JP2005109641A - Server, method for providing information of public key, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology whereby a user can simply acquire information to discriminate the validity of a public key. <P>SOLUTION: An XKMS server 1 connected to an authentication system 2 of an authentication station and a terminal 3 of a user using a public key KP via a network includes: a management processing request mediation section 101 for mediating a request about management of the public key KP from the terminal 3 to the authentication system 2; a log file 10F for recording contents of the mediated request together with request resultant information as log information 81; an inquiry reception section 103 for receiving an inquiry as to whether or not the public key KP is valid from the terminal 3; a validity discrimination section 105 for discriminating whether or not the public key KP is valid on the basis of the log information 81 as to the public key KP associated with the inquiry; and a result transmission section 106 for transmitting a result of discrimination by the validity discrimination section 105 to the terminal 3 being the inquiry source. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to information management of public keys used in public key cryptosystems.

  Conventionally, a public key cryptosystem has been widely used as one of the encryption technologies. According to the public key cryptosystem, even when exchanging data with a large number of users, just prepare a pair of public key and secret key, and copy and distribute the public key to the data exchange partner It's okay. That is, it is not necessary to prepare a different key for each exchange partner as in the common key method.

  Also, the public key cryptosystem has a feature that data encrypted with one key can be decrypted only with the other key. For example, data encrypted with a public key can be decrypted only with a corresponding private key, and data encrypted with a private key can be decrypted only with a corresponding public key.

  Because of these characteristics, the public key cryptosystem is used as follows for an electronic signature (also called a digital signature, digital ID, or electronic seal stamp) that confirms the validity of the data transmission source. It is used. That is, the transmission source user encrypts the data with his / her private key and transmits it to the other party. The user who has received this tries to decrypt the data with the public key distributed by the user of the transmission source. If the decryption is successful, it is confirmed that the data transmission source is valid. The digitally signed data, that is, encrypted data, can also be disclosed on a server on the network as described in Japanese Patent Application Laid-Open No. 2004-133620.

  However, when the secret key is stolen, there is a risk that illegal data is transmitted from a person pretending to be a legitimate user or the data is tampered with in the process of transmission.

  Therefore, the user of the transmission source registers his / her public key with a certificate authority that is a third party organization, and transmits an electronic certificate (digital certificate) indicating the validity of the public key from the certificate authority. Can be issued for the other party. Accordingly, the transmission partner can more reliably determine the legitimacy of the transmission source based on the electronic certificate. The public key that has lost its validity is published by a certificate revocation list (CRL).

  However, it is a heavy burden for a user who has received a public key electronic certificate or CRL to analyze the structure of the chain of the electronic certificate or to verify the CRL. Therefore, it is required to easily obtain information on the validity of the public key.

  XKMS (XML Key Management Specification) as described in Non-Patent Document 1 has been proposed as a standard for more easily using such a public key cryptosystem environment, that is, PKI (Public Key Infrastructure). However, this XKMS only defines messages and protocols. Further, Non-Patent Document 1 describes that it is assumed that an XKMS server is provided between the user and the certificate authority using this XKMS, but there is nothing about its specific use and configuration. It is not assumed.

Therefore, only the XKMS and XKMS server described in Non-Patent Document 1 cannot solve the above-described problem of enabling a user to easily obtain information regarding the validity of a public key.
JP 2002-169909 A "Technical Explanation-XML Key Management Specification (XKMS 2.0)-", May 2002, Oki Electric Industry Co., Ltd., Katsumi Ikegami

  In view of the above-described problems, an object of the present invention is to enable a user to easily obtain information for determining the validity of a public key in a public key method.

  A server according to the present invention is a server connected via a network to a certificate authority that issues an electronic certificate of a public key and a user terminal device that uses the public key, from the terminal device to the certificate authority Management request mediating means for mediating requests relating to management of public keys, log recording means for recording the contents of the request mediated by the management request mediating means together with the result information of the requests, and the terminal device Based on the log of the public key related to the inquiry, which is recorded in the log recording means, and the inquiry accepting means for receiving an inquiry as to whether the public key is valid, the public key is valid Validity determination means for determining whether or not the result is valid, and result transmission means for transmitting the result of the determination by the validity determination means to the terminal device as an inquiry source. The features.

