Generating and verifying trusted digital time stamp

• US 7,890,765 B2
• Filed: 05/20/2008
• Issued: 02/15/2011
• Est. Priority Date: 01/13/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Zhang, Jian, Xie, Dong, Shao, Ling
• Primary Examiner(s): Zand; Kambiz
• Assistant Examiner(s): Powers; William S
• Application Number:
  US12/123,892
• Publication Number:
  US 20080288779A1
• Time in Patent Office: 1,001 Days
• Field of Search: 713/178
• US Class Current: 713/178
• CPC Class Codes: G06F 21/645 using a third party
• CPC Class Codes: G06F 21/725 operating on a secure reference time value
• CPC Class Codes: G06F 2221/2151 Time stamp
• 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

Abstract

Methods, apparatus and systems for generating a trusted digital time stamp as well as a public time source. It includes, an apparatus for receiving and recording public time information and a method for verifying a digital time stamp. A method for generating a trusted digital time stamp includes: obtaining a first time information and a corresponding random code from a public time source; and generating a digital time stamp using a first time information and random code. A method for verifying a digital time stamp includes: recording time information and corresponding random codes transmitted by a public time source; retrieving time information and a random code contained in the time stamp; and comparing a retrieved random code from the time stamp with one of the recorded random codes that corresponds to a time information in the time stamp, if they are consistent, the time stamp is determined to be trusted, otherwise the time stamp is determined to be not trusted.

Claims

1. A method for verifying a digital time stamp, comprising:

recording time information and corresponding random codes transmitted by a public time source;

retrieving time information and a random code contained in the time stamp; and

comparing said retrieved random code from the time stamp with one of the recorded random codes that corresponds to said time information in the time stamp, if they are consistent, the time stamp is determined to be trusted, otherwise the time stamp is determined to be not trusted.

2. The method for verifying a digital time stamp according to claim 1,

wherein said time stamp further includes a local digital signature;

said method further comprises;

checking whether the local digital signature of the time stamp is legal or not, and determining that the time stamp is not trusted if the local digital signature of said time stamp is not legal.

3. The method for verifying a digital time stamp according to claim 1, wherein said time stamp further includes a time stamp server'"'"'s digital signature;

said method further comprises;

checking whether said time stamp server'"'"'s digital signature is legal or not, and determining that the time stamp is not trusted if said time stamp server'"'"'s digital signature is not legal.

4. An article of manufacture comprising a non-transitory computer usable medium having computer readable program code embodied therein for causing verification of a digital time stamp, the computer readable program code in said article of manufacture comprising computer readable program code causing a computer to effect the steps of claim 1.