Ex Parte Jeffries et al

Patent Trial and Appeal Board

Apr 19, 2018

13495210 (P.T.A.B. Apr. 19, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
13/495,210 06/13/2012 Clark Debs Jeffries
77351 7590 04/20/2018
IBM CORP. (AUS)
C/O THE LAW OFFICE OF JAMES BAUDINO, PLLC
2313 ROOSEVELT DRIVE
SUITE A
ARLINGTON, TX 76016
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.
AUS920040414US2 7161
EXAMINER
WILLIAMS, JEFFERY L
ART UNIT PAPER NUMBER
2495
MAILDATE DELIVERY MODE
04/20/2018 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte CLARK DEBS JEFFRIES and MOHAMMAD PEYRA VIAN
Appeal 2016-007 686
Application 13/495,210
Technology Center 2400
Before CAROLYN D. THOMAS, BRUCE R. WINSOR, and
IRVINE. BRANCH, Administrative Patent Judges.
WINSOR, Administrative Patent Judge.
DECISION ON APPEAL
Appellants 1 appeal under 35 U.S.C. § 134(a) from the final rejection
of claims 13-27, which constitute all the claims pending in this application.
We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.
1 The real party in interest identified by Appellants is International Business
Machines Corporation. App. Br. 3.
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STATEMENT OF THE CASE
Appellants' disclosed "invention relates generally to computer
security and, more particularly, to denial of service ["DoS"] attacks." Spec.
i-f 1. Claim 13, which is illustrative, reads as follows:
13. A method for protecting a server against denial of
service attacks, comprising:
maintaining, by a server having a processing device, a
window over a sequence number space, the sequence number
space including sequence numbers that are sequentially
assigned by the server to respective challenge messages issued
by the server for verifying legitimate requests for service, the
window comprising a leading edge sequence number and a
trailing edge sequence number;
receiving a request;
determining a challenge message should be sent;
selecting the leading edge sequence number as a
challenge sequence number;
assigning the challenge sequence number to a challenge
message;
assigning a problem to the challenge message;
sending the challenge message, wherein the challenge
message comprises the problem and the challenge sequence
number;
receiving a response message, wherein the response
message comprises a solution to the problem and the challenge
sequence number;
discarding the response message if the challenge
sequence number is not within the window;
discarding the response message if the solution is not
correct; and
performing a session if the response message is not
discarded.
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Claims 13-27 stand rejected under 35 U.S.C. § 112, second
paragraph, as being indefinite for failing to particularly point out and
distinctly claim the subject matter which the applicant regards as the
invention. See Final Act. 2--4.
Claims 13-21 stand rejected under 35 U.S.C. § 101 because the
claimed invention is directed to patent-ineligible subject matter. See Final
Act. 4.
Claims 13-27 stand rejected under 35 U.S.C. § 103(a)2 as being
unpatentable over Bleichenbacher et al. ("Bleichenbacher,") (US 7, 143, 163
Bl; issued Nov. 28, 2006; filed July 26, 2000). See Final Act. 5-10.
Rather than repeat the arguments here, we refer to the Briefs ("App.
Br." filed [date]; "Reply Br." filed [date]) for the positions of Appellants;
the Final Office Action ("Final Act." mailed [date]) and Examiner's Answer
("Ans." mailed [date]) for the reasoning, findings, and conclusions of the
Examiner; and the Specification ("Spec." filed [date]). Only those
arguments actually made by Appellants have been considered in this
decision. Arguments that Appellants did not make in the Briefs have not
been considered and are deemed to be waived. See 37 C.F.R.
§ 41.37(c)(l)(iv) (2015).
2 All prior art rejections are under the provisions of 35 U.S.C. in effect prior
to the effective date of the Leahy-Smith America Invents Act of 2011 ("pre-
AIA"). Final Act 2.
