File management program and file management device

Abstract

To enable a user to easily perform a task of combining an electronic file with a time stamp token corresponding thereto without being aware of whether or not the electronic file has a structure allowing addition of the time stamp token to itself.SOLUTION: A file management device implemented by causing a computer to execute a file management program determines which of combination forms selected from a direct type combination form with a time stamp token being added to an electronic file itself and an attachment type combination form with the electronic file being attached to a wrapper file and the time stamp token being added to the wrapper file to which the electronic file is attached should be used to combine a target file being an electronic file to be managed with a time stamp token (S3, S4, S5, S7, and S12), and depending on the result, combines the target file with the time stamp token using either the direct type or attachment type combination form (S15).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a file management program and a file management apparatus for managing electronic files using time stamps. [Background Art]

[0002] Today, methods for managing electronic files using time stamps are widely prevalent. Methods for managing electronic files using time stamps are generally as follows.

[0003] A user transmits a hash value of an electronic file that the user desires to manage using a time stamp to a time stamp authority (TSA). The time stamp authority encrypts (applies an electronic signature to) a combination of the received hash value and time information indicating the current time using the private key of the time stamp authority. Further, the time stamp authority generates a time stamp token by attaching a public key certificate including a public key corresponding to the private key to the encrypted hash value and the time information. Then, the time stamp authority transmits the generated time stamp token to the user. The user respectively stores the electronic file that the user desires to manage using a time stamp, and the time stamp token received from the time stamp authority (the time stamp token corresponding to the electronic file).

[0004] Subsequently, the user can use a timestamp token corresponding to the electronic file to prove the existence and integrity of the electronic file. That is, the timestamp token contains an encrypted hash value and time information. The user decrypts this encrypted hash value and time information using the public key contained in the timestamp token. Based on the time information obtained from the timestamp token in this way, the user can prove that the electronic file existed at the date and time indicated by that time information. Furthermore, the user can generate a hash value of the electronic file, compare that hash value with the hash value obtained from the timestamp token using the public key as described above, and prove that the two match, thereby proving that the electronic file has not been tampered with after the date and time indicated by the time information obtained from the timestamp token.

[0005] By the way, when managing electronic files using timestamps, it is important to clearly link the electronic file with its corresponding timestamp token. To clearly link the electronic file with its corresponding timestamp token, it is preferable to generate a single electronic file that combines the electronic file and its corresponding timestamp token. There are two methods for generating a single electronic file that combines the electronic file and its corresponding timestamp token.

[0006] The first method involves attaching a timestamp token to the electronic file itself, for example, by embedding the timestamp token within the electronic file. Currently, PDF files have a structure that allows them to embed timestamp tokens. When the electronic file is a PDF file, this method allows for the direct linking of the electronic file and its corresponding timestamp token, thereby clearly establishing a connection between the electronic file and its corresponding timestamp token. When linking an electronic file and its corresponding timestamp token using the first method, the hash value of the electronic file itself is sent to a timestamp certification authority to obtain the timestamp token. This timestamp token contains encrypted data of the hash value of the electronic file itself and time information.

[0007] The second method involves attaching an electronic file to a file wrapper file and then adding a timestamp token to the file wrapper to which the electronic file is attached. A file wrapper file is an electronic file that has a structure that allows other electronic files to be attached to it, and a structure that allows timestamp tokens to be attached to it (e.g., embedded). PDF files have these structures and can therefore be used as file wrapper files. Among electronic files that users wish to manage using timestamps, there are some, such as text files, CSV (Comma Separated Values) files, and Word files, that do not have a structure that allows timestamp tokens to be attached to them. For such electronic files, the second method allows the electronic file and its corresponding timestamp token to be linked via a file wrapper file, thereby clearly linking the electronic file and its corresponding timestamp token. When linking an electronic file and its corresponding timestamp token using the second method, the electronic file is attached to the file wrapper file, and then the hash value of the file wrapper to which the electronic file is attached is sent to a timestamp certification authority to obtain a timestamp token. The timestamp token contains encrypted hash value and time information of the file wrapper to which the electronic file is attached.

[0008] Japanese Patent Publication No. 2017-182433 (Patent Document 1) describes a technique for managing timestamps by embedding them in PDF files. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2017-182433 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The two methods described above allow for the linking of electronic files with their corresponding timestamp tokens, clearly establishing an association between the electronic files and their timestamp tokens. However, the following problems exist.

[0011] If an electronic file has a structure that allows it to attach a timestamp token, such as a PDF file, then the electronic file and its corresponding timestamp token can be combined using the first method described above. However, if an electronic file does not have a structure that allows it to attach a timestamp token, such as a text file or CSV file, then the electronic file and its corresponding timestamp token cannot be combined using the first method. In such cases, the electronic file and its corresponding timestamp token must be combined using the second method described above. As a result, when a user performs the task of combining an electronic file and its corresponding timestamp token using, for example, a personal computer, they must determine for themselves whether or not the electronic file has a structure that allows it to attach a timestamp token. This determination is not easy for, for example, a general office worker who is not particularly familiar with information processing technology.

[0012] Furthermore, when a user performs the task of combining an electronic file with its corresponding timestamp token using, for example, a personal computer, the procedure for operating the personal computer differs significantly depending on whether the electronic file and its corresponding timestamp token are combined using the first method or the second method. Specifically, when combining an electronic file with its corresponding timestamp token using the first method, the user must calculate the hash value of the electronic file itself, send that hash value to a time authentication authority to obtain a timestamp token, and then attach that timestamp token to the electronic file itself. On the other hand, when combining an electronic file with its corresponding timestamp token using the second method, the user must attach the electronic file to a file wrapper, then calculate the hash value of the file wrapper to which the electronic file is attached, send that hash value to a time authentication authority to obtain a timestamp token, and then attach that timestamp token to the file wrapper. When performing the task of combining an electronic file with its corresponding timestamp token, the user must switch the procedure for operating the personal computer depending on whether or not the electronic file has a structure that allows a timestamp token to be attached to it. This is cumbersome and inconvenient for users.

[0013] The present invention has been made in view of the problems described above, for example, and the object of the present invention is to provide a file management program and a file management device that enable users to easily combine an electronic file with a corresponding timestamp token without having to be aware of whether or not the electronic file has a structure that allows it to attach a timestamp token to itself. [Means for solving the problem]

[0014] To solve the above problems, the file management program of the present invention is a file management program for causing a computer to function as a file management device that manages electronic files using time stamps, wherein the file management device comprises a combination determination unit that determines which combination form to use to combine a target file, which is an electronic file to be managed, with a time stamp token, from a first combination form in which a time stamp token is attached to the electronic file itself, and a second combination form in which the electronic file is attached to a package file and a time stamp token is attached to the package file to which the electronic file is attached; and a combination processing unit that, as a result of the combination determination, when the target file and the time stamp token are combined using the first combination form, obtains a time stamp token including the hash value of the target file from a time stamp issuing device and attaches the obtained time stamp token to the target file itself, and when the result of the combination determination, the target file and the time stamp token are combined using the second combination form, attaches the target file to a package file, obtains a time stamp token including the hash value of the package file to which the target file is attached from the time stamp issuing device, and attaches the obtained time stamp token to the package file to which the target file is attached.

[0015] In the file management program of the present invention described above, the merge determination unit may make the merge determination based on the file format of the target file. Alternatively, in the file management program of the present invention described above, the merge determination unit may make the merge determination based on the file format of the target file and security settings or modifiable settings applied to the target file. Alternatively, in the file management program of the present invention described above, the merge determination unit may examine the structure of the target file and make the merge determination based on the file format of the target file and the results of examining the structure of the target file. Alternatively, in the file management program of the present invention described above, the merge determination unit may make the merge determination for the target file based on the results of a merge determination previously made for an electronic file having the same identification information as the identification information of the target file.

[0016] Furthermore, the file management program of the present invention may include a timestamp token storage processing unit that obtains a timestamp token including the hash value of the target file from a timestamp issuing device and performs a timestamp token storage processing that stores the obtained timestamp token in a storage device provided on or connected to the computer without combining it with the target file, and the combination determination unit makes a determination as to whether to combine the target file and the timestamp token by one of the first combination form and the second combination form, or whether to not combine the target file and the timestamp token, and the timestamp token storage processing unit may perform the timestamp token storage processing if, as a result of the combination determination, the target file and the timestamp token are not combined.

[0017] Furthermore, in the file management program of the present invention described above, if there are multiple target files and, as a result of the merging determination, each target file and a timestamp token are merged according to the second merging form, the merging processing unit may attach the multiple target files to a single file, obtain a timestamp token from the timestamp issuing device that includes the hash value of the single file to which the multiple target files are attached, and add the obtained timestamp token to the single file to which the multiple target files are attached.

[0018] To solve the above problems, the file management device of the present invention is a file management device that manages electronic files using time stamps, and is characterized by comprising: a combination determination unit that determines which combination form to use to combine a target file, which is an electronic file to be managed, with a time stamp token, from a first combination form in which a time stamp token is attached to the electronic file itself, and a second combination form in which the electronic file is attached to a package file and a time stamp token is attached to the package file to which the electronic file is attached; and a combination processing unit that, as a result of the combination determination, if the target file and the time stamp token are combined using the first combination form, obtains a time stamp token including the hash value of the target file from a time stamp issuing device and attaches the obtained time stamp token to the target file itself; and if the result of the combination determination, the target file and the time stamp token are combined using the second combination form, attaches the target file to a package file, obtains a time stamp token including the hash value of the package file to which the target file is attached from the time stamp issuing device, and attaches the obtained time stamp token to the package file to which the target file is attached. [Effects of the Invention]

[0019] According to the present invention, users can easily combine an electronic file with its corresponding timestamp token without having to be aware of whether or not the electronic file has a structure that allows it to attach a timestamp token. [Brief explanation of the drawing]

[0020] [Figure 1] This is a block diagram showing a file management device and a timestamp issuing device according to a first embodiment of the present invention. [Figure 2] This diagram illustrates the direct and attached forms of linking electronic files and timestamp tokens, respectively. [Figure 3]These are explanatory diagrams respectively illustrating a single-attachment combination form and a multiple-attachment combination form of an electronic file and a time stamp token. [Figure 4] In the file management device according to the first embodiment of the present invention, this is an explanatory diagram showing a setting screen related to an attachment-type combination form. [Figure 5] In the file management device according to the first embodiment of the present invention, this is an explanatory diagram showing an attached file extension list. [Figure 6] In the file management device according to the first embodiment of the present invention, this is a flowchart showing processing for combining a target file and a time stamp token when a single-attachment combination form is set. [Figure 7] In the file management device according to the first embodiment of the present invention, this is a flowchart showing processing for combining a target file and a time stamp token when a multiple-attachment combination form is set. [Figure 8] In the file management device according to the first embodiment of the present invention, this is a flowchart showing combination processing. [Figure 9] In the file management device according to the first embodiment of the present invention, this is a flowchart showing time stamp token storage processing. [Figure 10] In the file management device according to the first embodiment of the present invention, this is an explanatory diagram showing one method for starting processing of combining an electronic file and a time stamp token. [Figure 11] In the file management device according to the first embodiment of the present invention, this is an explanatory diagram showing a result of processing for combining a target file and a time stamp token when a single-attachment combination form is set. [Figure 12] In the file management device according to the first embodiment of the present invention, this is an explanatory diagram showing a state where an envelope file to which an electronic file is attached via a single-attachment combination form and a time stamp token is added is opened in a reader application. [Figure 13]This is an explanatory diagram showing the result of a process for combining a target file and a timestamp token in a file management device according to the first embodiment of the present invention, when multiple attachment-type combination configurations are set. [Figure 14] This is an explanatory diagram showing the state in which a file envelope file, to which multiple electronic files are attached in a multiple attachment type combined form and to which a timestamp token has been added, is opened in a reader application in a file management device according to the first embodiment of the present invention. [Figure 15] This is a block diagram showing a file management device and a timestamp issuing device according to a second embodiment of the present invention. [Figure 16] This is an explanatory diagram showing log data in a file management device according to a second embodiment of the present invention. [Figure 17] This is an explanatory diagram showing a processing content setting list in a file management device according to a second embodiment of the present invention. [Figure 18] This flowchart shows the process of combining a target file and a timestamp token in a file management device according to a second embodiment of the present invention, when a single attachment type combination is set. [Figure 19] This flowchart shows the process of combining a target file and a timestamp token in a file management device according to a second embodiment of the present invention, when a single attachment type combination is set. [Figure 20] This is an explanatory diagram showing a form for inputting restrictions on the combination of an electronic file and a timestamp token in a file management device according to another embodiment of the present invention. [Modes for carrying out the invention]

[0021] [First Embodiment] A first embodiment of the file management program and file management device of the present invention will be described using Figures 1 to 14.

