Chakra Parvathaneni

Patent Trials and Appeals Board

Sep 5, 2019

15368001 - (D) (P.T.A.B. Sep. 5, 2019)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/368,001 12/02/2016 Chakra Parvathaneni 070852.000166-1 4041
125968 7590 09/05/2019
Vorys, Sater, Seymour and Pease LLP
(ImgTec)
1909 K St., N.W.
Ninth Floor
Washington, DC 20006
EXAMINER
AMBAYE, SAMUEL
ART UNIT PAPER NUMBER
2433
NOTIFICATION DATE DELIVERY MODE
09/05/2019 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
patlaw@vorys.com
vmdeluca@vorys.com
vorys_docketing@cardinal_ip.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte CHAKRA PARVATHANENI
____________________

Appeal 2018-009149
Application 15/368,0011
Technology Center 2400
____________________

Before MAHSHID D. SAADAT, ROBERT E. NAPPI, and
MICHAEL T. CYGAN, Administrative Patent Judges.

CYGAN, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF CASE
Introduction
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
Final Rejection of claims 1–8. App. Br. 1. We have jurisdiction under
35 U.S.C. § 6(b).
We REVERSE.

1 According to Appellant, Imagination Technologies Limited of Kings
Langley, United Kingdom, is the real party in interest. App. Br. 1.
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Application 15/368,001

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Disclosed Invention and Exemplary Claim
The disclosed invention relates to secure wireless communication
between a receiver and a transmitter. Abstract. A communication system
may use encryption to make eavesdropping on data traffic between stations
more difficult. Spec. ¶ 2. One approach is to use a pre-shared key, provided
at both a base station and an end point node. Id. This approach is
strengthened where the keys are renegotiated during an ongoing active
connection, which requires that the keys be shared between the
communicating stations. Id. When the receiving device determines that an
encrypted packet of data was received without error, but that the current
cipher key cannot decrypt the packet, the receiving device’s cipher key is
updated with the new cipher key. Id. ¶ 3. After updating with the new
cipher key, the receiving device waits for a retransmission of the packet,
which is then decrypted and authenticated with the updated cipher key. Id.
After authentication is passed, receipt of the packet is acknowledged and the
previous cipher key is discarded. Id.
Independent claim 1 is exemplary of the disclosed invention, and
reads as follows (with the disputed claim limitations italicized for emphasis):
1. A process of receiving encrypted communications in a
network, comprising:
receiving at a link layer of a receiving device a current
key, for use in decrypting packets of data received from a
transmitting device in a communication session;
receiving from the transmitting device a new key;
in response to determining that data contained in a
payload from a received packet cannot be decrypted using the
current key, updating, at the receiving device, the current key
with the new key; and
after updating the current key, waiting for a
retransmission of the packet, decrypting the payload of the
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packet using the updated current key, and only after
successfully decrypting the payload using the updated current
key acknowledging receipt of the packet.

App. Br. 10.
Independent claims 5 and 8 recite a device and storage medium,
respectively, having limitations analogous with those set forth in claim 1,
and are not argued separately from claim 1. App. Br. 7.
Examiner’s Rejection
The Examiner rejects claims 1–8 under 35 U.S.C. § 103 as being
obvious over Biederman et al. (US 2005/0071629 A1, published Mar. 31,
2005) (hereinafter, “Biederman”), in view of Iwama (US 2010/0091993 A1,
published Apr. 15, 2010).

ANALYSIS
We have reviewed the Examiner’s rejection (Final Act. 4–13), in light
of Appellant’s contentions that the Examiner has erred (App. Br. 5–9).
Further, we have reviewed the Examiner’s response to Appellant’s
contentions (Ans. 3–4), and the Reply Brief.
The Examiner rejects claim 1 as being obvious over Biederman in
view of Iwama. The Examiner finds Biederman to teach the limitations of
claim 1 with the exception of, after updating the current key, waiting for a
retransmission of the packet, decrypting the payload of the packet using the
updated current key, and only after successfully decrypting the payload
using the updated current key acknowledging receipt of the packet. Final
Act. 5–6. The Examiner finds Iwama to teach or suggest these limitations.
Id. at 6.
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The Examiner finds Iwama to teach updating, at the receiving device,
the current key with the new key, through Iwama’s instruction to perform
encryption key updating. Id. (citing Iwama Abstract ¶¶ 26, 46); Ans. 3–4.
The Examiner further finds Iwama to teach that subsequent to the key
updating, waiting for a retransmission of the packet, decrypting the payload
of the packet using the updated current key, and upon successful decryption
acknowledging receipt of the packet, through Iwama’s process described at
¶¶ 68–69. Final Act. 6.
Appellant characterizes the teachings of Iwama as providing for use of
the replaced cipher key, rather than the updated current key, to decrypt
payload received during the updating of the encryption key. App. Br. 6.
Appellant argues, inter alia, that Iwama does not teach or suggest waiting
for a retransmission of the packet and decrypting the retransmitted packet
using the updated current key, and acknowledging receipt of the packet only
after successful authentication of the packet. Id.; Reply Br. 1–2. Appellant
argues that Iwama’s process instead retrieves a stored old key, after a key
update, to perform decryption where information was encrypted with an old
key. App. Br. 2–3. Appellant further argues that the cited sections of
Iwama relate only to the key updating process itself, and not to receiving
packets of data, or what to do if data cannot be decrypted using a current
decryption key. Reply Br. 1–2.
We are persuaded by Appellant’s arguments. The Examiner has not
adequately explained what features in Iwama correspond to waiting for a
retransmission of a packet, decrypting the retransmitted packet using the
updated current key, and acknowledging receipt of the packet only after
successful authentication of the packet. Nor do we determine such features
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to be taught or suggested by Iwama. Appellant’s argument that Iwama
decrypts data with the old key, rather than with a new key as required by
claim 1, is supported by Iwama, which states that “the decoding section, if
unable to decode the received data using the updated new encryption key,
decodes that received data using the encryption key stored by the key storing
section.” Iwama ¶ 15; Id. ¶¶ 46, 72. Accordingly, we are persuaded by
Appellant’s arguments that the combination of Biederman and Iwama fails
to teach or suggest the invention of claim 1, as well as independent claims 5
and 8 which recite similar limitations. Because the Examiner’s rejection of
the remaining claims also relies on Iwama to teach or suggest the analogous
limitations in those claims, we similarly determine that the combination of
Biederman and Iwama fails to teach or suggest the invention of claims 2–8.
DECISION
We reverse the Examiner’s rejections of claims 1–8 under
35 U.S.C. § 103(a).

REVERSED