group of qp-q + 1. Therefore, if the prime factorization of N is easy, the order of multiplication of the remainder ring (Z / NZ) ^* modulo N can be obtained from p and q satisfying N = p · q. On the other hand, if this order is known and the power-residue result can be collided, it is known that the prime factorization of N can be performed using such information (for example, G. Miller. Riemanann's hypothesis and tests for primality. See Journal of Computer Systems Science, Vol. 13, pages 300-317, 1976.). That is, when N is a composite number, obtaining the above order is more difficult than performing prime factorization of N (if N is a composite number consisting of two prime numbers, these difficulties are Equivalent).

  Therefore, it is desirable that N be a natural number excluding a number that can be determined to be a prime number and that is difficult to be prime factorized. Note that “a number that can be determined to be a prime number” means a number that can be determined to be “prime” by using a prime number determination method publicly known at the time of filing this application, "Something" means a publicly known number.

Further, N may be a composite number that is a product of three or more prime numbers. In this case, even if the attacker can factor N, the attacker cannot easily calculate the order of multiplication of the remainder ring (Z / NZ) ^* modulo N. From the viewpoint of calculation efficiency, N is a natural number excluding a number that can be determined to be a prime number and is difficult to be prime factorized (however, when N is a composite number, N = p · q, It is desirable that p and q be sufficiently large prime numbers).

Further, a composite number N that is difficult to prime factor generation may be generated as a number close to a power of 2, for example, a composite number N that can be expressed in the form of 2 ^m −1. In such a composite number N, the remainder calculation by the composite number N can be calculated by replacing 2 ^m with 1, for example, and such an operation is realized by a shift operation or bit rearrangement in a normal CPU. be able to. Therefore, a high-speed remainder operation can be realized. Such a composite number N can be generated efficiently by a probabilistic algorithm, and tables of numbers that are difficult to factorize are known, so a composite number N close to a power of 2 is selected from such a table You may make it do.

  Further, g is preferably relatively prime to N. This is because if g is not relatively prime with N and information to that effect is known to the attacker, the attacker may be able to use the information of g as information for factoring N ( For example, a process of trying whether or not the divisor of g is a divisor of N can be considered.

  The control unit (203) of the depositor apparatus (2) controls the communication unit (23) of the depositor apparatus (2) to transmit the deposit data X and the tag Y to the administrator apparatus (1) (step S2 ). After this processing, the depositor apparatus (2) may delete the deposit data X and the tag Y from the storage unit.

  The control unit (103) of the administrator device (1) receives the deposit data X and the tag Y transmitted from the depositor device (2) via the communication unit (13) of the administrator device (1) ( Step S3).

  The control unit (103) of the administrator device (1) associates the deposit data X and the tag with the ID of the depositor device (2) registered in <preparation> in the storage unit of the administrator device (1). Y is stored. Furthermore, each ID (trustee identification information) of the trustee device (3-1,..., 3-d) selected by the control unit (103) of the manager device (1) is also the depositor device (2 ) And stored in the storage unit of the manager device (1) (step S4). In the first embodiment, it is assumed that the threshold T of the number of valid backup data is also stored in the storage unit of the administrator device (1) in association with the ID of the depositor device (2). The threshold T may be a value unique to the distributed backup system (5) (common to the depositor device), a value unique to the depositor device (2), or a value determined for each deposit data X. When the threshold T is determined by the depositor apparatus (2), the threshold T is also transmitted and received in the <preparation> stage or in the processes of steps S2 and S3. Furthermore, the transmission / reception time of the deposit data X may be associated with the ID of the depositor apparatus (2) and stored in the storage unit of the administrator apparatus (1).

  The control unit (103) of the manager device (1) controls the communication unit (13) of the manager device (1) to select the depositor device (3-1,... 3-d) (step S5). In addition, after this process, the administrator device (1) may delete the deposit data X from the storage unit.