[0022] (File management device, timestamp issuing device) Figure 1 shows a file management device 1 and a timestamp issuing device 21 according to the first embodiment of the present invention. In Figure 1, the file management device 1 has the function of managing electronic files using timestamps. Specifically, the file management device 1 has the function of clearly linking an electronic file with its corresponding timestamp token by generating a single electronic file in which the electronic file and its corresponding timestamp token are combined. In this embodiment, the file management device 1 is, for example, a personal computer, but the file management device 1 is not limited to a personal computer; it may also be a server computer or a mobile terminal such as a tablet or smartphone. Furthermore, the electronic file may be, for example, a document file, an image file, a video file, an audio file, etc., and the content of the data contained in the electronic file is not limited. Also, the electronic file is not limited to a data file; it may also be a program file.

[0023] The timestamp issuing device 21 is, for example, a server computer and has the function of issuing timestamps. The timestamp issuing device 21 is located at a Time Signature Authority (TSA), and the file management device 1 is located at, for example, a user's business premises, and the timestamp issuing device 21 and the file management device 1 are connected to each other so as to be able to communicate via a communication network 22 such as the Internet. When issuing a timestamp, the timestamp issuing device 21 performs the following processing. First, the timestamp issuing device 21 receives the hash value of an electronic file from the file management device 1. Next, the timestamp issuing device 21 generates a timestamp token. The timestamp token is generated by attaching time information indicating the current time to the received hash value, encrypting the hash value and time information with the Time Signature Authority's private key (applying a digital signature), and attaching a public key certificate containing the public key corresponding to the Time Signature Authority's private key to the encrypted hash value and time information. The timestamp token is a set of data including the encrypted hash value and time information, as well as the public key certificate. Next, the timestamp issuing device 21 sends the generated timestamp token to the file management device 1, the source of the hash value.

[0024] (Details of the file management system configuration) The file management device 1 comprises an arithmetic processing unit 2, a storage unit 3, a communication unit 4, an operation unit 5, and a display unit 6. The arithmetic processing unit 2 is, for example, a CPU (Central Processing Unit) and has the function of controlling the file management device 1. The storage unit 3 is, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and has the function of storing and saving information such as programs and data. The storage unit 3 may be built into the file management device 1, or it may be located outside the file management device 1 and connected to the file management device 1. The storage unit 3 is a specific example of a "storage device". The communication unit 4 has the function of controlling communication between the file management device 1 and the timestamp issuing device 21. The operation unit 5 is, for example, a keyboard, mouse, or touch panel, and is a means for the user to operate the file management device 1 or input data into the file management device 1. The display unit 6 is, for example, a display and is a means for displaying various information to the user.

[0025] Furthermore, the storage unit 3 stores a file management program that enables the personal computer to function as a file management device 1. The arithmetic processing unit 2 reads and executes the file management program stored in the storage unit 3, thereby functioning as a merge determination unit 7, a merge processing unit 8, a timestamp token storage processing unit 9, and an integrated control unit 10.

[0026] The combination determination unit 7 makes a determination regarding the selection of the form in which the electronic file that the user wishes to manage using a timestamp (hereinafter referred to as the "target file") and the timestamp token are combined. Specifically, the combination determination unit 7 determines whether to combine the target file and the timestamp token using a direct combination form in which the timestamp token is attached to the target file itself, or an attached combination form in which the target file is attached to a bundle file and the timestamp token is attached to the bundle file, or whether to not combine the target file and the timestamp token at all.

[0027] The merging processing unit 8 performs the process of merging the target file and the timestamp token. Specifically, if the merging determination unit 7 determines that the target file and the timestamp token should be merged using a direct merging method, the merging processing unit 8 obtains a timestamp token containing the hash value of the target file from the timestamp issuing device 21, adds the obtained timestamp token to the target file, and then stores the target file in the storage unit 3. On the other hand, if the merging determination unit 7 determines that the target file and the timestamp token should be merged using an attachment method, the merging processing unit 8 attaches the target file to a file wrapper, obtains a timestamp token containing the hash value of the file wrapper to which the target file is attached from the timestamp issuing device 21, adds the obtained timestamp token to the file wrapper to which the target file is attached, and then stores the file wrapper in the storage unit 3.

[0028] If the merge determination unit 7 determines that the target file and the timestamp token should not be merged, the timestamp token storage processing unit 9 obtains a timestamp token containing the hash value of the target file from the timestamp issuing device 21 and stores the obtained timestamp token in the storage unit 3 without merging it with the target file.

[0029] The integrated control unit 10 performs various settings on the file management device 1 based on user input, as well as various processes necessary to operate the file management device 1.

[0030] (Form of combining the target file and the timestamp token) The file management device 1 combines the target file with its corresponding timestamp token using the combination method that is suitable for the target file, from among direct combination methods and attached combination methods.

[0031] The direct merging method is a merging method in which the timestamp token is attached to the target file itself. Attaching the timestamp token to the target file itself means making the timestamp token a part of the target file, for example, by embedding the timestamp token within the target file. Note that the direct merging method is a specific example of the "first merging method".

[0032] The attachment-type merging method is a merging method in which the target file is attached to a bundle file, and a timestamp token is added to the bundle file to which the target file is attached. Adding a timestamp token to a bundle file means making the timestamp token a part of the bundle file, for example, by embedding the timestamp token inside the bundle file. A bundle file is an electronic file that has a structure that allows other electronic files to be attached to it, and a structure that allows timestamp tokens to be added to it. PDF files have these structures. File management device 1 uses a PDF file as the bundle file. Note that the attachment-type merging method is a specific example of the "second merging method".

[0033] (Direct coupling form) Figure 2(A) shows an example of a direct merging configuration. As shown in Figure 2(A), in the direct merging configuration, the target file 31 and the timestamp token 32 are merged by embedding the timestamp token 32 within the target file 31. For example, when the target file 31 with the timestamp token 32 embedded is moved from its current storage location to another storage location, the target file 31 and the timestamp token 32 move together as a single unit. In this way, by embedding the timestamp token 32 in the target file 31, it becomes extremely easy to handle the target file 31 and the timestamp token 32 as a single unit.

[0034] Currently, various types of electronic files exist, some of which have a structure that allows them to attach a timestamp token, while others do not. PDF files have a structure that allows them to attach a timestamp token. On the other hand, text files, CSV files, Word files, Excel files, JPEG files, etc., do not have a structure that allows them to attach a timestamp token. Program files, such as EXE files, also do not have a structure that allows them to attach a timestamp token. In order to combine a target file and a timestamp token using a direct combination method, the target file must be an electronic file that has a structure that allows it to attach a timestamp token. Therefore, if the target file is a PDF file, it is basically possible to combine the target file and the timestamp token using a direct combination method. However, if the target file is a text file, CSV file, or Word file, etc., it is not possible to combine the target file and the timestamp token using a direct combination method.

[0035] Furthermore, while PDF files have a structure that allows them to attach a timestamp token, depending on the internal settings of the PDF file, it may not be possible to attach a timestamp token to the PDF file itself. Specifically, if a PDF file has security settings applied, for example, if it is set so that it cannot be opened without entering a password, a timestamp token cannot be attached to the PDF file itself. Also, if the setting for modifying a PDF file is set to prohibit modification, for example, if the PDF file is set to read-only, a timestamp token cannot be attached to the PDF file itself. In such cases, even if the target file is a PDF file, it is not possible to combine the target file and the timestamp token using a direct merging method.

[0036] Furthermore, the standard structure of a PDF file is designed to allow a timestamp token to be attached to it. However, it has been found that PDF files with structures different from the standard structure, such as PDF files with parts of their structure altered or removed, are currently in circulation. When the structure of a PDF file differs from the standard structure, it may not be possible to attach a timestamp token to the PDF file itself. Therefore, if the target file is a PDF file with a structure different from the standard structure, it may not be possible to combine the target file and the timestamp token using a direct combination method.

[0037] (Attachment-type combination) Figure 2(B) shows an example of an attached-type merging configuration. As shown in Figure 2(B), in the attached-type merging configuration, first, the target file 33 is attached to the envelope file 34, and then, the timestamp token 35 is embedded inside the envelope file 34 to which the target file 33 is attached. As a result, the envelope file 34, the target file 33, and the timestamp token 35 are merged and integrated. For example, when the envelope file 34 to which the target file 33 is attached and the timestamp token 35 is embedded is moved from its current storage location to another storage location, the envelope file 34, the target file 33, and the timestamp token 35 are moved together as a single unit. In this way, by attaching the target file 33 to the envelope file 34 and embedding the timestamp token 35 in the envelope file 34, it becomes extremely easy to handle the target file 33 and the timestamp token 35 as a single unit.

[0038] The attachment-type merging method allows for the merging of a target file and a timestamp token, regardless of whether the target file is an electronic file with a structure that allows it to attach a timestamp token to itself. Therefore, even if the target file is a text file, CSV file, or Word file, the attachment-type merging method allows for the merging of the target file and the timestamp token. Furthermore, even if the target file is a PDF file that is in a state where it cannot attach a timestamp token to itself due to internal settings, or if the target file is a PDF file with a structure different from the standard structure, the attachment-type merging method allows for the merging of the target file and the timestamp token.

[0039] (Single attachment type and multiple attachment type) Furthermore, the attachment-type merging methods in the file management device 1 include a single attachment-type merging method and a multiple attachment-type merging method. Both of these merging methods are used when the process of merging target files and timestamp tokens is performed collectively for multiple target files using the attachment-type merging method.

[0040] Figure 3(A) shows a single-attachment type combination. In the single-attachment type combination, as shown in Figure 3(A), multiple target files 41, 42, and 43 are attached to multiple bundle files 44, 45, and 46, respectively, and multiple timestamp tokens 47, 48, and 49 are added to the multiple bundle files 44, 45, and 46 to which the multiple target files 41, 42, and 43 are attached, respectively. In the single-attachment type combination, there is a one-to-one correspondence between target files and bundle files, and also a one-to-one correspondence between target files and timestamp tokens. Furthermore, timestamp token 47 contains the hash value of bundle file 44 to which target file 41 is attached, encrypted together with time information. Similarly, timestamp token 48 contains the hash value of bundle file 45 to which target file 42 is attached, encrypted together with time information, and timestamp token 49 contains the hash value of bundle file 46 to which target file 43 is attached, encrypted together with time information. With the single-attachment type of merging, a combined version of the target file and its corresponding timestamp token can be generated for each target file. Therefore, the single-attachment type of merging is a convenient merging method for users who manage electronic files using timestamps individually for each electronic file.

[0041] Figure 3(B) shows a multi-attachment merging configuration. As shown in Figure 3(B), the multi-attachment merging configuration involves attaching multiple target files 51, 52, and 53 to a single package file 54, and then adding a single timestamp token 55 to the single package file 54 to which the multiple target files 51, 52, and 53 are attached. The timestamp token 55 contains the hash value of the package file 54 to which the multiple target files 51, 52, and 53 are attached, encrypted along with time information. The multi-attachment merging configuration allows for the generation of a combined file containing multiple target files and their corresponding single timestamp token. The package file is, so to speak, a bundle of multiple target files and their corresponding single timestamp token. Therefore, the multi-attachment merging configuration is a convenient configuration for users who want to manage multiple electronic files collectively using timestamps, or for users who want to reduce the number of timestamp tokens issued.

[0042] (combination judgment) The combination determination unit 7 determines whether to combine the target file and the timestamp token using a direct combination type or an attached combination type, or whether to not combine the target file and the timestamp token at all. Hereinafter, this determination will be referred to as the "combination determination".

