JP2005020651A - Validating method of time stamp informastion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To check the validity of time stamp information which is created by a new encryption scheme or a time stamping method without updating validation client software. <P>SOLUTION: A time stamp information service system is composed of client devices which are connected to one another on a communication network, time stamp information issuing devices, trusted third-party organization devices and a time stamp information validating server device. In this system, when the time stamp information validating server device accepts a message which requires the validation of time stamp information from a client device, it analyzes the time stamp information in the message and judges whether or not it can validate it in itself. If the validation is judged to be being possible, the time stamp information validating server device conducts validation in itself. If validation is judged to be impossible, it specifies the issuer device of the time stamp and requests it to conduct validation. After validation, it returns the created result of validation to the client device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a time stamp technique for guaranteeing the existence time of electronic data and the integrity of data thereafter. In particular, the present invention relates to a technique for verifying validity of time stamp information.
[0002]
[Prior art]
With the progress of IT technology, systems for e-commerce and e-government are becoming popular. In these systems, electronic data representing contracts and application forms are transmitted and received via a network such as the Internet. In order to comply with legal systems and guidelines, electronic data and transmission / reception logs must be stored for a certain period of time. In these systems, ensuring security is important. Specifically, it is important to prevent impersonation, tampering, eavesdropping and denial accompanying electronic data transmission / reception and to guarantee the authenticity of electronic data stored for a long time.
[0003]
In the public key infrastructure (PKI), an electronic signature for electronic data is created in order to ensure authentication and integrity of the electronic data (see, for example, Non-Patent Document 1). If the electronic signature is verified at a later date, it is possible to verify whether the electronic data has been tampered with or prevent the signer from refusing. For example, a verification method using a server for verifying an electronic signature has been proposed (see, for example, Patent Document 1).
[0004]
The time stamp service realizes a security function that is not provided by an electronic signature. This service provides a function of authenticating the existence time of electronic data and guaranteeing the integrity of the subsequent data (for example, see Non-Patent Document 2).
[0005]
The time stamp service includes a client device that requests time stamp information for electronic data and a server device that issues time stamp information. The client device obtains a hash value (message digest value) of the electronic data using a hash function, and transmits the data to the server device. The server device creates time stamp information that cryptographically links the received hash value and the reliable current time information, and returns the information to the client. At a later date, by verifying this time stamp information, it becomes possible to verify the existence time of electronic data and verify the presence or absence of tampering.
[0006]
As a method for verifying time stamp information, it is necessary to use a method depending on a method for creating time stamp information (see, for example, Non-Patent Document 2 and Non-Patent Document 3). For example, in the case of time stamp information with an electronic signature, the time stamp information is verified by verifying the electronic signature. If the time stamp information is created by the link token method, the time stamp information can be verified by accessing the time stamp issuer device that can verify the validity of the link information included in the time stamp information. It is necessary to verify the sex.
[0007]
[Patent Document 1]
JP-A-8-101868 (page 5-17, FIG. 1)
[Non-Patent Document 1]
Carlyle Adams, written by Steve Lloyd, translated by Yuichi Suzuki, “PKI Public Key Infrastructure Concepts, Standards, Deployment”, Pearson Education Publishing, July 15, 2000, p. 41-52
[Non-Patent Document 2]
ISO / IEC 18014-1, "Information technology Security technologies Time-stamping services Part 1: Framework", October 1, 2002
[Non-Patent Document 3]
ISO / IEC 18014-2, “Information technology Security technologies Time-stamping services Part 2: Mechanisms producing independent tokens”, December 15, 2002
[0008]
[Problems to be solved by the invention]
A time stamp technology that authenticates the existence time of electronic data and guarantees the integrity of the subsequent electronic data is a relatively new technology. Therefore, it is expected that new time stamp methods will be proposed and implemented in the future. In addition, as the IT society matures in the future, electronic data corresponding to time stamp information created by various time stamp methods is expected to be widely distributed.
[0009]
In the conventional technology, a client device that has received time stamp information created by a new encryption algorithm or time stamp technology cannot verify the validity of the data, or can verify the validity. The trouble of changing the verification client software occurs.
[0010]
Further, when the verification server apparatus receives time stamp information that cannot be verified by itself, there arises a problem that the time stamp information cannot be verified.
[0011]
Further, when verifying time stamp information in a business such as a company, a central government, or a local government, it is necessary to perform verification based on a verification policy set by each organization. The conventional technique does not clarify the verification method based on the verification policy.
[0012]
Therefore, an improved time stamp information verification technique is desired.