  The control units (303-1,..., 303-d) of the trustee devices (3-1,..., 3-d) respectively have their own communication units (33-1,..., 33). The deposit data X transmitted from the manager device (1) is received via -d) (step S6).

  Each trustee device (3-1, ..., 3-d) is controlled by a control unit (303-1, ..., 303-d) of each trustee device (3-1, ..., 3-d). The deposit data X is stored as backup data in the storage section d) (step S7). In this way, the deposit data X is normally distributed and backed up to a plurality of trustee devices.

<Renewal procedure>
Each process of step S1-S7 is implemented regularly or irregularly according to a plurality of deposit data. Also, the deposit data X once deposited can be distributed and backed up again. However, the administrator device (1) compares the deposit data X received from the depositor device (2) with the deposit data X received before, and if there is no change of 1 bit, the transmission / reception time of the deposit data X It is not necessary to update only to the latest and perform other processing. If the changed part is smaller than the deposit data X currently stored, the process of adding the changed part ΔX may be performed in accordance with the above-described process. This update procedure is an arbitrary process.

<Verification procedure>
The administrator device (1) can be used regularly or irregularly in response to a request from the depositor device (2), in the event of any accident or trouble, or at regular intervals. It is verified whether the backup data of each depositor device (3-1,..., 3-d) that is the deposit destination of the deposit data X is correctly stored as the backup data of the deposit data X.

  When the verification start is notified from the administrator device (1), the verification data generation unit (301-1, ..., 301-d) of each trustee device (3-1, ..., 3-d). However, using the backup data stored in its own storage unit, verification data, which is information capable of verifying the identity between the deposit data X and the backup data, is generated (step S8).

  The control unit (303-1, ..., 303-d) of each trustee device (3-1, ..., 3-d) has its own communication unit (33-1, ..., 33-d). d) is controlled, and the verification data generated by its own verification data generation unit (301-1,..., 301-d) is transmitted to the administrator device (1) (step S9).

  The control unit (103) of the administrator device (1) is transmitted from each trustee device (3-1, ..., 3-d) via the communication unit (13) of the administrator device (1). The verification data is received (step S10).

Then, the verification unit (104) of the manager device (1) performs the deposit data X and the backup data stored in the trustee device for each trustee device (3-1,..., 3-d). Are verified using the tag Y and verification data (step S11). The number s that has been successfully verified (the number of backup data stored by the trustee device is the correct backup data of the deposit data X) is stored in the storage unit of the administrator device (1).
The above is the <Verification Procedure>.

  A specific verification method is a protocol that can confirm which trustee device is correctly storing the deposit data X as backup data, and even if a person who stole the protocol (a fraudster) imitates it, A method in which an unauthorized person cannot pretend that the deposit data X is stored as backup data is preferable.

Although the verification method is not limited, an example will be described here.
[Verification method]
<1> The random number generation unit of the administrator device (1) selects a random number rε [0,..., N], and calculates R = g ^r (mod N).
<2> The verification start unit of the administrator device (1) generates a session ID, and an electronic signature (for example, specified by a Schnorr signature (ISO / IEC14888-3)) using a random number r as a secret key and R as a public key. , It is performed on the session ID, and this is set as σ.
<3> The control unit (103) of the administrator device (1) controls the communication unit (13) to assign R, signature σ, and session ID to each trustee device (3-1, ..., 3-d). ). The control unit of each trustee device (3-1,..., 3-d) receives R, signature σ, and session ID from the administrator device via its own communication unit.
<4> Each trustee device (3-1,..., 3-d) has R∈ {(Z / NZ) ^* | (a / N) = 1, a and N are relatively prime} and a session ID. The signature σ corresponding to is confirmed. If it cannot be confirmed, the process is stopped.
<5> When the above confirmation is made, the verification data generation unit of each trustee device (3-1,..., 3-d) calculates H = R ^X (mod N) (in step S8). Equivalent). However, X is the backup data memorize | stored in the memory | storage part of a trustee apparatus.
<6> The control unit of each trustee device (3-1,..., 3-d) controls its own communication unit and transmits H to the administrator device (corresponding to step S9). The control unit of the manager device (1) receives H from each trustee device (3-1,..., 3-d) via its own communication unit (corresponding to step S10).
<7> The verification unit (104) of the administrator device (1) confirms that H = Y ^r (mod N) for each trustee device (3-1,..., 3-d). If the verification is successful, the verification is successful.