  Preferably, the log recording unit records the expiration date as part of the log when the request relates to acquisition of information indicating the expiration date of the public key, and the request relates to the expiration of the public key. Information indicating whether or not the revocation has succeeded is recorded as a part of the log, the validity determination means that the revocation is successful in the log for the public key related to the inquiry Is included, or when the expiration date of the public key is included and the expiration date has passed, it is determined that the public key is not valid.

  Alternatively, the log extracted by the log extraction unit may be transmitted together with the determination result by the validity determination unit, or may be transmitted instead of the determination result.

  Or, a log extracting unit that extracts all the logs stored in the log recording unit according to a command from the terminal device, a log transmitting unit that transmits the extracted log to the terminal device that is a command source, Have

  Alternatively, log extraction means for extracting the log related to the keyword designated from the terminal device from the log recording means, and log transmission means for transmitting the extracted log to the designated terminal device.

  According to the present invention, the user can easily acquire the validity of the public key in the public key method. In addition, it is possible to reduce the processing load on the certificate authority and the terminal device and the load on the entire network.

  1 is a diagram showing an example of the overall configuration of a system having an XKMS server 1 according to the present invention, FIG. 2 is a diagram showing an example of a functional configuration of the XKMS server 1, and FIG. 3 is log information stored in a log file 10F It is a figure which shows the example of 81. FIG.

  As shown in FIG. 1, the XKMS server 1 according to the present invention can be connected to an authentication system 2 and a terminal device 3 via a communication line 4. As the communication line 4, the Internet, an intranet, a public line, a dedicated line, or the like is used. TCP / IP or HTTP is used as the communication protocol.

  The authentication system 2 is operated by a certificate authority (CA), which is a third party that manages electronic certificates. This authentication system 2 registers public keys, issues digital certificates for registered public keys, issues public information such as a certificate revocation list (CRL), and public key expiration dates. This is a system that uses a computer or the like to perform public key management processing such as confirmation.

  Note that “certificate authority” may mean an organization that only performs authentication of electronic certificates. However, in general, the “certification authority” is often used to mean an organization composed of three departments: a registration authority, a certificate authority in the narrow sense, and a verification authority. In this embodiment, “certificate authority” is used to mean the latter.

  The terminal device 3 is installed with a program such as an e-mail or a Web browser, and can exchange data with other terminal devices 3 and the like. As the terminal device 3, a personal computer, a workstation, a PDA (Personal Digital Assistant), a mobile phone terminal, or the like is used. Multifunction peripherals (MFPs) that integrate functions such as a copier, printer, scanner, FAX, or document server can also be used.

In addition, the terminal device 3 has a program (hereinafter referred to as “encryption application program”) for encrypting data by the public key cryptosystem and decrypting the encrypted data. For example, in the following case, the user of the terminal device 3 uses the encryption application program.
(1) When decrypting data obtained from another user and encrypted with the other user's private key using the other user's public key.
(2) When decrypting data obtained from another user and encrypted with the user's own public key, using the user's own secret key.
(3) In order to transmit the user's own data (personal information, etc.) to other users (for example, a government office, a bank, a credit sales company, or an Internet provider), the data using the public key of the other users When encrypting, etc.
(4) A case where the user of the terminal device 3 encrypts the data using the user's own private key in order to transmit the data to another user.

  In the above cases (1) and (3), since the public key of another user is used, it is necessary to confirm whether or not this public key is valid. If the public key is not valid, in the case of (1) above, data that has been altered by a malicious party in the process of communication is acquired and used, or data from a person who has impersonated a legitimate user is acquired. This is because, in the case of (3) above, there is a risk that the transmitted personal information may be stolen or altered by a malicious person.

  In the cases (2) and (4) above, the user of the terminal device 3 needs to distribute the public key corresponding to his / her private key to other users. Therefore, it is desirable to register the public key with the certificate authority and obtain trust for other users.

  The XKMS server 1 is configured based on XKMS (XML Key Management Specification), which is one of the specifications proposed for using a public key infrastructure (PKI). As the XKMS server 1, a UNIX (registered trademark) server or a so-called PC server is used.

  As will be described later, the XKMS server 1 can be said to play a role like a front-end server of a certificate authority (authentication system 2). Therefore, the certificate authority may manage the XKMS server 1. Alternatively, an Internet provider or the like can operate the XKMS server 1 as part of the Web service.

  The magnetic storage device of the XKMS server 1 includes a management processing request mediation unit 101, a log recording unit 102, an inquiry receiving unit 103, a log extracting unit 104, an effectiveness determining unit 105, a result transmitting unit 106, and the like as shown in FIG. A program and data for realizing functions such as the CRL acquisition unit 107 are installed. These programs and data are loaded into the RAM as required, and the programs are executed by the CPU. Hereinafter, functions and processing contents of each unit in FIG. 2 will be described.

