JP2008090786A - Online storage system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an online storage system and method capable of safely and efficiently utilizing a large amount of data stored in a server, when the data is used from a client via a network. <P>SOLUTION: A control part 190 searches an authentication table for a user identifier (u), creates authentication information R (s<SB>i</SB>) out of both an encrypted virtual disk S<SB>i</SB>registered in a pair with the user identifier (u) and a received authentication information generation factor R, and sends this information to the client 2. Another control part 290 receives the authentication information R (s<SB>i</SB>) from the server 1, controls a determining part 244, reads virtual disk verification information C (s<SB>i</SB>) to a RAM 25, and verifies whether or not the received authentication information R (s<SB>i</SB>) is correct. If the verification result indicates that it is not correct, a request for starting a session is suspended and the process is terminated; if the verification result indicates that it is correct, the process is continued. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an online storage system and method in which a user uses server data via a network from a client. More particularly, the present invention relates to an online storage system and method for protecting a client from viruses and other malicious applications by verifying the validity of the data before accessing the data from the client to the server. .

  With the development of network technology, client / server systems are widely used. Along with the improvement in computer performance, these systems also have a wide variety of usage forms such as enormous processing data and complicated processing contents.

  As such a system, there is a conventional first system (for example, Patent Document 1) that transfers huge data from a server to a client and performs advanced processing on the client side, and a huge data stored on the server side. A second conventional system that arbitrarily processes data from the client side has been proposed.

  The first conventional system stores the operating system (OS), applications, data, etc. used by the client in the storage device of the server, and the client obtains the OS etc. via the network and starts the personal computer (PC). Network system. The data to be transferred from the server to the client is huge because not only the data is stored in the server storage device as in the so-called file server but also the OS and applications are stored in the server storage device. I can say that. Moreover, it can be said that sophisticated processing is performed on the client side in that not only data processed by the client application but also an OS necessary for starting the client is acquired via the network.

As a conventional second system, Gmail using Ajax technology can be cited. In this case, e-mail data stored on the server side is used from the Ajax engine downloaded by the client. Unlike the form in which the conventional second system stores and uses both the e-mail application and the e-mail data in the client, it can be said that the client side arbitrarily processes huge data stored on the server side. .
JP-A-2005-149334

  In the conventional first and second systems, the client uses the data stored on the server side in a reliable manner. However, in practice, the server may receive unauthorized intrusion and data may be manipulated illegally. In the case of the conventional first system, there is a case where a program for obtaining information illegally is incorporated in the OS or application used by the client. In the case of the conventional second system, the attached data of the mail is There are cases in which a virus program is illegally replaced.

  In order to avoid these cases, it is necessary for the client to verify the validity of the data stored on the server side using some means.

  On the other hand, as a technique for confirming the validity of data, there is a method of inputting data into a predetermined hash function and matching the output. In the method using the hash function, the verification side, that is, the client side needs to hold a copy of the target data. Therefore, in order for the client to verify the validity, it is necessary to download all target data from the server in advance. In the case of the first conventional system, the client needs to temporarily store a large amount of data for validity verification before using the target data, that is, before starting the OS. Inconvenience arises from the viewpoint. Further, in the case of the conventional second system, it is necessary to transfer a large amount of data to the client once even when only a part of the mail data is used, which causes inconvenience from the viewpoint of transfer efficiency.

  An object of the present invention is to provide an online storage system and method capable of realizing safe and efficient use when a large amount of data stored on a server side is used from a client via a network. .

An online storage system according to the present invention provides:
A server, a client, and a network that connects the server and the client so that they can communicate with each other;
The server is
Receiving means for receiving an authentication information generation factor from the client;
Storage means for storing a cryptographic virtual disk in combination with a user identifier;
Authentication information generating means for generating authentication information from the authentication information generating factor and the encrypted virtual disk;
Transmitting means for transmitting the authentication information to the client;
The client
Authentication information generating factor generating means for generating the authentication information generating factor;
Transmitting means for transmitting the authentication information generation factor to the server;
Receiving means for receiving the authentication information;
And determining means for determining whether or not the authentication information is correct, and suspending the processing if the authentication information is not correct.

