JP2004341866A - Communal computer system, communal computer using method, communal computer using processing program, and storage medium recording the program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communal computer system capable of keeping high security without requiring a user's attention to an environment and a file formed by the user, a communal computer using method, a communal computer using program, and a storage medium recording the program. <P>SOLUTION: This communal computer system α comprises a server S1 arranged in at least one base, and a plurality of communal computers C1j arranged in a plurality of bases. The communal computer C1j comprises a main control means 5 for generating a session key for encrypting a file group, and an encrypting/decoding server reading/writing means 9 for backing up encrypted differential information in the server S1 with the encrypted session key and decoding the encrypted session key with a secret key to decode the encrypted differential information with the session key. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shared-use computer system, a shared-use computer usage method, and a shared-use computer usage processing program that enable a computer (especially a personal computer) of a general-purpose operation system to be used safely even in a shared usage form such as a rental office or a remote office. And a recording medium on which the program is recorded.
[0002]
[Prior art]
Conventionally, in rental offices and remote offices, personal computers with a general-purpose operation system existing at the location are shared (hereinafter referred to as "shared use personal computers"), or personal computers are used by themselves (hereinafter referred to as "shared personal computers"). , "Bring-in personal computer.")
[0003]
[Problems to be solved by the invention]
However, when using a carry-in personal computer, individual settings such as network settings can be personalized, and although the use environment can be customized, carrying the personal computer itself is an essential condition, which is inconvenient. Was.
[0004]
On the other hand, when using a shared personal computer (a general stand-alone personal computer; OS (Operating System), Windows (registered trademark) 95, Windows (registered trademark) 98, Windows (registered trademark) XP, etc.) manufactured by Microsoft Corporation, In order to remotely connect to your company's network or connect to the Internet, you have to change the network connection in advance and make various settings of the mail software, even when entering Japanese Since Japanese dictionaries and the like are also used jointly, it is inefficient and inconvenient, and the user must always pay attention to the safety when saving files on the hard disk.
[0005]
As a method of solving such a security problem, there is a method of using a shared computer disclosed in Patent Document 1. With this shared computer usage method, when using a personal computer, the user can continue to use the environment that he or she used before on another computer, and the shared computer is installed in multiple places In such a case, even when the installation locations are different places, the environment that the user has used before can be similarly used by another personal computer.
[0006]
In other words, in the method of using a shared computer described in Patent Document 1, a personal computer that backs up the usage environment and a personal computer that restores the usage environment are separate, and even if they are installed in different places, Can be restored without any inconvenience.
[0007]
Regarding the security when files are stored on the hard disk, the shared computer encrypts the information used by the user with a key at the shared computer, and encrypts the encrypted text by the server for the shared computer. When the shared computer that can be connected to the server is separately used and stored in the storage unit as encrypted difference information, the shared difference information is shared with the key stored in an IC (Integrated Circuit) that can be used only by the user. The encrypted difference information is decrypted by the shared computer using the key as a parameter, that is, encryption to the encrypted difference information and decryption of the encrypted difference information are performed by the common key cryptosystem. .
[0008]
The location of Patent Document 1 is described below.
[Patent Document 1]
JP 2001-34580 A
[0009]
However, the technique disclosed in Patent Literature 1 discloses that a file newly created at the end of use of the shared computer after decryption of the encrypted difference information using the key stored in the IC card as a parameter at the start of use of the shared computer. Since it is necessary to encrypt the updated file, the key stored in the IC card needs to be stored in the shared computer from the start to the end of use of the shared computer.
[0010]
Therefore, it is necessary to delete the key when transferring the key stored in the IC card or when the use of the shared computer ends, so that the work becomes troublesome, and when the key is forgotten to be deleted from the shared computer. In some cases, the key may be stolen (disclosed) by a third party.
[0011]
Also, instead of transferring the key to the shared computer and holding it, it is conceivable to leave the IC card inserted in the card reader / writer. In an environment where users use shared computers, there is a risk that the card may be stolen by a third party while the user is going to the bathroom, and there is still room for improvement in terms of security .
[0012]
Here, the main objects to be solved by the present invention are as follows.
That is, an object of the present invention is to provide a shared use computer system capable of maintaining high security without assuming that the user pays attention to an environment constructed by the user and a file created by the user, It is an object of the present invention to provide a computer use method, a shared use computer use processing program, and a recording medium on which the program is recorded.
[0013]
Other objects of the present invention will become apparent from the description of the specification, drawings, and particularly from the claims.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the system of the present invention is provided with a server provided at one or more bases, a server provided at each of a plurality of bases, and connected to the server via a communication means, so A plurality of shared use computers used by a user, and the shared use computer has a preset common initial environment, and each user stored in the common initial environment and the server at the start of use. A shared use computer system configured to construct the use environment of each user in the common initial environment based on the difference information from the use environment set by the user, and to return to the common initial environment at the end of use. The shared computer uses a file stored and set in a storage unit of a specific shared computer among the shared computers. Main control means for generating a session key for encrypting the file group; encrypting the file group using the session key as a parameter; and the session key using the user's public key provided on the server as a parameter. While encrypting the file group and backing it up in the storage means on the server together with the encrypted session key as encrypted difference information, while using the specific or other shared computer. Decrypting the encrypted session key stored in the storage means on the server with the secret key paired with the public key stored in the IC card held by the user as a parameter, An encryption / decryption server that decrypts the encrypted difference information as a parameter and constructs the common initial environment Characteristic configuration take steps comprising the writing means.
[0015]
On the other hand, the method of the present invention includes a server provided at one or more bases, and a server provided at each of a plurality of bases and connected to the server via a communication means to be used by an unspecified number of users. A plurality of shared use computers, and the shared use computer has a preset common initial environment, and is set by the individual users stored in the common initial environment and the server at the start of use. A method of using a shared-use computer configured to construct the use environment of each user in the common initial environment based on difference information from the use environment and to return to the common initial environment at the end of use, The computer used when encrypting a group of files stored and set in the storage means of a specific shared computer among the shared computers. First, a session key is generated, the file group is encrypted using the session key as a parameter, and the session key is encrypted using the user's public key provided on the server as a parameter. The encrypted file group is backed up as encrypted difference information together with the encrypted session key in the storage means on the server, and finally, the user uses the shared computer or another shared computer. In this case, the encrypted session key stored in the storage means on the server is decrypted with the secret key paired with the public key stored in the IC card held by the user as a parameter, A characteristic configuration technique for decrypting the encrypted difference information using a session key as a parameter is employed.