  In the exemplified verification method, the session ID is used. However, the present invention is not limited to this. Any information can be used as long as it is a value that cannot be fraudulent for the administrator device and the trustee device and is different every time. Is possible. For example, it is possible to use time information by a time signal station, or a combination of the ID of the administrator device (1) and the ID of the trustee device (for example, bit string combination of both IDs represented by bit strings).

  When using the communication network (6) that can guarantee the communication destination (for example, SSL partner authentication using PKI (Public Key Infrastructure)), an unpublished patent application (Japanese Patent Application No. 2005-204954) ) Can be used for the verification method.

  This authentication technique is a technique that enables a specified or unspecified device to prove and verify that predetermined information is held therein. According to this authentication technology, the administrator device communicably connected to the trustee device in which the backup data is stored is identical to the backup data and arbitrary comparison information (corresponding to deposit data). To verify. The administrator device has contents that depend on the contents of the comparison information, and includes verification information having an information amount that does not depend on the information amount of the comparison information, and first arbitrary information that is arbitrary information in the first storage unit. Remember. Further, the administrator device generates an authentication information generation factor for causing the trustee device to generate authentication information using the first arbitrary information stored in the first storage unit, and the generated authentication information generation factor is entrusted. To the user device. The trustee device receives the authentication information generation factor and uses the authentication information generation factor and the backup data stored in the second storage unit, and the content depends on the contents of the authentication information generation factor and the backup data. And authentication information having an information amount that does not depend on the information amount of the backup data. Next, the trustee device transmits this authentication information to the administrator device. The administrator device receives the authentication information transmitted by the trustee device, and the determination unit of the administrator device has the authentication information between the verification information and the first arbitrary information stored in the first storage unit, It is determined whether or not a predetermined relationship is established. Thereby, the manager device verifies that the backup data stored in the trustee device is the same as the comparison information.

  Further, the administrator device that performs the verification procedure may not be the same as the administrator device that is the distribution source of the deposit data X (the administrator device for verification and the administrator device for deposit data distribution are separated). The specification is possible, and a database in which the ID, the deposit data X, the tag Y and the like are associated with each other may be shared by both administrator apparatuses. In such a case, the electronic device or the like may be used to indicate that the administrator device that has distributed the deposit data X and the administrator device that performs the verification procedure are the same or the device that is entrusted to perform the verification procedure.

  The determination unit (105) of the administrator device (1) stores the number s (the number of backup data stored in the trustee device that is the correct backup data of the deposit data X) and the storage unit that have been successfully verified. The difference t from the threshold value T is determined (step S12).

  When the number s of successful verifications is smaller than the threshold T, the control unit (103) of the administrator device (1) selects new trustee devices and transmits the deposit data X to these trustee devices ( Step S13). If there is no deposit data X in the manager device (1), the deposit data X may be received again from the depositor device (2) and transmitted to the new trustee device. In addition, when the depositor device (2) does not have the deposit data X, the backup data may be received from the depositor device that has been successfully verified and transmitted to the new trustee device. The newly selected trustee device may be a trustee device that has failed verification, or may be a device other than the trustee device that has failed verification. The number of newly selected trustee devices is t or more. This is because there are T or more trustee devices that store backup data of the deposit data X.

<Return procedure>
The administrator device (1) can be used regularly or irregularly in response to a request from the depositor device (2), in the event of any accident or trouble, or at regular intervals. A procedure for returning the backup data stored in the trustee device to the depositor device (2) is performed.