  The management processing request mediation unit 101 performs processing for mediating a request (request) related to management of a user's public key from the terminal device 3 to the certificate authority. The user makes various requests regarding management of public keys such as registration, revocation (revocation), recovery, or disclosure of expiration dates of public keys.

  For example, the registration of the public key KP is performed by managing the public key in the following procedure. The user activates the application program for encryption in his / her terminal device 3 to generate the secret key KS and the public key KP paired therewith. The generated public key KP is encrypted with the public key of the certificate authority together with the registration application information 71 describing predetermined items designated by the certificate authority of the request destination. The encrypted public key KP and registration application information 71 are transmitted to the XKMS server 1.

  Then, the management processing request mediation unit 101 transfers the public key KP and registration application information 71 transmitted from the terminal device 3 to the authentication system 2 of the certificate authority that is the registration destination. In the authentication system 2, the transmitted public key KP and registration application information 71 are decrypted, the identity of the requesting user is confirmed based on the contents of the registration application information 71, and the user corresponds to the public key KP. Confirmation of the owner of the secret key KS and confirmation of the accuracy of the contents of the request (application) are performed. If these items are confirmed, the public key KP of the user of the terminal device 3 is registered. As a result, the certificate authority can issue an electronic certificate of the public key KP. The processing result in the authentication system 2 is notified to the XKMS server 1.

  The log recording unit 102 records the contents of all communications performed by the XKMS server 1 with the authentication system 2 or the terminal device 3 as log information 81 in the log file 10F as shown in FIG. Therefore, the contents of the request for management of the public key KP mediated by the management processing request mediation unit 101 to the certification authority (authentication system 2) and the processing result of the request at the certification authority are also recorded as log information 81.

  Examples of items described in the log information 81 include “UserName”, “AuthInfo”, “Time”, “Request”, “CA”, and “Result”. In “UserName”, the user name of the user who has requested the certificate authority to manage the public key KP is recorded. In “AuthInfo”, the identification information of the user who made the management request and the identification information of the key to be managed are recorded.

  In “Request”, the contents of a request relating to management of the public key KP, such as registration (Register), discovery (Locate), or revocation (Revocation), are recorded. In “CA”, the name of the certificate authority of the requesting certificate authority is recorded. In “Time”, the requested date and time are recorded. Alternatively, the time when the requested process is completed may be recorded. In “Result”, the processing result is recorded.

  In addition, it is required to recover the public key KP and issue a certificate. Further, information disclosure regarding the expiration date of the public key KP may be requested. In the “Result” of the log information 81 in this case, the disclosed expiration date may be recorded together with the result of whether or not the processing is successful.

  The log information 811 means that the registration of the public key KP “Maru” with respect to the certificate authority A is successful. The log information 812 means that the public key KP “maru” is found in the certificate authority B, that is, the public key KP is valid at least at the time of making the request. On the other hand, the log information 813 means that the public key KP has not been found in the certificate authority A, that is, it is not valid at least in the certificate authority A. The log information 814 means that the revocation of the public key KP “tesName” was requested but failed.

  Returning to FIG. 2, every time a CRL (electronic certificate revocation list) is issued by the certificate authority, the CRL acquisition unit 107 acquires the CRL. That is, the CRL acquisition unit 107 serves as an interface between the XKMS server 1 and a repository that manages public information of the certificate authority.

  The inquiry reception unit 103 receives an inquiry regarding the validity of the public key KP from the terminal device 3. The log extraction unit 104 extracts log information 81 regarding the public key KP related to the accepted query from the log file 10F.

  The validity determination unit 105 determines the validity of the public key KP related to the inquiry based on the log information 81 extracted by the log extraction unit 104 and the CRL acquired by the CRL acquisition unit 107 as follows. Do.

  For example, if at least one of the extracted log information 81 includes information indicating “Revoke” and “success”, it is determined that the public key KP has expired and is not valid. . When there is no log information 81 indicating “Revoke” and “success”, and the expiration date of the public key KP indicates after the current time, it is determined that the public key KP is valid. To do. Alternatively, if the CRL indicates that the public key KP is revoked, it is determined that the public key KP is not valid regardless of the contents of the log information 81.