[0016]
Further, the processing program of the present invention is provided to a server provided at one or more bases and connected to the server via a communication means while being provided at a plurality of bases, respectively. A plurality of shared use computers, and the shared use computer has a preset common initial environment, and is set by the individual users stored in the common initial environment and the server at the start of use. A shared use computer use processing program configured to construct the use environment of each user in the common initial environment based on difference information from the use environment, and to return to the common initial environment at the end of use, In the above-mentioned shared use computer, of the shared use computers, the information is stored and set in the storage means of a specific shared use computer. When encrypting the file group, first, a session key is generated, the file group is encrypted using the session key as a parameter, and the session key is encrypted using the user's public key provided on the server as a parameter. A step of encrypting a key; and a step of backing up the encrypted file group as encrypted differential information together with the encrypted session key in storage means on the server. When the shared computer or another shared computer is used, the secret key paired with the public key stored in the IC card possessed by the user is stored in the storage means on the server as a parameter. Decrypts the encrypted session key, and uses the session key as a parameter to encrypt the encrypted Take the characteristic procedure of the procedure for decoding the broadcast, a series execution.
[0017]
Further, a recording medium on which the processing program of the present invention is recorded is a recording medium on which the program according to the characteristics of the processing program of the present invention is recorded, and is mounted on a shared computer constituting the shared computer system, and Take the characteristic procedure to record the procedure for practicing the program procedure.
[0018]
More specifically, in solving the problem, the present invention achieves the above object by adopting novel characteristic constituent means, methods, procedures, and procedures from the respective upper concepts to lower concepts, which are enumerated below. Is made.
[0019]
A first feature of the system of the present invention is that a server provided at one or more bases and a server provided at each of a plurality of bases and connected to the server via communication means, A plurality of shared use computers used for the, and the shared use computer has a preset common initial environment, at the start of use by the common initial environment and the individual user stored in the server A shared use computer system configured to construct the use environment of each user in the common initial environment based on the difference information from the set use environment and to return to the common initial environment at the end of use, The shared computer encrypts a group of files stored and set in a storage unit of a specific shared computer among the shared computers. Main control means for generating a session key to be encrypted, and encrypting the file group with the session key as a parameter, encrypting the session key with the user's public key provided on the server as a parameter, While backing up the encrypted file group as encrypted difference information together with the encrypted session key in the storage means on the server, when using the specific or other shared computer, the The encrypted session key stored in the storage means on the server is decrypted using the secret key paired with the public key stored in the IC card possessed by the server as a parameter, and the encryption is performed using the session key as a parameter. An encryption / decryption server reader / writer for decrypting difference information and constructing the common initial environment If, in the configuration adopted interoperable computer system comprising comprises a.
[0020]
A second feature of the system of the present invention is that the encrypted difference information in the first feature of the present invention system is such that the encrypted difference information stored in the storage means of the shared computer is backed up in the storage means of the server. In this case, the previously used encrypted difference information stored in the storage unit of the server is compared with the encrypted difference information currently stored in the storage unit of the shared computer. The present invention resides in adoption of a configuration of a shared computer system in which only encrypted difference information changed from used encrypted difference information is used as encrypted difference information.
[0021]
A first feature of the method of the present invention is that a server provided at one or more bases, a server provided at each of a plurality of bases and connected to the server via communication means, and an unspecified number of users A plurality of shared use computers used for the, and the shared use computer has a preset common initial environment, at the start of use by the common initial environment and the individual user stored in the server A shared use computer usage method configured to construct the use environment of each user in the common initial environment based on difference information from a set use environment, and to return to the common initial environment at the end of use. The shared computer encrypts a group of files stored and set in a storage unit of a specific shared computer among the shared computers. At this time, first, a session key is generated, the file group is encrypted using the session key as a parameter, and the session key is encrypted using the user's public key provided on the server as a parameter. The encrypted file group is backed up as encrypted differential information together with the encrypted session key in a storage unit on the server, and finally, the user is able to use the shared computer or another shared computer. Is used, the encrypted session key stored in the storage means on the server is decrypted using the secret key paired with the public key stored in the IC card held by the user as a parameter. And a shared computer that decrypts the encrypted difference information using the session key as a parameter. In the configuration adoption of the way.
[0022]
According to a second feature of the method of the present invention, the encrypted difference information in the first feature of the method of the present invention is such that the encrypted difference information stored in the storage means of the shared computer is backed up in the storage means of the server. In this case, the previously used encrypted difference information stored in the storage unit of the server is compared with the encrypted difference information currently stored in the storage unit of the shared computer. The present invention resides in adopting a configuration of a shared computer use method in which only encrypted difference information changed from used encrypted difference information is used as encrypted difference information.
[0023]
A first feature of the processing program of the present invention is that a server provided at one or more bases, a server provided at each of a plurality of bases and connected to the server via a communication means, and A plurality of shared use computers used by a user, and the shared use computer has a preset common initial environment, and each user stored in the common initial environment and the server at the start of use. A shared use computer use processing program configured to construct the use environment of each user in the common initial environment based on the difference information from the use environment set by the user and to return to the common initial environment at the end of use. In addition, in the above-mentioned shared use computer, in the shared use computer, storage / setting is performed in storage means of a specific shared use computer. When encrypting the file group obtained, first, a session key is generated, the file group is encrypted using the session key as a parameter, and the public key of the user provided on the server is used as a parameter. A step of encrypting the session key, and then a step of backing up the encrypted file group in the storage unit on the server together with the encrypted session key as encrypted difference information, and finally, When the user uses the shared computer or another shared computer, storage means on the server using a secret key paired with the public key stored in an IC card owned by the user as a parameter Decrypts the encrypted session key stored in the In the configuration adopted interoperable computer use processing programs and procedures for decoding the difference information, the formed by a series run.
[0024]
A second feature of the processing program of the present invention is that the encrypted difference information in the first feature of the processing program of the present invention is obtained by replacing the encrypted difference information stored in the storage means of the shared computer with the storage means of the server. When the backup is performed, the previously used encrypted difference information stored in the storage unit of the server is compared with the encrypted difference information currently stored in the storage unit of the shared computer. Is to adopt a configuration of a shared use computer use processing program in which only encrypted difference information changed from previously used encrypted difference information is used as encrypted difference information.
[0025]
A first feature of a recording medium on which the processing program of the present invention is recorded is a recording medium on which the processing program according to the first or second feature of the present invention is recorded. The present invention resides in adopting a configuration of a recording medium in which a shared use computer use processing program, which is mounted on the constituent shared use computer and records a procedure for practicing the integrated program procedure, is recorded.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, before describing an embodiment of the shared use computer system of the present invention, a shared use computer that can realize the present invention, in particular, a shared PC (hereinafter, referred to as “SPC”) will be described.
