Ex Parte Bennett et al

Patent Trial and Appeal Board

Jun 27, 2016

13301206 (P.T.A.B. Jun. 27, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/301,206 11/21/2011
16000 7590 06/29/2016
Comcast
c/o Ballard Spahr LLP
999 Peachtree Street, Suite 1000
Atlanta, GA 30309
FIRST NAMED INVENTOR
Christopher J. Bennett
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
26141.0013Ul 8431
EXAMINER
LESNIEWSKI, VICTOR D
ART UNIT PAPER NUMBER
2493
NOTIFICATION DATE DELIVERY MODE
06/29/2016 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):
USpatentmail@ballardspahr.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte CHRISTOPHER J. BENNETT, DOUGLAS M. PETTY,
KENNETH P. MILLER, and ALEXANDER MEDVINSKY
Appeal2014-009358
Application 13/301,206
Technology Center 2400
Before JEAN R. HOMERE, CAROLYN D. THOMAS, and
KARA L. SZPONDOWSKI, Administrative Patent Judges.
SZPONDOWSKI, Administrative Patent Judge.
DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner's
Final Rejection of claims 1-29. We have jurisdiction under 35 U.S.C.
§ 6(b ).
We REVERSE.
Appeal2014-009358
Application 13/301,206
STATEMENT OF THE CASE
Appellants' invention is directed to a system and method for
authenticating data. (Spec. i-f 1 ). Claim 1, reproduced below, with the
disputed limitations in italics, is illustrative of the claimed subject matter:
1. A method for authentication comprising:
receiving, by a computing device, a data block comprising a
plurality of first secret elements and a comparator element associated
with one or more of the plurality of first secret elements;
processing, by the computing device, the data block to
determine a select first secret element of the plurality of first secret
elements;
generating, by the computing device, a second secret element
based upon the select first secret element;
generating, by the computing device, a non-secret element
based upon the second secret element; and
comparing the non-secret element to the comparator
element to determine authentication.
REJECTIONS
Claims 1-9, 13, 14, 17, 18, 20, 22-27, and 29 stand rejected under 35
U.S.C. § 103(a) as being unpatentable over the combination of Kocher et al.
(US 8,386,800 B2; issued Feb. 26, 2013) and Bar-El (US 2011/0116635 Al;
published May 19, 2011).
Claims 10, 11, 15, 16, and 21 stand rejected under 35 U.S.C. § 103(a)
as being unpatentable over the combination of Kocher, Bar-El, and Engels et
al. (US 2012/0011360 Al, published Jan. 12, 2012).
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Appeal2014-009358
Application 13/301,206
Claims 12, 19, and 28 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over the combination of Kocher, Bar-El, and Gantman et
al. (US 8,437,473 B2; issued May 7, 2013).
ANALYSIS
Issue: Did the Examiner err in finding the combination of Kocher and
Bar-El teaches or suggests "receiving, by a computing device, a data block
comprising a plurality of first secret elements," as recited in independent
claim 1 and commensurately recited in independent claims 14 and 22?
The Examiner identifies Kocher's KRooT (root key) as the claimed first
secret element, but finds Kocher "does not explicitly state the first secret
element is one of a plurality of first secret elements provisioned to the target
device in the message." (Ans. 2; see also Final Act. 3--4, citing Kocher col.
6, 11. 4--18). Therefore, the Examiner relies on Bar-El, which "shows that
multiple functional keys may be used to reveal further cryptographic
material down the chain." (Ans. 3; see also Final Act. 4, citing Bar-El i-f 15).
The Examiner admits both Kocher and Bar-El utilize a root key to decrypt
an initial portion of the received data, but "the rejection does not purport to
transfer a root key[.]" (Ans. 3; see also Ans. 4). Accordingly the Examiner
finds:
it would have been obvious to one of ordinary skill in the art at
the time of the applicant's invention to modify the system of
Kocher by adding the ability for receiving a data block
comprising a plurality of first secret elements as provided by
Bar-El (see paragraph 15, functional keys included in message
to target device). One of ordinary skill in the art would have
recognized that key provisioning techniques require additional
security against exposing the key material to untrusted users
(see Bar-El, paragraph 8).
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Application 13/301,206