The online storage method according to the present invention includes:
An online storage method through a network for connecting a server and a client so that they can communicate with each other,
An authentication information generation factor generating step for generating an authentication information generation factor on the client side;
A first transmission step of transmitting the authentication information generation factor to the server;
A first receiving step of receiving the authentication information generating factor on the server side;
An authentication information generating step for generating authentication information based on a cryptographic virtual disk stored on the server side in combination with a user identifier and the authentication information generation factor;
A second transmission step of transmitting the authentication information to the client;
A second receiving step of receiving the authentication information on the client side;
A first determination step of determining whether or not the authentication information is correct and suspending the processing when the authentication information is incorrect.

  According to the present invention, a client who intends to use data held in a server can verify the validity of data without transferring a large amount of data at hand. In addition, when data is used and updated, information necessary for verifying the validity is also updated, so that the validity of the data can be verified without being transferred each time a large amount of data is used.

  As a result, it is possible to protect a client who intends to use the data from a virus or an unauthorized program that may be included in the data held in the server. In addition, the present invention can be used for the purpose of preventing in advance damage to customers that may be caused by accidents or data abnormalities by an unauthorized third party by a provider that provides services for managing customer data.

In the online storage system according to the present invention, preferably,
The client
A storage means for storing a disk decryption key;
When the determination unit determines that the authentication information is correct, the processing is continued and the transmission unit of the client transmits the disk decryption key to the server,
The server is
Virtual disk generation means for generating the virtual disk by decrypting the encrypted virtual disk with the disk decryption key;
Determining whether or not the virtual disk is correct, and further comprising a determining means for interrupting the processing if the virtual disk is incorrect;
More preferably,
When the determination unit of the server determines that the virtual disk is correct, the processing is continued and the authentication information generation factor, the authentication information, and the disk decryption key are deleted from the server.

In the online storage method according to the present invention, preferably,
In the first determination step, when it is determined that the authentication information is correct, the process continues and a third transmission step of transmitting the disk decryption key stored in the client to the server;
A virtual disk generation step of generating the virtual disk by decrypting the encrypted virtual disk with the disk decryption key;
A second determination step of determining whether or not the virtual disk is correct and suspending the processing if the virtual disk is incorrect;
More preferably,
6. The process according to claim 5, wherein when the virtual disk is determined to be correct in the second determination step, the process is continued and the authentication information generation factor, authentication information, and disk decryption key are deleted from the server. Online storage methods.

Embodiments of an online storage system and method according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an online storage system according to the present invention. In FIG. 1, the online storage system includes a server 1, a client 2, and a network 3 that connects the server 1 and the client 2 so that they can communicate with each other.

  The server 1 includes a communication unit 13, a RAM 15, an external storage device 17, a virtual disk encryption processing unit 101, a virtual disk encryption key generation unit 102, an encryption communication processing unit 103, an authentication information generation unit 141, a control Unit 190 and iSCSI target 1000.

The communication unit 13 can be connected to a communication device (for example, a communication cable) that can communicate with the outside of the server 1. The external storage device 17 is a hard disk, the program needed to prove that the holding virtual encrypted disk s _i is a certification target, data and the like necessary in the process of this program is stored . Data obtained by the program processing is stored in the RAM 15 and the external storage device 17. An example of the authentication table stored in the RAM 15 is shown in FIG.

In the present embodiment, it is assumed that the virtual encryption disk s _i consists of a bit string. When the server 1 is realized by a computer, all information (for example, information in a text format that can be understood by humans) is stored in the external storage device 17 as a bit string expressed in binary.

  In the server 1, each program stored in the external storage device 17 and data necessary for the processing of each program are read into the RAM 15 as necessary and processed by a CPU (not shown), and the virtual disk encryption processing unit 101, virtual disk An encryption key generation unit 102, an encryption communication processing unit 103, an authentication information generation unit 141, and a control unit 190 are realized.

  The iSCSI target 1000 is software or hardware for providing a server function in iSCSI, which is a protocol for using storage on an IP network.

