JP2004289471A - Signature instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To freely modify electronic documents even after signature data generation. <P>SOLUTION: Inherent signature data are generated to a facility information file (Step S3), and the signature data and the facility information file are paired, namely, the signature data and the facility information file are made another file to be stored in the same folder (Step S4). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a signature device that generates signature data unique to an electronic document such as document data and graphic data.
[0002]
[Prior art]
Conventionally, as such a technique, for example, when an electronic document is transmitted by e-mail or the like, malicious data is embedded in the electronic document by embedding signature data unique to the electronic document and prohibiting modification of the electronic document. It is known to prevent unauthorized alteration (falsification) of electronic documents by a third party.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional technology, in order to embed signature data in an electronic document and to prohibit modification of the electronic document, for example, when a plurality of persons co-create one electronic document, the signature data is added to the electronic document. Once embedded, the co-author, as well as the malicious third party, cannot modify the electronic document.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the unsolved problem of the above-described conventional technology, and a signature device capable of freely changing an electronic document even after signature data is generated. The task is to provide.
[0004]
[Means for Solving the Problems]
In order to solve the above problems, a signature device according to the present invention includes a signature generation unit that generates signature data unique to an electronic document, and a pair of signature data generated by the signature generation unit and the electronic document. And conversion means. As a method of integrating the signature data and the electronic document, for example, a method of storing the signature data and the electronic document in separate files (separate bodies) and storing them in the same folder, a method of storing the signature data and the electronic document in the same hierarchy, and the like are exemplified. Can be
[0005]
Therefore, in the signature device according to the present invention, the signature data unique to the electronic document and the electronic document are paired, that is, since the signature data and the electronic document are separated, the signature data is deleted. It does not matter that the signature data does not correspond to the electronic document, and the electronic document can be changed freely.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example in which the signature device of the present invention is used for a personal computer serving as a terminal of a computer-aided facility management system will be described with reference to the drawings. Note that Computer Aided Facility Management (CAFM) is a technology for managing and utilizing information (facility information) required for facility operation management.
[0007]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. In the figure, reference numeral 1 denotes a server for managing facility information, and 2 denotes a facility management company or a construction company that performs facility maintenance work or the like at the request of the management company. 3 are a plurality of personal computers that can be connected to each other.
As shown in FIG. 2, the personal computer 2 includes a microprocessor 4 having a CPU, a RAM 5 for forming various work areas, and a keyboard 6, a display 7, an I / O for mediating data input / output with the Internet 3 and the like. / F8, which are connected to each other via a bus 9 which is a signal line for transferring data so as to be able to exchange data. Then, the microprocessor 4 executes transmission / reception processing for transmitting or receiving an electronic document (facility information file) including facility information to / from the server 1. This transmission / reception process is a process executed when a user performs a predetermined keyboard operation on the personal computer 2, and as shown in the flowchart of FIG. A display command for displaying a message prompting the user to select whether to transmit or receive the facility information file is output to the display 7 of the personal computer 2.
[0008]
Next, the process proceeds to step S2, where it is determined whether the user has performed a predetermined keyboard operation for selecting transmission of the facility information file. If the user has performed the predetermined keyboard operation (Yes), the process proceeds to step S3. The process proceeds to step S6 if not (No).
In step S3, signature data is generated for the facility information file. Specifically, the facility information file is compressed with the public key authenticated by the certificate authority, and the compression result is used as signature data. Here, the public key is a one-way hash algorithm for compressing data of an arbitrary length into data of a fixed length.
[0009]
Next, the process proceeds to step S4, where the signature data and the facility information file generated in step S3 are paired. Specifically, the signature data, the facility information file, and the public key are stored as separate files and stored in the same folder (facility information folder).
Next, the process proceeds to step S5, in which the facility information folder storing the facility information file and the like in step S4 is compressed, and the compression result is transmitted to the server 1 via the Internet 3, and then the calculation process is terminated. As a method of transmitting the compressed facility information folder, for example, a method of attaching the facility information folder to an e-mail and transmitting the e-mail to the address of the server 1 can be cited.
