JP7084525B1 - Organization signature key sharing device, organization signature key sharing system, organization signature key sharing program and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism capable of securely sharing a private key without using an IC card when digitally signing an organization to which a plurality of people belong. A system including a server and an organization signature key sharing device, wherein the organization signature key sharing device creates an organization signature key, divides the created organization signature key, and has a first fixed distributed key and a first. A distributed key creation unit that creates a user distributed key and a first padding distributed key for the first user, and a first fixed distributed key created for the first user by dividing the organization signature key. Of the first user distributed key and the first padding distributed key, the first user distributed key and the first padding distributed key are combined to create the first user intermediate key, and the first user intermediate key is divided. It is provided with a distributed key change unit that creates a second user distributed key and a second padding distributed key for the second user, and the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified. be. [Selection diagram] Fig. 2

Description

In the present disclosure, one signature key is divided into a plurality of pieces, and each of the divided signature keys is used for sequential signing, thereby creating the same signature value as when signing with one signature key before the division. It is about an electronic signature device.

In an electronic signature using public key cryptography, an electronic signature is created using a private key, and the correctness of the electronic signature is confirmed using the public key. An electronic signature has the same meaning as a handwritten signature in that only the owner can have the private key used to create the signature.
In electronic signature, as one of the methods that only the owner can have the private key, there is a method of storing the private key in a security device such as an IC card having resistance to duplication and performing electronic signature processing.
As another method, there is a technique of dividing a private key, distributing and storing each divided key in a plurality of different places, and collecting and creating the private key in one place only when creating a signature (for example, Patent Document). 1).

Japanese Unexamined Patent Publication No. 2010-231404

When the security is ensured by storing the private key in the IC card by the method of Patent Document 1, an electronic signature process using the private key by the IC card is required, and the cost and processing of mounting the IC card device are required. There are problems such as the burden of the above, the cost of the certificate for each individual, and the trouble of distributing each IC card to each owner.
This disclosure is made to solve the above-mentioned problems when digitally signing an organization to which a plurality of people belong, and is a mechanism that enables secure sharing of a private key without using an IC card. The purpose is to provide.

The organization signature key sharing device according to the present disclosure is a system including a server and an organization signature key sharing device, and the organization signature key sharing device creates an organization signature key, divides the created organization signature key, and obtains the first. 1 Fixed distributed key, 1st user distributed key, and 1st padding distributed key are created for the 1st user. The distributed key creation unit and the organization signature key are divided and created for the 1st user. , The first user intermediate key is created by synthesizing the first user distributed key and the first padding distributed key among the first fixed distributed key, the first user distributed key, and the first padding distributed key, and the first user. The first user distributed key and the second user distributed key are provided with a distributed key change unit that divides the intermediate key and creates a second user distributed key and a second padding distributed key for the second user. It is a key that can be specified arbitrarily.

According to the present disclosure, when digitally signing an organization to which a plurality of people belong, the private key can be safely shared without using an IC card.

The block diagram of the organization signature key sharing system which concerns on Embodiment 1. FIG. The functional block diagram of the organization signature key sharing system which concerns on Embodiment 1. FIG. The hardware configuration diagram of the organization signature key sharing system which concerns on Embodiment 1. FIG. The data structure diagram of the organization signature key sharing system which concerns on Embodiment 1. FIG. The flow diagram of the organization signature key sharing process which concerns on Embodiment 1. FIG. The functional block diagram of the organization signature key sharing system which concerns on modification 1 of Embodiment 1. FIG. The block diagram of the organization signature key sharing system which concerns on Embodiment 2. The functional block diagram of the organization signature key sharing system which concerns on Embodiment 2. The flow diagram of the organization signature key sharing process which concerns on Embodiment 2. FIG. The block diagram of the organization signature key sharing system which concerns on Embodiment 3. The functional block diagram of the organization signature key sharing system which concerns on Embodiment 3. The hardware configuration diagram of the organization signature key sharing system which concerns on Embodiment 3. The flow diagram of the organization signature key sharing process which concerns on Embodiment 3.

Embodiment 1.
*** Configuration of Embodiment 1 ***
The first embodiment is a system configuration of one organization signature key sharing device which is a dedicated management terminal for the signature key of the organization and one server for storing the distributed key and data.
Using the organization signature key sharing device, the first user who is an administrator creates a temporary organization signature key, and the second user who is a user gives the temporary organization signature key the organization signature for the second user. About the process of changing the temporary organization signature key created by the first user who is the administrator for the second user to the organization signature key for the second user by changing to the key. explain.
In the present embodiment, the organization signature key sharing device is a dedicated terminal used by the user when creating or changing a distributed key or signing an organization using the distributed key.
A user is an organization user who belongs to an organization.
The organization signature key is a private key that creates the signature value of the organization.
The distributed key is a plurality of private keys created by dividing one private key, and by signing with all the distributed keys, the same signature value as when signing with the private key before division is obtained. It is divided so that it can be created.
The data to be signed is some kind of electronic file, and any structure may be used as long as it can be given an electronic signature.
The act of signing is to calculate the signature value of the data to be signed with the organization signature key which is a private key or the distributed key created by dividing the organization signature key.

FIG. 1 is a configuration diagram of an organization signature key sharing system 1.
In this embodiment, the organization signature key sharing device 20, the network 30, and the server 10 are configured.
It should be noted that each device connected to the network 30 stores information necessary for communication with other devices, and can transmit and receive information to and from each other.