  The client 2 includes a communication unit 23, a RAM 25, an external storage device 27, a virtual disk encryption processing unit 201, a virtual disk encryption key generation unit 202, a virtual communication unit 203, a verification information generation unit 241, and a random number generation. Unit 242, authentication information generation factor generation unit 243, determination unit 244, control unit 290, virtual terminal 2000, and iSCSI initiator 2200.

  The communication unit 23, RAM 25, and external storage device 27 have the same configuration as the communication unit 13, RAM 15, and external storage device 17, respectively. In the client 2, each program stored in the external storage device 27 and data necessary for the processing of each program are read into the RAM 25 as necessary and processed by a CPU (not shown), and the virtual disk encryption processing unit 201, virtual disk An encryption key generation unit 202, a virtual communication unit 203, a verification information generation unit 241, a random number generation unit 242, an authentication information generation factor generation unit 243, a determination unit 244, and a control unit 290 are realized.

  The virtual terminal 2000 is software that artificially creates PC hardware that operates on the PC as the client 2, and is specifically realized by VMware (Vmware), Virtual PC (Microsoft), or the like. . The iSCSI initiator 2200 is software or hardware that provides a client function in iSCSI.

  FIG. 3 is a diagram showing the operation of the online storage system according to the present invention. In this case, the iSCSI target 1000 and the iSCSI initiator 2200 are realized by software, and the virtual terminal 2000 can use the storage device connected to the iSCSI target 1000 via the network 3 by controlling the iSCSI initiator 2200. . Further, it is assumed that the update to the virtual disk h occurring during the operation is reflected by updating the virtual disk h as needed.

  The operation of the online storage system according to the present invention will be described in more detail with reference to FIGS. FIG. 4 is a flowchart of pre-processing in the online storage system according to the present invention. The server 1 generates a user identifier u indicating the user of the virtual terminal 2000 and a user password p corresponding to the user identifier u (step S101).

  Next, the client 2 acquires the user identifier u and the user password p using a secure means such as a portable medium, and stores it in the external storage device 27 (step S102). The user identifier u and the user password p are concealed from the outside from the viewpoint of safety.

  As a common parameter in the online storage system, a sufficiently large number N and a number g less than N are stored in advance in the external storage devices 17 and 27 (steps S103 and S104). N is preferably a number that is difficult or unknown from a safety standpoint. The preset natural number ν is stored in the external storage device 27 (step S105).

The external storage device 17, a virtual disk _{h 0} is stored to the virtual terminal 2000 is utilized (step S106). The control unit 190 controls the virtual disk 102 and generates a disk encryption key k ₀ for encrypting the virtual disk h ₀ (step S107). Next, the control unit 190 controls the virtual disk encryption processing unit 101, a virtual disk _{h 0} with disk encryption key _{k 0} is encrypted to generate an encrypted virtual disk _{s 0} (step S108).

Next, the server 1 generates virtual disk verification information C (s ₀ ) from the encrypted virtual disk s ₀ using the following formula (1) (step S109). Note that the encryption virtual disk s ₀ is identified with a binary number notation of a natural number.
C (s ₀ ) = g ^s0 modN (1)

Control unit 190 registers the user identifier u indicating a user of the virtual disk _{h 0,} a set of user password p, and encryption virtual disk _{s 0} corresponding to the user identifier u in the authentication table of the RAM 15 (step S110). The virtual disk verification information C (s ₀ ) is moved from the server 1 to the client 2 using means such as portable media or a network (steps S111 and S112). Control unit 190 deletes the virtual disk _{h 0} from RAM15, and an external storage device 17 (step S113).

  FIG. 5 is a flowchart of connection processing in the online storage system according to the present invention. This routine starts the virtual terminal 2000 from a disk image managed on the server 1 side. After establishing a VPN that allows secure communication between the server 1 and the client 2, the server 1 encrypts the virtual terminal 2000. The virtual disk held in the state is verified. When the virtual disk is correctly verified, the virtual disk is decrypted, and the client 2 uses it. Here, a series of processes from establishment of the VNP connection, activation and termination of the virtual terminal 2000, and disconnection of the VNP connection are referred to as a session.

