AUTHENTICITY ASSURANCE SYSTEM FOR SPREADSHEET DATA

• US 20080294903A1
• Filed: 04/18/2008
• Published: 11/27/2008
• Est. Priority Date: 05/23/2007
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: MIYAZAKI, Kunihiko, HATANO, Yasuo
• Application Number:
  US12/105,436
• Publication Number:
  US 20080294903A1
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 40/18 of spreadsheets form-filling G06F40/174

Abstract

A method is provided for applying a redactable signature method capable of verification even after deletion (blacking-out) of a part of a signed electronic document to spreadsheet data.

By giving an ID for a redactable signature to a cell to be processed in the processed data by a spreadsheet program, which part in the file corresponds to the cell to be processed can be easily determined when the data is outputted as a file.

Claims

1. An authenticity assurance system for spreadsheet data, comprising a signed spreadsheet data creator device, wherein

the spreadsheet data has at least one cell element data item corresponding to a cell, as component element, and

the signed spreadsheet data creator device comprises:

a spreadsheet unit which manages the spreadsheet data by the cell element data item;

a unit which generates a random number for the at least one cell element data item corresponding to at least one cell that is a target of authenticity assurance, in the cell constituting the spreadsheet data;

a unit which combines the cell element data item with the corresponding generated random number and calculates a hash value for the combined data; and

a redactable signature generating unit which calculates a signature value for at least one hash value combination; and

wherein

the spreadsheet unit comprises a unit which generates signed spreadsheet data by giving a redactable signature ID to the cell element data item corresponding to the at least one cell that is the target of authenticity assurance.

2. The authenticity assurance system for spreadsheet data according to claim 1, wherein

in the signed spreadsheet data creator device,

the spreadsheet unit comprises a unit which specifies, as the target for authenticity assurance, a cell for which an instruction is received from a user through an input device.

3. The authenticity assurance system for spreadsheet data according to claim 2, wherein

in the signed spreadsheet data creator device,

the spreadsheet unit comprises a unit which changes background color of the cell that is the target for authenticity assurance, for which the instruction from the user is received.

4. The authenticity assurance system for spreadsheet data according to claim 1, wherein

in the signed spreadsheet data creator device,

the spreadsheet unit comprises a unit which adds the generated signature value and the random number to the signed spreadsheet data.

5. The authenticity assurance system for spreadsheet data according to claim 1, further comprising a disclosed spreadsheet data creator device comprising:

a spreadsheet unit which manages the signed spreadsheet data by the cell element data item; and

a redaction processing unit which deletes the random number corresponding to the cell element data that is the target of the redaction processing, from the signed spreadsheet data;

wherein

the spreadsheet unit comprises;

a unit which receives specification of a cell that is the target of the redaction processing, identifying an ID for the redactable signature given to the specified cell, and transmitting the ID to the redaction processing unit; and

a unit which produces a disclosed document in which the cell element data item that is the target of the redaction processing is deleted or replaced by one of a character, symbol, figure and multimedia data, with which deletion is recognizable; and

the redaction processing unit identifies the cell element data that is the target of the redaction processing, based on the ID for the redactable signature.

6. The authenticity assurance system for spreadsheet data according to claim 5, wherein

the spreadsheet unit comprises a unit which specifies the cell specified by the user as the target for the redaction processing, through an input device that the disclosed spreadsheet data creator device comprises.