FIG. 2 is a functional configuration diagram showing a functional configuration of the organization signature key sharing system 1.
The organization signature key sharing device 20 includes a distributed key creating unit 201, a distributed key changing unit 202, a storage unit 203, a communication unit 204, and an input / output unit 205.
The distributed key creation unit 201 temporarily creates an organization signature key, divides the created organization signature key, and creates a first fixed distributed key 300, a first user distributed key 301, and a first padding distributed key 302. do.
The distributed key changing unit 202 synthesizes the first user distributed key 301 and the first padding distributed key 302 to temporarily create a user intermediate key, divides the created user intermediate key, and uses a new user distributed key. A second user distribution key 303 and a new padding distribution key 304 are created.
The first fixed distributed key 300 is a distributed key that is not changed after creation, the first user distributed key 301 and the second user distributed key 303 are distributed keys that can be changed by the user, and the first padding distributed key 302 is a distributed key. The first user distributed key 301 is a distributed key that is changed when the first user distributed key 301 is changed, and the second padding distributed key 304 is a distributed key that is changed when the second user distributed key 303 is changed.
The signature value created by sequentially using the first fixed distributed key 300, the first user distributed key 301, and the first padding distributed key 302 is the signature value created by signing using the organization signature key. It has the same signature value.
Further, the signature value created by sequentially signing the first user distributed key 301 and the first padding distributed key 302 synthesizes the signed first user distributed key 301 and the first padding distributed key 302. A signature created by sequentially using the second user distributed key 303, which is a new user distributed key created by dividing the user intermediate key created in the above process, and the second padded distributed key 304, which is a new padding distributed key. The signature value is the same as the value.
The storage unit 203 stores the created first user distribution key 301 and the second user distribution key 303.
The communication unit 204 communicates with the server 10 connected via the network 30.
The input / output unit 205 accepts input from the user and outputs information to the user.

The server 10 includes a server storage unit 101 and a server communication unit 102.
The server storage unit 101 stores the first fixed distribution key 300, the first padding distribution key 302, the second padding distribution key 304, and the key management data 411.
The server communication unit 102 communicates with the organization signature key sharing device 20 connected via the network 30.

Each function of the organization signature key sharing system 1 having the above configuration is realized by the hardware as shown in FIG. This hardware includes a processing device 501 such as a CPU (Central Processing Unit), a storage device 502 such as a ROM (Read Only Memory) and a hard disk device, a communication device 503 connected to other hardware by a network 30, a keyboard, and the like. It has a configuration in which an input / output device 504 such as a mouse, a speaker, and a display is connected by a bus. The CPU may have its own memory.
In the present embodiment, the organization signature key sharing device includes a processing device 501, a storage device 502, a communication device 503, and an input / output device 504, and the server 10 includes a processing device 501 and a storage device 502. , Communication device 503 and the like.
The number of processing devices 501 may be plural, and the plurality of processing devices 501 may execute programs that realize each function in cooperation with each other.

FIG. 4 is a data structure diagram.
The key management data 411 includes items of an organization ID that identifies an organization, a distributed key group ID that identifies a distributed key group, and a distributed key group that is information on a combination of distributed keys. The distributed key group holds combination information in the order of fixed distributed key, user distributed key, and padding distributed key so that each distributed key can be identified. It should be noted that the fixed distributed key, the user distributed key, and the padding distributed key are set as separate items, and the three items are treated as a distributed key group. Using other means such that each distributed key and its combination can be identified. May be good.
Since a plurality of combinations of distributed keys can be shared within the same organization, the key management data 411 is unique between the organization ID and the distributed key group ID.
Further, as will be described later, the key management data 411 is changed by the distributed key creating unit 201 and the distributed key changing unit 202.

*** Operation of Embodiment 1 ***
The operation of the organization signature key sharing system 1 will be described with reference to the flow chart of FIG.
In FIG. 5, the organization signature key sharing device 20 that receives the distributed key creation request by designating the organization 1 having the organization ID “S1” from the first user who is the administrator creates the distributed key and is the user. The flow of the process in which the organization-signed key sharing device 20 that has received the distribution key change request from the second user changes the distribution key will be described.

When the input / output unit 205 of the organization signature key sharing device 20 receives the distribution key creation request by designating the organization ID "S1" and the distribution key group ID "G1" from the first user, the distribution key creation unit 201 receives the distribution key creation request. Temporarily create an organization signing key. After that, the distributed key creation unit 201 divides the created organization signature key into a first fixed distributed key 300 which is a fixed distributed key, a first user distributed key 301 which is a user distributed key, and a padding distributed key. The first padding distribution key 302 is created. After that, the distributed key creation unit 201 deletes the temporarily created organization signature key. After that, the distributed key creation unit 201 assigns a key ID to the created distributed key and creates distributed key group information (step S101).
Here, the distributed key ID "300" is assigned to the first fixed distributed key 300, the distributed key ID "301" is assigned to the first user distributed key 301, and the distributed key ID "" is assigned to the first padding distributed key 302. It is assumed that the distributed key group information of "300, 301, 302" is created assuming that "302" is numbered.
Although not specifically described, the issuance of a digital certificate to an organization signature key is the same as the certificate issuance process by a general certificate authority.

After that, the distributed key creation unit 201 stores the first user distributed key 301 in the storage unit 203, and uses the communication unit 204 to store the first fixed distributed key 300, the first padding distributed key 302, and the organization ID “S1”. , The distributed key group ID “G1”, the distributed key group information, and the distributed key storage request are transmitted to the server 10 (step S102).

The key management unit 103 that receives the distributed key storage request through the server communication unit 102 stores the received first fixed distributed key 300 and the first padding distributed key 302 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID “S1”, the distributed key group ID “G1”, and the distributed key group information (step S103).