  The result transmission unit 106 transmits the discrimination result by the validity discrimination unit 105 as the discrimination result information 72 to the query source terminal device 3 together with the log information 81 of the public key KP related to the query extracted by the log extraction unit 104. .

  The user of the terminal device 3 determines whether to use the public key KP inquired about validity with reference to the determination result information 72 and the log information 81 received from the XKMS server 1. If the public key KP has already been revoked, sending data encrypted using the public key KP to other users can be seen by a malicious person or altered in the course of communication. There is a risk of being. In addition, the transmitted data may be transmitted from an unauthorized user (spoofing), or may be tampered with in the middle of the communication path. Therefore, it is desirable not to use the received data.

  As described above, the contents of the communication that the XKMS server 1 exchanges with the authentication system 2 and the terminal device 3 are all recorded in the log file 10F. Therefore, the fact that the XKMS server 1 has transmitted the discrimination result information 72 to the terminal device 3 and the content of the discrimination result information 72 are also recorded as log information 81 in the log file 10F. As a result, when there is an inquiry about the validity of the same public key KP thereafter, it is possible to quickly determine the validity by referring to the log information 81.

  The user of the terminal device 3 can request the XKMS server 1 to disclose the list of log information 81. When there is such a request, the log extracting unit 104 extracts all the log information 81 if at least one log information 81 is recorded in the log file 10F. The result transmission unit 106 transmits all the extracted log information 81 as a list to the requesting terminal device 3. In addition, when the user designates a public key or its owner as an extraction keyword, the log extraction unit 104 extracts only log information 81 that matches the keyword. The result transmitting unit 106 transmits the list to the requesting (designating) terminal device 3 as a list.

  FIG. 4 is a flowchart for explaining an example of the processing flow of the XKMS server 1. Each process shown in FIG. 4 is realized by executing a program stored in a magnetic storage device or a ROM of the XKMS server 1 by the CPU. Next, a processing procedure for the public key KP in the XKMS server 1 will be described with reference to a flowchart.

  In FIG. 4, when the XKMS server 1 receives a request regarding management of the public key KP from the user of the terminal device 3 (# 1), the XKMS server 1 notifies the authentication system 2 of the certificate authority as necessary (# 1). 2). That is, it mediates a request regarding management of the public key KP from the user to the certificate authority. The management processing result related to the request is acquired from the certificate authority, and recorded in the log file 10F as log information 81 together with the content of the request (# 3). Note that the processes of steps # 2 and # 3 are executed whenever necessary. Moreover, it may be executed in parallel with the processing of steps # 4 to # 7 described below.

  When an inquiry about the validity of the public key KP is received from the user of the terminal device 3 (# 4), the log information 81 related to the public key KP is extracted from the log file 10F (# 5). The validity of the public key KP is determined based on the extracted log information 81 (# 6), and the determination result is notified to the inquiry source user (# 7). The determination result may be notified together with the extracted log information 81.

  Further, in step # 4, when an inquiry is made by specifying the owner of the public key KP as a keyword, the log information 81 corresponding to the keyword is extracted and transmitted to the user (# 5, # 7). .

  According to the present embodiment, the XKMS server 1 mediates a request relating to management of the public key KP from the terminal device 3 to the certificate authority, and records the contents relating to the processing at that time as log information 81 in the log file 10F. Then, according to the request from the user, the log information 81 is disclosed or the validity of the public key KP is determined. This reduces direct processing requests from the terminal device 3 to the certificate authority (for example, a request for issuing an electronic certificate), thereby reducing the processing burden on the certificate authority and the terminal device 3 and the load on the entire network. can do. Further, the network administrator can easily monitor a request for issuing an electronic certificate for each user and the result thereof by referring to the log information 81 for maintenance and management of the network. Can help.

  The validity determination unit 105 of the XKMS server 1 may be provided in the terminal device 3 so that the validity of the public key KP is determined by the terminal device 3. Other functions of the XKMS server 1 can also be provided in the terminal device 3.

  In addition, the configuration of the entire XKMS server 1 and the terminal device 3 or each unit, the processing content, the processing order, and the like can be appropriately changed in accordance with the spirit of the present invention.

  As described above, according to the present invention, the validity of a public key can be easily confirmed for a user who transmits and receives data via a network. Therefore, it is useful for promoting encryption at the time of data transmission / reception and enhancing the safety of data exchange.

