Document management system, document processing computer, signature generating computer, storage medium storing program for document management, and document management method

• US 20070050626A1
• Filed: 02/09/2006
• Published: 03/01/2007
• Est. Priority Date: 08/25/2005
• Status: Abandoned Application

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Kakehi, Rumiko, Tokie, Katsuji
• Application Number:
  US11/350,617
• Publication Number:
  US 20070050626A1
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 21/645 using a third party
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A document management system for generating a digest of document data and generating signature data to be attached to the document data includes a document data storage part that stores document data, a document digest generating part that generates a digest of the document data, a thumbnail data generating part that generates thumbnail data of the document data, a signature value generating part that encrypts the document digest to generate a signature value, and a signature data generating part that generates signature data based on the thumbnail data and the signature value.

Claims

1. A document management system for generating a digest of document data and generating signature data to be attached to the document data, the document management system comprising:

a document data storage part that stores document data,

a document digest generating part that generates a digest of the document data,

a thumbnail data generating part that generates thumbnail data of the document data,

a signature value generating part that encrypts the document digest to generate a signature value, and

a signature data generating part that generates signature data based on the thumbnail data and the signature value.

16. The document management system according to claim 1, wherein

the signature data generating part generates the signature data by encrypting the thumbnail data and the signature value.

2. A document processing computer applied to a document management system for generating a digest of document data on a document processing computer, and generating signature data to be attached to the document data using a digital signature on a signature generating computer, comprising:

a document data storage part that stores document data;

a document digest generating part that generates a digest of the document data;

a thumbnail data generating part that generates thumbnail data of the document data;

a transmission part that transmits the thumbnail data and the document digest to the signature generating computer; and

a reception part that receives signature data that is generated based on the thumbnail data and the signature value.

3. A signature generating computer, applied to a document management system for generating a digest of document data on a document processing computer, and generating signature data to be attached to the document data using a digital signature on a signature data generating computer, comprising:

a reception part that receives thumbnail data and a document digest that have been transmitted from the document processing computer;

a signature value generating part that encrypts the document digest to generate a signature value;

a signature data generating part that generates signature data based on the thumbnail data and the signature value; and

a transmission part that transmits the signature data to the document processing computer.

17. The signature generating computer according to claim 3, wherein

the signature data generating part generates the signature data by encrypting the thumbnail data and the signature value.

4. A document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, comprising:

a document data storage part that stores document data;

a first document digest generating part that generates a first digest of the document data stored in the document data storage part;

a thumbnail data generating part that generates thumbnail data of the document data;

a signature value generating part that encrypts the first digest to generate a signature value;

a signature data generating part that generates signature data based on the thumbnail data and the signature value;

a registration part that registers the signature data in correspondence with the document data;

a document digest decoding part that decodes the signature value to get the first digest;

a second document digest generating part that generates a second digest of the registered document data that corresponds to the signature data; and

a document verification part that verifies the signature data based on the decoded first digest and the second digest.

5. A document processing computer applied to a document management system for generating a digest of document data on a document processing computer, and generating signature data to be attached to the document data using a digital signature on a signature generating computer, comprising:

a document data storage part that stores document data;

a first document digest generating part that generates a first digest of the document data stored in the document data storage part;

a thumbnail data generating part that generates thumbnail data of the document data;

a transmission part that transmits the thumbnail data and the first digest to the signature generating computer;

a reception part that receives signature data that is generated based on the thumbnail data and the signature value from the signature generating computer;

a document digest decoding part that decodes the signature value to get the first digest;

a second document digest generating part that generates a second digest of the registered document data that corresponds to the signature data; and

a document verification part that verifies the signature data based on the decoded first digest and the second digest.

6. A document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, comprising:

a document data storage part that stores document data;

a document digest generating part that generates a digest of the document data stored in the document data storage part;

a thumbnail data generating part that generates thumbnail data of the document data;

a display that displays the thumbnail data;

a thumbnail data regenerating part that generates another thumbnail data for which compression rate is different when regeneration of the thumbnail data is requested;

a signature value generating part that encrypts the digest of the document data to generate a signature value; and

a signature data generating part that generates signature data based on the thumbnail data and the signature value.

