Time stamp generating system

• US 7,200,682 B2
• Filed: 08/20/2002
• Issued: 04/03/2007
• Est. Priority Date: 05/08/2002
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yoshiura, Hiroshi, Miyazaki, Kunihiko, Matsuki, Takeshi, Takaragi, Kazuo, Susaki, Seiichi, Sasaki, Ryoichi, Matsumoto, Tsutomu, Iwamura, Mitsuru, Toyoshima, Hisashi
• Primary Examiner(s): SALAD, ABDULLAHI ELMI
• Application Number:
  US10/223,677
• Publication Number:
  US 20030212828A1
• Time in Patent Office: 1,687 Days
• Field of Search: 713/178, 709/248, 709/229, 370/350, 705/71
• US Class Current: 709/248
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps

Abstract

A time stamp generating system has a time distribution server for generating time data depending on time and a user PC for holding time certification objective digital data. The time distribution server generates time data corresponding to a time point and distributes the time data. The user PC calculates time stamp generating data by using the time certification objective data as an input, acquires the time data generated by the time distribution server, and processes the time data on the basis of the time stamp generating data to obtain a time stamp.

Claims

1. A time stamp generating system comprising:

a time distribution server; and

a user PC that holds time certification objective data,

wherein said time distribution server repeatedly generates time data corresponding to a time point and independent from the time certification objective data, and repeatedly distributes said time data; and

said user PC computes time stamp generating data by using said time certification objective data as an input in a predetermined manner, acquires the time data based on an intended time point, distributed from said time distribution server, and generates a time stamp on the basis of said time data and said time stamp generating data computed by using the time certification objective data as an input.

2. A time stamp generating system according to claim 1, wherein said time distribution server generates a pseudo-random number series calculated from a seed value without regard to the time certification objective data and when generating said time data, extracts a pseudo-random number of a predetermined length corresponding to said time point from said pseudo-random number series to provide said time data which is independent from the time certification objective data.

3. A time stamp generating system according to claim 1, wherein said user PC calculates time stamp generating data by using the time certification objective data as an input and when obtaining said time stamp, acquires partial data of said time data, which partial data is designated by said time stamp generating data, to provide the acquired partial data as said time stamp.

4. A time stamp generating system according to claim 1, wherein said time distribution server transmits time data generated depending on the present time to a plurality of user PC'"'"'s by using a broadcasting communication path.

5. A time stamp generating system according to claim 1, wherein said user PC calculates a secondary time stamp acquiring time and secondary time stamp generating data on the basis of said acquired time data and time certification objective data, and processes said time data at the secondary time stamp acquiring time on the basis of the secondary time stamp generating data to obtain a secondary time stamp.

6. A time stamp generating system according to claim 5, wherein when calculating the secondary time stamp acquiring time and secondary time stamp generating data, said user PC further calculates secondary time distribution server designating data and when acquiring said time data, said user PC obtains secondary time data from the secondary time distribution server designating data.

7. A time stamp generating system according to claim 1, wherein when generating said time data, said time distribution server adds position information of said time distribution server.

8. A time stamp generating system comprising:

a time distribution server; and

a user PC that holds time certification objective digital data,

wherein said user PC computes time stamp generating data by using the time certification objective data as an input in a predetermined manner and transmits said time stamp generating data to said time distribution server; and

said time distribution server repeatedly generates time data corresponding to a time point and independent from the time certification objective digital data, receives said time stamp generating data from said user PC, processes said time data on the basis of said time stamp generating data to obtain a time stamp, and repeatedly transmits said time stamp to said user PC.