  First, the client 2 makes a session start request to the server 1 (steps S201 and S202). The control units 190 and 290 perform client user authentication using the user identifier u and the user password p. Specifically, an authentication method such as MS-CHAPv2 is used. If the user authentication is not completed correctly, it is determined that the user is an unauthorized user, the session start request is rejected, and the process is terminated. If the user authentication is completed correctly, it is determined that the user is a legitimate user and the process is continued. The cryptographic communication processing units 103 and 203 establish a VPN connection. Specifically, a key exchange protocol such as IKE is used, and an encryption communication key is supplied by both the server 1 and the client 2 (steps S203 and S204).

  The control unit 290 controls the random number generation unit 242 to generate a random number r (step S205), controls the authentication information generation factor generation unit 243, and determines the authentication information generation factor R based on g, N, and r. It generates (step S206) and controls the communication unit 23 to transmit the authentication information generation factor R to the server 1 (step S207).

The control unit 190 controls the communication unit 13 to receive the authentication information generation factor R from the client 2 (step S208), controls the authentication information generation unit 141, and sets the user identifier u authenticated in step S204 to the authentication table. The authentication information R (s _i ) is generated from the encrypted virtual disk s _i registered in combination with the user identifier u and the received authentication information generation factor R (step S209), and the communication unit 13 is controlled. Then, the authentication information R (s _i ) is transmitted to the client 2 (step S210).

The control unit 290 controls the communication unit 23 to receive the authentication information R (s _i ) from the server 1 (step S211), and controls the determination unit 244 to store the virtual disk verification information C (s _i ) in the RAM 25. And whether the received authentication information R (s _i ) is correct is verified based on whether the following equation (2) is satisfied (step S212).
R (s _i ) = C (s _i ) ^r mod N (2)

If the verification result is not correct, it is determined that there is a suspicion that the cryptographic virtual disk s _i held by the server 1 has been improperly processed since the end of the previous session, and the session start request is canceled. The process ends (step S213). Note that the virtual disk h needs to be re-registered in order to be able to start the session again. Specifically, the encryption virtual disk s _i decoded by the disk decryption key k _i, after generating the virtual disk h _i, after the contents of the virtual disk h _i is confirmed whether it is safe, virtual disk h the _i it is necessary to perform the processing as a virtual disk h ₀ of the above-mentioned pre-processing.

If the result of the verification is correct, the encryption virtual disk s _i the server 1's to continue processing as a safe state. The control unit 290 reads the disk decryption key k _i corresponding to the encrypted virtual disk s _i held by the server 1 from the external storage device 27 (step S214), controls the communication unit 23, and transmits it to the server 1 (step S215). ).

The control unit 190 controls the communication unit 13 and receives the disk decryption key k _i from the client 2 (step S216). Virtual disk encryption processing unit 101, an encryption virtual disk _{s i} decoded by the disk decryption key _{k i,} to generate a virtual disk _{h i} (step S217). At this time, the encrypted virtual disk s _i is not deleted but held in the external storage device 17. As a result of this process, it is determined whether or not the virtual disk h _i has been correctly generated (step S218). If the virtual disk h _i has not been correctly processed, the control unit 190 stops the session start request process and performs the process. The process ends (step S219). If the decryption process is completed normally, the process is continued.

The server 1 deletes the authentication information generation factor R, the authentication information R (s _i ), and the disk decryption key k _i that are unnecessary in the subsequent processing from the RAM 15 and the external storage device 17 (step S222). Similarly, the client 2 also deletes the authentication information generation factor R, the authentication information R (s _i ), and the disk decryption key k _i that are unnecessary in the following processing from the RAM 25 and the external storage device 27 (step S223).

Control unit 190 activates the iSCSI target 1000 and makes it available a virtual disk _{h i} from the outside (step S224). Similarly, the control unit 290 activates the virtual machine 2000 and the iSCSI initiator 2200 (step S225).

Thereafter, the iSCSI initiator 2200 and the iSCSI target 1000 perform connection and communication based on the iSCSI protocol. Virtual machine 2000 via the iSCSI initiator 2200 and iSCSI target 1000 is utilized as a disk that is connected to the virtual disk _{h i} to the virtual machine 2000.

