JP2009104327A - File management system and file management program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide file transfer technology with high confidentiality of encryption, and simplifying encryption management. <P>SOLUTION: A file management server 2 transferring a file to a terminal according to a request from the terminal has: a request information generation part 24a receiving the request of the transfer from the terminal, and generating request information; a file acquisition part 23 acquiring the file to be transferred based on the request information; an encryption key generation part 24b acquiring a terminal unique code of the terminal having requested the transfer as an encryption key generation kind, and generating an encryption key; an encryption part 24c encrypting the file to be transferred by the encryption key; and a file transfer part 24d transferring the encrypted file to the terminal having requested the transfer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a file management technique for transferring a file to a terminal in response to a request from the terminal.

  By using a file management technique for transferring a file to the terminal in accordance with request information transmitted from the terminal, the client terminal can obtain a file stored in the server computer via the network. The scale of networks such as the Internet and in-house LANs has been expanded, and such a large-scale network makes it possible to exchange information over a wide area, while those who are not legitimate recipients illegally This also increases the risk of obtaining and using files. A typical technique implemented to suppress such illegal file use is file encryption. For example, when performing cryptographic communication between entities, one entity obtains a conversion key using a common key generated using its own private key and shared information that can be shared with the other entity during cryptographic communication. The plaintext is converted into ciphertext with the obtained conversion key and transmitted to the other entity, and the other entity uses the same common key and the shared information as the common key generated using its own private key. A cryptographic communication system that performs cryptographic communication between entities by decrypting a ciphertext transmitted with a conversion key obtained in this way into plaintext has been proposed (see, for example, Patent Document 1). In this cryptographic communication system, it is necessary to determine in advance a secret key and common information unique to the terminal, and the system operation becomes complicated.

  In addition, there is known an information management system that downloads a file from an information management database as a file server to a terminal under the management of the information management server. In this system, a file to be downloaded is encrypted and the encryption is performed. The terminal that receives the encrypted file secures file transmission security by accessing the information management server and receiving authentication after sending the decryption key to operate this file. (For example, refer to Patent Document 2). However, in this system, before the downloaded file is operated, there is a trouble that the information management server is accessed and the decryption key is transmitted.

JP 2001-156766 (paragraph numbers 0013, 0041, 0042, FIG. 2) JP 2006-185212 A (paragraph number 0064-0081, FIG. 11-12)

  In view of the above situation, an object of the present invention is to provide a file transfer technique that has high secrecy by encryption and simplifies the encryption management.

  In order to solve the above-described problem, a file management system according to the present invention is a file management system that transfers a file to a terminal in response to a request from the terminal, and receives the transfer request from the terminal and generates request information. A request information generation unit, a file acquisition unit for acquiring a file to be transferred based on the request information, and an encryption key generation unit for generating an encryption key by acquiring a terminal-specific code of a terminal that has requested transfer as an encryption key generation type And an encryption unit that encrypts the file to be transferred with the encryption key, and a file transfer unit that transfers the encrypted file to the terminal that requested the transfer.

  According to the above configuration, as the key generation type of the encryption key and the decryption key, the terminal unique code that can be specified and extracted by the file management system and the terminal that requested the transfer is used. There is no need to send the decryption key or their key generation seed for file transfer. In addition, this terminal-specific code is specific to the terminal that requested the transfer and is substantially unknown to others. By using such a terminal-specific code, all the files to be transferred are transferred by the terminal that requested the transfer. Since encryption is performed using different encryption keys, the secrecy is high, and the management of keys that guarantee the secrecy is simple.

  In one preferred embodiment of the present invention, a security level is set for the file to be transferred, and an authority level is set for each user of the terminal. It further includes an encryption determination unit that determines whether the file to be transferred needs to be encrypted based on a result of comparison with the authority level of the user of the terminal that requested the transfer.

  According to the above configuration, for example, when the confidential level of the file to be transferred is higher than the authority level of the user of the terminal that requested the transfer, the file is encrypted, and when it is low, the encryption is not performed. And a file management system capable of performing appropriate encryption as necessary.

