Appeal No. 1998-2466 Page 6
Application No. 08/508,747
document and the time stamp, see column 6, lines 1-
24. Haber discloses a method whereby a chain of
certificates are generated to “back-up” the time
stamp, or otherwise fix the order in which the time
stamped certificates are generated, i.e. any
document that is time stamped must have the time and
order in the chain of certificates correct for
authentication. Tysen teaches that the time stamp
is coordinated with UTC, see column 12, line 60. It
would have been obvious to one of ordinary skill in
the art at the time the invention was made to time
stamp a document with the time coordinated to UTC as
taught in Tysen in the trusted agency disclosed in
Haber in order to provide a common time reference
for all users.
From our review of the record, we agree with appellant
(brief, page 12) that the teachings of Haber and Tysen would
not have suggested steps or means for checking the time
accuracy of the machine time to verify the time accuracy of
the time-stamp. Appellant acknowledges (brief, page 10)
that Haber utilizes hashing of the time-stamped message and a
digital signature in a manner similar to that used by
appellant. However, appellant asserts (id.) that Haber
utilizes a different approach to verify the date and time when
a message is received by the time-stamp authority. Haber's
approach is to relate the time of receipt of the message to
the time of receipt of the previous and subsequent messages,
in order to show the veracity of the time-stamp. Appellants
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007