  FIG. 6 is a flowchart of disconnection processing in the online storage system according to the present invention. In this routine, the client 1 terminates the use of the virtual terminal 203, updates the authentication information, and disconnects the VPN. First, the client 2 terminates the use of the virtual terminal 200 and stops it (step) S401).

When the virtual terminal 2000 is stopped, the update content to the virtual disk h _i generated during the operation of the virtual terminal 2000 is determined, and the updated virtual disk is set to h _{i + 1} (step S402). When detecting the stop of the virtual terminal 2000, the control unit 290 controls the communication unit 23 to transmit a session end request to the client (step S403).

  The control unit 190 receives this session termination request via the communication unit 13 (step S404), and then the iSCSI target 1000 and the iSCSI initiator 2200 perform disconnection processing based on the iSCSI protocol (steps S405 and S406). .

The control unit 290 controls the virtual disk encryption key generation unit 202 to generate a disk encryption key k _{i + 1} for encrypting the virtual disk h _{i + 1} (step S407), and controls the communication unit 23 to control the disk encryption. The key k _{i + 1} is transmitted to the server 1 (step S408).

The control unit 190 controls the communication unit 13 to receive the disk encryption key k _{i + 1} from the client 2 (step S409). Control unit 190 controls the virtual disk encryption processing unit 101 encrypts the virtual disk _{h i + 1} by using the disk encryption key _{k i + 1,} to generate the encryption virtual disk _{s i + 1} (step S410).

Next, the server 1 generates virtual disk verification information C (s _{i + 1} ) from the encrypted virtual disk s _{i + 1} using the following equation (3) (step S411).
C (s _{i + 1} ) = g ^{si + 1} modN (3)

The control unit 190 controls the communication unit 13 and transmits the virtual disk verification information C (s _{i + 1} ) to the client 2 (step S412). The control unit 290 controls the communication unit 23 and receives the virtual disk verification information C (s _{i + 1} ) from the server 1 (step S413). The control unit 290 updates the virtual disk verification information and the contents of the disk encryption key to C (s _{i + 1} ) and k _{i + 1} , respectively (step S414), and transmits success or failure of the update to the server 1 (step S415).

If the update is successful, it is determined that the session is successfully completed, remove the encryption virtual disk s _i before starting the session from RAM15, and the external storage unit 17, is registered in the user identifier u and set in the authentication table cryptographic information virtual disks _{s i} and is updated to the encryption virtual disk _{s i + 1} (step S418).

If the update fails, it is determined that the session has ended abnormally, the session is invalidated, and the encrypted virtual disk s _{i + 1} is deleted from the RAM 15 and the external storage device 17 in order to roll back to the state before starting the session. (Step S419).

In order to prevent the virtual disk h _{i + 1} from being used illegally until the next session is started, the control unit 190 controls the virtual disk h _{i + 1} , the disk encryption key k _{i + 1,} and the virtual disk verification information C (s _{i + 1} ) is deleted from the RAM 15 and the external storage device 17 (steps S420 and S421).

  At the end of the disconnection process, the cryptographic communication processing units 103 and 203 disconnect the VPN connection. Specifically, the encryption communication key used on both sides is discarded and the communication connection is released (steps S422 and S423).

The present invention is not limited to the above-described embodiment, and many changes and modifications can be made.
For example, as a virtual disk encryption method, not only a common key encryption method in which the encryption key and the decryption key are the same, but also a public key encryption method in which the encryption key and the decryption key are different can be used.

  Regarding user authentication during connection processing, not only an authentication method using a user identifier and a password but also another authentication method for specifying a client user, such as a method using an electronic certificate, can be applied. With respect to the verification target data, the encryption and decryption processing can be omitted and the verification processing can be performed in plain text.

  Regarding the booting method of the virtual terminal, not only the booting method using the iSCSI protocol but also other booting methods for acquiring data necessary for starting the computer via the network, such as a method using the PXE (Preboot execution Environment). be able to.

