Appeal No.2003-0446
Application No.09/127767
unidirectional communication, i.e., one-way protocols such as
SKID3, distinct keys K(AB) and K(BA) may be used instead of the
same key K. Thus, the key K used in step (2) can be different
than the key K used in step (3). Therefore, we will sustain the
rejection of claims 4, 9, 10, 13, 16, and 17.
Group III: Claims 1-3, 5, 6 and 11.
The representative claim in this group is claim 1 which has
the same limitation as claim 12, namely, that the second
challenge is a count value. As explained supra, this does not
differ from Menezes because although his protocol uses a random
number as the second challenge he discloses that count values can
be substituted for random numbers. Since the same argument was
presented (Brief, pages 21-22) for claim 12 as for claim 1, the
same response is pertinent here.
An additional argument was made (Brief, page 22) that
Menezes does not provide a teaching or suggestion to increment a
sequence number or count value in response to receiving the first
challenge. However, this argument is not persuasive because
Menezes clearly indicates that sequence numbers (count values),
when utilized in authentication protocols, inherently do just
that. Specifically, Menezes states that "the simplest policy is
that a sequence number starts at zero, is incremented
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