  When the identity authentication unit of the administrator device (1) receives a notification of a return request for the deposit data X from the depositor device (2), for example, with the depositor device (2) that is the partner to be returned, User authentication is performed using the user ID and authenticator registered in <Preparation>. When the personal authentication is successful, the manager device (1) sends a notification to the trustee device that the deposit data X is sent to the manager device to the trustee device that has been successfully verified. The trustee device that has received this notification confirms that the notification is from the administrator device (1) (for example, verifies the electronic signature attached to the notification) and transfers the backup data to the administrator device (1). Send to. The administrator device (1) transmits the received backup data to the depositor device (2) that is the depositor. The administrator device (1) may check the consistency with the deposit data X again using the tag Y for the received backup data. If the depositor device (2) and the trustee device can communicate with each other, the administrator device (1) manages the deposit data X to the trustee device that has been successfully verified. Information indicating the depositor device (2) is transmitted to the trustee device together with a notification to the effect that it is transmitted to the device, and the trustee device that has received them sends the information to the depositor device (2) via the manager device (1). The backup data may be transmitted without it.

  In the first embodiment, the user device is divided into the depositor device and the trustee device from the standpoint of the deposit data X. However, since the user device can be either the depositor device or the trustee device, from the viewpoint of the user device. In this case, it is preferable that each user device has functions of a tag generation unit and a verification data generation unit.

<< Embodiment 2 >>
The first embodiment is a hybrid distributed backup system in which an administrator device is interposed between a depositor device and a trustee device. In the second embodiment, a P2P (Peer-to-Peer) type distributed backup system will be described.

  The difference from the first embodiment is that in the second embodiment, the depositor device (2) implements the function of the administrator device (1). Accordingly, items that are not different from those of the first embodiment are assigned the same reference numerals and description thereof is omitted.

  The distributed backup system according to the second embodiment is a depositor device that is a computer of a user who is a depositor of deposit data, and the depositor's computer that holds the deposit data deposited from the depositor device as backup data in the storage. Consists of trustee devices.

[Distributed backup system]
<Trustee device>
The hardware configuration example and the functional configuration example are the same as those in the first embodiment.

<Depositor Device>
The depositor apparatus in the second embodiment will be described. A hardware configuration example of the depositor apparatus is as shown in FIG.

  In the external storage device (27) of the depositor device (2a), a program for generating information used for verification related to the identity between the deposit data and the backup data from the deposit data, the trustee device holds the deposit data. A program necessary for verifying that the program is stored and data necessary for processing the program are stored (not limited to an external storage device, for example, a program or data stored in a ROM that is a read-only storage device). It may be memorized.) Further, data obtained by the processing of this program is appropriately stored in the storage unit.

  More specifically, when the deposit data X is stored in the external storage device (27) of the depositor apparatus (2a) in the external storage device (27) [or ROM etc.] of the depositor apparatus (2a). To do. In addition, a program for generating information (tag) that can verify the identity between the deposit data X and the backup data stored in the trustee device, using the deposit data X, and the trustee device backup data A program for verifying using verification data, which is information that can be used to verify the identity between deposit data and backup data, and the difference t between the number of backup data successfully verified and the threshold T A program or the like for determining is stored. In addition, a control program for controlling processing based on this program is also stored as appropriate.

  In the depositor apparatus (2a), each program stored in the external storage device (27) [or ROM, etc.] and data necessary for processing each program are read into the RAM (25) as necessary, and the CPU Interpretation is executed and processed in (24). As a result, the CPU (24) realizes predetermined functions (tag generation unit, verification unit, determination unit, control unit).

<System configuration>
A system configuration of the distributed backup system (5a) in the second embodiment will be described.
FIG. 7 is a diagram showing a system configuration of the distributed backup system (5a).

  In the first embodiment, a plurality of depositor devices (2a) and a plurality of trustee devices (3) are connected to each other via a communication network (6) such as the Internet. For convenience of explanation, the number of depositor apparatuses (2a) is one, and the reason is as described in the first embodiment.

