Ex Parte Raikar

Board of Patent Appeals and Interferences

Aug 31, 2010

10722822 (B.P.A.I. Aug. 31, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte AMIT RAIKAR
_____________

Appeal 2009-007105
Application 10/722,822
Technology Center 2400
____________

Before ROBERT E. NAPPI, JOHN C. MARTIN,
and ELENI MANTIS MERCADER, Administrative Patent Judges.

MANTIS MERCADER, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.
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STATEMENT OF THE CASE
Appellant appeals under 35 U.S.C. § 134(a) from the non-final
rejection of claims 1-26. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

INVENTION
Appellant’s Figure 3 is reproduced below:

Appellant’s Figure 3 depicts a group-based communication 300 for
dynamic source authentication having communication group member hosts
301, 302, 303, and 304 (Spec. 10:1-5).
Appellant’s claimed invention is directed to a group-based
communications environment 300 allowing a group host, such as host 301,
to multicast a message 399 to all members of the group, such as hosts 302,
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303, and 304, at one time. Each host is distributed a set of “P” keys for
generating message authentication codes (MACs) attached to outgoing
messages, where “P” is the number of keys. The sender of a message to the
group attaches “P” MACs to the outgoing message. The MACs are hashes
on the packet message data created with each of the “P” keys. No two hosts
use the same set of sender keys (e.g., “P” keys) to encrypt an outgoing
message.
Each receiver in the group is distributed a subset of the “P” keys with
which it verifies authenticity of a subset of the MACs (e.g., according to the
key the receiver holds), while the rest of the MACs can be assumed to be
correctly authenticated. For example, host 301 comprises subset keys 315.
In addition to the “P” keys and the subset of “P” keys, each host of the
group is distributed a set of complementary keys (e.g., CK keys). For
example, host 301 comprises CK keys 316. The CK keys are used for key
revocation when, for example, a host is added or removed from the group.
See Spec. 10-11.
Claim 1, reproduced below, is representative of the subject matter on
appeal:
1. A method for establishing secure group-based communication
comprising:
distributing a first set of keys to a plurality of hosts for encrypting
communication and for source authentication of group-based communication
between said plurality of hosts; and
distributing a second set of keys to said plurality of hosts for
dynamically modifying said first set of keys.

THE REJECTION
The Examiner relies upon the following as evidence of unpatentability:
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Sowa US 2002/0154776 A1 Oct. 24, 2002
The following rejection is before us for review:
The Examiner rejected claims 1-26 under 35 U.S.C. § 102(b) as being
anticipated by Sowa.

ISSUE
The pivotal issue is whether Sowa teaches the limitations of: “group-
based communication” and “dynamically modifying” a set of first keys, as
recited in representative claim 1.

FINDINGS OF FACT (FF)
The following Findings of Fact are supported by a preponderance of
the evidence:
1. Sowa teaches that the “Common Cipher Key (CCK) is a group key” in
the sense that multiple mobile stations (MSs) have the same CCK (¶
[0044]).
2. Sowa also teaches that while the CCK has no relation to a particular
talkgroup (TG), the CCK is geographically specific, i.e., the CCK
serves all units within a given location area (¶ [0044]).
3. Sowa teaches that that the CCK is a location based traffic key meant
for use with the encryption of group call traffic (¶ [0101]).
4. Sowa teaches that there could be more than one location having the
same CCK (¶ [0101]).
5. Sowa explicitly teaches that a CCK is identified by CCK-ID, and
through gradual rekeying, “[a] new CCK replaces the oldest CCK-ID”
(¶ [0101] (emphasis added)).
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6. Appellant’s Specification defines “modifying the sets of keys” as
“[r]e-keying” the keys (Spec. 17:12-17).

PRINCIPLES OF LAW
“During examination, ‘claims . . . are to be given their broadest
reasonable interpretation consistent with the specification, and . . . claim
language should be read in light of the specification as it would be
interpreted by one of ordinary skill in the art.’” In re Am. Acad. of Sci. Tech
Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004) (citation omitted); In re Morris,
127 F.3d 1048, 1053-54 (Fed. Cir. 1997). “[T]he specification ‘is always
highly relevant to the claim construction analysis. Usually, it is dispositive;
it is the single best guide to the meaning of a disputed term.’” Phillips v.
AWH Corp., 415 F.3d 1303, 1315 (Fed. Cir. 2005) (citation omitted).

ANALYSIS
Analysis regarding the limitation of a “group-based communication”
Appellant argues (Br. 10) that, contrary to the Examiner’s
interpretation of Sowa’s paragraph [0044], Sowa teaches that “‘the CCK has
no relation to a particular talk group (TG).’” Appellant further argues (Br.
10) that a geographic location does not define a group because Sowa
specifically states that the CCK has no relation to a talk group. Appellant
also argues (Br. 10) that because Sowa’s paragraph [0101] states that “it is
possible for more than one location area to have the same CCK,” a
geographic location can not be considered a communication group when a
different location can have the same CCK.
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We are not persuaded by Appellant’s arguments. Sowa teaches that
the “Common Cipher Key (CCK) is a group key” in the sense that multiple
MSs have the same CCK (FF 1). Sowa also teaches that while the CCK has
no relation to a particular TG, the CCK is geographically specific, i.e., the
CCK serves all units within a given location area (FF 2). Furthermore, Sowa
teaches that that the CCK is a location based traffic key meant for use with
the encryption of group call traffic (FF 3). Accordingly, Sowa teaches a
group key CCK which serves all members of a communication group in a
geographic location. Notice that the claim language does not recite a
specific type of a group such as a “talkgroup,” and thus, any communication
group (e.g., a location based communication group) would be sufficient to
meet the limitation of a “group-based communication” as recited in
representative claim 1.
We are also not persuaded by Appellant’s argument (Br. 10) regarding
multiple locations having the same CCK (see also FF 4), because multiple
locations, as opposed to a single location, just indicates the size of the group,
which may be enlarged to include group members from multiple locations.
Just because the size of the group is bigger, it does not mean it is not a
group.
Analysis regarding the limitation of a “dynamically modifying” a first
set of keys
Appellant further argues (Br. 11) that Sowa’s paragraph [0045] does
not teach “dynamically modifying said first set of keys,” because Sowa
teaches that “a GCK is defined for each talk group in the system,” and thus,
Sowa does not dynamically modify the CCK (e.g., the first set of keys)
because the CCK has “no relation to a particular talk group.”
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We are not persuaded by Appellant’s argument, and we agree with the
Examiner’s reference to Sowa’s Figure 14 (Ans. 7), because Sowa explicitly
teaches that a CCK is identified by CCK-ID, and through gradual rekeying,
“[a] new CCK replaces the oldest CCK-ID” (FF 5). Note that Appellant’s
Specification describes “modifying the sets of keys” by “[r]e-keying” the
keys (FF 6). Accordingly, Sowa does teach “dynamically modifying” a
CCK having a CCK-ID by rekeying a new CCK, based on the broadest
reasonable interpretation in view of Appellant’s Specification. See Phillips,
415 F.3d at 1315.
Accordingly, we will affirm the Examiner’s rejection of representative
claim 1, and for similar reasons, we will affirm the rejections of claims 2-26.

CONCLUSION
Sowa teaches the limitations of: “group-based communication” and
“dynamically modifying” a set of first keys.

ORDER
The decision of the Examiner to reject claims 1-26 is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(v).

AFFIRMED

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