(Final Act. 4; see also Ans. 3---6). The Examiner finds provisioning
functional keys is an alternative technique for supplying the device with
additional keys to further accomplish cryptographic functionality. (Ans. 4).
Appellants contend "Bar-El distinguishes between the functional keys
and a root key." (Reply Br. 2). Appellants argue KRooT of Kocher "will
never be transmitted in a data block" because "the two devices will negotiate
KRooT using a public key exchange." (App. Br. 6). Appellants further argue
the root key described in Bar-El "is assumed to pre-exist in all provisioned
devices." (App. Br. 6, citing Bar-El i-f 32). According to Appellants, "[i]f
the root key is assumed to pre-exist in all provisioned devices, then the
provisioning device has no reason to include the root key in a data block and
does not do so." (Id.) Therefore, Appellants argue "neither Kocher nor
Bar-El allows for a provisioning device to send a data block with the root
key." (App. Br. 6). Therefore, according to Appellants, because the
Examiner has identified Kocher' s KRooT as equivalent to the first secret
element
It follows then, that the Examiner's argument, viewed properly,
is that the root key of Kocher is transmitted as part of the data
block. Put another way, if the key KRooT is a selected one of the
plurality of first secret elements or shared key, it necessarily
follows that it was received as contents of the data block.
Accordingly, Appellant has articulated the only sound
reasoning based on the arguments set forth by the Examiner:
that the combination of Kocher and Bar-El must allow for a
provisioning device to send a data block to a provisioned
device, wherein the data block includes the root key.
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Application 13/301,206
(Reply Br. 3). Appellants further argue because "KRooT is derived through
the negotiation between the devices[,] Therefore, the addition of the
provisioning in Bar-El to transmit KRooT to the decrypting device would be
unnecessary and expose the communication to risk of breach." (App. Br. 9).
Further, Appellants argue the Examiner's position to rely on the functional
key provisioning of Bar-El "would require a complete reconfiguration of the
operation of Kocher" because the public key negotiation "is not simply a
value that can be inserted into a data block and forwarded to the decrypting
device." (App. Br. 9).
We are persuaded by Appellants' arguments. Having considered the
Examiner's findings, we find the Examiner has failed to sufficiently explain
how the combination of Kocher and Bar-El teaches or suggests the disputed
limitation. Specifically, the Examiner contends the rejection does not
purport to transfer a root key as part of the data block, which we find is
inconsistent with the Examiner's reliance on Kocher's KRooT throughout the
remainder of the claim for the "first secret element" limitation. (See Final
Act. 3; Ans. 2). As Appellants point out, and we agree, Bar-El distinguishes
between a root key and a functional key. Therefore, the Examiner's reliance
on the functional keys of Bar-El to teach or suggest "receiving ... a data
block comprising a plurality of first secret elements" is inconsistent with the
Examiner's reliance on Kocher's KRooTto teach or suggest the "first secret
element" throughout the remainder of the claim, particularly because the
Examiner's modification to Kocher simply "add[s] the ability for receiving a
data block comprising a plurality of first secret elements as provided by Bar-
El." (See Ans. 5). In other words, we agree with Appellants that the
Examiner's reliance on Kocher's KRooT throughout the claim for the "first
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Application 13/301,206
secret element" necessarily requires that KRooT is received as part of the data
block. Consequently, we are constrained by the record before us to find the
Examiner erred in finding the combination of Kocher and Bar-El teaches
or suggests the disputed limitation. Accordingly, we do not sustain the
Examiner's rejection of independent claim 1, and independent claims 14 and
22, which recite substantially the same limitation. For the same reasons, we
do not sustain the Examiner's rejection of dependent claims 2-13, 15-21,
and 23-29.
DECISION
For the above reasons, the Examiner's rejection of claims 1-29 is
reversed.
REVERSED
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