JP2005045622A - Access control system, terminal device, coalition attribute certificate authority server, and access control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an access control system capable of reducing operational costs associated with a change in the number of domains. <P>SOLUTION: There is provided the access control system for requesting access to an access control apparatus by using a threshold attribute certificate. The access control system includes a distributed key producing means that divides key information for producing the threshold attribute certificate into n pieces (n is a natural number of 2 or more). The system has distributed key producing means for making it possible to produce the threshold attribute certificate when k pieces of signatures have been collected that have been obtained by using each of divided k pieces (k is a natural number defined as 1<k≤n) of the key information; a distributed signature producing means for subscribing a message by means of the distributed key produced by the distributed key producing means to produce the distributed signature; and a threshold attribute certificate producing means for producing the threshold attribute certificate when receiving a plurality of the distributed signatures produced by the distributed signature producing means, and then preparing the threshold attribute certificate when at least t pieces of the received distributed signatures have been gathered from among n pieces thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

As a method for realizing joint management of access control for resources commonly used in a plurality of domains using an attribute certificate, for example, Non-Patent Document 1 shown below is described.
This is because access control such as “a common resource (data, etc.) cannot be updated without the user's approval from t (t ≦ n) domains out of n domains” using a certificate-based infrastructure. It is realized. As a result, it is possible to prevent one domain from updating resources without permission from another domain.

  The outline of the method in Non-Patent Document 1 is as follows. First, processing for issuing a threshold attribute certificate will be described with reference to FIGS. Here, it is assumed that there are n domains, each domain has one public key certificate authority and a plurality of users, and the public key certificate authority has already issued public key certificates to the users of the domain. . In FIG. 8, first, each domain cooperates to establish one simultaneous attribute authority. The public / private key pair of the simultaneous attribute certificate authority is generated by executing a certain protocol “distributed RSA key generation” while the domains communicate with each other. Thereby, one public key and n distributed secret keys are generated (step S100). This public key is used as a public key of the simultaneous attribute certificate authority, and n distributed secret keys are held one by one by each domain (step S101). Here, there is no single secret key as a simultaneous attribute certificate authority.

  Next, each domain requests the attribute certificate authority to transmit an attribute certificate template (unsigned attribute certificate) (step S102), and receives an unsigned attribute certificate transmitted from the attribute certificate authority. . In this unsigned attribute certificate, the shared resource name and the “n number” are used, such as “a group that requires approval from users in t domains out of n domains for access to the shared resource O”. The threshold description such as “t approvals” is included. In each domain (n), one user who handles the shared resource is selected from each domain, and the users sign using the distributed secret key of their own domain (however, other domains have their domain's own domain). A distributed secret key), a threshold attribute certificate indicating that it belongs to “a group that requires the approval of users from t domains out of n in order to update the shared resource O” It is created (step S103) and transmitted to the simultaneous attribute authority (step S104).

  The simultaneous attribute authority uses the n threshold attribute certificates and performs signature combination processing on the n signatures using (n, n) -distributed signature (the private key is not restored at this stage as well). ), A threshold attribute certificate that is the signature of the attribute certificate authority for the attribute certificate signed in each domain is created (step S105), and transmitted to the terminal of each user (step S106). Thereby, the threshold attribute certificate is stored in each domain (step S107). Here, all domains store the same threshold attribute certificate.

  Next, a case where authentication is performed using a threshold attribute certificate generated based on the above-described procedure will be described with reference to FIG. Here, the shared resource is stored in the server P, and the server P trusts the public key certification authority and the simultaneous attribute certification authority of each domain. The server P does not permit access unless there is a valid threshold attribute certificate and the signatures of the threshold number (that is, t) users described therein. Here, a case will be described in which when n = 3 and t = 2, the user of one domain updates the shared resource O with the cooperation of the user of the other domain.

