Method and system for recovering the validity of cryptographically signed digital data

• US 20060059357A1
• Filed: 08/08/2005
• Published: 03/16/2006
• Est. Priority Date: 10/22/1999
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yoshiura, Hiroshi, Miyazaki, Kunihiko, Matsuki, Takeshi, Takaragi, Kazuo, Toyoshima, Hisashi, Susaki, Seiichi, Sasaki, Ryoichi
• Granted Patent: US 7,694,126 B2
• Time in Patent Office: Days
• US Class Current: 713/178
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/645 using a third party
• CPC Class Codes: G06F 2221/2101 Auditing as a secondary aspect
• CPC Class Codes: G06Q 20/3825 Use of electronic signatures
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/3252 using DSA or related signature schemes, e.g. elliptic based signatures, ElGamal or Schnorr schemes
• CPC Class Codes: H04L 9/50 using hash chains, e.g. blockchains or hash trees

Abstract

According to the present invention, techniques, including a method and system, for restoring and/or validating data and/or associated signature log entries are provided. One embodiment of the present invention provides a method for validating a restored message, having an entry generated in a signature log for a message, where the entry includes cryptographic information associated with the message. Next, when said message is lost, the restored message is generated responsive to a request; and the restored message is validated using the signature log. In another embodiment a method for validating a selected log entry by using a signature log having a plurality of recorded log entries is provided. The method includes: computing a cryptographic value for the selected log entry; and determining if the cryptographic value is part of another recorded log entry.

Claims

1. A method for validating a restored message, comprising:

generating an entry in a signature log for a message, wherein said entry comprises cryptographic information associated with said message;

when said message is lost, generating said restored message responsive to a request; and

validating said restored message using said signature log.