[0013]
[Means for Solving the Problems]
The present invention has been devised to solve the above problems, and can verify the validity of time stamp information created by a new encryption algorithm or time stamp technology without updating the verification client software. Provide technology.
[0014]
In addition, the present invention provides a technique capable of verifying even when the verification server apparatus determines that it cannot verify itself.
[0015]
The present invention also provides a method in which a verification server apparatus verifies time stamp information based on a verification policy.
[0016]
In one aspect, the time stamp information verification method of the present invention comprises a client device, a time stamp information issuing device, a trusted third party organization device, and a time stamp information verification server device connected to each other via a communication network. Is a time stamp information verification method in a time stamp information service system, and a time stamp information verification server device for verifying validity of time stamp information receives a message requesting verification of time stamp information from a client device. , Analyze the time stamp information in the message, determine whether it can be verified in the time stamp information verification server device, if it is determined to be verifiable, execute verification in the time stamp information verification server device, If you decide you ca n’t verify, A time stamp issuer device is identified, a verification result is received from the identified time stamp issuer device, a verification result data is generated based on the verification result, and transmitted to the client device. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 shows a time stamp service system configuration showing an embodiment of the present invention. The time stamp service system includes a plurality of client devices 100, a time stamp information issuing device 102, a trusted third party organization device 104, a time stamp information verification server device 106, and a communication network 150 to which these devices are connected. .
[0019]
The client device 100 is a client device that issues a request to the time stamp information issuing device 102 in order to obtain time stamp information for electronic data such as contracts and applications, or audit log data such as communication logs and system logs. is there. In addition, the client device 100 makes a verification request to the time stamp information verification server device 106 in order to confirm the validity of the time stamp information.
[0020]
The time stamp information issuing device 102 is a device that receives a request from the client device 100 and issues time stamp information. Each of these time stamp information issuing devices may implement a unique time stamp method. This apparatus also provides a time stamp information verification function depending on the time stamp method used. For example, the time stamp information issuing device 102-B that creates time stamp information of the link token method provides a function of verifying the time stamp information of the created link token method.
[0021]
The trusted third-party organization device 104 is a highly reliable service device used when verifying an electronic signature using the PKI technology. Specifically, it represents a certificate authority apparatus that issues public key certificates, a registration authority apparatus for public key certificates, a repository apparatus that manages a public key certificate revocation list, an OCSP responder apparatus, and the like. The trusted third party organization device 104 provides a service to the time stamp information verification server device 106 as needed.
[0022]
The time stamp information verification server device 106 receives a time stamp information verification request message from the client device 100 and provides a service for verifying the time stamp information. The time stamp information verification server device 106 includes a communication processing unit 108 that performs communication processing with other devices on the communication network 150, and time stamp information analysis that performs processing to analyze time stamp information in the received time stamp information verification request message. 110, a time stamp information verification executing unit 112 that provides a function for verifying the validity of time stamp information, verification method management data 114 that stores data defining a verification method for each time stamp information, and a time stamp information verification policy Policy management data 116 for storing data defining data, public key certificate data owned by the time stamp information verification server device, private key data, and a key store 118 for storing self-certificate data of a trusted certificate authority. ing. The key store may store information (for example, a revocation list of a public key certificate) acquired by using a service of a trusted third-party organization apparatus 104. The detailed operation of the time stamp information verification server device will be described later.
[0023]
The time stamp information verification server device 106 is preferably a computer including a network connection device that allows a large number of simultaneous accesses and has high-speed processing capability. Specifically, it is realized by a workstation having a large computer or a plurality of central processing units.
[0024]
Further, since the time stamp information verification server device 106 provides a time stamp information verification service to the client device 100, high reliability is required. Therefore, it is preferable that the platform system that operates the time stamp information verification processing program has security measures. Specifically, it is desirable that the OS be provided with measures to prevent unauthorized access to the file system and cracking acts via the network. Furthermore, it is desirable to manage important data such as public key certificate data and private key data on tamper-resistant hardware.
[0025]
It is assumed that the time stamp information issuing device 102 and the trusted third-party organization device 104 also adopt a platform equivalent to the time stamp information verification server device 106.
[0026]
The client device 100 may be a general-purpose personal computer having a central processing unit, an input device such as a keyboard and a mouse, a storage device such as a hard disk and a RAM, an output device such as a CRT display, a liquid crystal display and a printer, and a network device for communication. realizable. Of course, the computer is not limited to a personal computer, and any computer having an input device, an output device, and a communication device for a user may be used.