  One user generates an application form that he wishes to access (update) the shared resource O (step S200), and generates a signature for the generated application form using his / her private secret key (step S201). ), And transmits the generated signature as a request (a) to the user of the other domain (step S202). Here, the message generated in step S200 and the public key certificate of one user are also transmitted. When the other user agrees to a message that he / she wants to update the shared resource O, a request (b) is signed with his / her private secret key, and the other user's public key certificate is sent along with the other user's public key certificate. Send to user's terminal. When one user receives the request (b) and the public key certificate of the other user (step S203), the threshold attribute certificate stored in step S107 of FIG. a) The signature for the application (request (b)) and the public key certificate of the signer (the public key certificate of the other user) are transmitted to the file server storing the shared resource O (step S204). .

The file server verifies the validity of the threshold attribute certificate received from the terminal (step S205), and if it is valid, reads the threshold t from the description content of the threshold attribute certificate, and requests it using each user's public key certificate. Is verified (step S206), and whether there are t or more valid signatures is verified (step S206). When the number of valid signatures is t or more, updating of the shared resource O is permitted (step S207). If at least one of the verification results in step S205 and step S206 is “NO”, access is denied (step S208).
H.Khurana, V.Gligor, and J.linn, “Reasoning about Joint Administration of Access Policies for Coalition Resources,” IEEE international Conference on Distributed Computer Systems-ICDCS2002, Vienna, july 2002.Internet <URLhttp: //www.glue .umd.edu / ~ hkhurana / Icdcs2002_full_manuscript.pdf>

  However, in the above-described prior art, the number (n) of domains may change. That is, entry of a new domain or withdrawal of an existing domain may occur. Further, the threshold (t) may be changed even if the number of domains does not change. When these occur, the method according to Non-Patent Document 1 regenerates the key pair of the simultaneous attribute certification authority, redistributes the public key of the simultaneous attribute certification authority to the file server, regenerates the threshold attribute certificate, threshold attribute It is necessary to perform redistribution of the certificate and revocation processing of the threshold attribute certificate that has been used before, and an operation cost related to these is generated. In addition, as these costs increase, the service suspension time becomes longer. Therefore, it is desired to reduce these costs as much as possible.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an access control system, a terminal device, a simultaneous attribute certification authority server, and an access control program that can reduce operation costs associated with changes in the number of domains. Is to provide.

  In order to achieve the above object, the present invention provides an access control system that makes an access request to an access control apparatus using a threshold attribute certificate, and includes key information for generating a threshold attribute certificate. The threshold value is obtained when k signatures obtained using k pieces of key information (n is a natural number satisfying 1 <k ≦ n) are collected. A distributed key generation unit that generates a distributed key for enabling generation of an attribute certificate; a distributed signature generation unit that generates a distributed signature by signing a message with the distributed key generated by the distributed key generation unit; Threshold attribute certificate generating means for receiving a plurality of distributed signatures generated by the distributed signature generating means and generating a threshold attribute certificate when at least k of the received distributed signatures are collected. Special It is a sign.

  The present invention also provides a terminal device in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and a simultaneous attribute certification authority server are connected. The key information for generating a book is divided into n pieces (n is a natural number greater than or equal to 2), and k pieces (k is a natural number satisfying 1 <k ≦ n) are used to obtain k A distributed key generating means for generating a distributed key for enabling generation of the threshold attribute certificate when collecting a plurality of signatures, and a distributed signature by signing a message with the distributed key generated by the distributed key generating means Distributed signature generating means for generating a distributed signature, distributed signature receiving means for receiving a distributed signature generated by another terminal device having a distributed key corresponding to the generated distributed key, and received by the distributed signature receiving means. Threshold attribute certificate generation requesting means for requesting generation of a threshold attribute certificate by transmitting the distributed signature and the distributed signature generated by the distributed signature generating means to the simultaneous attribute certificate authority server, and the simultaneous attribute certificate authority server Access request means for receiving a threshold attribute certificate transmitted from the server and transmitting the threshold attribute certificate to the access control device to make an access request.