  The technical features of the file management system according to the present invention described above can also be applied to similar file management programs and file management methods. For example, the file management program in the present invention is a file management program for a file management system that transfers a file to the terminal in response to a request from the terminal, and generates request information upon receiving a transfer request from the terminal A function to acquire a file to be transferred based on the request information, a function to acquire a terminal unique code of a terminal that has requested transfer as an encryption key generation seed, and an encryption key to generate the encryption key. A computer realizes a function of encrypting a file to be transferred and a function of transferring the encrypted file to a terminal that has requested the transfer. Naturally, such a file management program can also obtain the effects described in the above-described file management system, and can further incorporate the above-described additional technology.

[First Embodiment]
Embodiments of a file management system according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a plurality of terminals 1a, 1b,... (Hereinafter collectively referred to as terminal 1) and a file management server 2 as a file management system for managing file transfer to the terminal 1 and the like. Connected via the network 3, the file transfer system of the first embodiment is constructed. The network 3 used in this file transfer system may be a relatively small closed network such as an in-house LAN, or a large-scale open WAN including the Internet. A mixed network may be used.

  First, in the computer of the terminal 1a (the same applies to other terminals 1b and the like), as a function related to the present invention, a GUI unit that controls output to the monitor 51 and input from the operation input device 41 such as a keyboard and a mouse. 11, a terminal unique code table 12 in which a terminal unique code held by itself is registered, a request file receiving unit 13 that receives a file requested to be transferred (hereinafter referred to as a request file) from the file management server 2, and a received request A decryption management unit 14 for decrypting files and the like, a network interface 15 as a transmission / reception unit for transmitting data to the network 3, and the like are constructed by software and / or hardware.

  When the received request file is encrypted, the decryption management unit 14 acquires a terminal unique code registered in the terminal unique code table 12 as a decryption key generation seed and generates a decryption key 14a. And a decrypting unit 14b for decrypting the request file encrypted using the generated decryption key.

  The terminal-specific code in the present invention is inherently owned by the terminal, can be specified by the terminal, and can be read only by the terminal itself, and is practically known to others or other terminals. It satisfies the condition of not getting. Examples of satisfying such conditions include a terminal body serial code, a MAC address, a serial code of a program such as an OS installed in the terminal, a CPU number, and a serial code of an embedded device such as a hard disk. Furthermore, the hard disk capacity, the RAM capacity, the CPU clock value, etc. can be used because they can be distinguished by combining them. Further, in some cases, a terminal specific code is generated at a predetermined timing in the terminal, and a dynamic code having a different value every time the terminal specific code is generated can be generated. For example, it can be generated by combining a basic code such as a terminal ID given in advance with a variable code such as a time code that changes over time.

  On the other hand, the computer of the file management server 2 includes, as a function related to the present invention, a terminal unique code recording unit 21 that records in advance a terminal unique code of each terminal 1 constructing the file transfer system, and various files. , A file acquisition unit 23 for acquiring a request file to be transferred, a transfer management unit 24 for encrypting the request file, a network interface 25 as a transmission / reception unit for data transmission to the network 3, etc. Are built in software and / or hardware.

  Here, a schematic diagram of a data structure in the terminal specific code recording unit 21 is illustrated in FIG. As shown in the figure, the terminal-specific code recording unit 21 can record a plurality of types of terminal-specific codes for each terminal code. Since this terminal unique code is information that can be known (readable) only by individual terminals, it is collected regularly or irregularly and recorded in advance in the terminal unique code recording unit 21. It may be performed directly through an operation input device (not shown) of the management server 2 or may be collected from the terminal 1 via the network 3. Note that collection of terminal-specific codes via the network 3 is performed regularly or irregularly by a terminal-specific code collection unit (not shown), and particularly when the dynamic code described above is adopted as the terminal-specific code, the collection timing It is preferable that a dynamic code is newly generated on the terminal side in accordance with the above.

  The file storage unit 22 stores various files acquired via the network 3 or a media drive of the file management server 2 (not shown). The file acquisition unit 23 acquires a request file from the file storage unit 22 or via the network 3 based on request information described later.