[0027]
The SPC is a personal computer that enables a business person or the like who is out of the office to work in a personal computer environment similar to his / her office, and is provided in a joint work space (a rental office, a joint work space in his company, etc.). Will be installed.
[0028]
Here, the target user may be, for example, a business person or a student who wants to read e-mails from a company, school, or the Internet while going out, or surf the Internet with an Internet connection, as well as an office on a business trip. And the like who wants to use a personal computer application, and who wants to lose time between schedules.
[0029]
The shared personal computer (SPC) adopts a general-purpose OS (Windows (registered trademark) 98, Windows (registered trademark) XP, etc.) as the OS, and installs several types of document creation software and a web browser as standard applications. And can be used jointly by users.
[0030]
(Basic principles of shared use computer system)
Hereinafter, the shared use computer system will be described with reference to the accompanying drawings. 1, 2, and 3 show configuration diagrams of the shared use computer systems α, α1, and α2, respectively. The configuration of the system itself may be a configuration other than the shared use computers α, α1, and α2 shown in FIGS. 1 to 3, depending on the size of the configuration, the scale of maintenance of the communication network, and the like. And can be changed as appropriate according to the needs of the user.
[0031]
First, the shared use computer system α shown in FIG. 1 will be described. The shared use computer system α connects an internal communication network NWC such as a LAN constructed in the company C and an internal communication network NW1 such as a LAN constructed in the rental office L1 to the Internet via the gateway GW. It is a system configuration that can be freely connected to various external information communication networks (communication means) NW.
[0032]
A server SC and a personal computer are connected to the internal communication network NWC constructed in the company C. For the purpose of explanation, one personal computer CC among personal computers will be described.
[0033]
Usually, the user accesses the server SC from the personal computer CC and uses in-house network services such as reading and writing of e-mail, various network services, and file server access, and also prepares materials in the personal computer CC. Is going.
[0034]
On the other hand, in the internal communication network NW1 of the rental office L1, a shared use personal computer (hereinafter simply referred to as "PC") C1j (subscript j corresponds to the personal computer numbers 1 to M in the rental office L01). However, a single device may be connected) and the server S1 on the internal communication network NW1 is connected.
[0035]
The server S1 stores data of a user information database D11 and an encrypted difference file group D12 as appropriate. When and when data is stored will be described in detail with reference to the following embodiment.
[0036]
The shared use computer system α is a system in which the user goes to the rental office L01 with an arbitrary contract and can use the personal computer C1j in the same use environment as the personal computer CC of the company C. Therefore, a server S1 for saving (backing up) and restoring (restoring) the working environment is always required.
[0037]
The shared use computer system α1 shown in FIG. 2 is another form of the shared use computer system α shown in FIG. 1, and has a plurality of rental offices such as rental offices L01, L02,..., L0N.
[0038]
The rental office L0k (the subscript k is the number of the rental office and an arbitrary number from 1 to N) is one base of the rental office in the shared computer system α. It has the same configuration as L01, and includes a server Sk and personal computers Ck1,..., Ckj (the subscript k is an arbitrary number from 1 to N and corresponds to k in L0k).
[0039]
The shared use computer system α2 shown in FIG. 3 is different from the shared use computer systems α and α1 in that there are a plurality of rental offices such as rental offices L01 to L0N and one or more rental offices are installed in the plurality of rental offices. The configuration is such that a server S for a plurality of personal computers C11,..., CNj can be freely connected by an external communication network NW such as the Internet. , CNj installed at each rental office have the same configuration as the personal computer in FIG.
[0040]
In the shared use computer system α2, unlike the shared use computer system α1, the server S is installed only in the common office L0 without the server S1,..., SN being installed in each rental office. That is, when accessing the file group (difference information file group) in the shared use computer system α2, the server S is accessed from all the bases of the rental offices L01,..., L0N via the external communication network NW such as the Internet. By doing so, the work environment can be similarly saved and restored from any personal computer.
[0041]
Here, the basic configuration of the shared use computer system is not limited to those shown in FIGS. 1, 2 and 3, and in the server SC of the company C, the servers S1 installed in the rental office L0k or the common office L0,. , SN, and S can be provided. The configuration of the shared use computer system can be appropriately changed within a range in which the shared use computer system described below is realized.
[0042]
(Basic principles of using shared computers)
Hereinafter, the sharing computer system will be described by describing the use procedure of the personal computer C11 installed in the rental office L01 in the sharing computer system α with reference to FIG. It can be easily understood that the same applies to the case of the shared computer systems α1 and α2 in FIGS. Further, it is obvious without proof that the shared use computer system α1 shown in FIG. 4 has different usages as shown in FIG. 2 and FIG.
[0043]
Further, the terms “company C” and “rental office L01” in the figure merely facilitate understanding of the configuration and features of the present invention, and do not limit the content of the present invention. A company is only an example of a place where a personal computer is used most frequently, and a rental office is merely an example of a collaborative work space.
[0044]
<First use procedure>
First, the flow when the rental office L01 is used for the first time will be described. When using for the first time, the following procedures 1 to 5 will be followed. Procedure 1 is as follows. When using the rental office L01, the user accesses the server S1 from the company C (self-dedicated personal computer CC) in advance and registers user information including a user ID and a password in the user information database D11 at the first use. (The data flow is indicated by F1.) Preferably, the password is an encrypted password.
[0045]
Procedure 2 is as follows. When the user goes to the rental office L01 thinking of using the rental office L01, the user is at a position where, for example, the personal computer C11 can be used. Authentication is performed (the data flow is indicated by F2).
[0046]
Procedure 3 is as follows. Using the personal computer C11 in which the environment is constructed by the above procedure 2, connection to the Internet NW and creation of various documents are performed (F3).
[0047]
Step 4 is as follows. When the use of the personal computer C11 is finished, the use environment (including the information stored in the personal computer C11) is stored as an encrypted difference file group D12 of the server S1. This includes the fact that the information deleted from the personal computer C11 is deleted from the encrypted difference file group D12 (the data flow is indicated by F4). In the procedure 3, the procedure 4 may be arbitrarily or periodically performed according to a change in the hard disk of the personal computer C11.
[0048]
Procedure 5 is as follows. The information in the personal computer C11 is completely deleted from all the encrypted difference information stored in the first storage area HD1 (described later) of the hard disk HD. For example, the first storage area HD1 of the used hard disk HD is formatted. The first storage area HD1 is an area in which a user's use environment is constructed. By constructing the user's use environment in the first storage area HD1, security can be ensured.
[0049]
As described above, the user's behavior and use procedure for the first use are performed using procedure 1 → procedure 2 → procedure 3 → procedure 4 → procedure 5 as a standard. The deformation will be described later.