  Further, the present invention is a simultaneous attribute certification authority server in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and the simultaneous attribute certification authority server are connected, A distributed signature receiving unit that receives a distributed signature transmitted from the terminal device; a threshold attribute certificate generating unit that generates a threshold attribute certificate based on the distributed signature received by the distributed signature receiving unit; and the threshold attribute And transmitting means for transmitting the threshold attribute certificate generated by the certificate generating means to the terminal device.

  The present invention also provides an access control program used for a terminal device in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and a simultaneous attribute authority server are connected. Then, the key information for generating the threshold attribute certificate is divided into n pieces (n is a natural number of 2 or more), and each of the divided k pieces of key information (k is a natural number satisfying 1 <k ≦ n). Generating a distributed key for enabling generation of the threshold attribute certificate when collecting k signatures obtained by using the signature, and generating a distributed signature by signing a message with the generated distributed key A step of receiving a distributed signature generated by another terminal device having a distributed key corresponding to the generated distributed key, and generating the received distributed signature by itself Transmitting a shared signature to the simultaneous attribute authority server and requesting generation of a threshold attribute certificate; receiving a threshold attribute certificate transmitted from the simultaneous attribute authority station server and transmitting the threshold attribute certificate to the access control apparatus; And making the computer execute an access requesting step.

  The present invention also provides a threshold used for a simultaneous attribute authority server in an access control system in which a terminal device that requests access to the access control apparatus using a threshold attribute certificate and the simultaneous attribute authority server are connected. An attribute certificate generation program, the step of receiving a distributed signature transmitted from the terminal device, the step of generating a threshold attribute certificate based on the received distributed signature, and the generated threshold attribute certificate Transmitting to the terminal device, causing the computer to execute.

  As described above, according to the present invention, the key information for generating the threshold attribute certificate is divided into n pieces, and k pieces of signatures obtained by using the divided pieces of key information are collected. In such a case, a distributed key for generating a threshold attribute certificate is generated, a distributed signature is generated using the distributed key, and a threshold attribute certificate is generated in the simultaneous attribute certificate authority. As a result, even if the number of domains changes, it is sufficient to generate a secret key again and issue a threshold attribute certificate as necessary. Distribution costs can be eliminated. In addition, since the threshold attribute certificate is generated as necessary, the valid period can be shortened, and the valid period can be eliminated depending on the operation. The need for revocation processing can be eliminated. If the threshold value does not change or decreases, only the secret key needs to be generated again, so the key pair of the simultaneous attribute authority is regenerated, and the public key of the simultaneous attribute authority is redistributed to the file server This eliminates the need for this and eliminates the costs associated with these.

Hereinafter, an access control system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a configuration of an access control system according to an embodiment of the present invention.
In this figure, the simultaneous attribute certificate authority server 40 is connected to a network 80 via a router 70. The file server 50 is connected to the shared resource database 60 and is connected to the network 80 via the router 70. The key management device 11, the domain device 12, and the client terminal 13 are managed within a certain domain and connected to the network 80 via the router 70. The key management device 21, the domain device 22, the client terminal 23, the key management device 31, the domain device 32, and the client terminal 33 are each managed in one domain, and are connected to the network 80 via the router 70. Here, there are three domains, domain 10, domain 20, and domain 30. The domain here is a jurisdiction range of the public key certificate authority, and is, for example, a unit such as a certain department or company.

  Next, the configuration of the client terminal 13 will be described. FIG. 2 is a schematic block diagram showing the configuration of the client terminal. In this figure, a CPU (central processing unit) 131 that controls each unit of the client terminal 13, an external storage device 132 that stores various data, a communication device 133 that performs communication, an input device 134 that includes a keyboard, a mouse, and the like, a CRT A display device 135 configured by (Cathode Ray Tube), a liquid crystal display device, and the like, and a memory 136 are connected via a bus or a communication line.