  The transfer management unit 24 receives a transfer request from the terminal 1 via a file transfer request screen (see FIG. 3) displayed on the monitor 51 of the terminal 1, and generates a request information, a terminal specific code An encryption key generation unit 24b that reads out a terminal unique code of a terminal that has requested transfer from the recording unit 21 (hereinafter referred to as a transfer destination terminal), acquires the terminal unique code as an encryption key generation type, and generates an encryption key. The encryption unit 24c encrypts the request file using the encrypted key, and the file transfer unit 24d transfers the encrypted request file to the transfer destination terminal. Note that the encryption by the encryption unit 24c is performed so that the terminal unique code held by the transfer destination terminal can be decrypted with the decryption key generated using the decryption key generation seed.

  Next, the flow of the file transfer process of the file transfer system in the first embodiment will be described with reference to FIGS. Here, it is assumed that a specific type such as an OS serial code installed in each terminal 1 is set in advance as the terminal unique code to be used.

  First, based on FIG. 4, the flow of processing for encrypting and transferring a request file to the transfer destination terminal in the file management server 2 will be described. First, the terminal 1 constructing this file transfer system specifies a request file on the file transfer request screen illustrated in FIG. 3 and the like, thereby accepting a file transfer request (# 10). Then, the request file and the terminal code of the terminal (transfer destination terminal) are specified from the received request, and request information including these pieces of information is generated (# 20). In addition to this, for example, when downloading from the HP, the user or terminal information is acquired from the authentication information to the HP, the file information is acquired from the file designation on the download request screen, and a combination of these is requested. Information may be generated. When only the user name is acquired, the terminal used by the user may be specified as the transfer destination terminal using the authentication information at the time of login of each terminal. Of course, in the case of a system that collects operation logs from each terminal or a system that collects asset information such as software information installed on each terminal, the user name included in such operation logs and asset information It may be specified.

  Based on the request information, a request file is acquired from the file storage unit 22 or via the network 3 (# 30). Subsequently, by using the terminal code of the transfer destination terminal, the terminal unique code of the transfer destination terminal is read from the terminal unique code recording unit 21 shown in FIG. 2, and this terminal unique code is acquired as an encryption key generation type ( # 40). Then, an encryption key is generated based on the encryption key generation type (# 50), and the encryption key can be decrypted with the decryption key generated as the decryption key generation type. The request file is encrypted using (# 60), and the encrypted request file is transferred to the transfer destination terminal 1 (# 70). As a procedure for transferring a file via the network 3, it is common to adopt a procedure defined in FTP, but the present invention is not limited to this, and a file using the HTTP protocol is used. Transfer or other file transfer may be used.

  Next, based on FIG. 5, the flow of the decryption process in the transfer destination terminal that has received the request file will be described. Upon receiving the request file (# 200), the transfer destination terminal 1 that has received the encrypted request file from the file management server 2 reads the corresponding terminal specific code from the terminal specific code table 11, and stores this terminal specific code. Obtained as a decryption key generation seed (# 201). Then, a decryption key is generated based on this decryption key generation type (# 202), and the request file is decrypted using this decryption key (# 203). The terminal-specific code that is the generation type of the decryption key and the terminal-specific code that is the generation type of the encryption key obtained by encrypting the received request file are the same (here installed in the transfer destination terminal 1) Therefore, the encryption key and the decryption key are the same and function as a so-called common key. Therefore, the received request file can be decrypted using the generated decryption key.

  According to the above-described embodiment, as the key generation type of the encryption key and the decryption key, the terminal specific code that can be specified and extracted on both the file management server 2 side and the transfer destination terminal 1 side is used. There is no need to send a key, a decryption key, or their key generation seed for file transfer. In addition, this terminal-specific code is specific to the transfer destination terminal and is substantially unknown to others, and by using such a terminal-specific code, the file to be transferred is encrypted differently depending on the terminal that requested the transfer. Since encryption is performed using a key, the secrecy is high and the management of the key that guarantees the secrecy is simple.