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REJECTION UNDER 35 U.S.C. § 112
Issue
The issue presented by Appellants' arguments is whether the
Examiner errs in concluding the recitation of "discarding the response
message if the challenge sequence number is not within the window" renders
claim 13 is indefinite for failing to "particularly point[] out and distinctly
claim[] the subject matter which the applicant regards as his invention,"
35 U.S.C. § 112, 2d paragraph.
Analysis
Although based on underlying questions of fact, the ultimate question
of indefiniteness is a question of law that is reviewable de nova. See
Nautilus, Inc., v. Biosig Instruments, Inc., 134 S.Ct. 2120, 2130 n.10 (2014);
In re Packard, 751 F.3d 1307, 1311 (Fed. Cir. 2014). Language in a claim is
unclear if it is "ambiguous, vague, incoherent, opaque, or otherwise unclear
in describing and defining the claimed invention ... ," Packard, 751 F.3d at
1311, or if it is "is amenable to two or more plausible claim constructions ..
. ,"Ex parte Miyazaki, 89 USPQ2d 1207, 1211 (BPAI 2008) (precedential);
see also Ex parte McAward, 2017 WL 3669566 (PTAB 2017) (precedential)
(discussing the test for indefiniteness during prosecution and affirming
Miyazaki's continued precedential status (at *2, n.3)).
The Examiner explains that the step of "discarding the response
message if the challenge sequence number is not within the window,"
recited in claim 13 will never occur. Final Act. 3. The Examiner reaches
this conclusion by applying the usual conventions of antecedent basis in
claim construction. Id. We agree with this analysis, as far as it goes. Claim
13 recites "the window comprising a leading edge sequence number,"
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"selecting the leading edge sequence number as a challenge sequence
number[, and] assigning the challenge sequence number to a challenge
message" (emphases added). Thus, the claim recites that the "challenge
sequence number" and the "leading edge sequence number are the same
number and that number is within the window. The claim further recites that
"the response message comprises ... the challenge sequence number," i.e.,
the same number that is within the window. There is no recitation in the
claim of the numbers that comprise the window changing in such a way as to
not comprise the "leading edge sequence number"/"challenge sequence
number." Therefore, the Examiner's claim construction is plausible.
Appellants contend that, when read in light of Appellants'
Specification, the "window" recited in claim 13 shifts with the sending of
challenge messages and the receiving of response messages, with the
"leading edge sequence number" shifting with the sending of challenge
messages, and the "trailing edges sequence number" shifting with the receipt
of a response messages. App. Br. 7-8 (citing Spec. i-fi-126-30). Therefore,
Appellants argue, the "challenge sequence number" may or may not lie
within the window as it exists when the response message is received. Id.
In other words, Appellants assert that it is a plausible claim construction,
indeed that it is the correct claim construction, to ignore usual principles of
antecedent basis and treat the recited "leading edge sequence number" as
potentially changing between the sending of the challenge message and the
receipt of a corresponding response message. Although Appellants' claim
construction appears to improperly import un-recited limitations into the
claims (see In re Van Geuns, 988 F.2d 1181, 1184 (Fed. Cir. 1993),
Appellants' specification explains that when challenge messages are sent,
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the leading edge of the window advances by one, and when response
message is received, the window shrinks the trailing edge by one (see Spec.
i-fi-126-30), i.e., a shifting effect. Therefore, we accept, arguendo, that
Appellants' asserted claim construction is plausible.
Even accepting Appellants' argued claim construction as plausible,
however, we are faced with a claim that "is amenable to two or more
plausible claim constructions," Miyazaki, 89 USPQ2d at 1211, and is,
therefore, indefinite. Independent claims 22 and 25 recite substantially
similar limitations and are indefinite for the same reasons as claim 13.
Claims 14--21, 23, 25, 26, and 27 variously depend, directly or indirectly,
from claims 12, 22, and 25 and inherit the indefiniteness of the claim from
which they depend. Accordingly, we sustain the rejection of claims 13-27
for indefiniteness.
REJECTION UNDER 35 U.S.C. § 101
Issue
The issue presented by Appellants' arguments is whether the
Examiner errs in concluding that claim 13 is patent-ineligible under
35 U.S.C. § 101 because it is directed to an abstract idea without
significantly more.
Analysis
Patent eligibility is a question of law that is reviewable de nova.