[0050]
<Second and subsequent steps>
Next, the second and subsequent use procedures will be described. From the second time onward, use of the personal computer can be continued from the previous work environment, and the following procedure is used.
[0051]
Step 6 is as follows. When the user thinks of using the rental office L01 after the second time and goes to the rental office L01, the user is in a position where the personal computer C11 (here, it is not necessary to be the same as the personal computer used last time) is available. Prior to using C11, the validity of the user is authenticated at the second and subsequent use, and the environment saved in the previous procedure 4 is restored from the encrypted difference file group D12 to the personal computer C11 (the data flow is shown in F6). )
[0052]
After that, the above procedure 3, procedure 4, and procedure 5 are performed in order. That is, the second and subsequent user actions and usage procedures are performed using procedure 6 → procedure 3 → procedure 4 → procedure 5 as a standard.
[0053]
Here, regarding the embodiment of the present invention, the following points are mentioned as remarkable matters. First, the user usually works in a company, but can use the shared personal computer at any rental office while going out.
[0054]
Secondly, when the user uses the personal computer in the rental office, the user can continue to use the environment from where he or she previously used the rental office. That is, the use environment can be continuously used regardless of the personal computer installed in any rental office.
[0055]
Thirdly, it is possible to keep the security of the user's data without any special awareness of the user.
[0056]
The basic principle of the shared computer system α and the use procedure thereof according to the embodiment of the present invention has been described above. The internal configuration and use of the shared computer system α and the program for realizing the same will be described below. These will be described in detail with reference to the drawings as system examples, method examples, program examples, and recording medium examples.
[0057]
(System example)
FIG. 5 is a diagram showing an internal configuration of the shared use computer system α according to the system example of the embodiment of the present invention. It should be noted that FIG. 2 shows the internal configuration of the range necessary for carrying out the present invention, and naturally includes functions provided in ordinary servers and personal computers, and is omitted in the drawings.
[0058]
Further, the internal configuration of FIG. 5 is not limited to the shared computer system α shown in FIG. 1, but is the same even when applied to the shared computer systems α1 and α2 shown in FIGS. , FIG. 5 is a diagram for explaining the internal configuration and functions thereof, and furthermore, the method for utilizing the difference information of the present invention. The internal communication networks NWC, NW1,..., The external communication network NW, the gateway GW, etc. are indicated by lines L. It is. Arrows F1,..., F6 indicate exchange of various information.
[0059]
First, an internal configuration of the shared personal computer C1j (j is an arbitrary number) will be described. The shared personal computer C1j is connected to an IC card R / W (reader / writer) 11 that reads an IC card 10 necessary for using the shared personal computer C1j. As will be described later, the IC card 10 stores a user ID, a password, a secret key XKi paired with the public key YKi held in the server S1, and the like.
[0060]
The input means 4 is a keyboard, a mouse, a microphone, or the like, and is provided for a user to issue a command to the shared personal computer C1j or to display a result.
[0061]
The main control means 5 controls the inside of the shared personal computer C1j. More specifically, a password or the like relating to a user's input from the input unit 4 is obtained and passed to a card information reading / writing unit 6 described later, or the user ID acquired by the card information reading / writing unit 6 from the IC card R / W 11. Etc., and has a function of collating with the user information database D11.
[0062]
When backing up a group of files recorded on the shared personal computer C1j to the server S1, the file list FL1i from the server S1 is read and the file list FL2i stored in the second storage area HD2 of the hard disk HD is read. It also has a function of reading and activating the difference extracting means 8, passing the file information stored in the file lists FL1i and FL2i to the difference extracting means 8, and generating a session key SKi.
[0063]
The card information reading / writing means 6 has a function of controlling the operation of the IC card R / W 11 in accordance with a command from the main control means 5, and more specifically, a password required by a user input from the main control means 5. When it is acquired, it has functions such as collating the password with the password of the user recorded on the IC card 10 and reading the secret key XKi unique to the user.
[0064]
The difference extraction unit compares the file information of the file list FL2i read from the second storage area HD2 of the hard disk HD of the shared use personal computer C1j with the file information FL1i stored on the server S1, and compares the changed file list and the deleted file. It has a function of creating a list and sending it to the encryption / decryption server read / write means 9.
[0065]
The encryption / decryption server read / write means 9 sequentially encrypts the files corresponding to the sent modified file list in file units, using the session key SKi from the main control means as a parameter, and stores the session key SKi in the server S1. After encrypting with the above public key YKi, a session key SKi is added to each file, and a unique file is created as an encrypted difference file group D12 in the area of the user ID (user ID = i) of the IC card 10 on the server S1. It has a function of giving a file name (for example, a serial number of 1, 2, 3) and copying.
[0066]
On the other hand, a function of deleting a file corresponding to the deletion file list sent from the difference extracting unit 11 from the encrypted difference file group D12 in the area of the user ID (user ID = i) of the IC card 3 on the server S1. Is also provided.
[0067]
The common initial environment restoring means 7 is a means for restoring the common initial environment in the second storage area HD2 of the shared personal computer C1j. The creation of the common initial environment will be described later. Specifically, for example, a CD-ROM in which a common initial environment is recorded is inserted into a start-up recording medium drive (for example, a CD-ROM drive; not shown) attached to the shared personal computer C1j, and the shared personal computer C1j is inserted. A common initial environment is realized by turning on the power of C1j and booting from the CD-ROM.
[0068]
The hard disk HD is divided into the first storage area HD1 and the second storage area HD2 as described above. The storage areas HD1 and HD2 store changed files, unchanged files, a file list FL2i, and the like. Means.
[0069]
Next, the internal configuration of the server S1 will be described. The server S1 includes at least a setting registration unit 2, a CGI program 3, a user information database D11, and an encrypted difference file group D12.
[0070]
The setting registration means 2 is a means for a user who intends to use the common use personal computer C1j to provide S1 with registration of user information including a user ID and a password, and is constituted by a web server or the like. Also, the CGI program 3 is provided for realizing the processing on the server S1 side of the setting registration unit 2, and it is an existing unit, so that no special explanation will be required.
[0071]
Next, the self-dedicated personal computer CC will be described. It is necessary that the self-dedicated personal computer CC has at least the WEB browser 1. Although not shown, it is needless to say that input / output means for a keyboard, a mouse, and a display must also be provided.
[0072]
The details of each unit have been described above with respect to the system example according to the embodiment of the present invention. The operation of each unit will be described in detail with the following method example.
[0073]
(Example of method)
In the following, according to the procedure described above with reference to FIGS. 1 and 5, the details of each part of the shared computer system α will be described, and a method example of the embodiment of the present invention will be described. Note that, among the above procedures, procedures 3 and 5 are well-known items, and thus description thereof will be omitted. FIG. 8 shows a flowchart summarizing the processing procedure of this example of the method. The description will be given later.
