Ex Parte Little et al

Patent Trial and Appeal Board

Feb 11, 2016

10483282 (P.T.A.B. Feb. 11, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
10/483,282 01/08/2004 Herbert A Little
52169 7590 02/16/2016
INTEGRAL INTELLECTUAL PROPERTY INCJBlackBerry
4400 Bathurst Street, Suite 10
TORONTO, ON M3H 3R8
CANADA
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.
BB/l 0369-US-PCT3 2480
EXAMINER
DEBNATH, SUMAN
ART UNIT PAPER NUMBER
2495
NOTIFICATION DATE DELIVERY MODE
02/16/2016 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):
USPTO@INTEGRALIP.COM
MIRIAM@INTEGRALIP.COM
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte HERBERT A. LITTLE and MICHAEL G. KIRKUP
Appeal2013-009323
Application 10/483,282
Technology Center 2400
Before JOHN A. JEFFERY, ERIC B. CHEN, and ANDREW J. DILLON,
Administrative Patent Judges.
JEFFERY, Administrative Patent Judge.
DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner's
decision to reject claims 1--44 and 46-49. Claim 45 was cancelled. We
have jurisdiction under 35 U.S.C. § 6(b). We affirm.
STATEMENT OF THE CASE
Appellants' invention processes encrypted messages at a mobile
device. After the device receives an encrypted message comprising
encrypted content and encryption information for accessing the encrypted
content, the accessing information is stored to memory and retrieved to
decrypt the encrypted content when the encrypted message is later accessed.
See generally Abstract. Claim 1 is illustrative:
Appeal2013-009323
Application 10/483,282
1. A method for processing encrypted messages at a
communication device, the method comprising:
receiving at the communication device an encrypted
message comprising at least one encrypted session key and
encrypted content, the at least one encrypted session key
comprising an individual encrypted session key associated with
the communication device, the individual encrypted session key
encrypted with a public key and usable, when decrypted using a
private key associated with the public key, to decrypt the
encrypted content of the encrypted message;
accessing the encrypted message;
identifying the individual encrypted session key
associated with the communication device;
decrypting the individual encrypted session key to obtain
a decrypted session key that is unique to the encrypted
message; and
storing the decrypted session key to memory;
wherein, when the encrypted content of the encrypted message
is accessed multiple times, the stored decrypted session key is used
each of the multiple times to decrypt the encrypted content of the
encrypted message.
THE REJECTIONS
The Examiner rejected claims 1--4, 6, 10, 11, 14--26, 38--44, and 46-
49 under 35 U.S.C. § 103(a) as unpatentable over Hanna (US 2002/0136410
Al, published Sept. 26, 2002) and Morley et al. (US 2003/0206635 Al,
published Nov. 6, 2003). Final Act. 2-12. 1
The Examiner rejected claim 5 under 35 U.S.C. § 103(a) as
unpatentable over Hanna, Morley, and Heinonen (US 6,925,568 B 1, issued
Aug 2, 2005). Final Act. 12-13.
1 Throughout this opinion, we refer to (1) the Final Rejection mailed October
25, 2012 ("Final Act."); (2) the Appeal Brief filed January 22, 2013 ("App.
Br."); (3) the Examiner's Answer mailed May 23, 2013 ("Ans."); and (4) the
Reply Brief filed July 23, 2013 ("Reply Br.").
2
Appeal2013-009323
Application 10/483,282
The Examiner rejected claims 7-9 under 35 U.S.C. § 103(a) as
unpatentable over Hanna, Morley, and Finkelstein (US 5,410,602, issued
Apr. 25, 1995). Final Act. 13-14.
The Examiner rejected claims 12 and 13 under 35 U.S.C. § 103(a) as
unpatentable over Hanna, Morley, and Schmeling (US 7,299,502 B2, issued
Nov. 20, 2007). Final Act. 14--15.
The Examiner rejected claims 27-37 under 35 U.S.C. § 103(a) as
unpatentable over Hanna, Morley, and Perlman (US 2002/0116705
Al,published Aug. 22, 2002). Final Act. 15-18.
THE OBVIOUSNESS REJECTION OVER HANNA AND MORLEY
Regarding claim 1, the Examiner finds that Hanna (1) receives and
accesses an encrypted message with at least one encrypted session key,
namely a symmetric key, and (2) identifies and decrypts the session key.
Final Act. 2-3. Although the Examiner acknowledges that Hanna does not
store the decrypted session key to memory to decrypt the message's
encrypted content when the encrypted content is accessed repeatedly, the
Examiner cites Morley for teaching (1) storing a program key, which is also
said to be a session key, and (2) loading that key each time an associated
encrypted program is to be played back. Final Act. 3--4; Ans. 3-10. In light
of these teachings, the Examiner concludes that it would have been obvious
to store Hanna's decrypted session key to decrypt content on multiple
accesses to save processing time and power by only having to decrypt the
session key once. Final Act. 3--4.