[Distributed backup method processing procedure]
Next, the processing procedure of the distributed backup method in the distributed backup system (5a) will be described descriptively.
The second embodiment shows one basic embodiment, and can be extended to various embodiments without departing from the gist of the present invention. Hereinafter, a description will be given with reference to FIGS.

  The <preparation> described in the first embodiment is not necessary in the second embodiment unless there are special circumstances.

<Deposit procedure>
Using the deposit data X, the tag generator (201) of the depositor apparatus (2a) uses the deposit data X and backup data stored in the depositor apparatuses (3-1,..., 3-f). Information (tag) Y capable of verifying the identity is generated (step S1a). The property of the tag Y and its generation algorithm are the same as in the first embodiment.

  The control unit (203) of the depositor apparatus (2a) selects the trustee apparatus (3-1, ..., 3-d) and controls the communication unit (23) of the depositor apparatus (2). The deposit data X is transmitted to the selected trustee devices (3-1,..., 3-d) (step S2a). The storage unit of the depositor device (2) stores at least the tag Y, and each ID (trustee) of the depositor devices (3-1,..., 3-d) to which the deposit data X is distributed. (Identification information) is also stored. In the second embodiment, it is assumed that the threshold value T of the number of valid backup data is also stored in the storage unit of the depositor apparatus (2). After this processing, the depositor apparatus (2) may delete the deposit data X from the storage unit.

  The control units (303-1,..., 303-d) of the trustee devices (3-1,..., 3-d) respectively have their own communication units (33-1,..., 33). The deposit data X transmitted from the depositor apparatus (2a) is received via -d) (step S3a).

  Each trustee device (3-1, ..., 3-d) is controlled by a control unit (303-1, ..., 303-d) of each trustee device (3-1, ..., 3-d). The deposit data X is stored as backup data in the storage section d) (step S4a). In this way, the deposit data X is normally distributed and backed up to a plurality of trustee devices.

<Renewal procedure>
Each process of step S1-S4a is implemented regularly or irregularly according to a plurality of deposit data. Also, the deposit data X once deposited can be distributed and backed up again. If the changed part is smaller than the deposit data X currently stored, the process of adding the changed part ΔX may be performed in accordance with the above-described process. This update procedure is an arbitrary process.

<Verification procedure>
The depositor device (2a) is provided with each depositor device (3) to which the deposit data X is deposited when some accident or trouble occurs, or at regular or irregular intervals, such as at regular intervals. −1,..., 3-d) is verified as to whether the backup data of deposit data X is correctly stored.

  When the verification start is notified from the depositor apparatus (2a), the verification data generation unit (301-1, ..., 301-d) of each trustee apparatus (3-1, ..., 3-d). However, using the backup data stored in its own storage unit, verification data, which is information capable of verifying the identity between the deposit data X and the backup data, is generated (step S5a).

  The control unit (303-1, ..., 303-d) of each trustee device (3-1, ..., 3-d) has its own communication unit (33-1, ..., 33-d). d) is controlled, and the verification data generated by its own verification data generation unit (301-1,..., 301-d) is transmitted to the depositor apparatus (2a) (step S6a).

  The control unit (203) of the depositor apparatus (2a) is transmitted from each depositor apparatus (3-1, ..., 3-d) via the communication unit (23) of the depositor apparatus (2a). The verification data received is received (step S7a).

Then, the verification unit (204) of the depositing device (2a) calculates the deposit data X and the backup data stored in the trustee device for each trustee device (3-1,..., 3-d). The identity is verified using the tag Y and verification data (step S8a).
A specific verification method is as described in the first embodiment.
The above is the <Verification Procedure>.

  Now, the determination unit (205) of the depositor apparatus (2a) stores the number s (the number of backup data stored in the depositor apparatus that is the correct backup data of the deposit data X) and the storage unit that have been successfully verified. The difference t from the threshold value T is determined (step S9a).