It is a figure which shows the example of the whole structure of the system which has XKMS server which concerns on this invention. It is a figure which shows the example of a functional structure of a XKMS server. It is a figure which shows the example of the log information stored in a log file. It is a flowchart explaining the example of the flow of a process of a XKMS server.

Explanation of symbols

1 XKMS server (server)
2 Authentication system 3 Terminal device 4 Communication line (network)
72 Discrimination result information 81 Log information (log)
101 Management processing request mediation section (management request mediation means)
102 Log recording unit (log recording means)
103 Inquiry receiving unit (inquiry receiving means)
104 Log extractor (log extractor)
105 Effectiveness discriminating unit (effectiveness discriminating means)
106 Result transmitter (result transmitter, log transmitter)
10F log file (log recording means)
KP public key

Claims (9)

A server connected via a network to a certificate authority that issues an electronic certificate of a public key and a user terminal device that uses the public key,
Management request mediation means for mediating a request for management of public keys from the terminal device to the certificate authority;
Log recording means for recording the content of the request mediated by the management request mediating means as a log together with the result information of the request;
Inquiry accepting means for accepting an inquiry as to whether or not the public key is valid from the terminal device;
Validity determination means for determining whether or not the public key is valid based on the log of the public key related to the inquiry recorded in the log recording means;
A result transmitting means for transmitting the result of the determination by the validity determining means to the terminal device of the inquiry source;
A server characterized by comprising: The log recording unit records the expiration date as a part of the log when the request relates to acquisition of information indicating the expiration date of the public key, and the request relates to the expiration of the public key. Records information indicating whether the revocation was successful as part of the log,
The validity determination means includes, when the log for the public key related to the inquiry includes information indicating that the revocation has been successful, or includes information indicating the expiration date of the public key, and the expiration date is If so, determine that the public key is not valid,
The server according to claim 1. Log extracting means for extracting all the logs stored in the log recording means in accordance with a command from the terminal device;
Log transmitting means for transmitting the extracted log to the command source terminal device,
The server according to claim 1 or 2. Log extracting means for extracting from the log recording means the log related to the keyword specified from the terminal device;
Log transmission means for transmitting the extracted log to the designated terminal device;
The server according to claim 1 or 2. A server connected via a network to a certificate authority that issues an electronic certificate of a public key and a user terminal device that uses the public key,
Management request mediation means for mediating a request for management of public keys from the terminal device to the certificate authority;
Log recording means for recording the content of the request mediated by the management request mediating means as a log together with the result information of the request;
Log extraction means for extracting from the log recording means the log for the public key specified by the terminal device;
Log transmission means for transmitting the log extracted by the log extraction means to the terminal device of the designation source;
A server characterized by comprising: A computer connected over a network to a certificate authority that issues a public key digital certificate
A process for accepting a request for public key management from a user;
Processing to notify the request to the certificate authority;
A process of recording the content of the request together with the result information of the request as a log in a log recording unit;
A process of accepting an inquiry from the user as to whether the public key is valid;
A process of determining whether or not the public key is valid based on the log of the public key related to the inquiry recorded in the log recording unit;
A process of notifying the inquiry source user of the result of the determination;
A method for providing public key information, characterized in that: A computer connected over a network to a certificate authority that issues a public key digital certificate
A process for accepting a request for public key management from a user;
Processing to notify the request to the certificate authority;
A process of recording the content of the request together with the result information of the request as a log in a log recording unit;
Processing for extracting the log for the public key designated by the user from the log recording means;
A process of notifying the extracted user of the extracted log;
A method for providing public key information, characterized in that: A computer program used in a computer having a function of communicating with a certificate authority that issues an electronic certificate of a public key,
A process for accepting a request for public key management from a user;
Processing to notify the request to the certificate authority;
A process of recording the content of the request together with the result information of the request as a log in a log recording unit;
A process of accepting an inquiry from the user as to whether the public key is valid;
A process of determining whether the public key is valid based on the log of the public key related to the inquiry recorded in the log recording unit;
A process of notifying the inquiry source user of the result of the determination;
A computer program for causing a computer to execute. A computer program used in a computer having a function of communicating with a certificate authority that issues an electronic certificate of a public key,
A process for accepting a request for public key management from a user;
Processing to notify the request to the certificate authority;
A process of recording the content of the request together with the result information of the request as a log in a log recording unit;
Processing for extracting the log for the public key designated by the user from the log recording means;
A process of notifying the extracted user of the extracted log;
A computer program for causing a computer to execute.

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