Dealertrack, Inc. v. Huber, 674 F.3d 1315, 1333 (Fed. Cir. 2012). To be
statutorily patentable, the subject matter of an invention must be a "new and
useful process, machine, manufacture, or composition of matter, or [a] new
and useful improvement thereof." 3 5 U.S. C. § 101. The Supreme Court has
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held that there are implicit exceptions to the four categories of patentable
subject matter identified in § 101, including (1) laws of nature, (2) natural
phenomena, and (3) abstract ideas. Alice Corp. Pty. Ltd. v. CLS Bank Int 'l,
134 S. Ct. 2347, 2355 (2014). Further, the Court has "set forth a framework
for distinguishing patents that claim [1] laws of nature, [2] natural
phenomena, and [3] abstract ideas from those that claim patent-eligible
applications of those concepts." Id., citing Mayo Collaborative Services v.
Prometheus Laboratories, Inc., 132 S. Ct. 1289 (2012). The evaluation
follows the two-part analysis set forth in Mayo: (1) determine whether the
claim is directed to a patent-ineligible concept, e.g., an abstract idea; and
(2) if an abstract idea is present in the claim, determine whether any element,
or combination of elements, in the claim is sufficient to ensure that the claim
amounts to significantly more than the abstract idea itself. See Alice, 134 S.
Ct. at 2355.
Claim 13 is directed to "[a] method for protecting a server against
denial of service attacks." A "method" falls within the definition of a
"process," as that term is used in used in 35 U.S.C. § 101. 35 U.S.C.
§ 1 OO(b) ("The term 'process' means process art or method."). Therefore,
claim 13, and its dependent claims, is directed to one of the four statutory
classes of subject matter. We next consider whether claim 13 is directed to a
judicial exception, i.e. an abstract idea under the first step of the Alice
framework.
The Examiner finds claim 13 is "directed to the abstract idea of
assigning numbers to challenge messages and the sending and receiving of
said challenge messages." Final Act. 4. The Examiner discounts the
recitation of the "server having a processing device" as "simply a reference
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to a generic computing device that stores sequence numbers." Id. The
Examiner further explains that the "recited steps (i.e. the 'receiving',
'determining', 'selecting', 'assigning', etc[.] ... ) are all entirely
disembodied from any particular machine", and "could broadly be
performed within the mind or implemented simply as an activity between
humans, without the involvement of any particular computer or machine."
Ans. 9.
Appellants contend that "[ c ]laim 13 is necessarily rooted in computer
technology to overcome a problem specifically arising in a server
responding to requests for service and guarding against denial of service
attacks." App. Br. 12. We agree with Appellants.
In applying the first step of the Alice analysis "[ w ]e must first
determine whether the claims at issue are directed to a patent-ineligible
concept," such as an abstract idea. Alice, 134 S. Ct. at 2355. "[T]he
'directed to' inquiry applies a stage-one filter to claims, considered in light
of the specification, based on whether 'their character as a whole is directed
to excluded subject matter."' Enfish, LLC v. Microsoft Corp., 822 F.3d
1327, 1335 (Fed. Cir. 2016) (quoting Internet Patents Corp. v. Active
Network, Inc., 790 F.3d 1343, 1346 (Fed. Cir. 2015)).
The Specification discloses that a goal of the claimed invention is to
provide "a countermeasure solution for protecting servers against DoS
attacks that enables victim servers to sustain service availability during such
attacks." Spec. ,-r 3. In response to a request to initiate a session between a
client and the server, the server sends a challenge message to the requesting
client that includes a sequence number and a challenge problem. Spec. Fig.
5. The server only initiates the session if the client responds with the
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correct answer to the problem and with a sequence number that falls within a
range of sequence number (i.e., a "window") that indicates that the response
associated with a recent request. Id. The Specification describes the
invention's advantages as follows:
Generally, the system 100 is directed to a generic front-
end solution for protecting against Dos attacks. The system 100
is typically light weight and does not require changes to
existing protocols, and does not require the use of
cryptographic techniques. Moreover, it does not require the
server 190 to perform computationally intensive operations and
maintain state information about individual requests from
clients. The server 190 leaves the burden on the client to prove
its legitimacy (through the disclosed front-end protocol) before
agreeing to engage in session establishment.
Spec. i-f 35.