  The control unit (203) of the depositor device (2a) selects a new trustee device and transmits the deposit data X to these trustee devices when the number of successfully verified s is less than the threshold value T ( Step S10a). If the deposit data X does not exist in the depositor apparatus (2a), backup data may be received from the depositor apparatus that has been successfully verified and transmitted to the new trustee apparatus. The newly selected trustee device may be a trustee device that has failed verification, or may be a device other than the trustee device that has failed verification. The number of newly selected trustee devices is t or more. This is because there are T or more trustee devices that store backup data of the deposit data X.

<Return procedure>
The depositor device (2a) stores the backup data stored in the trustee device periodically or irregularly, such as when some accident or trouble occurs, or at regular intervals. Perform the procedure for requesting the return in (2).

  The depositor apparatus (2a) transmits a notification to the depositor apparatus that the deposit data X is transmitted to the depositor apparatus (2a) to the depositor apparatus that has been successfully verified. The trustee device that has received the notification confirms that the notification is from the depositor device (2a) (for example, verifies the electronic signature attached to the notification), and stores the backup data as the depositor device (2a). Send to. The depositor apparatus (2a) may reconfirm the consistency with the deposit data X using the tag Y for the received backup data.

  In the second embodiment, the user device is divided into the depositor device and the trustee device from the standpoint of the deposit data X. However, since the user device can be either the depositor device or the trustee device, from the viewpoint of the user device. In this case, each user device preferably has the functions of a tag generation unit, a verification data generation unit, a verification unit, and a determination unit.

  The distributed backup system, distributed backup method, and the like according to the present invention are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention. For example, the tag generation method and the verification method can be changed as appropriate. The processes described in the distributed backup system / distributed backup method are not only executed in chronological order according to the order described, but also executed in parallel or individually as required by the processing capability of the apparatus that executes the processes. It may be done.

  Further, when the processing functions in the manager device, depositor device, and trustee device are realized by a computer, the processing contents of the functions that the administrator device, depositor device, and trustee device should have are described by a program. By executing this program on a computer, the processing functions of the manager device, depositor device, and trustee device are realized 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. Specifically, for example, as a magnetic recording device, a hard disk device, a flexible disk, a magnetic tape or the like, and as an optical disk, a DVD (Digital Versatile Disc), a DVD-RAM (Random Access Memory), a CD-ROM (Compact Disc Read Only). Memory), CD-R (Recordable) / RW (ReWritable), etc., magneto-optical recording medium, MO (Magneto-Optical disc), etc., semiconductor memory, EEP-ROM (Electronically Erasable and Programmable-Read Only Memory), etc. Can 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 administrator device, the depositor device, and the trustee device are configured by executing a predetermined program on the computer. However, at least a part of these processing contents is implemented in hardware. It may be realized.

  The present invention is useful for distributed backup of data.

The block diagram which illustrated the hardware constitutions of the depositor apparatus (2). The block diagram which illustrated the hardware constitutions of the administrator apparatus (1). The block diagram which illustrated the hardware constitutions of the trustee apparatus (3). The figure which illustrated the system configuration of the distributed backup system (5). The functional block diagram of the administrator apparatus (1) which concerns on Embodiment 1, a depositor apparatus (2), and a trustee apparatus (3). FIG. 3 is a diagram showing a processing flow in the first embodiment. The figure which illustrated the system configuration of the distributed backup system (5a). The functional block diagram of the depositor apparatus (2a) which concerns on Embodiment 2, and a trustee apparatus (3). The figure which shows the processing flow in Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Administrator apparatus 2 Depositor apparatus 2a Depositor apparatus 3, 3-1, 3-2, ..., 3-f Trustee apparatus 5 Distributed backup system 5a Distributed backup system 104 Verification part 105 Determination part 201 Tag generation part 204 Verification unit 205 Determination unit 301-1,..., 301-d Verification data generation unit

Claims (6)