Appellants argue that the cited prior art does not teach or suggest
storing a decrypted session key to memory to decrypt encrypted content each
3
Appeal2013-009323
Application 10/483,282
of multiple times that the encrypted message is accessed, as claimed. App.
Br. 10-13; Reply Br. 2--4. According to Appellants, not only is Morley
inapplicable to email messages, but rather decrypts video content, but
Morley's program key is transmitted independently of the digital stream,
unlike Hanna which transmits a key with the message. App. Br. 10-11;
Reply Br. 4--5.
These distinctions are said to bring into question whether skilled
artisans would reasonably modify Hanna in view of Morley as the Examiner
proposes. Id. Appellants reason that because Hanna transmits a session key
as part of an encrypted message, the Examiner's proposed combination
requires storing at least part of that message in decrypted form, thus
defeating Hanna's access control scheme and rendering Hanna unsuitable for
its intended purpose, namely preventing decryption using an ephemeral key
after it expires. App. Br. 13-14.
Appellants add that the Examiner's motivation to combine the
references, namely to reduce processor load and time delays, is found only
in Appellants' disclosure and, therefore, is the result of impermissible
hindsight. App. Br. 14--16.
ISSUES
(1) Under§ 103, has the Examiner erred in rejecting claim 1 by
finding that Hanna and Morley collectively would have taught or suggested
storing a decrypted session key to memory to decrypt a received message's
encrypted content when the encrypted content is accessed repeatedly?
(2) Is the Examiner's combining the teachings of Hanna and Morley
supported by articulated reasoning with some rational underpinning to
4
Appeal2013-009323
Application 10/483,282
justify the Examiner's obviousness conclusion? This issue turns on whether
the Examiner's proposed combination renders Hanna unsuitable for its
intended purpose, and whether the Examiner's articulated reason to combine
the references resulted from impermissible hindsight.
ANALYSIS
We begin by construing the key disputed limitation of claim 1 which
recites, in pertinent part, a "session key." Appellants' Specification does not
define the term "session key," but does refer to a session key as a key used
to decrypt the content of many types of encrypted messages, such as Secure
Multipurpose Internet Email Extensions (S/MIME) or Pretty Good Privacyâ„¢
(PGP) email messages,for example. Spec. 2:6-10. Our emphasis on this
description's exemplary language underscores that these encrypted email
messages are but two examples of many types of encrypted messages that
are decrypted with session keys and, therefore, are not limited to email
messages, let alone those two particular types of email messages. That
Appellants' claim 1 does not specify that the encrypted message is an email
message, unlike dependent claim 26, only bolsters this conclusion. Under
claim differentiation principles, then, the encrypted message in claim 1 must
encompass something other than email; otherwise, claim 26 would be
superfluous. See Free Motion Fitness, Inc. v. Cybex Int'!, Inc., 423 F.3d
1343, 1351 (Fed. Cir. 2005).
Therefore, Appellants' proposed construction of "session key" in the
context of secure email (Reply Br. 2-3) is inapposite, for leaving aside
Appellants' reliance on Wikipedia-a non-peer-reviewed Internet source of
5
Appeal2013-009323
Application 10/483,282
dubious reliability2---claim 1 is not so limited. In fact, the term "session" is
defined quite broadly by a recognized networking dictionary as a "[r]elated
set of communications transactions between two or more network devices."
Cisco Systems, Inc., DICTIONARY OF INTERNETWORKING TERMS AND
ACRONYMS 320 (2001). Accordingly, under its broadest reasonable
interpretation, a "session key" is a key associated with a related set of
communications transactions between two or more network devices.
Based on this interpretation, we see no error in the Examiner's
position that Hanna's symmetric key and Morley's program key both
constitute "session keys" (Final Act. 2-3) at least to the extent that they are
associated with communications transactions between network devices. And
as the Examiner indicates, Morley's theater subsystem decrypts a received
encrypted program key, and stores this decrypted "session key" in memory
to decrypt programs upon playback. Ans. 3--4 (citing Morley i-fi-1 7 6-77).
This technique at least suggests that this stored key is used each time the
particular program is played back which could be multiple times-an
obvious variation. See Morley i1 77.
We see no reason why this technique could not be applied to Hanna's
messaging system to preclude the need for the recipient to decrypt the
symmetric or "session" key with the ephemeral key every time the message
2 See Bing Shun Liv. Holder, 400 F. App'x 854, 857 (5th Cir. 2010)
(unpublished) (noting Wikipedia's unreliability and citing Badasa v.
Mukasey, 540 F.3d 909, 910-11 (8th Cir. 2008)); see also Ex parte Three-
Dimensional Media Group, Ltd., No. 2009-004087, 2010 WL 3017280
(BP AI 2010) (non-precedential), at * 17 ("Wikipedia is generally not
considered to be as trustworthy as traditional sources for several reasons, for
example, because (1) it is not peer reviewed; (2) the authors are unknown;
and (3) apparently anyone can contribute to the source definition").