[0027]
The communication network 150 can be realized by a communication network such as a wired network such as a public network, the Internet, and an ISDN network, or a wireless network using a communication satellite.
[0028]
In the time stamp service system, when communicating between devices via the communication network 150, measures may be taken to prevent device impersonation, tampering with communication data, wiretapping of communication data, and the like. This can be realized by using SSL (Secure Sockets Layer) communication technology.
[0029]
Each function and each processing unit of each of the above devices is realized by executing a program stored in the storage device by each central processing unit. In addition, each program may be stored in advance in each storage device, and if necessary, propagates over a communication network or a communication network that is a removable storage medium or communication medium that can be used by the device. It may be introduced from another device via a carrier wave.
[0030]
FIG. 2 is a flowchart showing a procedure in which the time stamp information verification server device 106 verifies the time stamp information. The time stamp information verification server device 106 receives a time stamp information verification request message from the client device 100 (step 202).
[0031]
The time stamp information verification request message includes at least time stamp information data described later. Moreover, the electronic data itself corresponding to this time stamp information may be included.
[0032]
Further, the electronic data corresponding to the time stamp information data may be integrally encoded in a known format format. For example, the electronic data corresponding to the time stamp information may be encoded in a data format or XML format unique to the application program. Information regarding these encoding methods can be indicated using a communication protocol between the client apparatus 100 and the time stamp information verification server apparatus 106. For example, information indicating an encoding format can be included in an HTTP content header.
[0033]
The time stamp information verification server device 106 analyzes the time stamp information in the received time stamp information verification request message, refers to a time stamp verification method management table to be described later, and determines whether or not it can be verified by itself ( Step 204, Step 206).
[0034]
If it is determined that it can be verified by itself, the time stamp information is verified (step 208). For example, an example of a processing procedure when verifying time stamp information created by an independent token method using the PKI technique shown in ISO18014-2 is as follows.
(1) When electronic data corresponding to the time stamp information is included in the time stamp information verification request message, a message digest value of the electronic data is obtained using the corresponding hash function, and this value is included in the time stamp information. Confirm that it is the same as the message digest value.
(2) The validity of the public key certificate included in the time stamp information is confirmed by using the revocation list of the public key certificate stored in the key store 118 or the service of a trusted third-party organization device. To do.
(3) The electronic signature of the time stamp information is verified using the public key included in the public key certificate whose validity has been confirmed.
(4) If other signed data is included, verification is performed in the same manner as described above.
[0035]
If it is determined that it cannot be verified by itself, the time stamp verification method management table is referred to, the issuer device of this time stamp information is selected, and the verification method is specified (step 210). Next, the time stamp information issuing device is requested to verify the time stamp information, and the verification result is received (steps 212 and 214).
[0036]
When the time stamp information verification server device 106 obtains the verification result of the time stamp information, the time stamp information verification server device 106 generates verification result data, and transmits the generated verification result data as a response to the request to the requested client device 100 (step). 216, step 218).
[0037]
As described above, since the client device 100 can entrust the time stamp information verification server device 106 to verify time stamp information that is not supported by its own verification software, it is troublesome to modify the software of the client device. Disappears. In addition, since the time stamp verification server device 106 can delegate verification of time stamp information that cannot be verified by itself to the time stamp information issuing device 102, the service satisfaction that the verification service cannot be provided to the client device 100 is achieved. It can avoid the degrading situation.
[0038]
FIG. 3 shows an example of the structure of time stamp information data created by the time stamp information issuing apparatus 102. The field 302 stores a time stamp identifier for uniquely specifying time stamp information in the time stamp issuing device unit. A field 304 stores a message digest value of electronic data to be time stamped. A field 306 is time information generated by referring to the time source of the time stamp information issuing device 102. For example, time information based on Greenwich Mean Time (format is YYYY-MM-DD-HH-MM-SS, etc.) is included. A field 308 is an identifier indicating a time stamp information issuance policy. The issuance policy is information managed by the time stamp information issuing device 102, and the time stamp information issuing device 102 issues time stamp information based on this information. For example, there are a policy for issuing time stamp information for testing, and a policy for issuing time stamp information that meets standards for e-government. A field 310 is an identifier for specifying a time stamp information issue source device. The time stamp information verification server device 106 uses the information in this field to identify the time stamp information issuing source device. The field 312 includes certificate information for indicating validity of the time stamp information. As an example, the electronic signature of the time stamp information issuing apparatus for the information in the fields 302 to 310 and the field 314 is included. In addition, if the time stamp information is created by the link token method, the link information managed by the time stamp information issuing source device is included. The field 314 includes additional information related to time stamp information. For example, an identifier of a hash function for obtaining a message digest value in the field 304, accuracy information of time information in the field 306, and the like are included.