As information necessary to change the created distributed key from the first user to the second user, the organization ID "S1" and the distributed key group ID "G1" are securely used, such as verbal or encrypted data. After transmitting the information by any means, the input / output unit 205 of the organization signature key sharing device 20 receives the organization ID "S1", the distributed key group ID "G1", and the distributed key group ID "G2" for change from the second user. When the distribution key change request is received, the distribution key change unit 202 sends a padding information acquisition request to the server 10 together with the organization ID "S1" and the distribution key group ID "G1" by using the communication unit 204. Transmit (step S104).

Upon receiving the padding information acquisition request through the server communication unit 102, the key management unit 103 uses the received organization ID "S1" and the distributed key group "300, 301, 302" associated with the distributed key group ID "G1" as key management data. The first padding distributed key 302 acquired from 411 and associated with the distributed key ID "302" of the padding distributed key of the acquired distributed key group information is acquired from the server storage unit 101 and a copy is created. After that, the key management unit 103 uses the server communication unit 102 to transmit a copy of the first padding distribution key 302 and a padding information transmission notification to the organization signature key sharing device 20 (step S105).

The distributed key changing unit 202 of the organization signature key sharing device 20 that has received the notification of sending the padding information through the communication unit 204 acquires the first user distributed key 301 from the storage unit 203 and makes a copy. After that, the distributed key changing unit 202 synthesizes the copy of the first user distributed key 301 and the received copy of the first padding distributed key 302 to temporarily create the first user intermediate key, and the created first user. The intermediate key is divided to create the second user distribution key 303 and the second padding distribution key 304. After that, the distributed key changing unit 202 deletes the temporarily created copy of the first user intermediate key, the copy of the first user distributed key 301, and the copy of the first padding distributed key 302. After that, the distributed key changing unit 202 assigns a key ID to the created distributed key and creates distributed key group information (step S106).
Here, it is assumed that the distributed key ID "303" is assigned to the second user distributed key and the distributed key ID "304" is assigned to the second padding distributed key, and the distributed key group of "300, 303, 304" is assigned. It is assumed that the information has been created.

After that, the distributed key changing unit 202 stores the second user distributed key 303 in the storage unit 203, and uses the communication unit 204 to use the communication unit 204 to store the second padding distributed key 304, the organization ID “S1”, and the distributed key for change. The group ID "G2", the distributed key group information, and the distributed key change / save request are transmitted to the server 10 (step S107).

The key management unit 103 that receives the distributed key change storage request through the server communication unit 102 stores the received second padding distributed key 304 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID “S1”, the distributed key group ID “G2”, and the distributed key group information (step S108).

The above is the operation of the first embodiment.
The signature value created by sequentially using the first fixed distributed key 300, the first user distributed key 301, and the first padding distributed key 302 is used as the first signature value, and the first fixed distributed key 300 and the second The signature value created by sequentially signing the user distributed key 303 and the second padding distributed key 304 is used as the second signature value, and the signature value created by signing with the organization signature key that signs the organization is used as the organization signature value. Then, the first signature value, the second signature value, and the organization signature value are the same.

*** Effect of Embodiment 1 ***
By changing only the user distributed key and padding distributed key, a new combination of distributed keys (fixed distributed key, user distributed key, and padding distributed key) that creates the signature value of the organization is not aligned in one place. Since it is possible to create a combination of distributed keys that create the signature value of the organization, the risk of leakage of the signature key can be reduced.

Since a security device such as an IC card is not required, the cost of implementing the security device and the trouble of distribution are not required.

<Modification 1>
In the first embodiment, each functional component is realized by software. However, as a modification 1, each functional component may be realized by hardware. The difference between the first modification and the first embodiment will be described.

With reference to FIG. 6, the configuration of the organization signature key sharing system 1 according to the modification 1 will be described.
When each functional component is realized by hardware, an electronic circuit 505 is provided in place of the processing device 501 and the storage device 502. The electronic circuit 505 is a dedicated circuit that realizes the functions of the processing device 501 and the storage device 502.

The electronic circuit 505 includes a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC (INTERGRATED CIRCUIT), a GA (GATE ARRAY), an ASIC (APPLICATION SPECIFIC INTERCUIT), and an FPGA (FIELD-PROGRAMABLE). GATE ARRAY) is assumed.
Each functional component may be realized by one electronic circuit 505, or each functional component may be distributed and realized by a plurality of electronic circuits 505.

<Modification 2>
As a modification 2, some functional components may be realized by hardware, and other functional components may be realized by software.

The processing device 501, the storage device 502, and the electronic circuit 505 are referred to as a processing circuit. That is, the function of each functional component is realized by the processing circuit.

<Modification 3>
In the second embodiment, the user distribution key is realized by a physical file. However, as a modification 3, the user distribution key may be realized by a password specified by the user. The difference between the third modification and the second embodiment will be described.
The password may be replaced with a PIN (PERSONAL IDENTIFICATION NUMBER) or another password.

The data structure diagram is the same as that in FIG. 4, but only the contents of the data set in the key management data 411 are different.
In the distributed key group of the key management data 411, a password is set instead of the distributed key ID of the user distributed key.

*** Operation of variant 3 ***
The operation of the modification 3 will be described with reference to the flow chart of FIG.
In the third modification, the organization signature key sharing device 20 that receives the distribution key creation request by designating the organization 1 having the organization ID “S1” and the password “P1” from the first user who is the administrator is the distribution key. The flow of the process of changing the distributed key by the organization-signed key sharing device 20 that receives the request for changing the distributed key from the second user who is the user will be described.
It should be noted that steps S102 to S103 and step S108 are the same as those in the first embodiment.

