Ex Parte Mizikovsky et al

Patent Trial and Appeal Board

Feb 22, 2013

10861895 (P.T.A.B. Feb. 22, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte SEMYON MIZIKOVSKY and
MICHAEL MARCOVICI
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Appeal 2010-002726
Application 10/861,895
Technology Center 2600
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Before: ERIC B. CHEN, JOHNNY A. KUMAR, and
MICHAEL J. STRAUSS, Administrative Patent Judges.

STRAUSS, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-002726
Application 10/861,895

2
STATEMENT OF CASE
Appellants appeal under 35 U.S.C. § 134(a) from a rejection of claims
1-27. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

According to Appellants, the claims are directed to techniques for
managing sequence numbers used in the AKA protocol so that the number
of resynchronization procedures can be reduced. This allows the mobile unit
to securely pass the value of the next expected synchronization sequence
number to the network. The network can then use this information to select a
sequence number that will be acceptable to the mobile unit. Consequently,
authentication tokens transmitted to the mobile unit can include an
acceptable value of the sequence number so the mobile unit will not need to
re-synchronize with the network. Instead of the mobile unit re-
synchronizing, the invention allows the authentication center to synchronize
its sequence numbers to the sequence numbers used by the mobile unit, i.e.,
the authentication center can self-synchronize to the sequence numbers used
by the mobile unit. App. Br. 7.
Claim 1, reproduced below, is illustrative of the claimed subject
matter:
1. A method of wireless communication with at least one
mobile unit and at least one authentication center, the method
comprising:
generating at least one access request including information
indicative of at least a first sequence number associated with the
mobile unit, the first sequence number corresponding to an
authentication vector; and
receiving at least one message based upon the access request,
the message comprising at least a second sequence number
Appeal 2010-002726
Application 10/861,895

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selected by the authentication center the second sequence
number selected to be acceptable to the mobile unit based on
the first sequence number indicated by said at least one access
request so that the second sequence number used by the
authentication center is synchronized with the first sequence
number used by the mobile unit.

REFERENCES
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Carroll US 7,131,006 B1 Oct. 31, 2006
Marcovici EP 1168870 A1 Jan. 2, 2002

REJECTIONS
1

The Examiner rejected claims 1-27 under 35 U.S.C. § 103(a) as being
unpatentable over Marcovici and Carroll. Ans. 3.

APPELLANTS’ CONTENTION
2

Appellants argue that “Carroll does not describe or suggest selecting
the second sequence number used by the authentication center so that it is
synchronized with the first sequence number used by the mobile unit.” App.
Br. 8-9.

1
Based on the dependencies of the claims and the dispositive issue, we
decide the appeal of the rejection of claims 1-27 on the basis of claim 1.
2
We note that Appellants’ arguments present additional issues; however, we
do not reach these issues, as this contention is dispositive of the appeal.
Appeal 2010-002726
Application 10/861,895

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ISSUE
Appellants’ contention presents the issue whether the combination of
Marcovici and Carroll teaches or suggests the disputed claim limitation
rendering the claims obvious under 35 U.S.C. § 103(a).

ANALYSIS
Appellants contend that “Carroll does not describe or suggest
selecting the second sequence number used by the authentication center so
that it is synchronized with the first sequence number used by the mobile
unit.” App. Br. 8-9. In particular, Appellants argue that:
Carroll describes a modification of the conventional
AKA that allows a roaming mobile unit to use a temporary
sequence number for authentication with a serving network.
Carroll teaches that the temporary sequence number functions
in exactly the same manner as the conventional sequence
number except that the temporary sequence number is used for
a relatively short period of time compared to the conventional
sequence number. In particular, Carroll teaches that the
temporary sequence number is established for the duration of
the MS 130 roaming in the SN 120 network area and the
temporary sequence numbers are used for mutual authentication
of the MS 130 and the SN 120. For example, the MS 130
successfully authenticates the SN 120 if
TSQNsn(i)>TSQNms/usim. Carroll further teaches that the TSON
does not impact the maintenance of the SQN. See Carroll, col.
8, ll. 14-48.
App. Br. 8-9.
Therefore, Appellants argue, “the temporary sequence numbers
described by Carroll are established completely independently of the values
of the sequence numbers SON(i) and SONres” in contrast to “the second
sequence number used by the authentication center [selected] so that it is
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synchronized with the first sequence number used by the mobile unit.” App.
Br. 9.
The Examiner responds that:
“Adjusting a value indicating use of the key can include
incrementing a sequence number corresponding to a number of
times the key has been used. The method may further include
using the key to compute a cipher key for encrypting
communication between the service network and the station.
The method may also include negotiating use of a
cryptographic primitive between the service network and the
home environment network." (Carroll, Co1.5; 18-25, Col. l0; 8-
14). Thus, it is evidently, the explanations above are directed to
telecommunications systems and methods for based on the first
sequence number the second sequence number selected which
is requested via mobile station, that positively, edify by
CARROLL. Hence, it is believed that CARROLL still teaches
the claimed limitations.
Ans. 9 (emphasis omitted).
We agree with Appellants that the Examiner has erred. The Examiner
has not identified what features in Carroll correspond to the first and second
sequence number, much less how the sequence numbers are synchronized.
In particular, the Examiner fails to identify disclosure by Carroll of
the claimed synchronization of the second sequence number, i.e., that the
“second sequence number used by the authentication center is synchronized
with the first sequence number used by the mobile unit.” While Carroll
discloses the problem of loss of synchronization and the need to re-
synchronize (see, e.g. col 3, ll. 30-32; col. 8, ll. 40-47; col. 9, ll. 32-37; and
col. 10, ll. 23-31), the Examiner fails to identify any disclosure of
synchronizing the two.
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Accordingly, we will not sustain the rejection of claim 1 and, for the
same reason, the rejection of independent claims 14 and 22 and dependent
claims 2-13, 15-21, and 23-27.

CONCLUSION
Appellants have persuaded us of error in the Examiner’s decision to
reject independent claim 1 and, for the same reasons, independent claims 14
and 22 and dependent claims 2-13, 15-21, and 23-27. Thus, we will not
sustain the Examiner's rejection of claims 1-27 under 35 U.S.C. § 103(a).

DECISION
The decision of the Examiner to reject claims 1-27 is reversed.

REVERSED

ELD