The memory 136 stores a service use program, a communication program, a distributed key generation program, and an operating system, which are programs for receiving provision of services of the access control system.
The distributed key generation program divides key information for generating a threshold attribute certificate into n pieces (n is a natural number greater than or equal to 2), and k pieces (k is a natural number satisfying 1 <k ≦ n). A distributed key generation function for generating a distributed key for enabling generation of the threshold attribute certificate when k signatures obtained by using each information are collected, and a distributed key generated by the distributed key generation function A distributed signature generating function for signing a message to generate a distributed signature and a distributed key receiving function for receiving a distributed signature generated by another terminal device having a distributed key corresponding to the generated distributed key. Further, the distributed key generation program transmits the distributed signature received by the distributed signature reception function and the distributed signature generated by the distributed signature generation function to the simultaneous attribute certificate authority server 40 to request generation of a threshold attribute certificate. It has a certificate generation request function and an access request function for receiving a threshold attribute certificate transmitted from the simultaneous attribute certificate authority server 40, transmitting it to the access control apparatus, and making an access request.

  The threshold attribute certificate here is a certificate indicating that the user belongs to a group of people who can access the shared resource database 60, and is issued from the simultaneous attribute certificate authority server 40. In addition, the threshold attribute certificate describes the content “accessible to shared resources”. The distributed key here corresponds to a distributed secret key. The distributed secret key is each secret key when the data corresponding to the secret key is distributed by some method among the public key and secret key pair in the public key cryptography, and is also referred to as a partial secret key. There are a method (a) that first generates a secret key and then distributes it, and a method (b) that generates a distributed secret key that is a secret key that has been distributed from the beginning without generating a secret key. In this embodiment, the method (b) is applied. In the method (b), (n, n) -distributed key generation processing for constructing an environment in which an effective signature can be generated when all n persons cooperate, and any t persons out of n persons (t≤ n) (t, n) -distributed key generation process for constructing an environment that can generate a valid signature when cooperating, and in any distributed key generation process, each domain has its own private key By executing a certain protocol (multi-party protocol) while keeping the information secret, one public key and n distributed secret keys are finally generated.

  Also, in the distributed signature here, after (n, n) -distributed key generation, all n persons cooperate to generate a valid signature (n, n) -distributed signature and (t, n)-After distributed key generation, arbitrary t of n persons cooperate to generate a valid signature (t, n)-distributed signature.

  In addition, the CPU 131 reads and executes the operating system, service use program, distributed key generation program, and communication program stored in the memory 136, thereby executing a distributed key generation function, a distributed signature generation function, a distributed key reception function, a threshold value. An attribute certificate generation request function and an access request function are realized. Note that the configurations of the client terminal 23 and the client terminal 33 are the same as the configuration of the client terminal 13, and thus the description thereof is omitted.

Next, the configuration of the key management device 11 will be described. FIG. 3 is a schematic block diagram showing the configuration of the key management device 11.
In this figure, a key management device 11 includes a CPU 111 that controls each unit, a communication device 113 that performs communication, a memory 116, and a tamper resistant device that has a function of preventing data stored in the memory 116 from being illegally accessed from the outside. 117 is connected via a bus or a communication line.

  The memory 116 stores a communication program and an operating system, and has a storage area for storing a distributed key. The CPU 111 reads and executes the operating system and communication program stored in the memory 406. Note that the configurations of the key management device 21 and the key management device 31 are the same as the configuration of the key management device 11, and thus the description thereof is omitted.

Next, the simultaneous attribute certificate authority server 40 will be described. FIG. 4 is a schematic block diagram showing the configuration of the simultaneous attribute certificate authority server 40.
In this figure, a simultaneous attribute certification authority server 40 is operated in a simultaneous attribute certification authority established by each domain in cooperation, a CPU 401 for controlling each part, an external storage device 402 for storing various data, and a router 70. A communication device 403 connected to the communication device 403, an input device 404 constituted by a keyboard, a mouse, etc., a display device 405 constituted by a CRT (Cathode Ray Tube), a liquid crystal display device, etc., and a memory 406 connected via a bus Is done.