[0043] (Content of the bond determination: Determination of the bond form) The join determination unit 7, in determining whether to join the target file and the timestamp token using a direct join method or an attachment-type join method, in principle, makes this determination based on whether or not the timestamp token can be attached to the target file itself. If the timestamp token can be attached to the target file itself, the join determination unit 7 determines to join the target file and the timestamp token using a direct join method. If the timestamp token cannot be attached to the target file itself, the join determination unit 7 determines to join the target file and the timestamp token using an attachment-type join method.

[0044] Whether or not a timestamp token can be attached to the target file itself can be determined by whether or not the target file is an electronic file with a structure that allows a timestamp token to be attached to it. Whether or not an electronic file has a structure that allows a timestamp token to be attached to it can be determined by the file format of the electronic file. The combination determination unit 7 basically determines whether to combine the target file and the timestamp token using a direct combination form or an attachment type combination form, based on the file format of the target file.

[0045] A PDF file, which is an electronic file having the PDF file format, has a structure that allows it to attach a timestamp token. On the other hand, electronic files that have a file format other than PDF, such as text files, CSV files, Word files, etc., do not have a structure that allows them to attach a timestamp token. Furthermore, currently, almost all electronic files other than PDF files do not have a structure that allows them to attach a timestamp token. Considering this situation, the combination determination unit 7 in this embodiment basically determines whether to combine the target file and the timestamp token using a direct combination form or an attachment combination form, based on whether the target file is a PDF file or not. That is, the combination determination unit 7 basically determines that if the target file is a PDF file, it will combine the target file and the timestamp token using a direct combination form, and if the target file is not a PDF file, it will combine the target file and the timestamp token using an attachment combination form. The file format of an electronic file can also be determined based on the file extension of the electronic file. In this embodiment, the combination determination unit 7 determines whether the target file is an electronic file having the PDF file format, i.e., a PDF file, based on the file extension of the target file.

[0046] Furthermore, as mentioned above, the structure of a PDF file may differ from the standard structure, in which case it may not be possible to attach a timestamp token to the PDF file itself. Therefore, even if a target file is determined to be a PDF file based on its file format, if the structure of that target file differs from the standard structure of a PDF file, it may not be possible to attach a timestamp token to the target file itself. Taking this into consideration, the merging determination unit 7, after determining that the target file is a PDF file based on its file format, examines the structure (internal structure) of the target file and, based on the result, makes a more precise determination as to whether or not a timestamp token can be attached to the target file itself. This determination can be made, for example, by comparing the structure of the target file with the structure of a publicly available PDF file (the standard structure of a PDF file).

[0047] Furthermore, as mentioned above, depending on the internal settings of the PDF file (e.g., security settings, modification permissions, etc.), it may not be possible to attach a timestamp token to the PDF file itself. Therefore, even if the target file is determined to be a PDF file based on its file format, it may not be possible to attach a timestamp token to the target file itself due to its internal settings. Taking this into consideration, the merging determination unit 7, after determining that the target file is a PDF file based on its file format, examines the internal settings of the target file and makes a more precise determination of whether or not a timestamp token can be attached to the target file itself based on those internal settings. Since the PDF file contains information (flags, etc.) indicating its internal settings, this determination can be made based on the information indicating its internal settings contained within the target file.

[0048] The merging determination unit 7 determines that the target file is a PDF file based on the file format of the target file, then examines the structure and internal settings of the target file, and if, for example, the target file has the standard structure of a PDF file and is in a state where it can attach a timestamp token to itself due to its internal settings, it determines to merge the target file and the timestamp token using a direct merging method. Alternatively, the merging determination unit 7 determines that the target file is a PDF file based on the file format of the target file, then examines the structure and internal settings of the target file, and if, as a result, the target file has a structure different from the standard structure of a PDF file, or is in a state where it cannot attach a timestamp token to itself due to its internal settings, it determines to merge the target file and the timestamp token using an attachment-type merging method.

[0049] (Content of the merger decision: Judgment on whether the merger is appropriate or not) Furthermore, the merging determination unit 7 makes a determination in the merging determination as to whether or not to merge the target file and the timestamp token. The purpose of this determination is to avoid a situation where, when merging the target file and the timestamp using an attachment-type merging method, the target file attached to the package file cannot be opened because the file format of the target file is highly likely to contain computer viruses or spyware.

[0050] In other words, the attachment-type merging method is a merging method in which the target file is attached to a file wrapper file, and a timestamp token is added to the file wrapper file to which the target file is attached. In order to realize the attachment-type merging method, the file wrapper file must be an electronic file that has a structure that allows other electronic files to be attached to it and that allows timestamp tokens to be added to it. PDF files have such a structure, so the file management device 1 uses PDF files as file wrapper files. PDF files have a function that prevents electronic files that are likely to contain computer viruses or spyware from being opened if they are attached to it. For example, EXE files (electronic files with the extension .exe), which are a type of program file, are generally known to be electronic files that are likely to contain computer viruses or spyware. When an EXE file is attached to a PDF file, the function of the PDF file may prevent the EXE file from being opened. Since the file management device 1 uses a PDF file as the envelope file, if the file management device 1 determines that the target file and the timestamp token should be combined using the attachment type of combination method, and the target file is attached to the envelope file, there is a risk that the target file cannot be opened if the file format of the target file is one that is highly likely to contain computer viruses or spyware. Taking the above into consideration, the combination determination unit 7, in its combination determination, makes a determination whether or not to combine the target file and the timestamp token, as an additional determination to the determination of whether or not to combine the target file and the timestamp token using either the direct type of combination method or the attachment type of combination method.

[0051] Specifically, the merging determination unit 7, after recognizing that the target file is not a PDF file based on the file format of the target file, determines whether to merge the target file and the timestamp token in an attached merge format, or not to merge the target file and the timestamp token.

[0052] Furthermore, the merging determination unit 7 determines whether to merge the target file and the timestamp token in an attached merged form, or not to merge the target file and the timestamp token, based on whether the file format of the target file is a file format that is not highly likely to contain computer viruses or spyware, etc.

[0053] Figure 4 shows the settings screen 11 for the attachment-type binding format. As shown in Figure 4, the middle section of the settings screen 11 for the attachment-type binding format is provided with an input form 13 for specifying file formats that are not likely to contain computer viruses or spyware, etc., by their electronic file extensions. Users can operate the operation unit 5 to input the extensions of electronic files that are not likely to contain computer viruses or spyware, etc., into the input form 13. As shown in Figure 5, the file management device 1 generates an attachment file extension list 62 that describes the extensions entered by the user into the input form 13, and stores this attachment file extension list 62 in the storage unit 3 as part of the attachment-type binding setting information 61 (see Figure 1). The binding determination unit 7 determines, based on the attachment file extension list 62, whether to bind the target file and the timestamp token in an attachment-type binding format, or not to bind the target file and the timestamp token.

[0054] The merging determination unit 7 determines to merge the target file and the timestamp token using the attachment-type merging method if the extension of the target file is described in the attachment file extension list 62. On the other hand, if the extension of the target file is not described in the attachment file extension list 62, the merging determination unit 7 does not immediately determine that the target file and the timestamp token will not be merged. Instead, it asks the user whether or not to merge the target file and the timestamp token using the attachment-type merging method (whether or not to attach the target file to the file wrapper file). If the user, in response to this inquiry, inputs an instruction to the file management device 1 indicating that the target file and the timestamp token will not be merged using the attachment-type merging method, the merging determination unit determines that the target file and the timestamp token will be merged using the attachment-type merging method.

[0055] The reason for prompting the user whether or not to combine the target file and the timestamp token in an attached format when the target file's extension is not listed in the attachment file extension list 62 is as follows:

[0056] It is difficult for users to identify all file formats that are not highly likely to contain computer viruses or spyware, and to enter the file extensions of electronic files containing those formats into input form 13. Therefore, there may be electronic files that have file formats that are not highly likely to contain computer viruses or spyware, but whose extensions are not entered into input form 13. Consequently, if the decision to combine the target file and the timestamp token in an attached format or not is made solely based on the attached file extension list 62, it is possible that the combination determination unit 7 may determine that the target file and timestamp should not be combined, even if the target file's file format is not highly likely to contain computer viruses or spyware. The above inquiry to the user is made to prevent such situations from occurring.

[0057] (Selection between single attachment type and multiple attachment type) When the file management device 1 combines a target file and its corresponding timestamp token using an attachment-type combination, it selects either a single-attachment combination or a multiple-attachment combination. The file management device 1 makes this selection according to user input. As shown in Figure 4, the upper part of the setting screen 11 for attachment-type combinations is provided with radio buttons 12 for setting either a single-attachment combination or a multiple-attachment combination. The user can operate the operation unit 5 to operate the radio buttons 12 and set either a single-attachment combination or a multiple-attachment combination. This setting made by the user is stored in the storage unit 3 as part of the attachment-type combination setting information 61 (see Figure 1).

[0058] (Specific processing steps) The following describes in detail the process of combining a target file with its corresponding timestamp token in the file management device 1. Figures 6 to 9 show the flow of the process of combining a target file with its corresponding timestamp token in the file management device 1. Figure 6 shows the flow of the process when a single attachment type of combination is set, and Figure 7 shows the flow of the process when a multiple attachment type of combination is set. The processes shown in Figures 8 and 9 are common to both the case where a single attachment type of combination is set and the case where a multiple attachment type of combination is set.

[0059] (If a single attachment type combination is set) First, we will explain the process of combining a target file with its corresponding timestamp token when a single attachment type combination is set. In the following explanation, we will use as an example the case where the user has selected "Invoice.pdf", "Design Drawing.pdf", "Proposal.docx", "Source Code.cpp", and "Calculation Program.exe" as electronic files that they wish to manage using timestamps, and has entered an instruction into File Management Device 1 to start the process of combining these electronic files with the timestamp tokens corresponding to these electronic files. Also, for the sake of explanation, we will assume that the attachment file extension list 62 only contains extensions "txt", "csv", and "docx" (see Figure 5).

[0060] When a user operates the control unit 5 to open a folder containing the above-mentioned electronic files, such as "Invoice.pdf," as shown in Figure 10, and selects these electronic files, they can, for example, right-click with the mouse to display the context menu 15, and then click, for example, "Add Timestamp" in the context menu 15 with the mouse, an instruction is input to the file management device 1 to start the process of combining the electronic files and their corresponding timestamp tokens for the above-mentioned electronic files selected by the user.

[0061] In step S1 in Figure 6, the file management device 1 recognizes that this instruction has been entered into the file management device 1 and starts the process of combining the electronic files and their corresponding timestamp tokens for the multiple electronic files selected by the user.

[0062] First, the merge determination unit 7 and merge processing unit 8 of the file management device 1 perform the processing steps S2 to S14 in Figure 6 for each of the multiple electronic files selected by the user. Steps S2 to S14 in Figure 6 include: (1) merge determination, that is, determining whether to merge the target file and the timestamp token using a direct merge form or an attachment merge form, or whether to merge the target file and the timestamp token at all; (2) saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token will be merged using a direct merge form; (3) attaching the target file to a bundle file and saving the bundle file to the storage unit 3 after it has been determined that the target file and the timestamp token will be merged using an attachment merge form; and (4) saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token will not be merged. Hereinafter, the processes in (2), (3), and (4) above will be referred to as "pre-merging processing". Furthermore, for the sake of clarity, the merge decision and pre-merger processing will be performed in the following order: "Invoice.pdf", "Design Drawing.pdf", "Proposal.docx", "Source Code.cpp", and "Calculation Program.exe".

[0063] First, the merge determination unit 7 reads "Invoice.pdf" as the target file from among the multiple electronic files selected by the user (Step S2). Next, the merge determination unit 7 determines whether "Invoice.pdf" is a PDF file based on its extension (Step S3). "Invoice.pdf" is a PDF file. Therefore, the merge determination unit 7 determines that "Invoice.pdf" is a PDF file (Step S3: YES). Next, the merge determination unit 7 examines the structure and internal settings of "Invoice.pdf" (Step S4). It is assumed that "Invoice.pdf" has the normal structure of a PDF file and is in a state where it can attach a timestamp token to itself through its internal settings. In this case, based on the results of examining the structure and internal settings of "Invoice.pdf", the merge determination unit 7 determines that "Invoice.pdf" has the normal structure of a PDF file and is in a state where it can attach a timestamp token to itself through its internal settings (Step S5: YES). At this point, it is determined that "Invoice.pdf" and the timestamp token will be merged using a direct merge method.