[0010]
On the other hand, in step S6, it is determined whether the user has performed a predetermined keyboard operation for selecting reception of the facility information file. If the user has performed the predetermined keyboard operation (Yes), the process proceeds to step S7. Otherwise (No), the process proceeds to step S2.
In step S7, the compressed facility information folder is received from the server 1 via the Internet 3, the reception result is decompressed (decompressed), and the facility information folder is returned to the original state before compression.
[0011]
Next, the process shifts to step S8 to confirm that the facility information file has not been falsified based on the signature data in the facility information folder. Specifically, the facility information file is compressed with the public key in the facility information folder decompressed in step S7, and it is determined whether or not the compression result matches the signature data. Has not been tampered with, otherwise it has been tampered with.
[0012]
Next, the process shifts to step S9 to confirm that the public key used in step S8 is valid. Specifically, an inquiry is made to a not-shown certificate authority via the Internet 3.
Further, the server 1 has a built-in microprocessor equipped with a CPU (not shown), and upon receiving the compressed facility information folder via the Internet 3, stores the facility information file of the facility information folder in a storage device. I do. This storage processing is executed when the server 1 receives the compressed facility information folder. As shown in the flowchart of FIG. 4, first, in step S10, the compressed facility information folder is decompressed. (Decompress) and restore the facility information folder to its original state before compression.
[0013]
Next, the process proceeds to step S11, where it is confirmed that the facility information file has not been falsified based on the signature data in the facility information folder decompressed in step S10, and the facility information folder is stored in the server 1 (not shown). Store in storage device.
Then, the process proceeds to step S12, where it is determined whether the compressed facility information folder is transmitted from the operation management company or transmitted from the construction company, and is transmitted from the operation management company. If it is, the process proceeds to step S14, and if it is transmitted from the contractor, the process proceeds to step S13. As a method of determining the transmission source of the compressed facility information folder, for example, when an electronic mail is used as the transmission means, a method of determining based on the address of the transmission source of the electronic mail may be used.
[0014]
In step S13, the facility information folder decompressed in step S11 is compressed again, and the compression result is transmitted to the personal computer 2 on the operation management company side via the Internet.
On the other hand, in step S14, registration is performed to guarantee the originality of the facility information file in the facility information folder decompressed in step S11. Specifically, the facility information file is compressed using the public key of the computer-supported facility management system, and the compression result is transmitted to an electronic document certification center (not shown) via the Internet.
[0015]
Next, the operation of the signature device of the present invention will be described in detail based on a specific situation.
First, in response to a request from the operation management company, the construction company generates a facility information file including a breakdown of the maintenance work of the facility with a predetermined application program of the personal computer 2, and then causes the personal computer 2 to execute transmission / reception processing. It is assumed that a predetermined keyboard operation is performed. Then, the transmission / reception processing is executed by the personal computer 2, and a display command is first output to the display 7 of the personal computer 2 in step S 1. When the output command is acquired by the display 7, a message prompting the user to select whether to transmit the facility information file to the server 1 or to receive the facility information file is displayed on the display 7.
[0016]
It is assumed that the contractor has performed a predetermined keyboard operation to select transmission of the facility information file in accordance with the message displayed on the display 7. Then, the determination in step S2 becomes “Yes”, and in step S3, signature data for the facility information file is generated as shown in FIG. 5A. In step S4, the signature data and the facility information file are paired. The facility information folder is compressed, that is, stored in the same facility information folder. In step S5, the facility information folder is compressed as shown in FIG. 5 (2), and the compression result is sent to the server 1 via the Internet 3.
[0017]
When the compressed facility information folder is acquired by the server 1, the server 1 executes a storage process. First, in step S10, the compressed facility information folder is decompressed, and the facility information folder is uncompressed. In step S11, it is confirmed that the facility information file has not been tampered with based on the signature data in the facility information folder, as shown in FIG. 5 is stored in the storage device (not shown), and in step S12, it is determined that the compressed facility information folder has been transmitted from the contractor. In step S13, the facility information folder as shown in FIG. The folder is compressed again, and the compression result is transmitted to the personal computer 2 on the operation management company side via the Internet 3.