18. The document management system according to claim 6, wherein

the signature data generating part generates the signature data by encrypting the thumbnail data and the signature value.

7. A document processing computer applied to a document management system for generating a digest of document data on a document processing computer, and generating a signature to be attached to the document data using a digital signature on a signature generating computer, comprising:

a document data storage part that stores document data;

a document digest generating part that generates a digest of the document data stored in the document data storage part;

a thumbnail data generating part that generates thumbnail data of the document data;

a transmission part that transmits the thumbnail data and the digest to the signature generating computer;

a thumbnail data regenerating part that generates another thumbnail data for which compression rate is different when regeneration of the thumbnail data is requested;

a retransmission part that transmits the regenerated thumbnail data to the signature generating computer.

8. A signature generating computer applied to a document management system for generating a digest of document data on a document processing computer, and generating a signature to be attached to the document data using a digital signature on the signature generating computer, comprising:

a reception part that receives thumbnail data and a document digest that have been transmitted from the document processing computer;

a display that displays the thumbnail data;

a thumbnail data retransmission request part that transmits a request for retransmission of thumbnail data to the document processing computer when the request is input;

a signature value generating part that encrypts the document digest to generate a signature value; and

a signature data generating unit that generates signature data based on the thumbnail data and the signature value.

19. The signature generating computer according to claim 8, wherein

the signature data generating part generates the signature data by encrypting the thumbnail data and the signature value.

9. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function as a document processing computer which belongs to a document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, the function comprising:

storing document data;

generating a digest of the document data;

generating thumbnail data of the document data;

transmitting the thumbnail data and the document digest to the signature generating computer; and

receiving signature data that is generated based on the thumbnail data and the signature value.

10. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function as a signature generating computer which belongs to a document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, the function comprising:

receiving thumbnail data and a document digest that have been transmitted from the document processing computer;

encrypting the document digest to generate a signature value;

generating signature data based on the thumbnail data and the signature value; and

transmitting the signature data to the document processing computer.

20. The storage medium according to claim 10, wherein

the signature data is generated by encrypting the thumbnail data and the signature value.

11. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, the function comprising:

storing document data;

generating a first digest of the stored document data;

generating thumbnail data of the document data;

encrypting the first digest to generate a signature value;

generating signature data based on the thumbnail data and the signature value;

registering the signature data in correspondence with the document data;

decoding the signature value to get the first digest;

generating a second digest of the registered document data that corresponds to the signature data; and

verifying the signature data based on the decoded first digest and the second digest.

12. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function as a document processing computer which belongs to a document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, the function comprising:

storing document data;

generating a digest of the stored document data;

generating thumbnail data of the document data;

transmitting the thumbnail data and the digest to the signature generating computer, generating another thumbnail data for which compression rate is different when regeneration of the thumbnail data is requested; and

transmitting the regenerated thumbnail data to the signature generating computer.

13. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function as a signature generating computer which belongs to a document management system for generating a digest of document data and generating signature data to be attached to the document data using a digital signature, the function comprising:

receiving thumbnail data and a document digest that have been transmitted from the document processing computer;

displaying the thumbnail data;

transmitting a request for retransmission of thumbnail data to the document processing computer when the request is input;

encrypting the document digest to generate a signature value; and

generating signature data based on the thumbnail data and the signature value.

14. A document management method for managing document data, with a document management system generating a digest of document data, and generating a signature to be attached to the document data, the method comprising:

storing document data;

generating a first digest of the stored document data;

generating thumbnail data of the document data;

encrypting the first digest to generate a signature value;

generating signature data based on the thumbnail data and the signature value;

registering the signature data in correspondence with the document data;

decoding the signature value to get the first digest;

generating a second digest of the registered document data that corresponds to the signature data; and

verifying the signature data based on the decoded first digest and the second digest.

15. A document management method for managing document data, with a document management system generating a digest of document data, and the document management system generating a signature to be attached to the document data, the method comprising storing document data;

generating a digest of the document data stored in the document data storage part;

generating thumbnail data of the document data;

displaying the thumbnail data;

generating another thumbnail data for which compression rate is different when regeneration of the thumbnail data is requested;

encrypting the digest of the document data to generate a signature value; and

generating signature data based on the thumbnail data and the signature value.