[0064] Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to enter a new file name for "Invoice.pdf" and a new save location. Suppose the user enters "ABC Product Related Documents 1.pdf" as the new file name for "Invoice.pdf" and "C:\Product Related Folder A" as the new save location for "Invoice.pdf". In this case, the merge determination unit 7 changes the file name of "Invoice.pdf" to "ABC Product Related Documents 1.pdf" according to the user's input and saves "ABC Product Related Documents 1.pdf" as a file to be added to "C:\Product Related Folder A" in the storage unit 3 (step S6).

[0065] Next, the merge determination unit 7 determines whether the merge determination and pre-merging processing have been completed for the multiple electronic files selected by the user (step S14). At this point, the merge determination and pre-merging processing have not been completed for the multiple electronic files selected by the user, so the result in step S14 is "NO", and the process returns to step S2.

[0066] Next, the merging determination unit 7 reads "design.pdf" as the target file from the multiple electronic files selected by the user (step S2), and determines that "design.pdf" is a PDF file based on its extension (step S3: YES). Next, the merging determination unit 7 examines the structure and internal settings of "design.pdf" (step S4). It is assumed that "design.pdf" does not have the normal structure of a PDF file, or that it is in a state where it cannot attach a timestamp token to itself due to its internal settings. In this case, based on the results of examining the structure and internal settings of "design.pdf", the merging determination unit 7 determines that "design.pdf" does not have the normal structure of a PDF file, or that it is in a state where it cannot attach a timestamp token to itself due to its internal settings (step S5: NO). At this point, it is determined that "design.pdf" and the timestamp token will be merged in an attached merging format.

[0067] In this case, the process moves from step S5 to step S8. In step S8, the merging processing unit 8 of the file management device 1 reads an empty file stored in the storage unit 3. An empty file is a file that does not yet have any electronic files attached (and of course, no timestamp token has been added), and specifically, it is such a PDF file. For example, the first page of an empty file has a string of characters or a drawing to allow the user to recognize that it is a file. The user can also set the save location of the empty file using the input form 14 at the bottom of the setting screen 11 for the attachment-type merging configuration shown in Figure 4. The set save location of the empty file is stored in the storage unit 3 as part of the attachment-type merging setting information 61 (see Figure 1). In this embodiment, one empty file is stored in the set save location, but the user can save multiple empty files in the set save location. For example, a user can create multiple empty file folders, each with a different string of text or image on the first page, give each of these empty file folders a different filename, and save these empty file folders to the save location set in the input form 14. In this case, in step S8 in Figure 6, the merging processing unit 8 displays a selection menu, for example, on the display unit 6, to allow the user to select from the saved multiple empty file folders.

[0068] Next, in step S8, the merging unit 8 attaches "design.pdf" to the empty file it read. Then, the merging unit 8 records information in the file that helps the user recognize "design.pdf" attached to the file, such as the file name and modification date (step S9).

[0069] Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to input the filename to be assigned to the package file to which "design drawing.pdf" is attached, and the save location to which that package file will be saved. Suppose the user inputs "ABC product related documents 2.pdf" as the filename to be assigned to the package file to which "design drawing.pdf" is attached, and "C:\product related folder A" as the save location for that package file. In this case, the merge determination unit 7 changes the filename of the package file to which "design drawing.pdf" is attached according to the user's input. At this point, the filename of the package file to which "design drawing.pdf" is attached is "empty package file type 1.pdf" (see input form 14 in Figure 4), so the merge determination unit 7 changes the filename of the package file to which "design drawing.pdf" is attached from "empty package file type 1.pdf" to "ABC product related documents 2.pdf". Next, the merge determination unit 7 saves "ABC product related documents 2.pdf" as a required package file in "C:\product related folder A" in the storage unit 3 (step S10). The process then moves to step S14, and since the merge determination and pre-merging processing have not yet been completed for the multiple electronic files selected by the user at this point, the process returns to step S2.

[0070] Next, the merging determination unit 7 reads "proposal.docx" as the target file from among the multiple electronic files selected by the user (step S2), and determines that "proposal.docx" is not a PDF file based on its extension (step S3: NO). Next, the merging determination unit 7 determines whether the extension of "proposal.docx" is described in the attachment file extension list 62 (step S7). As shown in Figure 5, the extension "docx" of "proposal.docx" is described in the attachment file extension list 62. Therefore, the merging determination unit 7 refers to the attachment file extension list 62 and determines that the extension of "proposal.docx" is described in the attachment file extension list 62. At this point, it is determined that "proposal.docx" and the timestamp token will be merged in an attachment-type merging format.

[0071] Next, the merging processing unit 8 reads an empty file folder stored in the memory unit 3 and attaches "Proposal.docx" to the read empty file folder folder. Then, the merging processing unit 8 records information that will help the user recognize "Proposal.docx" attached to the file folder folder, such as the file name and modification date of "Proposal.docx" (step S9).

[0072] Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to input the filename to be assigned to the attached file containing "Proposal.docx" and the save location for that file. Suppose the user inputs "ABC Product Related Documents 3.pdf" as the filename to be assigned to the attached file containing "Proposal.docx", and "C:\Product Related Folder A" as the save location for that file. In this case, the merge determination unit 7 changes the filename of the attached file containing "Proposal.docx" to "ABC Product Related Documents 3.pdf" according to the user's input. Subsequently, the merge determination unit 7 saves "ABC Product Related Documents 3.pdf" as a required attached file in "C:\Product Related Folder A" in the storage unit 3 (step S10). The process then moves to step S14, and since the merge determination and pre-merging processing have not yet been completed for the multiple electronic files selected by the user at this point, the process returns to step S2.

[0073] Next, the merging determination unit 7 reads "sourcecode.cpp" as the target file from the multiple electronic files selected by the user (step S2), and determines that "sourcecode.cpp" is not a PDF file based on its extension (step S3: NO). Next, the merging determination unit 7 determines whether the extension of "sourcecode.cpp" is described in the attachment file extension list 62 (step S7). As shown in Figure 5, the extension "cpp" of "sourcecode.cpp" is not described in the attachment file extension list 62. Therefore, the merging determination unit 7 refers to the attachment file extension list 62 and determines that the extension of "sourcecode.cpp" is not described in the attachment file extension list 62.

[0074] Next, the merge determination unit 7 asks the user whether or not to attach "source code.cpp" to the bundle file (step S11). For example, the merge determination unit 7 displays a form on the display unit 6 that includes a button to select whether or not to attach "source code.cpp" to the bundle file. Subsequently, the merge determination unit 7 determines whether or not to merge "source code.cpp" and the timestamp token in an attached merge format based on the user's input in response to the inquiry (step S12). Suppose the user selects to attach "source code.cpp" to the bundle file in response to the inquiry. In this case, the merge determination unit 7 determines that "source code.cpp" and the timestamp token should be merged in an attached merge format (step S12: YES).

[0075] Next, the merging processing unit 8 reads an empty file stored in the memory unit 3 and attaches "source code.cpp" to the read empty file. Then, the merging processing unit 8 records information in the file that will help the user recognize "source code.cpp" attached to the file, such as the file name and modification date (step S9).

[0076] Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to input the filename to be assigned to the bundle file to which "source code.cpp" is attached, and the save location to which that bundle file will be saved. Suppose the user inputs "ABC product related documents 4.pdf" as the filename to be assigned to the bundle file to which "source code.cpp" is attached, and "C:\product related folder A" as the save location for that bundle file. In this case, the merge determination unit 7 changes the filename of the bundle file to which "source code.cpp" is attached to "ABC product related documents 4.pdf" according to the user's input. Subsequently, the merge determination unit 7 saves "ABC product related documents 4.pdf" as a required bundle file in "C:\product related folder A" in the storage unit 3 (step S10). The process then moves to step S14, and since the merge determination and pre-merging processing have not yet been completed for the multiple electronic files selected by the user at this point, the process returns to step S2.

[0077] Next, the merging determination unit 7 reads "calculation program.exe" as the target file from the multiple electronic files selected by the user (step S2), and determines that "calculation program.exe" is not a PDF file based on its extension (step S3: NO). Next, the merging determination unit 7 determines whether the extension of "calculation program.exe" is described in the attachment file extension list 62 (step S7). As shown in Figure 5, the extension "exe" for "calculation program.exe" is not described in the attachment file extension list 62. Therefore, the merging determination unit 7 refers to the attachment file extension list 62 and determines that the extension of "calculation program.exe" is not described in the attachment file extension list 62.

[0078] Next, the merging determination unit 7 asks the user whether or not to attach "calculation program.exe" to the package file (step S11). Subsequently, based on the user's input in response to the inquiry, the merging determination unit 7 decides whether or not to merge "calculation program.exe" and the timestamp token in an attached merge format (step S12). Suppose the user does not choose to attach "calculation program.exe" to the package file in response to the inquiry. In this case, the merging determination unit 7 decides not to merge "calculation program.exe" and the timestamp token (step S12: NO).

[0079] Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to input the save location for "calculation program.exe". Suppose the user inputs "C:\product-related folder B" as the save location. In this case, the merge determination unit 7 saves "calculation program.exe" as a file that does not need to be added to "C:\product-related folder B" in the storage unit 3, according to the user's input (step S13).

[0080] Next, the merge determination unit 7 determines whether the merge determination and pre-merging processing have been completed for the multiple electronic files selected by the user (step S14). At this point, the merge determination and pre-merging processing have been completed for the multiple electronic files selected by the user, so the merge determination unit 7 proceeds to step S15.

[0081] Immediately before proceeding to step S15, in the storage unit 3, "C:\Product-related folder A" contains "ABC product-related documents 1.pdf" as a file that needs to be added, and "ABC product-related documents 2.pdf", "ABC product-related documents 3.pdf", and "ABC product-related documents 4.pdf" are each saved as bundle files that need to be added. The three bundle files that need to be added have "design drawings.pdf", "proposal.docx", and "source code.cpp" attached to them, respectively. In addition, "C:\Product-related folder B" contains "calculation program.exe" as a file that does not need to be added.

[0082] In step S15, the merging processing unit 8 performs a merging process on the files to be added and the bundle files to be added, and the timestamp token storage processing unit 9 performs a timestamp token storage process on the files that do not need to be added. The merging process includes the following two merging processes. The first merging process involves obtaining a timestamp token containing the hash value of the files to be added from the timestamp issuing device 21, adding the obtained timestamp token to the files to be added, and then overwriting and saving the files to be added. The second merging process involves obtaining a timestamp token containing the hash value of each bundle file to be added from the timestamp issuing device 21, adding the obtained timestamp token to the bundle files to be added, and then overwriting and saving the bundle files to the storage unit 3. The difference between the first and second merging processes is whether the electronic files being processed are files to be added or bundle files to be added, but the content of the processing is the same. Furthermore, the timestamp token storage process involves obtaining a timestamp token containing the hash value of the file that does not require timestamping from the timestamp issuing device, and storing the obtained timestamp token in the storage unit 3 without combining it with the file that does not require timestamping.

[0083] Figure 8 shows the contents of the merging process. In Figure 8, the merging processing unit 8 first reads "ABC product-related documents 1.pdf" which is stored in "C:\product-related folder A" in the storage unit 3 as a file to be added (step S21). Next, the merging processing unit 8 calculates the hash value of the read "ABC product-related documents 1.pdf" (step S22). Next, the merging processing unit 8 sends the calculated hash value of "ABC product-related documents 1.pdf" to the timestamp issuing device 21. The timestamp issuing device 21 generates a timestamp token that includes the encrypted hash value and time information of "ABC product-related documents 1.pdf" and a public key certificate, and sends this timestamp token to the file management device 1. The file management device 1 receives the timestamp token sent from the timestamp issuing device 21 (step S23). Next, the merging processing unit 8 adds the received timestamp token to "ABC product-related documents 1.pdf" (step S24). Next, the merging processing unit 8 overwrites the "ABC product-related documents 1.pdf" with the added timestamp token into the "C:\product-related folder A" in the storage unit 3 (step S25).

