Digital document management system, digital document management method, and digital document management program

Abstract

Disclosed is a digital document management program capable of achieving a third-party certification of document information with reduced amount of meta data. At the registration time of new document information, the digital document management program manages a digital signature created in association with document information. At the correction time of the document information, the program acquires partial identification information related to a corrected part of the document information before correction, creates a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information in association with the corrected document information. At the verification time, the program uses partial identification information, the partial identification information corresponding to a corrected part of the document information before correction, and digital signature to perform verification.

1 . A digital document management program that allows a computer to manage document information created and registered in a digital form, the program allowing the computer to execute: 
 a partial identification information generation step that divides the document information into a plurality of parts and generates partial identification information that represents, in an identifiable manner, the respective parts of the document information based on information included in the respective parts;    a digital signature creation step that creates a digital signature to be appended to the document information using the partial identification information;    a management step that manages the document information; and    a verification step that verifies the validity of the managed document information, wherein    at the registration time of new document information, the management step manages a digital signature created by the digital signature creation step in association with the document information and, at the correction time of the document information, it acquires partial identification information related to a corrected part of the document information before correction, allows the digital signature creation step to create a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information before correction in association with the corrected document information, and    the verification step uses the partial identification information and digital signature managed in association with the corrected document information by the management step and partial identification information newly created from the corrected document information by the partial identification information generation step to perform the verification.    
   
   
       2 . The digital document management program according to  claim 1 , wherein 
 the digital signature creation step uses a set of partial identification information created by the partial identification information generation step and a private key as parameters to create a digital signature according to a signature function.    
   
   
       3 . The digital document management program according to  claim 1 , wherein 
 the digital signature creation step uses an Aggregate signature function which is a kind of a group signature scheme and which is capable of aggregating a plurality of signatures on one signature.    
   
   
       4 . The digital document management program according to  claim 1 , wherein 
 the partial identification information managed in association with the corrected document information is managed separately from the corrected document information data.    
   
   
       5 . The digital document management program according to  claim 1 , wherein 
 the partial identification information is managed by being embedded in the corrected document information.    
   
   
       6 . The digital document management program according to  claim 1 , further comprising: 
 a policy information storage step that stores previously defined policy information; and    a partial correction information generation step that generates partial correction information which is information related to a correction history of a corrected part in the case where any correction has been made for the document information, wherein    in the case where any correction has been made for a part of the document information, the management step allows the partial correction information generation step to generate partial correction information and manages the generated partial correction information and policy information stored by the policy information storage step in association with the corrected document information, and    the verification step uses the partial correction information and policy information in addition to the partial identification information and signature information managed in association with the corrected document information by the management step to verify the validity of the document information.    
   
   
       7 . The digital document management program according to  claim 1 , 
 the partial identification information generation step divides document information into a plurality of parts and uses a hash function to generate partial identification information for respective parts of the document information.    
   
   
       8 . The digital document management program according to  claim 1 , wherein 
 the information managed by the management step is constituted by XML data having a hierarchical document structure.    
   
   
       9 . The digital document management program according to  claim 1 , wherein 
 the management step handles all digital information as original document information corresponding to version numbers, and    an access to the content of the original document information managed based on its version numbers can be controlled depending on the content thereof in the respective versions in an identifiable manner.    
   
   
       10 . A digital document management system that manages document information created and registered in a digital form, comprising: 
 a partial identification information generation section that divides the document information into a plurality of parts and generates partial identification information that represents, in an identifiable manner, the respective parts of the document information based on information included in the respective parts;    a digital signature creation section that creates a digital signature to be appended to the document information using the partial identification information;    a management section that manages the document information; and    a verification section that verifies the validity of the managed document information, wherein    at the registration time of new document information, the management section manages a digital signature created by the digital signature creation section in association with the document information and, at the correction time of the document information, it acquires partial identification information related to a corrected part of the document information before correction, allows the digital signature creation section to create a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information before correction in association with the corrected document information, and    the verification section uses the partial identification information and digital signature managed in association with the corrected document information by the management section and partial identification information newly created from the corrected document information by the partial identification information generation section to perform the verification.    
   
   
       11 . The digital document management system according to  claim 10 , wherein 
 the digital signature creation section uses a set of partial identification information created by the partial identification information generation section and a private key as parameters to create a digital signature according to a signature function.    
   
   
       12 . The digital document management system according to  claim 10 , wherein 
 the digital signature creation section uses an Aggregate signature function which is a kind of a group signature scheme and which is capable of aggregating a plurality of signatures on one signature.    
   
   
       13 . The digital document management system according to  claim 10 , wherein 
 the partial identification information managed in association with the corrected document information is managed separately from the corrected document information data.    
   
   
       14 . The digital document management system according to  claim 10 , wherein 
 the partial identification information is managed by being embedded in the corrected document information.    
   
   
       15 . The digital document management system according to  claim 10 , further comprising: 
 a policy information storage section that stores previously defined policy information; and    a partial correction information generation section that generates partial correction information which is information related to a correction history of a corrected part in the case where any correction has been made for the document information, wherein    in the case where any correction has been made for a part of the document information, the management section allows the partial correction information generation section to generate partial correction information and manages the generated partial correction information and policy information stored by the policy information storage section in association with the corrected document information, and    the verification section uses the partial correction information and policy information in addition to the partial identification information and signature information managed in association with the corrected document information by the management section to verify the validity of the document information.    
   
   
       16 . The digital document management system according to  claim 10 , 
 the partial identification information generation section divides document information into a plurality of parts and uses a hash function to generate partial identification information for respective parts of the document information.    
   
   
       17 . The digital document management system according to  claim 10 , wherein 
 the information managed by the management section is constituted by XML data having a hierarchical document structure.    
   
   
       18 . The digital document management system according to  claim 10 , wherein 
 the management section handles all digital information as original document information corresponding to version numbers, and    an access to the content of the original document information managed based on its version numbers can be controlled depending on the content thereof in the respective versions in an identifiable manner.    
   
   
       19 . A digital document management method that manages document information created and registered in a digital form by a computer, comprising: 
 a partial identification information generation step that divides the document information into a plurality of parts and generates partial identification information that represents, in an identifiable manner, the respective parts of the document information based on information included in the respective parts;    a digital signature creation step that creates a digital signature to be appended to the document information using the partial identification information;    a management step that manages the document information; and    a verification step that verifies the validity of the managed document information, wherein    at the registration time of new document information, the management step manages a digital signature created by the digital signature creation step in association with the document information and, at the correction time of the document information, it acquires partial identification information related to a corrected part of the document information before correction, allows the digital signature creation section to create a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information before correction in association with the corrected document information, and    the verification step uses the partial identification information and digital signature managed in association with the corrected document information by the management step and partial identification information newly created from the corrected document information by the partial identification information generation step to perform the verification.    
   
   
       20 . The digital document management method according to  claim 19 , wherein 
 the digital signature creation step uses a set of partial identification information created by the partial identification information generation step and a private key to create a digital signature according to an Aggregate signature function which is a kind of a group signature scheme and which is capable of aggregating a plurality of signatures on one signature.