File storage system and a NAS server

• US 20030187885A1
• Filed: 05/30/2002
• Published: 10/02/2003
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Itoh, Shinji, Miyazaki, Kunihiko, Bessho, Yoshiharu, Omoto, Narihiro
• Granted Patent: US 7,206,939 B2
• Time in Patent Office: Days
• US Class Current: 707/203
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

A reliably safe storage system is provided which makes provable the status of a file stored in a storage server at a time specified by a user and creates evidence information that will be effective in future. In response to a file status fixing request from the user over a network, a storage server generates file fixing guarantee data, including data publicized by a publication server, and saves the generated data with the file associated with the generated data.

Claims

1. A file storage system comprising at least one user'"'"'s computer and a storage server connected to said user'"'"'s computer over a network for storing files,

said storage server comprising:

means for generating file fixing guarantee data in response to a file status fixing request from said user'"'"'s computer, said file fixing guarantee data proving a status of the file at the time of the fixing request to a third party; and

means for storing the file fixing guarantee data so as to associate with said file.

2. The file storage system according to claim 1,

further comprising a publication server which publicizes digital data as validity-guaranteed data,

wherein the file fixing guarantee data generated by said storage server includes the validity-guaranteed data publicized by said publication server.

3. The file storage system according to claim 2, wherein

said file fixing guarantee data includes information on a file specified by the status fixing request and the information on the file has a logical relation the validity-guaranteed data, said logical relation being identifiable by a third party.

4. The file storage system according to claim 3, wherein the logical relation identifiable by a third party is formed by at least one of a hash function and a digital signature.

5. The file storage system according to claim 3, further comprising a condense server connected to said publication server and to said at least one storage server, wherein said condense server receives guarantee request data from said at least one storage servers, generates the validity-guaranteed data to be publicized on said publication server based on the guarantee request data and sends the generated validity-guaranteed data to said publication server and sends to said one least one storage server, a data required for a third party to identify a logical relation between the guarantee request data sent from said storage server and the validity-guaranteed data.

6. The file storage system according to claim 5, wherein the logical relation between the guarantee request data and the validity-guaranteed data is formed by at least one of a hash function and a digital signature.

7. A file storage system comprising at least one user'"'"'s computer and a storage server connected to said user'"'"'s computer over a network for storing files,

said storage server comprising:

first means for generating and storing each of the files with alteration preventing information attached, the alteration preventing information being generated based on the file stored previously to form a chain of generations of the file; and

a second means for publicizing a latest generation of the file at a specified time.

8. The file storage system according to claim 7, wherein

said first means adds a hysteresis signature to the file stored previously to generate the alteration preventing information.

9. The file storage system according to claim 7, further comprising a publication server connected to a plurality of said storage servers over the network wherein said publication server, in response to the publication by the storage server, receives the latest file from the storage server for publication.

10. A file storage system comprising at least one user'"'"'s computer, at least one a storage server connected to said user'"'"'s computer over a network for storing files, a condense server connected to said storage server over the network for proving a validity of files stored in each storage server, and a publication server connected to said condense server over the network for publicizing data,

said storage server comprising:

means for generating and storing each of the files with alteration preventing information attached, the alteration preventing information being generated based on the file stored previously to form a chain of generations of the file; and

means for adding a signature to the file, to which the alteration preventing information has been attached, using a private key in response to a file status fixing request from said user'"'"'s computer and then sending the file to said condense server as guarantee request data, and

said condense server comprising;

means for adding a hysteresis signature to the guarantee request data received from the storage server and storing the data as guarantee data;

means for generating validity-guaranteed data in a predetermined timing and sending the data to said publication server, said validity-guaranteed data having the hysteresis signature assigned, said hysteresis signature being generated from latest guarantee data; and

means for sending a sequence of data to said storage server, from which the guarantee request data has been sent, as file fixing guarantee data, said sequence of data being composed of data from the guarantee data generated based on the guarantee request data to said validity-guaranteed data.

11. The file storage system according to claim 10, wherein

said storage server sends the file fixing guarantee data, which is sent from said condense server, to said user'"'"'s computer, which includes means for storing the data, to verify the file on the user'"'"'s computer 102 based on the file fixing guarantee data.

12. A NAS server connected to at least one user'"'"'s computer over a network for storing files, wherein said NAS server is configured by the storage server in the file storage system according to claim 10.

13. A file storage method in a storage server connected to at least one client computer over a network and including a storage, said method comprising the steps, by said storage server, of:

generating file fixing guarantee data for proving to a third party a status of the file at the file fixing request time in response to a file status fixing request from said client computer; and

storing the generated file fixing guarantee data in said storage, said file fixing guarantee data being correlated with the file.

14. A computer-executable program that executes, using a computer, a file storage method in a storage server connected to at least one client computer over a network and including a storage, said method comprising the steps, by said storage server, of:

in response to a file status fixing request from said client computer, generating file fixing guarantee data for proving to a third party a status of the file at the time of the file fixing request; and

storing the generated file fixing guarantee data in said storage, said file fixing guarantee data being correlated with the file.