[0018]
Here, it is assumed that the operation management company performs a predetermined keyboard operation for causing the personal computer 2 to perform transmission / reception processing. Then, the transmission / reception processing is executed by the personal computer 2. First, through step S 1, a message prompting the user to select whether to transmit the facility information file to the server 1 or to receive the facility information file is displayed on the display 7 of the personal computer 2. Is done.
[0019]
According to the message displayed on the display 7, it is assumed that the operation management company has performed a predetermined keyboard operation for selecting reception of the facility information file. Then, the determination in step S2 becomes "No", and the determination in step S6 becomes "Yes". In step S7, the compressed facility information folder is received from the server 1 via the Internet 3, and the reception result is decompressed. In step S8, it is confirmed that the facility information file has not been falsified based on the signature data in the facility information folder decompressed in step S7, and in step S9, as shown in FIG. It is confirmed that the hash algorithm used for the confirmation is valid.
[0020]
Here, as shown in FIG. 5 (6), the operation management company deletes the signature data in the facility information folder, opens the facility information file by the corresponding application program of the personal computer 2, and stores the information in the facility information file. It is assumed that a predetermined correction is made to the included breakdown and a predetermined keyboard operation for causing the personal computer 2 to perform transmission / reception processing is performed. Then, the transmission / reception processing is executed by the personal computer 2. First, through step S 1, a message prompting the user to select whether to transmit the facility information file to the server 1 or to receive the facility information file is displayed on the display 7 of the personal computer 2. Is done.
[0021]
In accordance with the message displayed on the display 7, it is assumed that the operation management company has performed a predetermined keyboard operation for selecting transmission of the facility information file. Then, the determination in step S2 becomes "Yes", and in step S3, as shown in FIG. 5 (7), new signature data is generated in the corrected facility information file. In step S4, the signature data and the correction are generated. The obtained facility information file is stored in the same facility information folder. In step S5, the facility information folder is compressed as shown in FIG. 5 (8), and the compression result is sent to the server 1 via the Internet 3. You.
[0022]
Then, when the compressed facility information folder is acquired by the server 1, the server 1 executes a storage process. First, through the step S10, in a step S11, as shown in FIG. Based on the signature data in the folder, it is confirmed that the modified facility information file has not been tampered with, the facility information folder is stored in a storage device (not shown) of the server 1, and the compressed facility information is stored in step S12. It is determined that the information folder has been transmitted from the operation management company. In step S14, as shown in FIG. 5 (10), registration of the facility information file in the facility information folder for guaranteeing the originality is performed. Is
[0023]
As described above, in the present embodiment, the signature data and the facility information file are paired, that is, the signature data and the facility information file are separated from each other. It does not matter that the facility information file does not correspond to the facility information file, and the operation management company can freely change the facility information file.
In the above embodiment, step S3 of the arithmetic processing in FIG. 3 constitutes the signature generation means, and step S4 of the arithmetic processing in FIG. 3 constitutes the pairing means.
Further, the above embodiment is an example of the signature device of the present invention, and does not limit the configuration of the device.
[0024]
【The invention's effect】
As described above, in the signature device according to the present invention, the signature data unique to the electronic document and the electronic document are paired, that is, since the signature data and the electronic document are separated, the signature data is By deleting, there is no problem that the signature data does not correspond to the electronic document, and the electronic document can be freely changed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a signature device of the present invention.
FIG. 2 is a block diagram showing an internal configuration of the personal computer of FIG.
FIG. 3 is a flowchart showing transmission / reception processing executed in the personal computer of FIG. 1;
FIG. 4 is a flowchart showing a storage process executed in the server of FIG. 1;
FIG. 5 is an explanatory diagram for explaining the operation of the present invention.
[Explanation of symbols]
1 is a server 2 is a personal computer 3 is an Internet 4 is a microprocessor 6 is a keyboard 7 is a display 8 is an I / F
9 is a bus

Claims (1)

A signature apparatus comprising: signature generation means for generating signature data unique to an electronic document; and pairing means for pairing the signature data generated by the signature generation means with the electronic document.

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