  As the configuration described in the above embodiment in which the virtual terminal software uses a virtual disk, for example, in an online storage system including a server 1 ′ and a client 2 ′ as shown in FIG. The iSCSI initiator 2200 can be replaced with the Ajax engine 2300, the iSCSI target 1000 can be replaced with the Web server and the server application 1100, and the virtual disk can be replaced with the user disk.

  More specifically, an example in which the Ajax engine 2300 is software including a mail browsing interface, a server application operating on a Web server is a mail management server, and user data is mail data. Further, the Ajax engine 2300 does not need to be installed in the client 2 'in advance, and may be dynamically downloaded software.

It is a figure which shows the online storage system by this invention. An example of the authentication table stored in the RAM 15 is shown in FIG. It is a figure showing operation | movement of the online storage system by this invention. It is a flowchart of the pre-processing in the online storage system by this invention. It is a flowchart of the connection process in the online storage system by this invention. It is a flowchart of the cutting process in the online storage system by this invention. It is a figure showing the modification of operation | movement of the online storage system by this invention.

Explanation of symbols

1, 1 'server 2, 2' client 3 network 13, 23 communication unit 15, 25 RAM
17, 27 External storage device 101, 201 Virtual disk encryption processing unit 102, 202 Virtual disk encryption key generation unit 103 Encryption communication processing unit 141 Authentication information generation unit 190, 290 Control unit 203 Virtual communication unit 241 Verification information generation unit 242 Random number generation Unit 243 authentication information generation factor generation unit 244 determination unit 1000 iSCSI target 1100 Web server and server application 2000 virtual terminal 2100 Web browser 2200 iSCSI initiator 2300 Ajax engine

Claims (6)

A server, a client, and a network that connects the server and the client so that they can communicate with each other;
The server is
Receiving means for receiving an authentication information generation factor from the client;
Storage means for storing a cryptographic virtual disk in combination with a user identifier;
Authentication information generating means for generating authentication information from the authentication information generating factor and the encrypted virtual disk;
Transmitting means for transmitting the authentication information to the client;
The client
Authentication information generating factor generating means for generating the authentication information generating factor;
Transmitting means for transmitting the authentication information generation factor to the server;
Receiving means for receiving the authentication information;
An online storage system comprising: determining means for determining whether or not the authentication information is correct and interrupting the processing if the authentication information is incorrect. The client
A storage means for storing a disk decryption key;
When the determination unit determines that the authentication information is correct, the processing is continued and the transmission unit of the client transmits the disk decryption key to the server,
The server is
Virtual disk generation means for generating the virtual disk by decrypting the encrypted virtual disk with the disk decryption key;
The online storage system according to claim 1, further comprising: a determination unit that determines whether or not the virtual disk is correct and interrupts processing when the virtual disk is incorrect.   3. The server according to claim 2, wherein when the determination unit of the server determines that the virtual disk is correct, the processing is continued and the authentication information generation factor, the authentication information, and the disk decryption key are deleted from the server. Online storage system. An online storage method through a network for connecting a server and a client so that they can communicate with each other,
An authentication information generation factor generating step for generating an authentication information generation factor on the client side;
A first transmission step of transmitting the authentication information generation factor to the server;
A first receiving step of receiving the authentication information generating factor on the server side;
An authentication information generating step for generating authentication information based on a cryptographic virtual disk stored on the server side in combination with a user identifier and the authentication information generation factor;
A second transmission step of transmitting the authentication information to the client;
A second receiving step of receiving the authentication information on the client side;
A first determination step of determining whether or not the authentication information is correct and suspending the processing if the authentication information is not correct. In the first determination step, when it is determined that the authentication information is correct, the process continues and a third transmission step of transmitting the disk decryption key stored in the client to the server;
A virtual disk generation step of generating the virtual disk by decrypting the encrypted virtual disk with the disk decryption key;
5. The online storage method according to claim 4, further comprising a second determination step of determining whether or not the virtual disk is correct and suspending the processing if the virtual disk is incorrect.   6. The process according to claim 5, wherein if the virtual disk is determined to be correct in the second determination step, the process is continued and the authentication information generation factor, authentication information, and disk decryption key are deleted from the server. Online storage methods.

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