[0084] The merging unit 8 performs the same process on "ABC product related documents 2.pdf", "ABC product related documents 3.pdf", and "ABC product related documents 4.pdf", which are stored in "C:\product related folder A" in the storage unit 3 as files that require addition. In this way, when the process of adding a timestamp talk to each of the files that require addition and the files that require addition, namely "ABC product related documents 1.pdf", "ABC product related documents 2.pdf", "ABC product related documents 3.pdf", and "ABC product related documents 4.pdf", is completed (step S26: YES), the merging process is completed.

[0085] Figure 9 shows the contents of the timestamp token storage process. For example, after the merging process is completed, the timestamp token storage processing unit 9 starts the timestamp token storage process. In Figure 9, the timestamp token storage processing unit 9 first reads "calculation program.exe" stored in "C:\product-related folder B" in the storage unit 3 as a file that does not need to be added (step S31). Next, the timestamp token storage processing unit 9 calculates the hash value of the read "calculation program.exe" (step S32). Next, the timestamp token storage processing unit 9 sends the calculated hash value of "calculation program.exe" to the timestamp issuing device 21. The timestamp issuing device 21 generates a timestamp token that includes the encrypted hash value and time method of "calculation program.exe", as well as a public key certificate, and sends this timestamp token to the file management device 1. The file management device 1 receives the timestamp token sent from the timestamp issuing device 21 (step S33). Next, the timestamp token storage processing unit 9 saves the received timestamp token as an electronic file, for example, in "C:\product-related folder B" in the storage unit 3 (step S34). As a result, the "calculation program.exe" file and its corresponding timestamp token are saved in the same folder.

[0086] The timestamp token saving process terminates when the process of obtaining and saving a timestamp token for each of the files that do not require addition, stored in "C:\Product-related folder B" in storage unit 3, is completed. In this example, since the only file that does not require addition, stored in "C:\Product-related folder B" in storage unit 3, is "Calculation program.exe", the timestamp token saving process terminates when the process of obtaining and saving a timestamp token for "Calculation program.exe" is completed (step S35: YES).

[0087] Figure 11 shows the electronic files stored in the storage unit 3 after a process is executed to combine the target files and their corresponding timestamp tokens for the above-mentioned multiple target files, such as "Invoice.pdf," with a single attachment type combination configuration set. In Figure 11, "ABC Product Related Documents 1.pdf" stored in "C:\Product Related Folder A" is an electronic file in which "Invoice.pdf" and its corresponding timestamp token are combined. Specifically, it is a PDF file in which a timestamp token containing the hash value of "Invoice.pdf" is attached to "Invoice.pdf." Also, "ABC Product Related Documents 2.pdf" stored in "C:\Product Related Folder A" is an electronic file in which "Design Drawing.pdf" and its corresponding timestamp token are combined. Specifically, it is a PDF file in which a timestamp token containing the hash value of the package file to which "Design Drawing.pdf" is attached is attached to the package file to which "Design Drawing.pdf" is attached. Furthermore, "ABC Product Related Documents 3.pdf" stored in "C:\Product Related Folder A" is an electronic file that combines "Proposal.docx" and its corresponding timestamp token. Specifically, it is a PDF file in which a timestamp token containing the hash value of the attached file "Proposal.docx" is attached to the attached file's envelope file. Also, "ABC Product Related Documents 4.pdf" stored in "C:\Product Related Folder A" is an electronic file that combines "Source Code.cpp" and its corresponding timestamp token. Specifically, it is a PDF file in which a timestamp token containing the hash value of the attached file "Source Code.cpp" is attached to the attached file's envelope file. In addition, "C:\Product Related Folder B" stores "Calculation Program.exe" and its corresponding timestamp token, which has been digitized into an electronic file named "XXXX.xxx".

[0088] Figure 12 shows the state when "ABC Product Related Documents 3.pdf," saved in "C:\Product Related Folder A," is opened in a PDF file reader application. The first page of "ABC Product Related Documents 3.pdf" contains a string 71 indicating the file wrapper, the file name of "ABC Product Related Documents 3.pdf" 72, information 73 about the electronic files attached to "ABC Product Related Documents 3.pdf," and a timestamp 74. The reader application displays a list 75 of the electronic files attached to "ABC Product Related Documents 3.pdf." The user can open "Proposal.docx" in the list by, for example, clicking it with the mouse.

[0089] (When multiple attachment types are configured for combination) Next, we will explain the process of combining target files and their corresponding timestamp tokens when a multiple attachment type of combination is set. In the following explanation, we will use as an example the case where the user has selected "Invoice.pdf", "Design Drawing.pdf", "Proposal.docx", "Source Code.cpp", and "Calculation Program.exe" as electronic files that they wish to manage using timestamps, and has entered an instruction into the file management device 1 to start the process of combining these electronic files with the timestamp tokens corresponding to these electronic files. Also, for the sake of explanation, we will assume that the attachment file extension list 62 only contains extensions "txt", "csv", and "docx" (see Figure 5).

[0090] In Figure 6, which shows the process when a single attachment type is configured, and in Figure 7, which shows the process when a multiple attachment type is configured, common steps are denoted by the same reference numerals. In Figure 7, steps S8 to S10 in Figure 6 are replaced by steps S41 to S43. Also, in Figure 7, step S44, which does not exist in Figure 6, is added between steps S14 and S15. The following explanation will focus on steps S41 to S44 in Figure 7.

[0091] In Figure 7, assuming that the merge decision and pre-merger processing (steps S2-S7, S41, S42, and S11-S14) are performed in the order of "Invoice.pdf", "Design Drawing.pdf", "Proposal.docx", "Source Code.cpp", and "Calculation Program.exe", the processing in steps S2-S6 in Figure 7 is first executed for "Invoice.pdf". In step S6, based on user input, the file name of "Invoice.pdf" is changed to "ABC Product Related Documents 1.pdf", and this "ABC Product Related Documents 1.pdf" is saved as a file to be added to "C:\Product Related Folder A" in storage unit 3. After that, the process returns to step S2 based on the decision in step S14.

[0092] Next, the processes in steps S2 to S5 in Figure 7 are executed for "design.pdf". It is determined that "design.pdf" is a PDF file, but does not have the normal structure of a PDF file, or is unable to attach a timestamp token to itself due to internal settings. In that case, the process moves from step S5 to step S41.

[0093] In step S41, the merging processing unit 8 reads an empty file folder stored in the memory unit 3 and attaches "design.pdf" to the read empty file folder. Next, the merging processing unit 8 records information that will help the user recognize "design.pdf" attached to the file folder, such as the file name and modification date (step S42). Next, the merging processing unit 8 temporarily saves the file folder with "design.pdf" attached to it in the working memory area of ​​the memory unit 3 (step S43). After that, based on the decision in step S14, the process returns to step S2.

[0094] Next, steps S2, S3, and S7 in Figure 7 are executed for "proposal.docx," and it is determined that "proposal.docx" is not a PDF file, and that the extension "proposal.docx" is listed in the attachment file extension list 62. After that, the process moves from step S7 to step S41.

[0095] In step S41, the merging processing unit 8 reads the bundle file that has been temporarily stored in the working memory area of ​​the storage unit 3. The read bundle file already has "Design Drawing.pdf" attached to it. The merging processing unit 8 then adds "Proposal.docx" to the bundle file. Next, the merging processing unit 8 records information in the bundle file that will help the user recognize "Proposal.docx" attached to the bundle file, such as the file name and modification date (step S42). Next, the merging processing unit 8 temporarily saves (overwrites) the bundle file with "Design Drawing.pdf" and "Proposal.docx" attached to it in the working memory area of ​​the storage unit 3 (step S43). After that, based on the decision in step S14, the process returns to step S2.

[0096] Next, steps S2, S3, S7, S11, and S12 in Figure 7 are executed for "sourcecode.cpp". It is determined that "sourcecode.cpp" is not a PDF file and that the extension "sourcecode.cpp" is not listed in the attachment file extension list 62. Furthermore, as a result of querying the user, it is determined that "sourcecode.cpp" and the timestamp token should be combined in an attachment-type combined form. After that, the process moves from step S12 to step S41.

[0097] In step S41, the merging processing unit 8 reads the bundle file that has been temporarily stored in the working memory area of ​​the storage unit 3. The read bundle file already has "Design Drawing.pdf" and "Proposal.docx" attached to it. The merging processing unit 8 adds "Source Code.cpp" to the bundle file. Next, the merging processing unit 8 records information in the bundle file that will help the user recognize "Source Code.cpp" attached to the bundle file, such as the file name and modification date (step S42). Next, the merging processing unit 8 temporarily saves (overwrites) the bundle file with "Design Drawing.pdf", "Proposal.docx", and "Source Code.cpp" attached to it in the working memory area of ​​the storage unit 3 (step S43). After that, based on the decision in step S14, the process returns to step S2.

[0098] Next, steps S2, S3, S7 and S11-S13 in Figure 7 are executed for "calculation program.exe". It is determined that "calculation program.exe" is not a PDF file and that its extension is not listed in the attachment file extension list 62. Furthermore, as a result of querying the user, it is determined that "calculation program.exe" and the timestamp token should not be combined. Subsequently, "calculation program.exe" is stored in storage unit 3 as a file that does not need to be added. Next, in step S14, it is determined that the combination determination and pre-combination processing have been completed for the multiple electronic files selected by the user. After that, the process moves from step S14 to step S44.

[0099] In step S44, the merge determination unit 7 reads the bundle file containing "design drawing.pdf", "proposal.docx", and "source code.cpp" from the working memory area of ​​the storage unit 3. Next, the merge determination unit 7 displays an input form on the display unit 6, for example, and prompts the user to input the file name to be given to the bundle file containing "design drawing.pdf", "proposal.docx", and "source code.cpp", and the save location to save the bundle file. Suppose the user inputs "ABC product related documents 5.pdf" as the file name to be given to the bundle file, and "C:\product related folder A" as the save location for the bundle file. In this case, the merge determination unit 7 changes the file name of the bundle file containing "design drawing.pdf", "proposal.docx", and "source code.cpp" to "ABC product related documents 5.pdf" according to the user's input. Next, the combination determination unit 7 saves the "ABC product related documents 5.pdf" as a required package file in the "C:\product related folder A" in the storage unit 3.

[0100] Next, in step S15, the merging processing unit 8 performs a merging process, and the timestamp token saving processing unit 9 performs a timestamp token saving process. In the merging process, first, a timestamp token containing the hash value of "ABC product-related document 1.pdf" stored in "C:\product-related folder A" in the storage unit 3 is obtained as a file to be added, and this timestamp token is added to "ABC product-related document 1.pdf". Next, a timestamp token containing the hash value of "ABC product-related document 5.pdf" stored in "C:\product-related folder A" in the storage unit 3 is obtained as a file to be added, and this timestamp token is added to "ABC product-related document 5.pdf". Also, in the timestamp token saving process, a timestamp token containing the hash value of "calculation program.exe" stored in "C:\product-related folder B" in the storage unit 3 is obtained as a file that does not need to be added, and an electronic file of this timestamp token is saved in "C:\product-related folder B" in the storage unit 3.

[0101] Figure 13 shows the electronic files stored in the storage unit 3 after a process is executed to combine the target files and their corresponding timestamp tokens for the above-mentioned target files, such as "Invoice.pdf," with a multiple attachment type combination configuration set. In Figure 13, "ABC Product Related Documents 1.pdf" stored in "C:\Product Related Folder A" is an electronic file in which "Invoice.pdf" and its corresponding timestamp token are combined. Specifically, it is a PDF file in which a timestamp token containing the hash value of "Invoice.pdf" is attached to "Invoice.pdf." Also, "ABC Product Related Documents 5.pdf" stored in "C:\Product Related Folder A" is an electronic file in which "Design Drawing.pdf," "Proposal.docx," and "Source Code.cpp" and their corresponding timestamp tokens are combined. Specifically, it is a PDF file in which a timestamp token containing the hash value of the package file to which "Design Drawing.pdf," "Proposal.docx," and "Source Code.cpp" are attached is attached to the package file to which "Design Drawing.pdf," "Proposal.docx," and "Source Code.cpp" are attached. Additionally, the "C:\Product-related folder B" contains "Calculation program.exe" and its corresponding timestamp token, which is stored as an electronic file named "XXXX.xxx".