[Second Embodiment]
Next, a second embodiment of the file transfer system provided with the file management system according to the present invention will be described. In the second embodiment, in the first embodiment described above, a security level is set in the request file, and an authority level is set for each user of the terminal. A function is provided for determining whether the request file needs to be encrypted based on the result of comparison with the authority level of the user of the transfer destination terminal of the request file.

  FIG. 6 shows a functional block diagram of the file transfer system in the second embodiment. In addition, about the functional element similar to FIG. 1, it represents using the same code | symbol. The basic configuration is the same as in FIG. 1, but the authority level recording unit 26 in which the authority level of the user of the terminal is recorded in the file management server 2, and the sensitivity recording unit 27 in which the sensitivity of each file is recorded. The transfer management unit 24 determines whether or not the request file should be encrypted based on the comparison result between the confidential level of the request file and the authority level of the user of the transfer destination terminal of the request file. An encryption determination unit 24e is further provided.

  Here, both the authority level of the user and the confidential level of the file are represented by numerical values (points) of 5 levels from 1 to 5, and the authority level is pointed to the authority level recording unit 26 for each user name. The confidentiality level is recorded as a point in the confidentiality recording unit 27 for each file name, but other forms are also possible. Note that these authority level and secret level may be directly input by an operation input device (not shown) of the file management server 2 or may be acquired via the network 3.

  Next, based on FIG. 7, the flow of processing in the file management server 2 of the file transfer system in the second embodiment will be described. Detailed description of the same steps as those in FIG. 4 will be omitted. In this embodiment, when a request from the terminal 1 is received, a user who uses the transfer destination terminal by using authentication information at the time of login of each terminal in addition to the request file and the transfer destination terminal. Is also identified.

  First, a file transfer request is received from the terminal 1 (# 10), the request file, the transfer destination terminal, and the user of the transfer destination terminal are specified, and request information including these pieces of information is generated (# 20). When the request file is acquired based on the request information (# 30), the encryption determination unit 24e refers to the security level recording unit 27, and acquires the security level by comparing with the file name of the request file. (# 31).

  Subsequently, the encryption determination unit 24e refers to the authority level recording unit 26 and obtains the authority level by comparing with the user name of the transfer destination terminal (# 32). Then, the obtained confidentiality level is compared with the authority level to determine whether encryption is necessary (# 33). Here, it is determined to perform encryption only when the confidential level of the request file is higher than the authority level of the user of the transfer destination terminal. Therefore, when the confidential level point of the request file exceeds the authority level point (# 33 Yes branch), the same encryption process as in the first embodiment is performed, and the encrypted request file is transferred to the transfer destination terminal. (# 40 to # 70). On the other hand, if the confidential level point of the request file is equal to or lower than the authority level point (# 33 No branch), the steps of # 40 to # 60 are skipped and the process proceeds to # 70 to transfer without encryption. The request file is transferred to the destination terminal.

  In the transfer destination terminal that has received the request file, the decryption management unit 14 determines whether or not the request file is encrypted. Decryption is performed.

  By providing an encryption determination function as in the above-described embodiment, appropriate encryption can be performed as necessary. It should be noted that, instead of or in addition to the comparison between the confidential level and the authority level described above, it is of course possible to perform a determination to perform encryption when one of the levels exceeds a predetermined level.

[Third Embodiment]
Next, a third embodiment of the file transfer system provided with the file management system according to the present invention will be described. In the first embodiment described above, the encryption key and the decryption key for the request file are generated using the terminal-specific code as a generation seed. In the third embodiment, the terminal-specific code is generated as the generation seed for the encryption key and the decryption key. In addition to the code, it also uses file related information related to the request file.

  FIG. 8 shows a functional block diagram of the file transfer system in the third embodiment. In addition, about the functional element similar to FIG. 1, it represents using the same code | symbol. Although the basic configuration is the same as in FIG. 1, in this third embodiment, first, file transfer information generation for generating file related information related to the file from the request file is performed in the transfer management unit 24 of the file management server 2. 24f and a transfer information generation unit 24g for generating transfer information describing file related information. The file-related information can be selected from information related to the request file such as the name of the request file, the hash value of the request file, the creation date / time of the request file, the request date / time, and the transfer execution date / time.