When the input / output unit 205 of the organization signature key sharing device 20 receives a distribution key creation request by designating the organization ID "S1", the distribution key group ID "G1", and the password "P1" from the first user, the distribution key is created. The creation unit 201 temporarily creates an organization signature key. After that, the distributed key creation unit 201 divides the organization signature key created based on the password "P1" into the first fixed distributed key 300, which is a fixed distributed key, and the first user distributed key, which is a user distributed key. A 301 and a first padding distribution key 302, which is a padding distribution key, are created. After that, the distributed key creation unit 201 deletes the temporarily created organization signature key and the first user distributed key 301. After that, the distributed key creation unit 201 assigns a key ID to the created distributed key and creates distributed key group information (step S101).
In the third modification, the first user distribution key 301 indicates the password "P1".
Here, assuming that the distributed key ID "300" is assigned to the first fixed distributed key 300 and the distributed key ID "302" is assigned to the first padding distributed key 302, "300, password" P1 ", 302 are assigned. It is assumed that one distributed key group information of "" has been created.

As information necessary for changing the created distributed key from the first user to the second user, the organization ID "S1", the distributed key group ID "G1", and the password "P1" are verbally or encrypted. After transmitting the data by secure means such as the password, the input / output unit 205 of the organization signature key sharing device 20 receives the organization ID "S1", the distributed key group ID "G1", and the distributed key group for change from the second user. When the ID "G2", the password "P1" as the current password, and the password "P2" as the new password are specified, and the distributed key change request is received, the distributed key changing unit 202 uses the communication unit 204 to perform the organization ID. Along with "S1" and the distributed key group ID "G1", a padding information acquisition request is transmitted to the server 10 (step S104).

Upon receiving the padding information acquisition request through the server communication unit 102, the key management unit 103 sets the received organization ID "S1" and the distributed key group "300, password" P1 ", 302" associated with the distributed key group ID "G1". Obtained from key management data 411. After that, the key management unit 103 acquires the password "P1" registered as the distributed key ID of the user distributed key of the distributed key group information as the registered password. After that, the key management unit 103 acquires the first padding distributed key 302 associated with the distributed key ID “302” of the padding distributed key of the distributed key group information from the server storage unit 101 and creates a copy. After that, the key management unit 103 uses the server communication unit 102 to transmit a copy of the registered password “P1” and the first padding distribution key 302, as well as a padding information transmission notification, to the organization signature key sharing device 20 (step). S105).

The distributed key changing unit 202 of the organization signature key sharing device 20 that has received the notification of sending padding information through the communication unit 204 compares the received registered password “P1” with the password “P1” that is the current password specified by the user. do.
If the comparison results are the same, the distributed key changing unit 202 combines the password "P2", which is a new password specified by the user, with the received copy of the first padding distributed key 302, and temporarily sets the first user intermediate key. Create a password. After that, the distributed key changing unit 202 divides the first user intermediate key created based on the password “P2” to create the second user distributed key 303 and the second padding distributed key 304. After that, the distributed key changing unit 202 deletes the temporarily created copy of the first user intermediate key, the second user distributed key 303, and the first padding distributed key 302. After that, the distributed key changing unit 202 assigns a key ID to the created distributed key and creates distributed key group information (step S106).
In the present embodiment, the second user distribution key 303 indicates the password "P2".
Here, it is assumed that the distributed key ID "304" is assigned to the second padding distributed key, and the distributed key group information of "300, password" P2 ", 304" is created.

After that, the distributed key changing unit 202 uses the communication unit 204 to store the distributed key change and save together with the second padding distributed key 304, the organization ID “S1”, the distributed key group ID “G2”, and the distributed key group information. The request is transmitted to the server 10 (step S107).

The above is the operation of the modified example 3.
For the password set in place of the distributed key ID of the user distributed key in the distributed key group of the key management data 411, the hash value of the password hashed is registered without directly registering the password in order to enhance security. You may. In that case, the password comparison compares whether the hash value of the password entered by the user and the hash value of the password registered in the distributed key group of the key management data 411 are the same.
In addition, an encrypted password may be registered to enhance security. In that case, the password comparison compares whether the password entered by the user and the decrypted password registered in the distributed key group of the key management data 411 are the same.

*** Effect of variant 3 ***
Since a password that is not physically stored is used instead of the user distribution key, the risk of leakage of the signature key can be further reduced.

<Modification example 4>
*** Configuration of variant 4 ***
In the first embodiment, a process of changing the temporary organization signature key created by the first user who is the administrator for the second user to the organization signature key for the second user by the second user will be described. did. In this case, since the temporary organization signature key created by the first user who is the administrator remains, both the first user and the second user can sign the organization.
In the fourth modification, the process of handing over the signature key, which enables only the second user to sign the organization by deleting the temporary organization signature key created by the first user who is the administrator. , The difference from the first embodiment will be described.

*** Operation of variant 4 ***
The operation of the organization signature key sharing system 1 will be described with reference to the flow chart of FIG.
In the fourth modification, the first user who is an administrator creates a temporary organization signature key, and the second user who is a user changes the temporary organization signature key to the organization signature key for the second user. Then, the flow of the process of deleting the first user distribution key 301 and the first padding distribution key 302 will be described.
By executing the modification 4, the user who can carry out the signature of the organization is changed from the first user to the second user, so that it can be said that the authority for carrying out the signature of the organization is delegated.
It should be noted that steps S101 to S105 are the same as those in the first embodiment.

The distributed key changing unit 202 of the organization signature key sharing device 20 that has received the notification of sending the padding information through the communication unit 204 acquires the first user distributed key 301 from the storage unit 203 and makes a copy. After that, the distributed key changing unit 202 synthesizes the copy of the first user distributed key 301 and the received copy of the first padding distributed key 302 to temporarily create the first user intermediate key. After that, the distributed key changing unit 202 divides the created first user intermediate key to create the second user distributed key 303 and the second padding distributed key 304. After that, the distributed key changing unit 202 deletes the temporarily created first user intermediate key, the copy of the first user distributed key 301, the copy of the first padding distributed key 302, and the first user distributed key 301. After that, the distributed key changing unit 202 assigns a key ID to the created distributed key and creates distributed key group information (step S106).

