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Electronic document processing system and method of forming digital signature

  • US 5,465,299 A
  • Filed: 11/29/1993
  • Issued: 11/07/1995
  • Est. Priority Date: 12/03/1992
  • Status: Expired due to Fees
First Claim
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1. A method of forming a digital signature to be added to an electronic document, comprising the steps of:

  • generating a former version electronic document;

    performing a hash total process to said former version electronic document to generate a former version hash total;

    performing an encipher process with at least said former version hash total and personal information of a signatory to generate a first digital signature;

    adding the first digital signature to the former version electronic document;

    changing the former version electronic document of a former version to which at least said first digital signature has already been added to generate a new version electronic document;

    creating version management information which describes the change between the former version and new version electronic documents;

    performing a hash total process to said new version electronic document to generate a new version hash total;

    performing an encipher process with at least said new version hash total, personal information of another signatory, and said version management information to generate a new digital signature; and

    altering at least a part of said first digital signature to correspond to said new version electronic document.

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