  In the third embodiment, the encryption key generation unit 24b combines the terminal unique code and the file related information to generate an encryption key generation type, and generates an encryption key used for encrypting the request file. Furthermore, the file transfer unit 24d transfers transfer information including file related information together with the request file to the transfer destination terminal.

  On the other hand, also on the terminal 1 side, the decryption key generation unit 14a combines the file-related information read from the transfer information transferred together with the request file with the terminal specific code read from the terminal specific code table 12 as a decryption key generation type. Generate a decryption key.

  Next, based on FIG. 9, the flow of processing in the file management server 2 of the file transfer system in the third embodiment will be described. In this case, it is assumed that specific types such as the serial code of the OS installed in each terminal 1 and the name of the request file are set in advance as the terminal unique code and file related information to be used. Detailed descriptions of the same steps as those in FIG. 4 are omitted.

  First, a file transfer request is received from the terminal 1 (# 10), a request file and a transfer destination terminal are specified, and request information including these pieces of information is generated (# 20). When a request file is acquired based on the request information (# 30), the name of the acquired request file is read and coded, and generated as file related information (# 34).

  Subsequently, the terminal unique code of the transfer destination terminal is read from the terminal unique code recording unit 21, and this terminal unique code and the file specifying code generated in step # 34 are combined and acquired as an encryption key generation type (# 40). Then, an encryption key is generated based on this encryption key generation type (# 50) so that the terminal-specific code and file related information held by the transfer destination terminal can be decrypted with the decryption key generated as the decryption key generation type. Then, the request file is encrypted using the generated encryption key (# 60).

  Further, information relating to the transfer of the encrypted request file, here, transfer information describing the file related information used as the encryption key generation seed is generated (# 64). Then, the encrypted request file and transfer information are transferred to the transfer destination terminal 1 (# 70).

  Next, the flow of the decryption process in the transfer destination terminal that has received the request file and the transfer information will be described with reference to FIG. First, when an encrypted request file and transfer information are received from the file management server 2 (# 300), file-related information is read from the transfer information (# 301). In addition, a corresponding terminal unique code is read from the terminal unique code table 12, and is acquired as a decryption key generation type in combination with the read terminal unique code and file related information (# 302). Then, a decryption key is generated based on this decryption key generation type (# 303), and the request file is decrypted using this decryption key (# 305). The terminal-specific code and file-related information that became the generation type of the decryption key match the terminal-specific code and file-related information that became the generation type of the encryption key obtained by encrypting the received request file (in this case, transfer Therefore, the encryption key and the decryption key are the same and function as a so-called common key. Therefore, the received request file can be decrypted using the generated decryption key.

  If the transfer information transmitted from the file management server 2 to the terminal 1 is also to be encrypted, it is convenient to encrypt it with an encryption key generated based on the terminal unique code. On the terminal 1 side, the received transfer information is decrypted with a decryption key generated based on its own terminal-specific code to read the file-related information, and then based on this file-related information and its own terminal-specific code The request file is decrypted with the generated decryption key.

  By creating the encryption key and the decryption key based on the combination of the terminal unique code and the file related information as in the above-described embodiment, the same terminal is always encrypted with a different encryption key. Security benefits. Note that this embodiment can also have the encryption determination function as in the second embodiment described above.

[Other Embodiments]
(1) In the above-described embodiment, the terminal 1 is provided with the terminal-specific code table 12 and the decoding management unit 14 to realize the decoding function, but in addition to this, the request file is transferred from the transfer destination terminal 1 to the terminal-specific. You may comprise as an automatic decompression | decompression form which takes in a code and self-decompresses (self-decoding).