[0102] Figure 14 shows the state when "ABC Product Related Documents 5.pdf," saved in "C:\Product Related Folder A," is opened in a PDF file reader application. The first page of "ABC Product Related Documents 5.pdf" contains a string 81 indicating the file wrapper, the file name of "ABC Product Related Documents 5.pdf" 82, information 83 about the three electronic files attached to "ABC Product Related Documents 5.pdf," and a timestamp 84. The reader application displays a list 75 of the electronic files attached to "ABC Product Related Documents 5.pdf." The user can open "Design Drawing.pdf," "Proposal.docx," or "Source Code.cpp" from the list by, for example, clicking with the mouse.

[0103] As described above, the file management device 1 of the first embodiment of the present invention determines whether to combine the target file and the timestamp token using a direct combination or an attachment combination. Therefore, users can easily combine electronic files and timestamp tokens without having to be aware of whether the electronic file has a structure that allows a timestamp token to be attached to it. With the file management device 1 of this embodiment, even general office workers who are not particularly familiar with information processing technology can easily and appropriately combine electronic files and timestamp tokens.

[0104] Furthermore, based on the result of the join determination, the file management device 1 executes a process to join the target file and its corresponding timestamp token using a direct join method, or a process to join the target file and its corresponding timestamp token using an attachment-type join method. Therefore, regardless of whether the target file and the timestamp token are joined using a direct join method or an attachment-type join method, that is, regardless of whether the electronic file has a structure that allows it to attach a timestamp token to itself, the user can perform the task of joining the target file and the timestamp token by simply performing a simple, common operation on the file management device 1.

[0105] Furthermore, the file management device 1 makes a decision on whether to combine files based on the file format of the target file. This allows the file management device 1 to easily determine whether the target file can have a timestamp token attached to it, and to easily select between a direct combination type and an attachment-type combination type.

[0106] Furthermore, the file management device 1 makes a decision on whether to combine files based on the file format of the target file and the security settings or modifiable settings applied to the target file. This allows the device to precisely and accurately determine whether a timestamp token can be attached to the target file itself, i.e., whether the target file and the timestamp token can be combined using a direct combination method, especially when the target file is a PDF file. In addition, even when the target file is a PDF file and, due to its internal settings, cannot attach a timestamp token to itself, the device can still combine the target file and the timestamp token using an attachment-type combination method.

[0107] Furthermore, the file management device 1 examines the structure of the target file and makes a decision on merging based on the file format and structure of the target file. This allows for a precise and highly accurate determination of whether a timestamp token can be attached to the target file itself, i.e., whether the target file and the timestamp token can be merged using a direct merging method, especially when the target file is a PDF file. Additionally, even when the target file is a PDF file and its structure differs from the standard PDF file structure, making it impossible to attach a timestamp token to the target file itself, the target file and the timestamp token can still be merged using an attachment-type merging method.

[0108] Furthermore, if the file format of the target file is one that is highly likely to contain computer viruses or spyware, the file management device 1 will not combine the target file and the timestamp token in an attached form. This prevents the target file attached to the file wrapper from becoming unopenable.

[0109] Furthermore, based on user input, the file management device 1 uses an attachment file extension list 62, which describes the extensions of electronic files that are not likely to contain computer viruses or spyware, to determine whether the file format of the target file is one that is not likely to contain computer viruses or spyware. As a result, by inputting into the file management device 1 (input form 13 on the settings screen for attachment-type merging format) file formats other than PDF that the user recognizes as being able to be reliably opened when attached to a file envelope based on the user's knowledge and experience, the file management device 1 can reliably merge the target file of that file format with the timestamp token using the attachment-type merging format.

[0110] Furthermore, when the single-attachment type combination mode is set, the file management device 1 combines the target file and the timestamp token using the single-attachment type combination mode. According to the single-attachment type combination mode, a combined version of the target file and its corresponding timestamp token can be generated for each target file. Therefore, users can manage electronic files using timestamps individually for each electronic file.

[0111] Furthermore, when a multi-attachment merging mode is set, the file management device 1 merges the target file and the timestamp token according to the multi-attachment merging mode. The multi-attachment merging mode can generate a file in which multiple target files and their corresponding timestamp tokens are merged. Additionally, the multi-attachment merging mode can generate a bundled file containing multiple target files. Therefore, users can manage multiple electronic files collectively using timestamps, and the number of timestamp tokens issued can be reduced.

[0112] [Second Embodiment] (File management system configuration) A second embodiment of the file management program and file management device of the present invention will be described using Figures 15 to 19. Figure 15 shows the file management device 91 and timestamp issuing device 21 of the second embodiment of the present invention. In the file management device 91 of the second embodiment shown in Figure 15, the same reference numerals are used for the same components as in the file management device 1 of the first embodiment shown in Figure 1. Hereinafter, the parts of the file management device 91 that differ from the file management device 1 will be mainly described, namely the combination determination unit 93, the combination processing unit 94, the log data generation unit 95, and the processing content setting unit 96.

[0113] The arithmetic processing unit 92 of the file management device 91 reads and executes the file management program stored in the storage unit 3, thereby functioning as a merge determination unit 93, a merge processing unit 94, a timestamp token storage processing unit 9, a log data generation unit 95, a processing content setting unit 96, and an overall control unit 10.

[0114] The merge determination unit 93 makes a merge determination, that is, it determines whether to merge the target file and the timestamp token using a direct merge form or an attachment merge form, or whether to merge the target file and the timestamp token at all. Similar to the merge determination unit 7 in the file management device 1 of the first embodiment, the merge determination unit 93 makes this merge determination based on the file format, internal settings and structure of the target file, and the attachment file extension list 62. In addition, the merge determination unit 93 makes a merge determination for the target file based on the results of merge determinations made in the past for electronic files having the same file name as the target file. Furthermore, the merge determination unit 93 performs the same pre-merger processing on the target file as the pre-merger processing that was made in the past for electronic files having the same file name as the target file. Note that the file name is a specific example of the "identification information" of the electronic file (target file).

[0115] The merging processing unit 94 performs the process of merging the target file and the timestamp token, similar to the merging processing unit 8 in the file management device 1 of the first embodiment. Furthermore, when merging the target file and the timestamp token using an attached merging method, the merging processing unit 94 performs the process of selecting the empty envelope file that was used when merging an electronic file having the same filename as the target file with the timestamp token using an attached merging method.

[0116] The log data generation unit 95 generates log data 97. The log data 97 is data that records the history of the process performed by the file management device 1 to combine the target file and the timestamp token. The log data 97 is stored in the storage unit 3.

[0117] The processing content setting unit 96 generates a processing content setting list 98. The processing content setting list 98 is data that describes the settings for the processing of combining an electronic file and a timestamp token. The processing content setting unit 96 generates the processing content setting list 98 based on the log data 97 generated by the log data generation unit 95. The processing content setting list 98 is also stored in the storage unit 3.

[0118] (Log data) Figure 16 shows log data 97. Log data 97 records the following information for each electronic file before merging, in chronological order of the date and time the process of merging the electronic file and the timestamp token was performed. (a) File name of the electronic file before merging: This is the file name of the electronic file that was read as the target file in the process of merging the target file and the timestamp token. (b) Modification date and time of the electronic file before merging: This is the modification date and time of the electronic file read as the target file at the start of the process in which the target file and the timestamp token are merged. (c) Filename of the empty envelope file used for the merging: This is the filename of the empty envelope file used when the target file and timestamp token were merged using an attached merge format during the process of merging the target file and timestamp token. If the target file and timestamp token were not merged during the process of merging the target file and timestamp token, "None" is recorded. (d) File name of the combined electronic file: This is the file name of the target file or package file to which the timestamp token was added and stored in the storage unit 3 during the process of combining the target file and the timestamp token. If the target file and the timestamp token were not combined and stored during the process of combining the target file and the timestamp token, the file name of that target file is recorded here. (e) Storage location of the combined electronic file: This is the storage location of the target file or package file to which the timestamp token has been added and stored in the storage unit 3 during the process of combining the target file and the timestamp token. If the target file and the timestamp token are not combined during the process of combining the target file and the timestamp token, the storage location of that target file is recorded here. (f) Date and time of saving the combined electronic file: This is the date and time of saving the target file or the bundled file that was saved in the storage unit 3 after the time stamp token was added during the process of combining the target file and the time stamp token. If the target file and the time stamp token were not combined during the process of combining the target file and the time stamp token, the date and time of saving that target file is recorded here. (g) Whether or not the files were joined: This indicates whether or not the target file and the timestamp token were joined during the process of joining the target file and the timestamp token.

[0119] (Processing content setting list) Figure 17 shows the processing content setting list 98. The processing content setting list 98 contains the following information for each electronic file: (a) File name of the electronic file (b) Whether or not a bond is necessary (c) Bonding form (d) File name of the empty envelope file to be used for joining (e) File name of the combined electronic file (f) Location to save the combined electronic file (g) Processing priority This information will be explained using "Proposal.docx" (the part enclosed by the dashed line in Figure 17) in the processing content setting list 98 as an example. (a) The file name of the electronic file is the file name including the extension "Proposal.docx". (b) Whether or not to combine indicates that it is necessary to combine "Proposal.docx" and the timestamp token. (c) Combination format indicates that "Proposal.docx" and the timestamp token will be combined in an attachment format. (d) The file name of the empty envelope file used for combining indicates the file name of the empty envelope file used when combining "Proposal.docx" and the timestamp token in an attachment format. (e) The file name of the electronic file after combining indicates the file name to be given to the electronic file in which "Proposal.docx" and the timestamp token have been combined, that is, the file name to be given to the envelope file to which "Proposal.docx" is attached and the timestamp token has been added. (f) The destination for saving the combined electronic file indicates the destination for saving the combined electronic file containing "Proposal.docx" and the timestamp token, that is, the destination for saving the bundled file to which "Proposal.docx" is attached and to which the timestamp token is added. (g) The processing execution priority indicates the priority for executing the process of combining "Proposal.docx" and the timestamp token when multiple electronic files, including "Proposal.docx", are selected by the user, and the file management device 1 performs the process of combining the electronic file and the timestamp token for each of the selected multiple electronic files. For example, in Figure 17, if the user selects "Invoice.pdf" with processing execution priority "0001", "Design Drawing.pdf" with processing execution priority "0002", and "Proposal.pdf" with processing execution priority "0003", the file management device 91 will first execute a process to combine "Invoice.pdf" with the timestamp token, then a process to combine "Design Drawing.pdf" with the timestamp token, and then a process to combine "Proposal.docx" with the timestamp token, based on the processing content setting list 98.

[0120] The processing content setting unit 96 generates a processing content setting list 98 from the log data 97, for example, as follows: First, based on the file names of the electronic files before merging recorded in the log data 97, it counts the number of times the process of merging the electronic file and the timestamp token has been performed for each electronic file, for example, 30 times for "Invoice.pdf" and 12 times for "Design Drawing.pdf". Next, it selects electronic files for which the process of merging the electronic file and the timestamp token has been performed a predetermined number of times (for example, 5 times) or more as candidate electronic files for registration. Next, for each candidate electronic file for registration, it determines whether the content of the process of merging the electronic file and the timestamp token (specifically, the file name of the empty envelope file used for merging (including "none"), the file name of the electronic file after merging, the save location of the electronic file after merging, and whether or not merging occurred) is the same each time. Next, based on the results of that determination, electronic files from the candidate electronic files for registration whose processing content for combining the electronic file and the timestamp token is the same each time are registered in the processing content setting list 98. Next, for the electronic files registered in the processing content setting list 98, the file name, whether or not combining is necessary, the combination method, the file name of the empty envelope file used for combining, the file name of the combined electronic file, the save location of the combined electronic file, and the processing execution priority are determined based on the log data 97, and these are written in the processing content setting list 98.