After that, the distributed key changing unit 202 stores the second user distributed key 303 in the storage unit 203, and uses the communication unit 204 to use the second padding distributed key 304, the organization ID “S1”, and the distributed key group ID “. "G1", the distributed key group ID "G2" for change, and the distributed key group information, as well as the distributed key change storage request, are transmitted to the server 10 (step S107).

The key management unit 103 that receives the distributed key change storage request through the server communication unit 102 stores the received second padding distributed key 304 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID "S1", the distributed key group ID "G2" for change, and the distributed key group information. After that, the key management unit 103 acquires the received organization ID “S1” and the distributed key group “300, 301, 302” associated with the distributed key group ID “G1” from the key management data 411. After that, the key management unit 103 deletes the first padding distributed key 302 associated with the distributed key ID “302” of the padding distributed key of the distributed key group information from the server storage unit 101. After that, the key management unit 103 deletes the received organization ID “S1” and one piece of data associated with the distributed key group ID “G1” from the key management data 411 (step S108).

*** Effect of Modification 4 ***
By deleting the temporary organization signature key created by the first user who is the administrator, only the second user can sign the organization.

Embodiment 2.
*** Configuration of Embodiment 2 ***
In the first embodiment, a process of changing the temporary organization signature key created by the first user who is the administrator for the second user to the organization signature key for the second user by the second user will be described. did.
In the second embodiment, a system configuration of two organization signature key sharing devices and one server is used, and a temporary organization signature key created by a first user who is an administrator for a second user is used as a second. The process of changing to the organization signature key for the second user by the user will be described as different from the first embodiment.
In the second embodiment, the first organization signature key sharing device is a dedicated device for creating a distributed key, and the second organization signature key sharing device is a dedicated device for changing the distributed key. There is no functional difference between the key sharing devices, and the first organization signature key sharing device and the second organization signature key sharing device are interchangeable.

FIG. 7 is a configuration diagram of the organization signature key sharing system 1.
In the second embodiment, the first organization signature key sharing device 20 (creating side) used by the first user, the second organization signature key sharing device 21 (changing side) used by the second user, and the network 30. And the server 10.
It should be noted that each device connected to the network 30 stores information necessary for communication with other devices, and can transmit and receive information to and from each other.

FIG. 8 is a functional configuration diagram showing a functional configuration of the organization signature key sharing system 1.
The first organization signature key sharing device 20 (creating side) includes a distributed key creating unit 201, a distributed key changing unit 202, a storage unit 203, a communication unit 204, and an input / output unit 205. The distributed key changing unit 202 is not used.
The second organization signature key sharing device 21 (change side) includes a distributed key creating unit 211, a distributed key changing unit 212, a storage unit 213, a communication unit 214, and an input / output unit 215. The distributed key creation unit 211 is not used.
The function of the distributed key creating unit 211 is the same as that of the distributed key creating unit 201 of the first embodiment.
The function of the distributed key changing unit 212 is the same as that of the distributed key changing unit 202 of the first embodiment.
The function of the storage unit 213 is the same as that of the storage unit 203 of the first embodiment.
The function of the communication unit 214 is the same as that of the communication unit 204 of the first embodiment.
The function of the input / output unit 215 is the same as that of the input / output unit 205 of the first embodiment.

*** Operation of Embodiment 2 ***
The operation of the organization signature key sharing system 1 will be described with reference to the flow chart of FIG.
In FIG. 9, the first organization signature key sharing device 20 (creator side) that receives the distributed key creation request by designating the organization 1 having the organization ID “S1” from the first user who is the administrator sets the distributed key. The created and created distributed key was sent to the second organization signature key sharing device 21 (changing side) used by the second user who is the user, and the distribution key change request was received from the second user. The flow of the process in which the organization signature key sharing device 21 (changing side) changes the distributed key will be described.

When the input / output unit 205 of the first organization signature key sharing device 20 (creating side) receives the distributed key creation request by designating the organization ID "S1" and the distributed key group ID "G1" from the first user. The distributed key creation unit 201 temporarily creates an organization signature key. After that, the distributed key creation unit 201 divides the created organization signature key into a first fixed distributed key 300 which is a fixed distributed key, a first user distributed key 301 which is a user distributed key, and a padding distributed key. The first padding distribution key 302 is created. After that, the distributed key creation unit 201 deletes the temporarily created organization signature key. After that, the distributed key creation unit 201 assigns a key ID to the created distributed key and creates distributed key group information (step S201).
Here, the distributed key ID "300" is assigned to the first fixed distributed key 300, the distributed key ID "301" is assigned to the first user distributed key 301, and the distributed key ID "" is assigned to the first padding distributed key 302. It is assumed that the distributed key group information of "300, 301, 302" is created assuming that "302" is numbered.
Although not specifically described, the issuance of a digital certificate to an organization signature key is the same as the certificate issuance process by a general certificate authority.

After that, the distributed key creation unit 201 stores the first user distributed key 301 in the storage unit 203, and uses the communication unit 204 to store the first fixed distributed key 300, the first padding distributed key 302, and the organization ID “S1”. , The distributed key group ID “G1”, and the distributed key storage request together with the distributed key group information are transmitted to the server 10 (step S202).

The key management unit 103 that receives the distributed key storage request through the server communication unit 102 stores the received first fixed distributed key 300 and the first padding distributed key 302 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID “S1”, the distributed key group ID “G1”, and the distributed key group information (step S203).