A distributed backup system including a depositor device and a plurality of trustee devices, wherein at least the depositor device and the trustee device can communicate with each other;
The depositor device is
Storage means for storing predetermined data to be backed up (deposit data), trustee identification information for identifying the trustee device to which the deposit data is deposited, and a threshold T for the number of valid backup data;
Tag generation means for generating information (tag) that can verify the identity between the deposit data and the backup data stored in the trustee device, using the deposit data;
A first pair of trustee device transmitting means for sending deposit data to the trustee device;
A trustee device receiving means for receiving verification data generated from the trustee device using the backup data stored in the trustee device, which is information capable of verifying the identity of the deposit data and the backup data; ,
Verification means for verifying the identity of the deposit data and the backup data stored in the trustee device using the tag and the verification data;
Determining means for obtaining a difference t between the number of backup data successfully verified and the threshold T;
A second counter trustee device transmitting means for sending the deposit data to at least t trustee devices when the number of backup data successfully verified is less than the threshold T;
Each of the above trustee devices
A depositor device receiving means for receiving deposit data transmitted from the depositor device;
Storage means for storing deposit data as backup data;
Verification data generation means for generating verification data using backup data stored in the storage means;
A distributed backup system comprising: a depositor apparatus transmitting means for transmitting verification data to a depositor apparatus. A distributed backup system including an administrator device, a depositor device, and a plurality of trustee devices, at least capable of communicating with each other between the administrator device and the depositor device, and between the administrator device and the trustee device. And
The depositor device is
Storage means for storing predetermined data (deposited data) to be backed up;
Tag generation means for generating information (tag) that can verify the identity between the deposit data and the backup data stored in the trustee device, using the deposit data;
An administrator device transmitting means for transmitting the deposit data and the tag to the administrator device;
The administrator device is
A depositor device receiving means for receiving deposit data and a tag transmitted from the depositor device;
Storage means for storing deposit data, a tag, trustee identification information for identifying a trustee device to which the deposit data is deposited, and a threshold value T for the number of valid backup data;
A first pair of trustee device transmitting means for sending deposit data to the trustee device;
A trustee device receiving means for receiving verification data generated from the trustee device using the backup data stored in the trustee device, which is information capable of verifying the identity of the deposit data and the backup data; ,
Verification means for verifying the identity of the deposit data and the backup data stored in the trustee device using the tag and the verification data;
Determining means for obtaining a difference t between the number of backup data successfully verified and the threshold T;
A second counter trustee device transmitting means for sending the deposit data to at least t trustee devices when the number of backup data successfully verified is less than the threshold T;
Each of the above trustee devices
Anti-manager device receiving means for receiving deposit data transmitted from the manager device;
Storage means for storing deposit data as backup data;
Using the backup data stored in the storage means, verification data generation means for generating verification data that is information capable of verifying the identity of the deposit data and the backup data;
A distributed backup system comprising an anti-manager device transmitting means for transmitting verification data to an administrator device. A distributed backup method,
The storage means of the depositor apparatus includes predetermined data (deposit data) to be backed up, depositor identification information for identifying the depositor apparatus to which the deposit data is deposited, and a threshold value for the number of valid backup data T is stored,
A tag generation step in which the tag generation means of the depositor apparatus generates information (tag) that can be verified using the deposit data and can verify the identity between the deposit data and the backup data stored in the depositor apparatus;
A first pair of trustee device transmitting means for sending the deposit data to the trustee device;
The depositor device receiving means of the depositor device receives deposit data transmitted from the depositor device;
A storage step in which the storage means of the trustee device stores the deposit data as backup data;
The verification data generation means of the trustee device uses the backup data stored in the storage means of the trustee device to generate verification data that is information that can verify the identity between the deposit data and the backup data Data generation step,
The depositor device transmission means of the trustee device transmits the verification data to the depositor device, and the depositor device transmission step;
The depositor device's counter-trustor device receiving means receives the verification data from the trustee device;
A verification step in which the verification means of the depositor device verifies the identity of the deposit data and the backup data stored in the trustee device using a tag and verification data;