  The memory 406 stores a threshold attribute certificate issuance program, a communication program, and an operating system, which are programs for providing an access control system service. The threshold attribute certificate issuance program includes a distributed signature receiving function for receiving a distributed signature transmitted from a client terminal, and a threshold attribute certificate generating function for generating a threshold attribute certificate based on the distributed signature received by the distributed signature receiving function. And a transmission function for transmitting the threshold attribute certificate generated by the threshold attribute certificate generation function to the client terminal.

  The simultaneous attribute certificate authority server 40 stores a public key corresponding to a distributed secret key generated by cooperation of a plurality of domains and a function of issuing an unsigned attribute certificate. Yes. The above-described CPU 401 reads and executes the operating system, threshold attribute certificate issuance program, and communication program stored in the memory 406, thereby realizing a distributed signature reception function, a threshold attribute certificate generation function, and a transmission function.

Next, the file server 50 will be described. FIG. 5 is a schematic block diagram showing the configuration of the file server 50.
In this figure, a file server 50 includes a CPU 501 for controlling each unit, an external storage device 502 for storing various data, a communication device 503 connected to the router 70 for communication, an input device 504 configured by a keyboard, a mouse, and the like, a CRT A display device 505 including a (Cathode Ray Tube), a liquid crystal display device, and the like, and a memory 506 are connected through a bus or the like.

  The memory 506 stores an attribute certificate verification program, a communication program, and an operating system. The attribute certificate verification program has a verification function for verifying whether the threshold attribute certificate transmitted from the client terminal is valid, and an access control function for permitting access to the shared resource database 60 if it is valid. . The CPU 501 reads out and executes the operating system, attribute certificate verification program, and communication program stored in the memory 506, thereby realizing a verification function and an access control function.

  Next, (1) an operation for generating a distributed secret key and (2) an operation at the time of accessing a common resource in the above-described access control system will be sequentially described with reference to the drawings. Here, a case will be described in which the shared resource database 60 can be accessed if two of the three domains agree. Here, a case where the client terminal 13 requests access to data in the shared resource database 60 will be described.

(1) Operation for Generating Distributed Secret Key First, an operation for generating a distributed secret key will be described with reference to the flowchart of FIG. Each domain 10, domain 20, and domain 30 cooperate to generate a distributed key that enables generation of a threshold attribute certificate if two of the three agree. Here, the client terminal 13 executes a distributed key generation program based on an instruction from the user input from the input device 134, generates a distributed secret key by (t, n) -distributed key generation processing, and generates The distributed secret key is stored in the management device 11 (step S11). Steps S10 and S11 are also performed in the client terminal 23 and the client terminal 33 in other domains, and a distributed secret key is generated and stored. Here, the simultaneous attribute certificate authority issues a public key corresponding to the secret key.

(2) Operation at Access to Common Resource Next, operation at access to the common resource will be described with reference to the flowchart of FIG. Based on the instruction from the user, the client terminal 13 requests the simultaneous attribute certificate authority server 40 to transmit an attribute certificate template (unsigned attribute certificate) (step S20). The unsigned attribute certificate transmitted from is received (step S21). This unsigned attribute certificate includes a description such as “a group for updating the shared resource O”. The client terminal 13 executes a service utilization program based on an instruction from the user, and generates a distributed signature by signing an unsigned attribute certificate using the distributed secret key stored in the key management device 11 ( Step S22). Then, an unsigned attribute certificate is transmitted to another client terminal 23 to request a signature (step S23).

  At the client terminal 23, an unsigned attribute certificate is signed using the distributed secret key stored in the key management device 21 (however, the other domain does not reveal its own distributed secret key) When the distributed signature is transmitted, the client terminal 13 receives the distributed signature (step S24), and combines the distributed signature generated at the client terminal 13 and the distributed signature generated at the client terminal 23 with the simultaneous attribute certificate authority. It transmits to the server 40 (step S25).