As information necessary for changing the created distributed key from the first user to the second user, the organization ID "S1", the distributed key group ID "G1", and a copy of the first user distributed key 301 are provided. After transmitting by a secure means such as verbal or encrypted data, the input / output unit 215 of the organization signature key sharing device 21 (change side) receives the organization ID "S1" and the distributed key group ID "G1" from the second user. And the distributed key group ID "G2" for change are specified, and when the distributed key change request is received, the distributed key changing unit 212 uses the communication unit 214 to perform the organization ID "S1" and the distributed key group ID "S1". Along with "G1", a padding information acquisition request is transmitted to the server 10 (step S204).
It is assumed that the received copy of the first user distribution key 301 is stored in the storage unit 213 of the organization signature key sharing device 21 (change side).

Upon receiving the padding information acquisition request through the server communication unit 102, the key management unit 103 uses the received organization ID "S1" and the distributed key group "300, 301, 302" associated with the distributed key group ID "G1" as key management data. The first padding distributed key 302 acquired from 411 and associated with the distributed key ID "302" of the padding distributed key of the acquired distributed key group information is acquired from the server storage unit 101 and a copy is created. After that, the key management unit 103 uses the server communication unit 102 to transmit a copy of the first padding distribution key 302 and a padding information transmission notification to the organization signature key sharing device 20 (step S205).

The distributed key changing unit 212 of the organization signature key sharing device 21 (changing side) that has received the padding information transmission notification through the communication unit 214 acquires a copy of the first user distributed key 301 from the storage unit 213. After that, the distributed key changing unit 202 synthesizes the copy of the first user distributed key 301 and the received copy of the first padding distributed key 302 to temporarily create the first user intermediate key. After that, the distributed key changing unit 202 divides the created first user intermediate key to create the second user distributed key 303 and the second padding distributed key 304. After that, the distributed key changing unit 202 deletes the temporarily created copy of the first user intermediate key, the copy of the first user distributed key 301, and the copy of the first padding distributed key 302. After that, the distributed key changing unit 202 assigns a key ID to the created distributed key and creates distributed key group information (step S206).
Here, it is assumed that the distributed key ID "303" is assigned to the second user distributed key and the distributed key ID "304" is assigned to the second padding distributed key, and the distributed key group of "300, 303, 304" is assigned. It is assumed that the information has been created.

After that, the distributed key changing unit 212 of the organization signature key sharing device 21 (changing side) stores the second user distributed key 303 in the storage unit 213, and uses the communication unit 214 to store the second user distributed key 304 and the organization. The ID "S1", the distributed key group ID "G2" for change, the distributed key group information, and the distributed key change storage request are transmitted to the server 10 (step S207).

The key management unit 103 that receives the distributed key change storage request through the server communication unit 102 stores the received second padding distributed key 304 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID “S1”, the distributed key group ID “G2”, and the distributed key group information (step S208).

The above is the operation of the second embodiment.

*** Effect of Embodiment 2 ***
By using two organization signature key sharing devices connected to the network, the convenience of the system configuration is improved as compared with the first embodiment.

*** Other configurations ***

Embodiment 3.
*** Configuration of Embodiment 3 ***
In the first embodiment, the organization signature key sharing system 1 for creating a distributed key with the organization signature key sharing device has been described.
In the third embodiment, the organization signature key sharing system 1 in which the distributed key is created by a dedicated device having excellent tamper resistance such as HSM (Hardware Security Module) will be described different from the first embodiment.

FIG. 10 is a configuration diagram of the organization signature key sharing system 1.
The third embodiment is different from the first embodiment in that the key creation device 60 is added.
The key creation device 60 is a dedicated device such as an HSM (Hardware Security Module) for safely creating a key.

FIG. 11 is a functional configuration diagram showing a functional configuration of the organization signature key sharing system 1.
In the third embodiment, the distributed key creation unit 201 creates a first fixed distributed key, a first user distributed key, and a first padding distributed key in cooperation with the key creating device 60.
The key creation device 60 includes a key creation unit 601 and a communication unit 602.
The key creation unit 601 temporarily creates an organization signature key, divides the created organization signature key, and creates a first fixed distributed key, a first user distributed key, and a first padding distributed key.
The communication unit 602 communicates with other devices connected via the network 30.

Each function of the organization signature key sharing system 1 having the above configuration is realized by the hardware as shown in FIG. This hardware includes a processing device 501 such as a CPU (Central Processing Unit), a storage device 502 such as a ROM (Read Only Memory) and a hard disk device, a communication device 503 connected to other hardware by a network 30, a keyboard, and the like. It has a configuration in which an input / output device 504 such as a mouse, a speaker, and a display is connected by a bus. The CPU may have its own memory.
In the present embodiment, the organization signature key sharing device includes a processing device 501, a storage device 502, a communication device 503, and an input / output device 504, and the server 10 includes a processing device 501 and a storage device 502. , Communication device 503, and the key creation device 60 shall include a processing device 501 and a communication device 503.
The number of processing devices 501 may be plural, and the plurality of processing devices 501 may execute programs that realize each function in cooperation with each other.

*** Operation of Embodiment 3 ***
The operation of the organization signature key sharing system 1 will be described with reference to the flow chart of FIG.
In FIG. 13, the organization signature key sharing device 20 that receives the distributed key creation request by designating the organization 1 having the organization ID “S1” from the first user who is the administrator creates the distributed key and is the user. The flow of the process in which the organization-signed key sharing device 20 that has received the distribution key change request from the second user changes the distribution key will be described.