[0074]
Prior to using the shared computer system α for the first time (between the procedure 1 and the procedure 2), the user is provided with the IC card 10 for each user who is indispensable for the use. Is registered with the user ID of the IC card 3 (user ID = i), the secret key XKi, the user ID and password set by the user in step 1.
[0075]
Here, i of the user ID and i at the time of attaching the secret key XKi are the same number. Further, a public key YKi paired with the secret key XKi is registered in the server S1.
[0076]
Here, the user ID is an ID for specifying a user. The public key YKi is a key for encrypting the session key SKi generated by the main control means 5 at the end of use of the personal computer C11, and the secret key XKi is used for encrypting the session key SKi at the start of use of the personal computer C11. The key to decrypt. The session key SKi is stored on the server S1 in association with each file information of the encrypted difference file group D12 one by one (one-to-one relationship).
[0077]
The password is for confirming the validity of the user holding the IC card 10 in the card. If the password is not entered through the input means 5 and collation (preferably collation in the IC card 3) is not performed, The IC card 3 cannot be accessed.
[0078]
<Procedure 1>
Procedure 1 is a procedure for registering a use environment in advance. The user accesses the setting registration unit 21 running on the server S1 of the rental office L01 from the personal computer CC of the company C and registers the personal computer environment in the server S1. Specifically, it is as follows.
[0079]
First, when the self-dedicated personal computer CC accesses the setting registration means 2 (constituted by a WEB server or the like) running on the server S1, the CGI program 3 is started, and the setting screen displayed by the setting registration means 2 is displayed on its own. It is displayed on the web browser 1 of the dedicated personal computer CC.
[0080]
FIG. 6 shows an example of the screen. The user inputs an arbitrary user ID and password from the setting screen 12 displayed on the web browser 1 or the like. Then, the CGI program 3 receives the user ID and the password from the setting registration unit 2, and registers the user ID and the password in the user information database D11 using the user ID = i as a key. At this point, procedure 1 ends.
[0081]
<Procedure 2>
Procedure 2 is a procedure in which the first-time user authenticates the validity of the user. At this time, it is assumed that the restoration of the common initial environment has been completed. That is, it is sufficient that the first storage area HD1 of the hard disk HD of the personal computer C1j has a common initial environment. The details of restoring the common initial environment and creating the common initial environment as a premise thereof will be described later.
[0082]
First, the user inputs the “password” registered in advance in the above procedure 1 from the screen of the personal computer C1j using the input unit 4 while viewing the display screen (not shown), and the main control unit 5 inputs the “password”. Remember password temporarily.
[0083]
Then, the main control unit 5 instructs the card information read / write unit 6 to read the user ID and the secret key XKi stored in the IC card 10 and passes the stored password to the card information read / write unit 6. .
[0084]
When the card information read / write means 6 receives the instruction and the password, the received password is checked on the IC card 10, the user ID and the secret key XKi are read, and the user ID and the secret key XKi are sent to the main control means 5. give.
[0085]
Then, the main control means 5 searches the user information database D11 on the server S1 for a record corresponding to the user ID = i, reads out the user ID on the record and the temporarily stored password, and then reads the user ID. Then, it is determined whether or not the password is the same as the input data and confirmed (authenticated). At this point, the IC card 10 may be extracted from the IC card R / W 11.
[0086]
The above-described authentication method may be a method such as MAC authentication of UNIX (registered trademark), and any method can be used as long as authentication can be performed. In step 2, the file list FL1i is created and stored on the server S1. Here, the i of the user ID and the suffix i of the file list FL1i are the same number.
[0087]
<Procedure 4>
Step 4 is a procedure for saving the usage environment in the server S1 when the use of the personal computer C1j ends. It should be noted that the backup need not be performed at the end, and may be performed arbitrarily and regularly while the personal computer C1j is in use.
[0088]
The point here is to minimize the time required for the user to make the backup itself, and the information sent from the personal computer C1j to the server S1 and stored in the server S1 is stored in the personal computer C1j (including the IC card 10). And the like. In the following description, the case when the personal computer C1j is terminated will be described.
[0089]
At the start of the backup process, a file list FL2i is created in the second storage area HD2 of the hard disk HD. Here, the i of the user ID and the suffix i of the file list FL2i are the same number.
[0090]
The file list FL2i stores file information. The file information includes a file name and a property, and the property includes a file size, a time stamp, and attribute information (such as read-only and hidden files). Information).
[0091]
Then, in the file list FL2i, new file information is stored for a newly created file, changed properties are stored for a changed file, and for a deleted file, for example, a minus is added to the file size. The property to which the attribute is assigned is stored.
[0092]
After reading the file list FL1i from the server S1 and reading the file list FL2i stored in the second storage area HD2 of the hard disk HD, the main control means 5 activates the difference extracting means 8 and stores the file list FL1i, FL2i in the file list FL1i. The stored file information is passed to the difference extracting means 8.
[0093]
Then, the difference extracting means 8 compares the file information of the file list FL1i read from the server S1 with the file information of the file list FL2i read from the second storage area HD2 of the hard disk HD, and recognizes the following recognition. I do.
[0094]
(1) A file that does not exist in the file list FL1i but exists in the file list FL2i is recognized as a new file.
(2) Regarding files existing in both the file lists FL1i and FL2i, files whose properties have been changed, for example, files whose attribute information and time stamp have been changed, or files whose file size has been changed, are updated files. recognize.
[0095]
(3) A file that exists in the file list FL1i but does not exist in the file list FL2i (that is, a file with a minus attribute added to the file size) is recognized as a deleted file.
(4) Files other than the above (1) to (3) are recognized as unmodified files.
[0096]
Then, based on the above recognition, the difference extracting means 8 sets the list of the file names for the files recognized as the new file and the changed file as a changed file list, and for the file recognized as the deleted file, Create each list as a deleted file list. Next, the difference extracting means 8 sends the changed file list and the deleted file list to the encryption / decryption server read / write means 9.
[0097]
The encryption / decryption server read / write means 9 sequentially encrypts the files corresponding to the changed file list obtained from the difference extraction means 8 in file units using the session key SKi as a parameter, and then stores the session key SKi on the server S1. After encrypting the public key YKi provided as a parameter as a parameter, a session key SKi is added for each file, and an encrypted difference file group D12 is stored in the area of the user ID (= i) of the IC card 10 on the server S1. A unique file name (for example, a serial number such as 1, 2, or 3) is assigned and copied.