  The simultaneous attribute certification authority server 40 executes a threshold attribute certificate issuance program to combine signatures between the distributed signature generated at the client terminal 13 and the distributed signature generated at the client terminal 23 using the distributed signature. Processing is performed to generate a threshold attribute certificate (step S26). Here, t distributed signatures are collected (two in this case), so that a threshold attribute certificate can be generated. Then, the generated threshold attribute certificate is transmitted to the client terminal 13 (step S27). The client terminal 13 transmits the threshold attribute certificate received from the simultaneous attribute certificate authority server 40, its own public key certificate, and the public key certificate in the client terminal 23 to the file server 50 (step S28).

  Upon receiving the threshold attribute certificate transmitted from the client terminal 13, the public key certificate in the client terminal 13, and the public key certificate in the client terminal 23, the file server 50 verifies the validity of the received threshold attribute certificate. (Step S29). If the verification result is valid, the file server 50 permits access from the client terminal 13 to the shared resource database 60 (step S30), and if not valid, denies access (step S31). After the access from the file server 50 is permitted, the client terminal 13 accesses the shared resource database 60 and updates the data.

  Here, the threshold (t) for updating the shared resource database 60 does not increase, the number of domains decreases due to withdrawal or the like, and (t, n) = (2,3) to (t, n) = ( In the case of changing to (2) and (2), it is necessary to update the key of the simultaneous attribute authority in order to prevent illegal signature generation due to collusion between the withdrawn domain and the existing domain. In this case, by using proactive technology (technology that updates only the distributed secret key without changing the public key) and generates the distributed secret key again, it is distributed while keeping the public key of the simultaneous attribute certification authority as it is By updating the secret key, it is not necessary to redistribute the public key of the simultaneous attribute certification authority to the file server, and the redistribution cost of the public key of the simultaneous attribute certification authority to the file server can be eliminated. .

  On the other hand, when a threshold value (t) increases, such as when one domain newly enters and changes from (t, n) = (2,2) to (t, n) = (3,3), the public key Update the key including.

  According to the embodiment described above, the threshold attribute certificate is generated when necessary, such as when accessing the shared resource database 60. “Redistribution” becomes unnecessary, and the cost related to “regeneration / redistribution of threshold attribute certificate” can be eliminated. In addition, regarding the threshold attribute certificate revocation process, the threshold attribute certificate is generated as necessary, so that the validity period of the threshold attribute certificate can be made shorter than before. It is possible to adapt to the “no-revocation list method” that takes into account the short-term property certificate specified in 509 and RFC 3281, and if this is used, the revocation process can be made unnecessary. .

  Further, in the above-described embodiment, the description of “a shared resource can be updated if t out of n people gather” is deleted, and a threshold attribute certificate is issued when t out of n people gather. Since key generation is possible, having a threshold attribute certificate can be regarded as evidence that “t out of n people have gathered”, so it is a necessary and sufficient condition for access permission. It is possible. As described above, by changing the definition of the threshold attribute certificate, the threshold attribute certificate is generated when necessary, so that it is not necessary to hold the threshold attribute certificate in advance. The cost of regenerating and redistributing documents can be eliminated.

  The access control system in the above embodiment is the 2000 version X. In an environment where there is a system based on a public key certificate in which attribute information is embedded, or a database in which the public key certificate and attribute information are associated, without being limited to a system realized using the attribute certificate of 509 It is also possible to apply to a system based on a public key certificate in Japan or a system using a simple signature server that does not use a public key infrastructure (PKI).

  1, a program for realizing a distributed key generation function, a distributed signature generation function, a distributed key reception function, a threshold attribute certificate generation request function, an access request function in the client terminal, and a distributed signature of the simultaneous attribute certificate authority server 40 A program for realizing the reception function and the threshold attribute certificate generation function is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the computer system and executed to perform access control. May be. The “computer system” here includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

It is a schematic block diagram which shows the structure of the access control system by one Embodiment of this invention. It is a schematic block diagram which shows the structure of a client terminal. 2 is a schematic block diagram showing a configuration of a key management device 11. FIG. 3 is a schematic block diagram showing a configuration of a simultaneous attribute certificate authority server 40. FIG. 2 is a schematic block diagram showing a configuration of a file server 50. FIG. It is a flowchart for demonstrating the operation | movement which produces | generates a distributed secret key. It is a flowchart for demonstrating the operation | movement at the time of access with respect to a common resource. It is a flowchart for demonstrating the production | generation process of the threshold value attribute certificate in a prior art. It is a flowchart for demonstrating the operation | movement at the time of access with respect to a shared resource in a prior art.