[0039]
FIG. 4 shows a time stamp information verification method management table that the time stamp information verification server device 106 refers to when verifying time stamp information. A field 402 indicates a unique identifier for identifying the time stamp information issuer. The field 404 includes information indicating a method for verifying the time stamp information created by the time stamp information issue source device. In this example, the resource name (tsa-001.jp/verify) and the access protocol (https) on the network that provides the verification service are shown using the URL. Of course, in addition to this, a detailed verification service request / response message specification may be included. The time stamp information verification server device 106 can search this table using the identifier of the time stamp information issuer in the received time stamp information as a key, and can select an appropriate verification method.
[0040]
As a premise of the present invention, when a time stamp information issuing device 102 adopting a new time stamp method is introduced, the identifier of the time stamp information issuing device 102 and its verification method are registered. It is supposed to be. As a specific example, there is a method in which an administrator with appropriate authority adds information using management software. Alternatively, the time stamp information issuing device 102 automatically notifies the time stamp verification server device 106 of the information using a predetermined protocol, and the time stamp verification server device automatically manages the information. There is also a method of adding to the table.
[0041]
In the example of FIG. 4, the time stamp information verification method for each time stamp issuer unit is managed. However, by using information included in the time stamp information data in FIG. The verification method may be managed. For example, the time stamp information verification method for each time stamp information identifier unit in the field 302 of FIG. 3 may be managed.
[0042]
FIG. 5 is an example of a verification policy information management table. The time stamp information verification server device 106 refers to the information in the verification policy information management table, corrects the verification result of the validity of the time stamp information, and creates verification result data to be described later. Field 502 represents an identifier that identifies the policy. A field 504 is a field indicating a policy classification. A field 506 and a field 508 indicate a policy item and a policy content, respectively. Field 510 includes information indicating the reason for the policy.
[0043]
For example, a policy having a value of policy identifier 0001 displays “warning” as a non-verified policy identifier for the result of verifying the validity of time stamp information having a value of 1.2.3.4.5555. It is necessary to put out. The reason for the warning is “because of the experimental time stamp”. The policy with the policy identifier 0002 indicates that it is necessary to advance the time zone of the time information included in the verification result by +9: 00, that is, Japan Standard Time. The policy identifier 0003 indicates that the locale (language setting) of the verification result needs to be Japanese. In the present invention, an example of a method for managing these verification policy information management tables is that an administrator with appropriate authority adds, modifies, and deletes a policy using management software.
[0044]
As described above, the validity of the time stamp information is verified not only by syntactic and cryptographic low-level verification such as verification of electronic signatures based on PKI technology, but also by semantics according to organizations such as nations and companies. It is possible to include a general high-level concept.
[0045]
FIG. 6 shows an example of the structure of the time stamp information verification result data created by the time stamp information verification server apparatus 106 after verifying the time stamp information. This information is returned to the client device 100. The field 602 includes time stamp information data sent from the client device 100. A field 604 includes verification result information. Examples of verification result data include binary data, XML data, and image information. The field 606 is additional information for the verification result. For example, the digital signature data of the time stamp information verification server device for guaranteeing the authenticity of the field 602 and the field 604 can be stored. The contents of the verification result data will be described later based on the verification result information display screen on the client device.
[0046]
FIG. 7 is a flowchart showing a procedure in which the time stamp information verification server device 106 creates verification result data with reference to the verification policy information management table of FIG.
[0047]
In step 702, the verification policy information management table is referenced to determine whether or not the verification result needs to be corrected (step 704). If necessary, the verification result is corrected (step 706).
[0048]
FIG. 8 is an example of a display screen of time stamp information verification result data displayed on the client device 100. In this example, the verification result data is expressed as an image image in the screen area 802. Since the verification policy referred to by the time stamp information verification server device 106 is reflected, the language from the region 804 to the region 814 is Japanese. The time information in the area 806 is displayed as Japan standard time. In the area 812, the verification result is shown, and an annotation “but with warning” is attached according to the verification policy. An area 814 lists identifiers indicating verification policies. Of course, the verification policy can be expressed in a readable manner.
[0049]
As described above, the client device can easily obtain and display the verification result according to the verification policy of the time stamp information verification server device without depending on the software or hardware environment of the client device 100. .