When the input / output unit 205 of the organization signature key sharing device 20 receives the distribution key creation request by designating the organization ID "S1" and the distribution key group ID "G1" from the first user, the distribution key creation unit 201 receives the distribution key creation request. The organization ID "S1" and the distributed key creation request are transmitted to the key creation device 60 using the communication unit 204 (step S301).

The key creation unit 601 of the key creation device 60 that receives the distributed key creation request through the communication unit 602 temporarily creates the organization signature key of the organization 1 from the received organization ID "S1". After that, the key creation unit 601 divides the created organization signature key into a first fixed distributed key 300 which is a fixed distributed key, a first user distributed key 301 which is a user distributed key, and a padding distributed key. 1 Create a padding distribution key 302. After that, the key creation unit 601 deletes the temporarily created organization signature key.
After that, the key creation device 60 uses the communication unit 602 to transmit the created first fixed distributed key 300, the first padding distributed key 302, and the distributed key storage request to the server 10.
After that, the key creation device 60 uses the communication unit 602 to share the created first user distributed key 301, the processing result information which is the information of the created distributed key, and the distributed key creation completion notification with the organization signature key. It is transmitted to the device 20 (step S302).
Although not specifically described, the issuance of a digital certificate to an organization signature key is the same as the certificate issuance process by a general certificate authority.
Further, in order to reduce the risk of leakage of the distributed key, when the created distributed key is sent, the public key sent to the key creation device 60 in advance is used as the first fixed distributed key 300 and the first padding distributed key 302. And the first user distributed key 301 are encrypted and sent, and the received server 10 or the organization signature key sharing device 20 decrypts with the private key and uses the distributed key. You may use it.

Upon receiving the distributed key storage request through the server communication unit 102, the key management unit 103 stores the received first fixed distributed key 300 and the first padding distributed key 302 in the server storage unit 101 (step 303).

Upon receiving the distribution key creation completion notification through the communication unit 204, the distribution key creation unit 201 stores the received first user distribution key 301 in the storage unit 203. After that, the distributed key creation unit 201 assigns a key ID to the created distributed key based on the received processing result information, and creates the distributed key group information (step S304).
Here, the distributed key ID "300" is assigned to the first fixed distributed key 300, the distributed key ID "301" is assigned to the first user distributed key 301, and the distributed key ID "" is assigned to the first padding distributed key 302. It is assumed that the distributed key group information of "300, 301, 302" is created assuming that "302" is numbered.

After that, the distributed key creation unit 201 uses the communication unit 204 to transmit the organization ID “S1”, the distributed key group ID “G1”, the distributed key group information, and the key management data creation request to the server 10. (Step S305).

Upon receiving the key management data creation request through the server communication unit 102, the key management unit 103 creates the key management data 411 from the received organization ID "S1", the distributed key group ID "G1", and the distributed key group information. (Step S306).

As information necessary to change the created distributed key from the first user to the second user, the organization ID "S1" and the distributed key group ID "G1" are securely used, such as verbal or encrypted data. After transmitting the information by any means, the input / output unit 205 of the organization signature key sharing device 20 receives the organization ID "S1", the distributed key group ID "G1", and the distributed key group ID "G2" for change from the second user. When the distribution key change request is received, the distribution key change unit 202 sends a padding information acquisition request to the server 10 together with the organization ID "S1" and the distribution key group ID "G1" by using the communication unit 204. Transmit (step S307).

Upon receiving the padding information acquisition request through the server communication unit 102, the key management unit 103 uses the received organization ID "S1" and the distributed key group "300, 301, 302" associated with the distributed key group ID "G1" as key management data. The first padding distributed key 302 acquired from 411 and associated with the distributed key ID "302" of the padding distributed key of the acquired distributed key group information is acquired from the server storage unit 101 and a copy is created. After that, the key management unit 103 uses the server communication unit 102 to transmit a copy of the first padding distribution key 302 and a padding information transmission notification to the organization signature key sharing device 20 (step S308).

The distributed key changing unit 202 of the organization signature key sharing device 20 that has received the notification of sending the padding information through the communication unit 204 acquires the first user distributed key 301 from the storage unit 203 and makes a copy. After that, the distributed key changing unit 202 synthesizes the copy of the first user distributed key 301 and the received copy of the first padding distributed key 302 to temporarily create the first user intermediate key, and the created first user. The intermediate key is divided to create the second user distribution key 303 and the second padding distribution key 304. After that, the distributed key changing unit 202 deletes the temporarily created copy of the first user intermediate key, the copy of the first user distributed key 301, and the copy of the first padding distributed key 302. After that, the distributed key changing unit 202 assigns a key ID to the created distributed key and creates distributed key group information (step S309).
Here, it is assumed that the distributed key ID "303" is assigned to the second user distributed key and the distributed key ID "304" is assigned to the second padding distributed key, and the distributed key group of "300, 303, 304" is assigned. It is assumed that the information has been created.

After that, the distributed key changing unit 202 stores the second user distributed key 303 in the storage unit 203, and uses the communication unit 204 to use the communication unit 204 to store the second padding distributed key 304, the organization ID “S1”, and the distributed key for change. The group ID "G2", the distributed key group information, and the distributed key change / save request are transmitted to the server 10 (step S310).

The key management unit 103 that receives the distributed key change storage request through the server communication unit 102 stores the received second padding distributed key 304 in the server storage unit 101. After that, the key management unit 103 creates the key management data 411 from the received organization ID “S1”, the distributed key group ID “G2”, and the distributed key group information (step S311).

*** Effect of Embodiment 3 ***
In the first embodiment, when the distributed key is created by the organization-signed key sharing device, all the distributed keys belonging to the distributed key group are temporarily arranged in one place, but in the third embodiment, the tamper-resistant resistant device is used. A distributed key is created by a highly reliable dedicated key creation device 60, and the created distributed key is directly sent from the key creation device 60 to each of the organization signature key sharing device 20 and the server 10 to belong to the distributed key group. Since it is not possible to temporarily arrange all the distributed keys in one place, the risk of leakage can be further reduced.