A determination step in which the determination means of the depositor apparatus obtains a difference t between the number of backup data successfully verified and the threshold T;
The second counter-trustor device that transmits the deposit data to at least t trustee devices when the number of backup data successfully verified by the second counter-trustee device transmission means of the depositor device is smaller than the threshold value T A distributed backup method comprising: a transmitting step; A distributed backup method,
The storage means of the depositor device stores predetermined data (deposit data) to be backed up,
The storage means of the administrator device stores a threshold value T for the number of valid backup data,
A tag generation step in which the tag generation means of the depositor device generates information (tag) that can verify the identity between the deposit data and the backup data stored in the trustee device, using the deposit data;
The manager device transmission means of the depositor device transmits the deposit data and the tag to the manager device;
The depositor device receiving means of the manager device receives the deposit data and tag transmitted from the depositor device;
A storage step in which the storage means of the manager device stores deposit data, a tag, and trustee identification information for identifying the trustee device that is the deposit destination of the deposit data;
A first pair of trustee device transmitting means for sending the deposit data to the trustee device;
The manager device receiving means of the trustee device receives the deposit data transmitted from the manager device;
A storage step in which the storage means of the trustee device stores the deposit data as backup data;
A verification data generation step in which the verification data generation means of the trustee device generates verification data, which is information capable of verifying the identity between the deposit data and the backup data, using the backup data stored in the storage means When,
The administrator device transmission means of the trustee device transmits the verification data to the administrator device;
The trustee device receiving means of the manager device receives the verification data from the trustee device;
A verification step in which the verification means of the administrator device verifies the identity of the deposit data and the backup data stored in the trustee device using the tag and the verification data;
A determination step in which a determination unit of the administrator device obtains a difference t between the number of backup data successfully verified and the threshold T;
When the second pair trustee device transmitting means of the manager device has less than the threshold value T for the backup data successfully verified, the second pair trustee device transmits the deposit data to at least t trustee devices. A distributed backup method comprising: a transmitting step; A depositor device in a distributed backup system comprising a depositor device and a plurality of trustee devices,
Storage means for storing predetermined data to be backed up (deposit data), trustee identification information for identifying the trustee device to which the deposit data is deposited, and a threshold T for the number of valid backup data;
Tag generation means for generating information (tag) that can verify the identity between the deposit data and the backup data stored in the trustee device, using the deposit data;
A first pair of trustee device transmitting means for sending deposit data to the trustee device;
A trustee device receiving means for receiving verification data generated from the trustee device using the backup data stored in the trustee device, which is information capable of verifying the identity of the deposit data and the backup data; ,
Verification means for verifying the identity of the deposit data and the backup data stored in the trustee device using the tag and the verification data;
Determining means for obtaining a difference t between the number of backup data successfully verified and the threshold T;
A depositor apparatus comprising a second pair of trustee apparatus transmitting means for transmitting deposit data to at least t trustee apparatuses when the number of backup data successfully verified is smaller than a threshold value T. An administrator device in a distributed backup system composed of an administrator device, a depositor device, and a plurality of trustee devices,
A pair that receives predetermined data (deposited data) to be backed up and information (tag) that can verify the identity between the deposited data and the backup data stored in the trustee device, transmitted from the depositor device. Depositor device receiving means;
Storage means for storing deposit data, a tag, trustee identification information for identifying a trustee device to which the deposit data is deposited, and a threshold value T for the number of valid backup data;
A first pair of trustee device transmitting means for sending deposit data to the trustee device;
A trustee device receiving means for receiving verification data generated from the trustee device using the backup data stored in the trustee device, which is information capable of verifying the identity of the deposit data and the backup data; ,
Verification means for verifying the identity of the deposit data and the backup data stored in the trustee device using the tag and the verification data;
Determining means for obtaining a difference t between the number of backup data successfully verified and the threshold T;
An administrator device comprising a second counter trustee device transmitting means for sending deposit data to at least t trustee devices when the number of backup data successfully verified is smaller than a threshold value T.

Images