[0121] For example, suppose that checking the filename of the electronic file before merging in log data 97 reveals that the process of merging the electronic file and the timestamp token for "Invoice.pdf" was performed 30 times. In this case, "Invoice.pdf" is selected as a candidate electronic file for registration. Then, checking log data 97 reveals that in the 30 processes of merging "Invoice.pdf" and the timestamp token, the filename of the empty envelope file used for merging was always "none", the filename of the merged electronic file was always "ABC Product Related Documents 1.pdf", the save location of the merged electronic file was always "C:\Product Related Folder A", and the presence or absence of merging was always "1". In this case, "Invoice.pdf" is registered in the processing content setting list 98. Next, for "Invoice.pdf", the filename, whether merging is necessary, the merging format, the filename of the empty envelope file used for merging, the filename of the merged electronic file, the save location of the merged electronic file, and the processing execution priority are determined based on log data 97, and these are described in the processing content setting list 98. For details, the file name of "Invoice.pdf" is copied from log data 97. Whether or not "Invoice.pdf" needs to be merged is copied from log data 97. The file name of the empty file used for merging "Invoice.pdf" is copied from log data 97. The file name of the electronic file after merging "Invoice.pdf" is copied from log data 97. The save location for the electronic file after merging "Invoice.pdf" is copied from log data 97. The merge format of "Invoice.pdf" is determined based on the file name of the empty file used for merging "Invoice.pdf" (including "none") and whether or not it was merged.Specifically, in log data 97, the filename of the empty envelope file used for merging "Invoice.pdf" is "none," and the merge status for "Invoice.pdf" is "1." In this case, the merge type for "Invoice.pdf" is a direct merge type. Furthermore, in log data 97, if the filename of the empty envelope file used for merging one electronic file is recorded, and the merge status for that electronic file is "1," the merge type for that electronic file is an attached merge type. Also, in log data 97, if the filename of the empty envelope file used for merging one electronic file is "none," and the merge status for that electronic file is "0," the merge type for "Invoice.pdf" is no merge.

[0122] The processing execution priority is determined based on the number of times the process of combining the electronic file and the timestamp token has been performed for the electronic file selected as an electronic file to be registered in the processing content setting list 98. The more times this process has been performed, the higher the processing execution priority. Furthermore, if the number of times the process of combining the electronic file and the timestamp token has been performed is the same for multiple electronic files selected as electronic files to be registered in the processing content setting list 98, the processing execution priority is determined based on, for example, the modification date and time of those electronic files.

[0123] As can be seen from the method of generating the processing content setting list 98 described above, the processing content setting list 98 registers electronic files in which the file management device 91 has previously performed the process of combining an electronic file and a timestamp token, with the same processing content, a predetermined number of times or more, and describes the processing content that was performed repeatedly.

[0124] (This is a join based on the results of past join decisions.) The merge determination unit 93 makes a merge determination for the target file based on the results of past merge determinations for electronic files having the same filename as the target file. The merge determination unit 93 then recognizes the results of past merge determinations for electronic files having the same filename as the target file based on the processing content setting list 98.

[0125] The processing content setting list 98 registers electronic files for which the file management device 91 has previously performed a process of combining the electronic file and a timestamp token a predetermined number of times or more with the same processing content. The processing content setting list 98 also describes whether or not the electronic file and timestamp token should be combined and the form of the combination. This description of whether or not the combination should be combined and the form of the combination match the combination of the timestamp token that was previously performed for that electronic file. Therefore, if an electronic file with the same file name as the target file is registered in the processing content setting list 98, the combination determination unit 93 can recognize the results of past combination determinations for electronic files with the same file name as the target file based on the processing content setting list 98, and can make a combination determination for the target file based on the recognized result of the combination determination.

[0126] The merge determination unit 93 recognizes the results of past merge determinations for electronic files having the same filename as the target file, based on the processing content setting list 98. Based on the recognized merge determination results, it performs a merge determination for the target file, thereby enabling a merge determination for that target file that matches the user's intentions. The principle is as follows:

[0127] Electronic files for which the file management device 91 has repeatedly performed the same processing to combine the electronic file and timestamp token more than a predetermined number of times are electronic files for which the user has repeatedly updated the content for some reason, combined it with the timestamp token using the same combination method (or not combined it with the timestamp token), given the same file name, and saved it to the same storage location more than a predetermined number of times. If a user has repeatedly updated the content of an electronic file, combined the electronic file and the timestamp token using the same combination method (or not combined the electronic file and the timestamp token), given the electronic file the same file name, and saved the electronic file to the same storage location more than a predetermined number of times, it is highly likely that the user will repeat this series of actions in the future. Therefore, the combination determination unit 93 recognizes the results of past combination determinations for electronic files having the same file name as the target file based on the processing content setting list 98, and makes a combination determination for the target file based on the recognized combination determination results, thereby making a combination determination for the target file that matches the user's intentions.

[0128] In this way, the merging determination unit 93 can make a merging determination for the target file that matches the user's intention based on the processing content setting list 98, thereby reducing the frequency of inquiries to the user during the process of merging the target file and the timestamp token. Specifically, in the process of merging the target file and the timestamp token in the first embodiment, that is, the process shown in Figure 6 or Figure 7, if the target file is not a PDF file and the extension of the target file is not described in the attachment file extension list 62, the merging determination unit 7 in the first embodiment asks the user whether or not to attach the target file to the envelope file (step S11 in Figure 6 or Figure 7). When the merging determination unit 93 in the second embodiment makes a merging determination for the target file based on the processing content setting list 98, this inquiry process to the user becomes unnecessary. Therefore, the frequency of inquiries to the user can be reduced. Thus, the burden on the user performing the task of merging electronic files and timestamp tokens can be reduced, and the task can be made easier.

[0129] For example, in the first embodiment, when making a merge decision regarding "source code.cpp", the merge decision unit 7 asks the user in step S11 in Figure 6 or 7 whether or not to attach "source code.cpp" to the bundle file. In contrast, in the second embodiment, if "source code.cpp" is registered in the processing content setting list 98, when the merge decision unit 93 makes a merge decision regarding "source code.cpp", it makes a merge decision regarding "source code.cpp" based on the processing content setting list 98 without asking the user whether or not to attach "source code.cpp" to the bundle file. This reduces the number of inquiries to the user and simplifies the user's work.

[0130] (Automation of pre-combination processing) In the file management device 91 of the second embodiment, the merge determination unit 93 performs the same pre-merging process on the target file as the pre-merging process previously performed on an electronic file having the same file name as the target file. The merge determination unit 93 then recognizes the same pre-merging process as the pre-merging process previously performed on an electronic file having the same file name as the target file based on the processing content setting list 98.

[0131] The pre-combination processing performed by the combination determination unit 93 includes the process of saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token should be combined using a direct combination method, and the process of saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token should not be combined. The processing content setting list 98 describes the file name of the combined electronic file and the storage location of the combined electronic file (including the storage location of the electronic file when it is not combined) for electronic files that the file management device 91 has previously performed a process of combining the electronic file and the timestamp token with the same processing content a predetermined number of times or more. These file names and storage locations match the file name and storage location of the combined electronic file that have been previously set for that electronic file. Therefore, if an electronic file with the same file name as the target file is registered in the processing content setting list 98, the combination determination unit 93 can recognize the same pre-combination processing that has been previously performed for an electronic file with the same file name as the target file based on the processing content setting list 98, and can perform the same pre-combination processing that has been recognized for that target file.

[0132] The merge determination unit 93 recognizes, based on the processing content setting list 98, the pre-merging process previously performed on an electronic file having the same filename as the target file. By performing the same pre-merging process on the target file as recognized, it can perform pre-merging processing on the target file that matches the user's wishes. This principle is the same as the principle by which the merge determination unit 93 can make a merge determination on the target file that matches the user's wishes based on the processing content setting list 98.

[0133] In this way, the merge determination unit 93 can perform pre-merging processing on the target file that matches the user's intentions based on the processing content setting list 98. As a result, in the process of saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token should be merged in a direct merge form, the new file name and save location of the target file can be automatically determined without prompting the user for input. Furthermore, in the process of saving the target file to the storage unit 3 after it has been determined that the target file and the timestamp token should not be merged, the save location of the target file can be automatically determined without prompting the user for input. Therefore, the number of times the user has to input the file names or save locations of these electronic files into the file management device 91 is reduced. Thus, the burden on the user can be reduced.

[0134] Furthermore, in the file management device 91 of the second embodiment, when the merging processing unit 94 merges a target file and a timestamp token using an attached merging method, it recognizes an empty file folder used when merging an electronic file having the same file name as the target file and a timestamp token using an attached merging method, based on the processing content setting list 98, and selects the recognized empty file folder. This allows the user to select an empty file folder that matches their intentions. This principle is the same as the principle by which the merging determination unit 93 can make a merging determination for the target file that matches the user's intentions based on the processing content setting list 98. In this way, because the merging processing unit 94 can select an empty file folder that matches the user's intentions based on the processing content setting list 98, the selection of an empty file folder can be performed automatically when merging a target file and a timestamp token using an attached merging method, without requiring input from the user. Therefore, the number of times the user has to operate the operation unit 5 to select an empty file folder is reduced. Thus, the burden on the user can be reduced.

[0135] (Specific processing steps) The following describes in detail the process of combining a target file with its corresponding timestamp token in the file management device 91. Figures 18 and 19 show the flow of the process of combining a target file with its corresponding timestamp token in the file management device 91. Figure 18 also shows the flow of the process when a single attachment type combination is set. Common steps in Figures 18 and 19, which show the process in this embodiment, and in Figure 6, which shows the process in the first embodiment, are denoted by the same reference numerals. In the process in this embodiment shown in Figures 18 and 19, steps S51 to S53 and steps S61 to S68 in Figure 19 are added to the process in the first embodiment shown in Figure 6. The following description will focus on the added steps S51 to S53 in Figure 18 and steps S61 to S68 in Figure 19. Furthermore, in this explanation, we will use as an example the case where the user has selected "Invoice.pdf," "Design Drawing.pdf," "Proposal.docx," "Source Code.cpp," and "Calculation Program.exe" as electronic files that they wish to manage using timestamps, and has entered an instruction into the file management device 91 to start the process of combining these electronic files with the timestamp tokens corresponding to these electronic files. It will also be assumed that the storage unit 3 stores a processing content setting list 98 with the contents shown in Figure 17. It will also be assumed that the storage unit 3 stores multiple empty envelope files, including "Empty Envelope File Type 1.pdf." Note that these multiple empty envelope files each have different content and designs on their first pages.

[0136] When a user operates the operation unit 5 and selects multiple electronic files, and then clicks "Add Timestamp" with the mouse, for example, an instruction is input to the file management device 91 to start the process of combining the electronic files and their corresponding timestamp tokens for the multiple electronic files selected by the user (see Figure 10). In response, the file management device 91 starts the process of combining the electronic files and their corresponding timestamp tokens for the multiple electronic files selected by the user (step S1: YES in Figure 18).

[0137] Assuming that the merge determination and pre-merger processing are performed in the order of "Invoice.pdf", "Design Drawing.pdf", "Proposal.docx", "Source Code.cpp", and "Calculation Program.exe", the merge determination unit 93 first reads "Invoice.pdf" as the target file (step S2). Next, the merge determination unit 93 reads the processing content setting list 98 shown in Figure 17 and determines whether an electronic file with the same filename as "Invoice.pdf" is described in the processing content setting list 98 (step S51). The processing content setting list 98 shown in Figure 17 has the same filename as "Invoice.pdf" described. Therefore, the merge determination unit 93 determines that an electronic file with the same filename as "Invoice.pdf" is described in the processing content setting list 98 (step S51: YES). In this case, the process moves from step S51 to step S61 in Figure 19.

[0138] In step S61, the merge determination unit 93 determines the merge format of "Invoice.pdf" based on the processing content setting list 98 (step S61). The processing content setting list 98 describes whether or not merge is necessary and the merge format for registered electronic files, so the merge determination unit 93 determines the merge format of "Invoice.pdf" based on these descriptions. According to the processing content setting list 98, the merge format of "Invoice.pdf" is a direct merge format. Therefore, the merge determination unit 93 determines that the merge format of "Invoice.pdf" is a direct merge format (step S62: YES). Next, the merge determination unit 93 determines the new file name of "Invoice.pdf" and the save location for "Invoice.pdf" based on the processing content setting list 98. The processing content setting list 98 describes that the file name of the merged electronic file for "Invoice.pdf" is "ABC Product Related Documents 1.pdf", and that the save location for the merged "Invoice.pdf" is "C:\Product Related Folder A". Based on these descriptions, the merge determination unit 93 determines the new file name for "Invoice.pdf" to be "ABC Product Related Documents 1.pdf" and the save location for "Invoice.pdf" to be "C:\Product Related Folder A". Then, the merge determination unit 93 changes the file name of "Invoice.pdf" to "ABC Product Related Documents 1.pdf" and saves "ABC Product Related Documents 1.pdf" as a file to be added to "C:\Product Related Folder A" in the storage unit 3 (step S63). After that, the process moves to step S14 in Figure 18. At this point, the merge determination and pre-merging processing have not been completed for the multiple electronic files selected by the user, so the result in step S14 is "NO", and the process returns to step S2.