The "part" in the above description may be read as "circuit", "process", "procedure", "processing" or "processing circuit".

The embodiments and modifications of the present disclosure have been described above. In the case of sharing the right to sign, such as when giving the authority to represent the organization signature to other users in the organization, it may be realized in the second embodiment. The case of handing over the right to sign, such as the case of delegating the authority of the organization signature to another user in the organization, may be realized in the third embodiment. Some of these embodiments and modifications may be combined and carried out. In addition, any one or several may be partially carried out. The present disclosure is not limited to the above embodiments and modifications, and various modifications can be made as necessary.

1 organization signature key sharing system, 10 servers, 20 organization signature key sharing device, 21 organization signature key sharing device, 30 network, 60 key creation device, 101 server storage unit, 102 server communication unit, 103 key management unit, 201 distributed key Creation unit, 202 distributed key change unit, 203 storage unit, 204 communication unit, 205 input / output unit, 211 distributed key creation unit, 212 distributed key change unit, 213 storage unit, 214 communication unit, 215 input / output unit, 300 1st Fixed distribution key, 301 1st user distribution key, 302 1st padding distribution key, 303 2nd user distribution key, 304 2nd padding distribution key, 411 key management data, 501 processing device, 502 storage device, 503 communication device, 504 Input / output device, 505 electronic circuit, 601 key creation unit, 602 communication unit.

Claims (9)

Of the first fixed distributed key, the first user distributed key, and the first padding distributed key created for the first user by dividing the organization signature key, the first user distributed key and the first padding distributed key. A first user intermediate key is created by synthesizing the key, and the first user intermediate key is divided to create a second user distributed key and a second padding distributed key for the second user.
Equipped with a distributed key change unit
Organization signature key sharing device. The organization signature key sharing device according to claim 1, wherein the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified. The organization signature key sharing device further
The organization signature key is created, the created organization signature key is divided, and the first fixed distribution key, the first user distribution key, and the first padding distribution key are created for the first user. do,
Equipped with a distributed key creation unit
The organization signature key sharing device according to claim 2. A system consisting of a server and an organization signature key sharing device.
The organization signature key sharing device is
An organization signature key is created, the created organization signature key is divided, and a first fixed distributed key, a first user distributed key, and a first padding distributed key are created for the first user.
Distributed key creation department and
Of the first fixed distributed key, the first user distributed key, and the first padding distributed key created for the first user by dividing the organization signature key, the first user distributed key The first user intermediate key is created by synthesizing the first padding distributed key, and the first user intermediate key is divided into a second user distributed key and a second padding distributed key for the second user. To create,
Equipped with a distributed key change unit
The organization signature key sharing system, wherein the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified. A system consisting of a server and an organization signature key sharing device.
The organization signature key sharing device is
An organization signature key is created, the created organization signature key is divided, and a first fixed distributed key, a first user distributed key, and a first padding distributed key are created for the first user.
Distributed key creation department and
Of the first fixed distributed key, the first user distributed key, and the first padding distributed key created for the first user by dividing the organization signature key, the first user distributed key The first user intermediate key is created by synthesizing the first padding distributed key, and the first user intermediate key is divided into a second user distributed key and a second padding distributed key for the second user. After creating, the first user distributed key and the first padding distributed key are deleted.
Equipped with a distributed key change unit
The organization signature key sharing system, wherein the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified. The organization signature key sharing system comprises a plurality of the organization signature key sharing devices.
The distributed key creation unit is provided in the first organization signature key sharing device.
The distributed key changing unit is provided in the second organization signature key sharing device.
The distributed key change unit is
From the first user distributed key and the first padding distributed key created by the distributed key creation unit of the first organization signature key sharing device, the second user distributed key and the second padding distributed key To create,
The organization signature key sharing system according to claim 4 or 5. The server
A key management unit that manages a combination of the fixed distributed key, the user distributed key, and the padding distributed key as key management data is provided.
When the distributed key creation unit creates the first fixed distributed key, the first user distributed key, and the first padding distributed key, the first fixed distributed key, the first user distributed key, and the first one. Register the combination with the padding distribution key in the key management data,
When the distributed key changing unit creates the second user distributed key and the second padding distributed key, the combination of the first fixed distributed key, the second user distributed key, and the second padding distributed key is used. Register in the key management data,
The organization signature key sharing system according to claim 6. An organization signature key is created, the created organization signature key is divided, and a first fixed distributed key, a first user distributed key, and a first padding distributed key are created for the first user.
Distributed key creation process and
Of the first fixed distributed key, the first user distributed key, and the first padding distributed key created for the first user by dividing the organization signature key, the first user distributed key The first user intermediate key is created by synthesizing the first padding distributed key, and the first user intermediate key is divided into a second user distributed key and a second padding distributed key for the second user. To create,
An organization signature key sharing program that performs a distributed key change process and causes a computer to function as an organization signature key sharing device characterized in that the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified. .. The distributed key creation department
An organization signature key is created, the created organization signature key is divided, and a first fixed distribution key, a first user distribution key, and a first padding distribution key are created for the first user.
The distributed key change part
Of the first fixed distributed key, the first user distributed key, and the first padding distributed key created for the first user by dividing the organization signature key, the first user distributed key The first user intermediate key is created by synthesizing the first padding distributed key, and the first user intermediate key is divided into a second user distributed key and a second padding distributed key for the second user. Create and
The organization signature key sharing method, wherein the first user distributed key and the second user distributed key are passwords that can be arbitrarily specified.

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