Explanation of symbols

10, 20, 30 Domain 13, 23, 33 Client terminal 40 Simultaneous attribute certificate authority server 50 File server 60 Shared resource database

Claims (5)

An access control system for requesting access to an access control device using a threshold attribute certificate,
The key information for generating the threshold attribute certificate is divided into n pieces (n is a natural number of 2 or more) and obtained by using each of the divided pieces of k pieces (k is a natural number satisfying 1 <k ≦ n). Distributed key generation means for generating a distributed key for enabling generation of the threshold attribute certificate when the k signatures collected are collected,
A distributed signature generation unit that generates a distributed signature by signing a message with the distributed key generated by the distributed key generation unit;
A threshold attribute certificate generating means for receiving a plurality of distributed signatures generated by the distributed signature generating means and generating a threshold attribute certificate when at least k of the received distributed signatures are collected;
An access control system comprising: A terminal device in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and a simultaneous attribute certificate authority server are connected,
The key information for generating the threshold attribute certificate is divided into n pieces (n is a natural number of 2 or more) and obtained by using each of the divided pieces of k pieces (k is a natural number satisfying 1 <k ≦ n). Distributed key generation means for generating a distributed key for enabling generation of the threshold attribute certificate when the k signatures collected are collected,
A distributed signature generation unit that generates a distributed signature by signing a message with the distributed key generated by the distributed key generation unit;
Distributed signature receiving means for receiving a distributed signature generated by another terminal device having a distributed key corresponding to the generated distributed key;
Threshold attribute certificate generation requesting means for transmitting the distributed signature received by the distributed signature receiving means and the distributed signature generated by the distributed signature generating means to the simultaneous attribute certification authority server to request generation of a threshold attribute certificate; ,
An access request means for receiving a threshold attribute certificate transmitted from the simultaneous attribute certification authority server, transmitting the threshold attribute certificate to the access control apparatus, and making an access request. A simultaneous attribute certificate authority server in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and the simultaneous attribute certificate authority server are connected,
Distributed signature receiving means for receiving a distributed signature transmitted from the terminal device;
Threshold attribute certificate generating means for generating a threshold attribute certificate based on the distributed signature received by the distributed signature receiving means;
A simultaneous attribute certificate authority server, comprising: a transmission unit configured to transmit the threshold attribute certificate generated by the threshold attribute certificate generation unit to the terminal device. An access control program used for a terminal device in an access control system in which a terminal device that requests access to the access control device using a threshold attribute certificate and a simultaneous attribute certificate authority server are connected,
The key information for generating the threshold attribute certificate is divided into n pieces (n is a natural number of 2 or more) and obtained by using each of the divided pieces of k pieces (k is a natural number satisfying 1 <k ≦ n). Generating a distributed key for enabling generation of the threshold attribute certificate when collecting the k signatures obtained;
Signing a message with the generated distributed key to generate a distributed signature;
Receiving a distributed signature generated by another terminal device having a distributed key corresponding to the generated distributed key;
Transmitting the received distributed signature and the distributed signature generated by itself to the simultaneous attribute certificate authority server to request generation of a threshold attribute certificate;
Receiving a threshold attribute certificate transmitted from the simultaneous attribute certification authority server, transmitting it to the access control device, and requesting access;
An access control program that causes a computer to execute. A threshold attribute certificate generating program used for a simultaneous attribute certification authority server in an access control system in which a terminal device that requests access to the access control apparatus using a threshold attribute certificate and a simultaneous attribute certification authority server are connected There,
Receiving a distributed signature transmitted from the terminal device;
Generating a threshold attribute certificate based on the received distributed signature;
Transmitting the generated threshold attribute certificate to the terminal device;
An access control program that causes a computer to execute.

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