[0139] Next, the merge determination unit 93 reads "design.pdf" as the target file (step S2 in Figure 18) and determines whether an electronic file with the same filename as "design.pdf" is registered in the processing content setting list 98 (step S51). The processing content setting list 98 shown in Figure 17 contains the same filename as "design.pdf". Therefore, the merge determination unit 93 determines that an electronic file with the same filename as "design.pdf" is described in the processing content setting list 98 (step S51: YES). Next, in step S61, the merge determination unit 93 determines the merge format of "design.pdf" based on the processing content setting list 98 (step S61). According to the processing content setting list 98, the merge format of "design.pdf" is an attached merge format. Therefore, the merge determination unit 93 determines that the merge format of "design.pdf" is an attached merge format (step S62: NO, step S64: YES). Next, the merge processing unit 8 selects an empty file based on the processing content setting list 98. According to the processing content setting list 98, the filename of the empty file to be used for merging "design.pdf" is "empty file type 1.pdf". Therefore, the merging processing unit 8 selects "empty file type 1.pdf" as the empty file and reads "empty file type 1.pdf" from the storage unit 3. Next, the merging processing unit 8 attaches "design.pdf" to the read empty file. Then, the merging processing unit 8 records information that will help the user recognize "design.pdf" attached to the file, such as the filename of "design.pdf" and the date and time of modification, in the file (step S66). Next, the merging determination unit 93 determines the filename to be assigned to the file to which "design.pdf" is attached, and the save location to save that file, based on the processing content setting list 98. Processing details setting list 98 states that the file name of the combined electronic file for "design drawing.pdf" is "ABC product related documents 2.pdf", and that the save location for the combined file for "design drawing.pdf" is "C:\product related folder A".Based on these descriptions, the combination determination unit 93 determines the file name to be assigned to the package file to which "Design Drawing.pdf" is attached to be "ABC Product Related Documents 2.pdf" and determines the save location to which the package file will be saved to be "C:\Product Related Folder A". Then, the combination determination unit 93 changes the file name of the package file to which "Design Drawing.pdf" is attached from "Empty Package File Type 1.pdf" to "ABC Product Related Documents 2.pdf" and saves "ABC Product Related Documents 2.pdf" as a package file that needs to be attached to the storage unit 3 in "C:\Product Related Folder A" (step S67).

[0140] Subsequently, the process returns to step S2 via step S14 in Figure 18. Next, steps S2 and S51 in Figure 18, and steps S61, S62 and S64-S67 in Figure 19 are executed for "Proposal.docx". As a result, "ABC Product Related Documents 3.pdf", which is the attached file containing "Proposal.docx", is saved as an attached file in "C:\Product Related Folder A" in the storage unit 3.

[0141] Subsequently, the process returns to step S2 via step S14 in Figure 18. Next, steps S2 and S51 in Figure 18, and steps S61, S62 and S64-S67 in Figure 19 are executed for "source code.cpp". As a result, "ABC product related documents 4.pdf", which is a bundle file to which "source code.cpp" is attached, is saved as a required bundle file in "C:\product related folder A" in storage unit 3.

[0142] Subsequently, the process returns to step S2 via step S14 in Figure 18. Next, for "calculation program.exe", the processes in steps S2 and S51 in Figure 18, and steps S61, S62, S64 and S68 in Figure 19 are executed. In step S68, the combination determination unit 93 determines "C:\product-related folder B" as the save location for saving the timestamp token corresponding to "calculation program.exe" based on the processing content setting list 98, and saves "calculation program.exe" as a file that does not need to be added to "C:\product-related folder B" in the storage unit 3.

[0143] Furthermore, if a user selects an electronic file not registered in the processing content setting list 98 and inputs an instruction to the file management device 91 to start the process of combining the electronic file and the timestamp token, in step S51 in Figure 18, the combination determination unit 7 determines that an electronic file with the same file name as the target file is not described in the processing content setting list 98. In this case, the result in step S51 is "NO", and the process proceeds to step S3 in Figure 18, where a process is executed to determine whether to combine the files based on the file format, internal settings and structure of the target file, as well as the attached file extension list 62.

[0144] If the merge determination and pre-merging processing are completed for all electronic files selected by the user (Step S14: YES), the merge process (see Figure 8) is performed on the files that require addition and the files that require addition, and the timestamp token preservation process (see Figure 9) is performed on the files that do not require addition (Step S15).

[0145] Next, the log data generation unit updates the log data 97 (step S52). Then, the processing content setting unit 96 updates the processing content setting list 98 based on the updated log data 97 (step S53).

[0146] The process of combining the target file and the timestamp token in the file management device 91, as described above, is the process when a single attachment type of combination is set, but the same process can be performed even when a multiple attachment type of combination is set.

[0147] According to the file management device 91 of the second embodiment of the present invention, the frequency of inquiries to the user during the process of combining a target file and a timestamp token can be reduced, the user's task of entering the file name or save location of the target file can be reduced, and the user's task of selecting an empty file envelope can be reduced. Therefore, the burden on the user performing the task of combining an electronic file and a timestamp token can be reduced, and the task can be made easier.

[0148] In each of the above embodiments, the decision of whether to combine the target file and the timestamp token using a direct combination method or an attachment-type combination method is basically made based on whether the target file is a PDF file or not (step S3 in Figures 6, 7, or 18). The present invention is not limited to this, and this decision may also be made based on whether the target file is another electronic file, such as an XML (Extensible Markup Language) file, that has a structure to which a timestamp token can be attached.

[0149] Furthermore, although a PDF file is used as the envelope file in each of the above embodiments, other electronic files that can attach electronic files to themselves and can have a timestamp token added to themselves may also be used as the envelope file.

[0150] Furthermore, in each of the above embodiments, a file extension list 62 describing the extensions of electronic files that are not likely to contain computer viruses or spyware is used to determine whether to combine the target file and the timestamp token in an attached form or not. However, the present invention is not limited to this, and a file extension list describing the extensions of electronic files that are likely to contain computer viruses or spyware may also be used to determine whether to combine the target file and the timestamp token in an attached form or not.

[0151] Furthermore, by displaying a form 99, such as the one shown in Figure 20, on the display unit 6, the combination format for linking the target file and the timestamp token can be restricted to either a direct type or an attached type based on user input.

[0152] Furthermore, in the second embodiment described above, the processing content setting unit 96 generates or updates the processing content setting list 98 based on the log data 97, but the user may also generate or update the processing content setting list 98.

[0153] Furthermore, in each of the above embodiments, as an example of how a user can input an instruction to the file management device 1 (91) to start the process of combining an electronic file and a timestamp token, as shown in Figure 10, the user can open a folder, select an electronic file, and then, for example, right-click with the mouse to display the context menu 15, and then click "Add Timestamp" in the context menu 15 with the mouse. However, the method by which a user can input an instruction to the file management device 1 to start the process of combining an electronic file and a timestamp token is not limited to this. For example, the user can open a file management program and drag an electronic file into the display area (window) of the file management program to start the process of combining that electronic file and the timestamp token.

[0154] Furthermore, the present invention may be modified as appropriate, provided that it does not contradict the gist or idea of ​​the invention as can be read from the claims and the specification as a whole, and file management programs and file management devices with such modifications are also included in the technical concept of the present invention. [Industrial applicability]

[0155] The file management program of the present invention can be used in application software for managing electronic files, or in document readers or operating systems that have the function of managing electronic files. Furthermore, the file management device of the present invention can be used in various devices that have the function of managing electronic files. [Explanation of symbols]

[0156] 1. 91 File Management Device 3 Storage unit (storage device) 7, 93 Connection judgment part 8, 94 Combination Processing Unit 9. Timestamp token storage and processing unit 21 Timestamp issuing device Target files: 31, 33, 41, 42, 43, 51, 52, 53 32, 35, 47, 48, 49, 55 Timestamp tokens 34, 44, 45, 46, 54 File folders 62. List of attachment file extensions

Claims

1. A file management program that enables a computer to function as a file management device that manages electronic files using timestamps, The aforementioned file management device is A combination determination unit performs a combination determination to determine which combination to use to combine the target file, which is the managed electronic file, with the timestamp token, from a first combination that attaches the timestamp token to the electronic file itself, and a second combination that attaches the electronic file to a file wrapper and attaches the timestamp token to the file wrapper to which the electronic file is attached. A file management program characterized by comprising a merging processing unit that, as a result of the merging determination, merges the target file and the timestamp token by the first merging form, obtains a timestamp token including the hash value of the target file from a timestamp issuing device, and attaches the obtained timestamp token to the target file itself; and, as a result of the merging determination, merges the target file and the timestamp token by the second merging form, attaches the target file to a package file, obtains a timestamp token including the hash value of the package file to which the target file is attached from the timestamp issuing device, and attaches the obtained timestamp token to the package file to which the target file is attached.

2. The file management program according to claim 1, characterized in that the merge determination unit performs the merge determination based on the file format of the target file.

3. The file management program according to claim 1, characterized in that the merge determination unit performs the merge determination based on the file format of the target file and the security settings or modifiable settings applied to the target file.

4. The file management program according to claim 1, characterized in that the merge determination unit examines the structure of the target file and makes the merge determination based on the results of examining the file format of the target file and the structure of the target file.

5. The file management program according to claim 1, characterized in that the merge determination unit performs the merge determination for the target file based on the results of the merge determination previously performed for an electronic file having the same identification information as the target file.

6. The system includes a timestamp token storage processing unit that obtains a timestamp token containing the hash value of the target file from a timestamp issuing device, and stores the obtained timestamp token in a storage device provided on or connected to the computer without combining it with the target file. The join determination unit makes a decision as to whether to join the target file and the timestamp token using one of the first join configurations or the second join configuration, or whether to not join the target file and the timestamp token. The file management program according to claim 1, characterized in that the timestamp token storage processing unit performs the timestamp token storage process when, as a result of the combination determination, the target file and the timestamp token are not combined.

7. The file management program according to claim 1, characterized in that, if there are multiple target files and, as a result of the joining determination, each target file and a timestamp token are joined by the second joining form, the joining processing unit attaches the multiple target files to a single file, obtains a timestamp token containing the hash value of the single file to which the multiple target files are attached from the timestamp issuing device, and adds the obtained timestamp token to the single file to which the multiple target files are attached.

8. The file management program according to claim 1, characterized in that, if there are multiple target files and, as a result of the joining determination, each target file and a timestamp token are joined by the second joining form, the joining processing unit attaches one target file to one bundle file, obtains a timestamp token containing the hash value of the bundle file to which the one target file is attached from the timestamp issuing device, and adds the obtained timestamp token to the bundle file to which the one target file is attached, and performs this process individually for each of the multiple target files.

9. A file management device that manages electronic files using timestamps, A combination determination unit performs a combination determination to determine which combination to use to combine the target file, which is the managed electronic file, with the timestamp token, from a first combination that attaches the timestamp token to the electronic file itself, and a second combination that attaches the electronic file to a file wrapper and attaches the timestamp token to the file wrapper to which the electronic file is attached. A file management device characterized by comprising a merging processing unit that, as a result of the merging determination, merges the target file and the timestamp token by the first merging form, obtains a timestamp token including the hash value of the target file from a timestamp issuing device, and attaches the obtained timestamp token to the target file itself; and, as a result of the merging determination, merges the target file and the timestamp token by the second merging form, attaches the target file to a package file, obtains a timestamp token including the hash value of the package file to which the target file is attached from the timestamp issuing device, and attaches the obtained timestamp token to the package file to which the target file is attached.

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