[0098]
On the other hand, the file corresponding to the deleted file list sent from the difference extracting means 8 is deleted from the encrypted difference file group D12 in the area of the user ID (= i) of the IC card 10 on the server S1. In addition, the file list FL2i created as described above is copied to the file list FL1i and stored on the server S1 together with the encrypted difference file.
[0099]
The above processing (differential / incremental backup processing) will be described in detail with reference to FIG. First, a file list FL1i is created and stored on the server S1 in a state (a) where the first storage area HD1 of the personal computer C1j is in the common initial environment. Here, the file list FL1i is empty.
[0100]
From this state, the personal computer C1j is used to perform common initial environment and change work such as new creation, update and deletion of files (b). In b, D '(t1) and E' (t1) indicate update files (the common initial environment corresponding to F (t0) is deleted), and G (t1), H (t1), and I (t1). Indicates a newly created file (this newly created file includes a file and a common initial environment). In addition, t indicates time, t1 and t2 indicate that time has elapsed with respect to t0, and the greater the number of numbers, the more time has elapsed with respect to t0.
[0101]
When files are backed up as encrypted difference information in the server S1 in this state, first, a file list FL2i is created as described above, and a portion of the file changed to the common initial environment based on the file list FL2i is created. The backup files D '(t1), E' (t1), G (t1), H (t1), and I (t1), which are the difference information, are copied, and the file list FL2i is copied to the file list FL1i and the server S1 is copied. (C).
[0102]
Next, when the personal computer C1j (not limited to the personal computer C1j) is used for the second time (not limited to the personal computer C1j), one is stored in the first storage area HD1 based on the file list FL1i stored in the server S1. The encrypted difference information D '(t1), E' (t1), G (t1), H (t1), and I (t1) whose properties have been changed with respect to the common initial environment constructed at the third time are downloaded, The deleted file is deleted based on the file list FL2i, and the encrypted difference information is restored to the common initial environment constructed for the first time (e).
[0103]
Next, using the personal computer C1j for the second time, the common initial environment and the change work such as new creation, update, and deletion of the file are performed as shown in f.
[0104]
When the changed file is backed up on the server S1 as the encrypted difference information after the end of this work, the file list FL1i is downloaded from the server S1 after the FL2i is created as described above, and the file list FL1i and the file list FL2i are copied. In comparison, the file that is the difference, that is, the upper two files indicated by g, is backed up as an encrypted difference file, and after the backup is completed, the file list FL2i is copied to the file list FL1i and stored on the server S1.
[0105]
Here, in the related art, the properties of the file changed in the common initial environment indicated by a are backed up (data over all stages of g), but in this case, the encryption backed up to the server S1 is performed. The difference information increases each time the personal computer C1j is used.
[0106]
On the other hand, in the embodiment of the present invention, the file list FL1i previously saved on the server S1 is compared with the file list FL2i created this time, and only the files having the difference therebetween are backed up. The size of files to be backed up can be reduced.
[0107]
Further, a conventional method for comparing the time stamp of the file in the file list FL1i stored in the server S1 with the time stamp of the file in the file list FL2i in the second storage area HD2, and backing up the file with the new time stamp. In the case where the time has been set back to the past for some reason while using the personal computer C1j, the time stamp of the changed file becomes older than the time stamp of the file list FL1i stored in the server S1. Therefore, the backup process is not performed.
[0108]
On the other hand, in the embodiment of the present invention, the file list FL1i previously saved on the server S1 and the file list FL2i created this time are compared irrespective of the time stamp, and only the difference files are backed up. This makes it possible to reliably back up the difference information even if the time goes back to the past for some reason while using the personal computer C1j.
[0109]
<Procedure 6>
Step 6 is a procedure when the same user uses the rental office L01 after the second time. First, it is indispensable to authenticate the validity of the user, and the encrypted difference file group D12 backed up according to the procedure 4 is restored on the personal computer C1j (it is not necessarily the personal computer used last time). An example will be described.
[0110]
The user inserts (or presents) his / her own IC card 10 whose user ID is i into the IC card R / W 11 connected to the personal computer C1j.
[0111]
Next, the user inputs the password registered in advance in the above procedure 1 from the screen of the personal computer C1j using the input unit 4 while viewing the display screen (not shown), and the main control unit 5 inputs the password. Temporarily store the password. Then, the main control means 5 instructs the card information reading / writing means 6 to read out the user ID and the secret key XKi stored in the IC card 10 and, at the same time, sends the temporarily stored password to the card information reading / writing means. Give it to 5 temporarily.
[0112]
When the card information read / write means 6 temporarily receives the instruction and the password, the received password is verified on the IC card 10 and the user ID (= i) and the secret key XKi are passed to the main control means 5.
[0113]
At this time, the main control means 5 searches the record corresponding to the user ID i on the server S1, reads out the user ID and the password on the record, and then stores the user ID and the password in the data input by the user. After determining and confirming that they are the same, a restore instruction is sent to the encryption / decryption server read / write means 9. At this time, the temporarily stored password is deleted.
[0114]
After that, the encryption / decryption server read / write means 9 receives the user ID and the secret key XKi from the main control means 5, reads out the files of the encrypted difference file group D12 together with the session key SKi, and reads out the session key SKi. The data is decrypted with the secret key XKi and sequentially written to the first storage area HD1 of the hard disk HD.
[0115]
As described above, in the embodiment of the present invention, the IC card 10 can be removed from the personal computer C1j after decrypting the encrypted differential information stored in the encrypted differential file group D12 of the server S1 at the start of using the personal computer C1j. When the user moves away from the personal computer C1j, the IC card 10 is not removed from the personal computer C1j, and the private key XKi does not reach the hands of a third party.
[0116]
Further, since the secret key XKi does not need to be retained and erased in the personal computer C1j until the use of the personal computer C1j is completed, the private key XKi is not passed to a third party by forgetting to erase it from the personal computer C1j.
[0117]
<Creating a common initial environment>
Here, the common initial environment will be described in detail. This common initial environment creation needs to be performed only once by the provider of the rental office L01 (office service provider) when the rental office is opened.
[0118]
Specifically, the following method is conceivable, but is not limited thereto. For example, an application such as DriveImagePRO that can restore all data on a hard disk HD to a state at the time of saving all data on a startup recording medium (for example, a CD-ROM) containing a common initial environment for all users is used. There is a method of creating a common initial environment while creating it on a CD-ROM or a method of storing it in a second storage area HD2.
[0119]
Further, the common initial environment including the common initial environment of all users may be in the second storage area HD2. Further, at this time, it is necessary to install other applications for creating documents and the like, and applications for services provided by the personal computer C1j of the rental office L01. The above is the procedure for creating the common initial environment.