[0050]
FIG. 9 is a flowchart showing another operation example of the time stamp information verification server apparatus in the configuration example of FIG. In step 902 and step 904, the time stamp information verification server apparatus accepts the time stamp information verification request, analyzes the time stamp information, and checks whether the information necessary for verifying the time stamp information is insufficient. Is determined (step 906). The determination method can be realized by searching the time stamp information verification method management table of FIG. 4 and finding necessary information and access method for each time stamp information. For example, if the time stamp information is created by the link token method, the necessary information is the link information, and the access method is a method of inquiring the time stamp information issuing device.
[0051]
When the time stamp information verification server device 106 determines that the information required for verification is insufficient, the time stamp information verification server device 106 selects a time stamp issuing source device having information necessary for verification, and requests the device for information required for verification. Information necessary for verification is obtained (steps 908, 910, and 912). When the information necessary for the verification is acquired, the verification process is executed in the same procedure as Step 208, Step 216, and Step 218 in FIG.
[0052]
【The invention's effect】
According to the present invention, the client device can verify the validity of time stamp information created by a new encryption algorithm or time stamp method without updating the verification client software.
[0053]
Further, according to the present invention, even when the time stamp information verification server apparatus determines that it cannot verify itself, it can verify.
[0054]
Further, according to the present invention, the verification server device can verify the time stamp information based on the verification policy.
[Brief description of the drawings]
FIG. 1 is a system and software configuration diagram showing an embodiment of the present invention.
FIG. 2 is a flowchart showing a time stamp information verification operation in the time stamp information verification server apparatus.
FIG. 3 is a structural example of time stamp information data.
FIG. 4 is an example of a data table that stores information on a time stamp information verification method;
FIG. 5 is an example of a data table that stores verification policy information of time stamp information.
FIG. 6 is a structural example of time stamp information verification result data.
FIG. 7 is a flowchart showing a time stamp information verification operation using a verification policy in the time stamp information verification server apparatus.
FIG. 8 is an example of a screen showing a verification result of time stamp information.
FIG. 9 is a flowchart showing another time stamp information verification operation in the time stamp information verification server apparatus;
[Explanation of symbols]
Client device ... 100, time stamp information issuing device ... 102, trusted third party organization device ... 104, time stamp information verification server device ... 106, communication processing unit ... 108, time stamp information analysis unit ... 110, time stamp information Verification execution unit ... 112, time stamp information verification method management data ... 114, time stamp information verification policy management data ... 116, key store ... 118, communication network ... 150.

Claims (6)

Time stamp information verification in a time stamp information service system comprising a client device, a time stamp information issuing device, a trusted third-party organization device, and a time stamp information verification server device connected to each other via a communication network A method,
The time stamp information verification server device that verifies the validity of the time stamp information,
Upon receiving a message requesting verification of time stamp information from the client device, the time stamp information in the message is analyzed,
Determine whether the time stamp information verification server device can verify,
When it is determined that verification is possible, verification is performed within the time stamp information verification server device,
If it is determined that it cannot be verified, specify the time stamp issuer device,
Request the verification to the identified time stamp issuer device and receive the verification result,
A time stamp information verification method comprising: generating verification result data based on the verification result and transmitting the verification result data to the client device. The time stamp information verification method according to claim 1,
The time stamp information verification server device includes:
A time stamp information verification method comprising verification policy information, and generating the verification result data based on the verification policy information. The time stamp information verification method according to claim 1,
The time stamp information verification method, wherein the verification policy information includes information indicating a semantic validity of the time stamp information. The time stamp information verification method according to claim 1,
The time stamp information verification method, wherein the verification policy information includes information for indicating a display form of a verification result. The time stamp information verification method according to claim 1,
The time stamp information verification server device includes information for identifying the verification policy information in the verification result data. Time stamp information verification in a time stamp information service system comprising a client device, a time stamp information issuing device, a trusted third-party organization device, and a time stamp information verification server device connected to each other via a communication network A method,
The time stamp information verification server device that verifies the validity of the time stamp information,
Upon receiving a message requesting verification of time stamp information from the client device, the time stamp information in the message is analyzed,
Determine whether the time stamp information verification server device can verify,
When it is determined that verification is possible, verification is performed within the time stamp information verification server device,
If it is determined that it cannot be verified, specify the time stamp issuer device,
Access the identified time stamp issuer device to obtain information necessary for verification,
Perform verification using the acquired information,
A time stamp information verification method comprising: generating verification result data based on a verification result and transmitting the verification result data to the client device.

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