6
Appeal2013-009323
Application 10/483,282
is accessed, as would be the case with the functionality in Morley's
paragraph 29. Under the Examiner's proposed enhancement to Hanna, after
the recipient uses the ephemeral key to decrypt the symmetric keys that are
then used to decrypt the message, the symmetric keys could then be stored at
least temporarily and retrieved when the recipient needs to decrypt the
message again-a scenario at least suggested by Morley's using stored
decrypted keys for later decryptions as noted previously.
Such an enhancement would not render Hanna unsuitable for its
intended purpose of preventing decryption using an ephemeral key after it
expires as Appellants contend (Br. 13-14), as that requirement would still be
met under the Examiner's position. Because subsequent decryptions are
possible using the stored decrypted symmetric keys under the Examiner's
proposed enhancement to Hanna, the ephemeral key is not needed in those
situations. Nevertheless, decryption using an ephemeral key would still be
prevented after expiration and, therefore, comport with Hanna's intended
purpose at least in that respect. That Appellants admit that Hanna does not
explicitly prohibit storing a decrypted session key (App. Br. 13) only further
bolsters the Examiner's position in this regard.
Nevertheless, even assuming, without deciding, that enabling
subsequent decryptions using stored decrypted symmetric keys entails some
risk to data security, such a risk may very well be offset by the advantages of
storing the decrypted symmetric keys, namely by needing to decrypt those
keys only once, thus conserving processing power and time that would
otherwise be used each time those keys were decrypted with the ephemeral
key. See Ans. 10. Such considerations amount to an engineering trade-off
well within the level of ordinarily skilled artisans.
7
Appeal2013-009323
Application 10/483,282
That Morley's program key is transmitted independently of the digital
stream, unlike Hanna which transmits a key with the message as Appellants
indicate (App. Br. 10-11; Reply Br. 4--5) is of no consequence here. As the
Examiner explains, Morley was not cited to show how the keys were
transmitted, but rather merely to show that it was known in the art to store
decrypted keys for later decryptions, and that it would have been obvious to
so enhance Morley. See Ans. 5---6.
That Morley does not state explicitly that its teachings apply to email
messages as Appellants contend (App. Br. 11; Reply Br. 4) is likewise of no
consequence here. Not only is claim 1 not limited to email messages as
noted previously, but it is well settled that "[t]he motivation [to combine
references] need not be found in the references sought to be combined, but
may be found in any number of sources, including common knowledge, the
prior art as a whole, or the nature of the problem itself." DyStar Textilfarben
GmbH & Co. Deutschland KG v. C.H. Patrick Co., 464 F.3d 1356, 1361
(Fed. Cir. 2006) (citation omitted). We see no error, then, in the Examiner's
articulated reason to combine the references, namely to save processing time
and power by decrypting the session key only once, for that rationale is
reasonably based at least implicitly on the prior art considered as a whole.
Ans. 6-7.
Appellants' contention that the Examiner's articulated reason to
combine the references is allegedly gleaned only from Appellants'
disclosure and based on impermissible hindsight (App. Br. 14--16) is
unavailing given the implicit teachings from the prior art considered as a
whole in light of the knowledge of ordinarily skilled artisans. In short,
enhancing Hanna by storing decrypted keys for later decryptions in light of
8
Appeal2013-009323
Application 10/483,282
Morley as the Examiner proposes merely applies "a known technique to a
piece of prior art ready for the improvement" to yield a predictable result.
See KSR Int 'l Co. v. Teleflex, Inc., 550 U.S. 398, 417 (2007). Accordingly,
the Examiner's combining the teachings of Hanna and Morley is supported
by articulated reasoning with some rational underpinning to justify the
Examiner's obviousness conclusion.
Therefore, we are not persuaded that the Examiner erred in rejecting
claim 1, and claims 2--4, 6, 10, 11, 14--26, 38--44, and 46--49 not argued
separately with particularity.
THE OTHER OBVIOUSNESS REJECTIONS
We also sustain the Examiner's obviousness rejections of claims 5, 7-
9, 12, 13, and 27-37. Final Act. 12-18. Despite nominally arguing these
claims separately, Appellants reiterate similar arguments made in connection
with claim 1, and allege that the additional cited references fail to cure those
purported deficiencies. App. Br. 16-18; Reply Br. 5. We are not persuaded
by these arguments for the reasons previously discussed.
CONCLUSION
The Examiner did not err in rejecting claims 1--44 and 46--49 under
§ 103.
DECISION
The Examiner's decision rejecting claims 1--44 and 46--49 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)(l )(iv).
9
Appeal2013-009323
Application 10/483,282
AFFIRMED
10