(2) In the above-described embodiment, a specific type is set in advance as a terminal-specific code to be used. However, when the terminal 1 has a plurality of types of terminal-specific codes, Correspondingly, it is also preferable to record a plurality of types of terminal unique codes for each terminal in the terminal unique code recording unit 21 and change the type of terminal unique code used for each transfer destination terminal 1. Further, a plurality of types of terminal-specific codes may be used as one encryption key generation type per terminal. At this time, if the type of the terminal-specific code to be used is selected at random, the secrecy is further improved and a security advantage is obtained. Moreover, it is good also as a form which manages time schedules, such as changing the classification of the terminal specific code to be used for every month. In addition, when one selected from a plurality of types of terminal-specific codes is used as an encryption key generation type, a selection information generation unit that generates selection information indicating the type of the selected terminal-specific code is provided. The selection information may be sent to the transfer destination terminal together with the request file or separately from the request file. In particular, in the form in which transfer information is transmitted as in the third embodiment described above, selection information may be included in this transfer information. Further, a mode in which the selection information generation unit is provided on the terminal side, selection of what terminal unique code is used for encryption is performed at the terminal, and the selection information is transmitted to the file management server 2 is also possible. Note that the file-related information can also employ various forms for the type change as described above.

(3) In the above-described embodiment, the terminal 1 includes an operation log generation unit that describes the operation content of the terminal, and the file management server 2 includes an operation log acquisition unit. A specific operation log (for example, the xth operation log) included in the operation log sequence being started is recorded in both the terminal 1 and the file management server 2, and the start time of such a computer or a specific operation log is recorded. May be regarded as a terminal-specific code and set as a key generation type to generate an encryption key or a decryption key.

(4) In the embodiment described above, the file storage function, the encryption function, and the file transfer function are integrated into the file management server 2 as the file management system. You may comprise with a server, an encryption server, and a file transfer server.

(5) In the above-described embodiment, the terminal unique code is not recorded in advance in the terminal unique code table 12 in each terminal 1, but such a table is omitted and the decryption key generation unit converts the terminal unique code into hardware or It is good also as a form which reads directly from each part, such as software.

Functional block diagram of the file transfer system in the first embodiment Explanatory drawing of terminal specific code recording part Figure showing the file transfer request screen The flowchart which shows the file encryption process in 1st Embodiment The flowchart which shows the file decoding process in 1st Embodiment Functional block diagram of the file transfer system in the second embodiment Flowchart showing file encryption processing in the second embodiment Functional block diagram of the file transfer system in the third embodiment Flowchart showing file encryption processing in the third embodiment The flowchart which shows the file decoding process in 3rd Embodiment

Explanation of symbols

1 Terminal 2 File management server (file management system)
12 Terminal Specific Code Table 13 Request File Receiving Unit 14 Decryption Management Unit 14a Decryption Key Generation Unit 14b Decryption Unit 21 Terminal Specific Code Recording Unit 22 File Storage Unit 23 File Acquisition Unit 24 Transfer Management Unit 24a Request Information Generation Unit 24b Encryption Key Generation 24c Encryption unit 24d File transfer unit 24e Encryption determination unit 24f File related information generation unit 24g Transfer information generation unit 26 Authority level recording unit 27 Sensitivity recording unit

Claims (3)

A file management system for transferring a file to a terminal in response to a request from the terminal,
A request information generating unit that receives a transfer request from the terminal and generates request information;
A file acquisition unit for acquiring a file to be transferred based on the request information;
An encryption key generation unit that acquires a terminal unique code of a terminal that has requested transfer as an encryption key generation seed and generates an encryption key;
An encryption unit for encrypting the file to be transferred with the encryption key;
A file transfer unit that transfers the encrypted file to the terminal that requested the transfer;
File management system with A security level is set for the file to be transferred, and an authority level is set for each user of the terminal,
Further comprising an encryption determination unit that determines whether or not the file to be transferred needs to be encrypted based on a comparison result between a security level of the file to be transferred and an authority level of a user of the terminal that has requested the transfer. Item 2. The file management system according to Item 1. A file management program for a file management system for transferring a file to a terminal in response to a request from the terminal,
A function of receiving a transfer request from the terminal and generating request information;
A function of acquiring a file to be transferred based on the request information;
A function for acquiring a terminal unique code of a terminal that has requested transfer as an encryption key generation seed and generating an encryption key;
A function of encrypting the file to be transferred with the encryption key;
A function of transferring the encrypted file to the terminal that requested the transfer;
Is a file management program that enables computers to realize

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