[0120]
<Restoring the common initial environment>
Further, since the shared use computer system α includes the shared use personal computer as an element of the configuration, the security of information related to one user is ensured, and the same user personal computer uses There is a need to maintain the environment. That work is restoring the common initial environment.
[0121]
The user inserts the recording medium for booting (eg, a CD-ROM for booting) created in the procedure for creating a common initial environment into a recording medium drive for booting (eg, a CD-ROM drive) attached to the personal computer C1j, and inserts the personal computer C1j. Turn on the power. Then, for example, after booting from the CD-ROM, a common initial environment is developed in the first storage area HD1.
[0122]
In addition, there is a method of starting up the OS of the second storage area HD2 and expanding the common initial environment on the second storage area HD2 to the first storage area HD1. Instead of booting the common initial environment from the CD-ROM described above, a boot from a server (not shown) on a network that can communicate with the personal computer C1j may be performed.
[0123]
<Procedure 8>
For example, in the shared use computer system α in FIG. 1, when the above procedure 1 from the personal computer CC of the company C is not performed, that is, when it is decided that the user wants to use the rental office L01, especially the procedure 1 In this case, the user goes to the rental office L1 and performs the following procedure 8 under the common initial environment.
[0124]
First, the user inserts (or presents) his / her own IC card 10 whose user ID is i into the IC card R / W 11 connected to the personal computer C1j. Next, the user inputs the user ID, the password, and the password set so that only the user can access the card at the time of issuing the card from the screen of the personal computer C1j by using the input unit 4 while viewing the display screen (not shown). Then, the main control means 5 stores the input data group.
[0125]
Then, the main control unit 5 instructs the card information read / write unit 6 to read the user ID and the key XKi stored in the IC card 10, and passes the stored password to the card information read / write unit 6. The above can be achieved by performing the same procedure as the procedure 6 described above, and can save time and effort in implementation. At this time (or at the beginning of the encrypted differential backup process), the user ID and the password are set in the user information database D11 of the server S1.
[0126]
FIG. 8 summarizes the flow of the procedure described above. Hereinafter, an example of the method will be described with reference to FIG. At this time, it is assumed that the shared use computer (SPC) has been restored to a common initial environment.
[0127]
First, it is determined whether the user has used the SPC (ST1). If the user has not used the SPC yet, a determination is made as to whether or not to perform SPC user registration in advance (ST2).
[0128]
When the user is registered in advance in ST2, the above procedure 1 is performed (ST3). The user who has gone through ST3 decides whether to actually use SPC or not (ST4). If he wants to use SPC, he follows the above procedure 2 (ST5). On the other hand, if user registration is not performed in advance in ST2 and an attempt is made to actually use SPC (ST6), step 8 is performed without step 1 and step 2 (ST7).
[0129]
Also, if the user has experience using the SPC in the past in ST1 and decides to actually use the SPC (ST8), if the user wants to use the SPC, the above procedure 6 is performed (ST9).
[0130]
After ST5, ST7 and ST9, the user uses the SPC (ST10), and during or after the use, stores the ciphertext of the difference information by the above procedure 5 (ST11). Depending on whether or not the first storage area HD1 is to be formatted (ST12), in the case of YES in ST12, the common initial environment is restored via the format of the first storage area HD1 (ST13). (ST14).
[0131]
Note that even if NO in ST12, it is not essential to perform ST13 since the format is substantially formatted in restoring the common initial environment in ST14. It simply gives the user a sense of security. Then, after ST14, the process returns to ST1 again. ST14 is normally performed by the administrator and provider of the SPC, but may be performed separately by the user.
[0132]
(Program example)
This processing program example corresponds to the above-described method example, and the processing procedure is an algorithm of the flow shown in FIG. In addition, this processing program example shows a program example for realizing the above-described method example, and thus details are left to the method example.
[0133]
When implementing the present processing program example, this processing program is read in advance by the shared use personal computers C11 to CNj constituting the shared use computer systems α, α1, and α2.
[0134]
First, a procedure (ST1) for determining whether or not the user has used the SPC is executed. If the user has not used the SPC, the user registration of the SPC is performed in advance. A procedure (ST2) for determining whether or not the determination is performed is executed.
[0135]
When the user is registered in advance in ST2, the procedure (ST3) for registering the use environment shown in the procedure 1 is executed. The user who has gone through ST3 determines whether or not to use the SPC (ST4). If so, the user executes the procedure (ST5) for authenticating the validity of the user shown in the procedure 2 above. Will be. On the other hand, if user registration is not performed in advance in ST2 and an attempt is made to actually use the SPC (ST6), the user does not perform steps 1 and 2 but steps shown in step 8 (step 8). ST7).
[0136]
Also, if the user has experience using the SPC in the past in ST1 and decides to actually use the SPC (ST8), if the user wants to use the SPC, the above procedure 6 is performed (ST9).
[0137]
After ST5, ST7, and ST9, the user uses the SPC (ST10), and during or after the use, executes the procedure of storing the ciphertext of the difference information by the procedure 5 (ST11), and the user himself / herself. Depends on whether or not to format the first storage area HD1 of the hard disk HD (ST12), and if the answer is YES in ST12, the restoration of the common initial environment is performed via the format of the first storage area HD1 (ST13). The procedure to be performed is executed (ST14).
[0138]
Note that even if NO in ST12, it is not essential to perform ST13 since the format is substantially formatted in restoring the common initial environment in ST14. It simply gives the user a sense of security. Then, after ST14, the process returns to ST1 again. ST14 is normally performed by the administrator and provider of the SPC, but may be performed separately by the user.
[0139]
(Example of recording medium)
Further, the recording medium example of the present invention allows the shared difference personal computer (SPC) to read the encrypted difference backup processing program in the above-mentioned shared use computer system, and makes the computer practicable according to the execution procedure of the present shared processing program example. It is a recording medium on which recording is performed.
[0140]
The representative system examples, method examples, processing program examples, and recording medium examples of the present invention have been described above, but the present invention is not necessarily limited to the above items. Modifications can be made as appropriate within the scope of achieving the object of the present invention and achieving the following effects.
[0141]
【The invention's effect】
According to the present invention, after decrypting the encrypted difference information stored in the storage means of the server at the start of use of the shared computer, the IC card can be removed from the shared computer, and the user can remove the IC card from the shared computer. As a result, the private key does not pass to the hands of a third party, and high security can be ensured.
[0142]
Also, there is no need to keep the private key in the shared computer and erase it until the end of use of the shared computer. Users no longer need to be particularly aware of security aspects.
[0143]
Further, the differential / incremental backup of the present invention reduces the capacity of files to be backed up by backing up only the differences between the previous file list stored on the server and the file list created by the current use of the shared computer. Therefore, the backup time can be shortened.
