Digital signing method

• US 20080098232A1
• Filed: 12/04/2007
• Published: 04/24/2008
• Est. Priority Date: 10/22/1999
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sakai, Mizuhiro, Matsumoto, Tsutomu, Miyazaki, Kunihiko, Takaragi, Kazuo, Susaki, Seiichi, Sasaki, Ryoichi, Moritsu, Toshiyuki, Iwamura, Mitsuru
• Granted Patent: US 7,770,009 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps

Abstract

According to the invention, techniques for authenticating that a digitally signed document is genuine. Specific embodiments according to the present invention can determine whether a digital signature was generated by a digital signature generator, or if the digital signature was generated by a third party posing as the digital signature generator. Specific embodiments can provide independent verification of digital signer identity based upon prior signed messages, time/date stamps, and the like. Techniques according to the present invention can be embodied in methods, apparatus, computer software and systems.

Claims

1. A digital signing method, comprising:

applying a secret key to a message to generate a digital signature for the message;

distributing a digital-signature-attached message including the generated digital signature and the message;

registering the digital-signature-attached message as log data with a log list; and

providing said log list responsive to a request.