[0144]
Furthermore, since the previous file list and the file list created by the current use are compared regardless of the time stamp, and only the files with the differences are backed up, the file list may be deleted for some reason while using the shared computer. Even if the time has been set back in the past, the difference information can be reliably backed up.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a shared use computer system α according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a shared use computer system α1 according to an embodiment of the present invention.
FIG. 3 is a configuration diagram of a shared use computer system α2 according to the embodiment of the present invention.
FIG. 4 is a configuration diagram of a shared use computer system α1 according to the embodiment of the present invention, which shows a use method different from that of the system α1 shown in FIG. 2; .
FIG. 5 is a block diagram showing an internal configuration of the shared use computer system α of the embodiment of the present invention.
FIG. 6 is a diagram illustrating an example of a setting screen provided by a setting registration unit of the server.
FIG. 7 is a diagram illustrating a differential / incremental backup in the embodiment of the present invention.
FIG. 8 is a flowchart illustrating a method of using the shared computer system according to the embodiment of the present invention.
[Explanation of symbols]
α, α1, α2 ... shared use computer system
NW: External communication network
L ... line
GW… Gateway
C… Company
CC: Self-dedicated personal computer
SC ... server
NWC: Internal communication network built in the company
L0, L1 to LN ... Rental office
S0, S1 to SN ... server
D11: User information database
D12: Encrypted difference file group
C11-CNj: Shared use personal computer
NW1 to NWN: Internal communication network built in rental office
F1 to F6 ... processing
FL1i, FL2i ... File list
HD: Hard disk
HD1: Hard disk of the first part
HD2: Hard disk of the second part
1. Web browser
2. Setting registration means
3: CGI program
4: Input means
5. Main control means
6 ... Card information reading / writing means
7: Common initial environment restoration means
8 difference extracting means
9: Encryption / decryption server read / write means
10 ... IC card
11 ... IC card R / W
12 Setting screen

Claims (7)

A server provided at one or more bases, and a plurality of shared use computers respectively provided at the plurality of bases and connected to the server via communication means and used by an unspecified number of users; And the shared use computer has a preset common initial environment, and the difference information between the common initial environment and the use environment set by each user stored in the server at the time of starting use is provided. A shared use computer system configured to construct the use environment of each user in the common initial environment based on the common initial environment, and to return to the common initial environment at the end of use,
The shared use computer,
Main control means for generating a session key for encrypting a group of files stored and set in a storage means of a specific shared use computer,
While encrypting the file group using the session key as a parameter, encrypting the session key using the user's public key provided on the server as a parameter, and encrypting the encrypted file group with encrypted difference information While backing up to the storage means on the server together with the encrypted session key as
When the specific or other shared use computer is used, the secret key paired with the public key stored in the IC card possessed by the user is stored in the storage means on the server as a parameter. Encryption / decryption server read / write means for decrypting an encrypted session key, decrypting the encrypted difference information using the session key as a parameter, and constructing the common initial environment.
A shared use computer system, characterized in that: The encrypted difference information includes:
When the encrypted difference information stored in the storage unit of the shared computer is backed up in the storage unit of the server, the encrypted difference information used last time stored in the storage unit of the server and the shared usage Comparing the encrypted difference information currently stored in the storage means of the computer, and in the case of a mismatch, only the encrypted difference information changed from the previously used encrypted difference information is used as the encrypted difference information.
The shared use computer system according to claim 1, wherein: A server provided at one or more bases, and a plurality of shared use computers respectively provided at the plurality of bases and connected to the server via communication means and used by an unspecified number of users; And the shared use computer has a preset common initial environment, and the difference information between the common initial environment and the use environment set by each user stored in the server at the time of starting use is provided. Based on the common initial environment, the use environment of each user is constructed, and a shared use computer using method configured to return to the common initial environment at the end of use,
The shared use computer,
When encrypting a group of files stored and set in the storage means of a specific shared use computer among the shared use computers,
First, a session key is generated, and the file group is encrypted using the session key as a parameter, and the session key is encrypted using the user's public key provided on the server as a parameter,
Next, the encrypted file group is backed up in the storage unit on the server together with the encrypted session key as encrypted difference information,
Finally, when the user uses the shared computer or another shared computer,
The encrypted session key stored in the storage means on the server is decrypted with the secret key paired with the public key stored in the IC card held by the user as a parameter, and the session key is used as a parameter. Decrypt the encrypted difference information as
A method of using a shared computer, characterized in that: The encrypted difference information includes:
When the encrypted difference information stored in the storage unit of the shared computer is backed up in the storage unit of the server, the encrypted difference information used last time stored in the storage unit of the server and the shared usage Comparing the encrypted difference information currently stored in the storage means of the computer, and in the case of a mismatch, only the encrypted difference information changed from the previously used encrypted difference information is used as the encrypted difference information.
4. The method according to claim 3, wherein the computer is used. A server provided at one or more bases, and a plurality of shared use computers respectively provided at the plurality of bases and connected to the server via communication means and used by an unspecified number of users; And the shared use computer has a preset common initial environment, and the difference information between the common initial environment and the use environment set by each user stored in the server at the time of starting use is provided. A shared use computer use processing program configured to construct the use environment of each user in the common initial environment based on the common initial environment, and to return to the common initial environment at the end of use,
In the shared use computer,
When encrypting a group of files stored and set in the storage means of a specific shared use computer among the shared use computers,
First, a procedure for generating a session key, encrypting the file group using the session key as a parameter, and encrypting the session key using the user's public key provided on the server as a parameter,
Next, a step of backing up the encrypted file group as encrypted difference information together with the encrypted session key in a storage unit on the server,
Finally, when the user uses the shared computer or another shared computer,
The encrypted session key stored in the storage means on the server is decrypted with the secret key paired with the public key stored in the IC card held by the user as a parameter, and the session key is used as a parameter. And a procedure for decrypting the encrypted difference information as
A shared use computer use processing program characterized by the above-mentioned. The encrypted difference information includes:
When the encrypted difference information stored in the storage unit of the shared computer is backed up in the storage unit of the server, the encrypted difference information used last time stored in the storage unit of the server and the shared usage Comparing the encrypted difference information currently stored in the storage means of the computer, and in the case of a mismatch, only the encrypted difference information changed from the previously used encrypted difference information is used as the encrypted difference information.
The computer-usable processing program according to claim 5, characterized in that: A recording medium recording the shared use computer use processing program according to claim 5 or 6,
The program is mounted on a shared computer constituting the shared computer system, and a procedure for practicing the integrated program procedure is recorded.
A recording medium having recorded thereon a shared use computer use processing program.

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