In other words, Appellants' invention provides a countermeasure
solution for protecting servers against DoS attacks by requiring the client to
provide a correct solution to a problem, otherwise discarding the request
thereby sustaining service availability. The Enfish court explained that
"[t]he Supreme Court has suggested that claims 'purport[ing] to improve the
functioning of the computer itself,' or 'improv[ing] an existing technological
process' might not succumb to the abstract idea exception." Enfish, 822
F.3d at 1335 (citing Alice, 134 S.Ct. at 2358-59). Claim 13 is directed to an
improved method of preventing a DoS attack, and purports to improve an
important aspect of server functionality/availability. Like the claims for a
self-referential database table at issue in Enfish, claim 13 is directed to "an
improvement [in] computer functionality itself, not [to] an economic or other
[process] for which the computer is used in its ordinary capacity" as a tool.
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Enfish, 822 F.3d at 1336. Therefore, claim 13 is not directed to an abstract
idea.
Because we hold that claim 13 is not directed to a patent-ineligible
concept (i.e., abstract idea) under the first step of the Alice analysis, we do
not reach the second step of the Alice analysis. Enfish, 822 F.3d at 1339
(citing Alice, 134 S. Ct. at 2355).
Accordingly, we do not sustain the rejection of claim 13, and claims
14--21, which depend form claim 13, as being directed to a patent-ineligible
abstract idea.
REJECTION UNDER 35 U.S.C. § 103
CLAIMS 13 AND 16-19
Issues
The issues presented by Appellants' arguments are as follows:
Does the Examiner err in finding that Bleichenbacher teaches or
suggests
maintaining ... a window over a sequence number space, the
sequence number space including sequence numbers that are
sequentially assigned by the server to respective challenge
messages issued by the server for verifying legitimate requests
for service, the window comprising a leading edge sequence
number and a trailing edge sequence number
(the "window" limitation) as recited in claim 13?
Does the Examiner err in finding Bleichenbacher teaches or suggests
"discarding the response message if the challenge sequence number is not
within the window" (the "sequence number discarding limitation"), as
recited in claim 1?
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The Window Limitation
Analysis
The Examiner finds Bleichenbacher teaches the window limitation,
presenting two alternative mappings. Final Act. 5---6 (citing Bleichenbacher
col. 9, 11. 18--40). We note that the window limitation, by analogy to a
physical window, represents an identifiable subset of the entire sequence
number space. See RANDOM HOUSE DICTIONARY OF THE ENGLISH
LANGUAGE 2177 (2d ed. unabr. 1987). The Examiner's first mapping (Final
Act. 5-6), in which the recited "window" is effectively mapped to be
coextensive with the entire "sequence number space" (claim 13) (see App.
Br. 15-16; Reply Br. 10), gives no effect to the term "window," and so we
do not rely on this mapping. In re Wilson, 424 F.2d 1382, 1385 (CCPA
1970) ("All words in a claim must be considered in judging the patentability
of that claim against the prior art."). Regarding the second alternative
mapping, Examiner explains that "Bleichenbacher discloses a space of
sequence numbers beginning from a pointer value (i.e. 'leading edge
sequence number') and ending at the last index number within the database
(i.e. 'trailing edge sequence number')." Final Act. 6.
Appellants contend that Bleichenbacher does not disclose the window
limitation because Bleichenbacher discloses pointers, rather than sequence
numbers, and does not maintain a window over the pointers. App. Br. 15.
Appellants' arguments are not persuasive of Examiner error.
The application of prior art references to a claim is not an ipsissimis
verbis test. In re Bond, 910 F.2d 831, 832 (Fed. Cir. 1990).
Bleichenbacher' s pointers are sent in challenge messages to a client
requesting service along with a problem to be solved by the client and are
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assigned sequentially to the challenge messages, being incremented after
each problem is sent. Bleichenbacher col. 9, 11. 35-37. We find
Bleichenbacher's pointers teach the recited "sequence numbers."
Furthermore, Bleichenbacher' s pointers each point to a particular problem in
a database of problems corresponding solutions (id. col. 9, 11. 23-24), thereby
teaching a "sequence number space."
As pointed out by the Examiner, the "window" is broadly recited,
with the only specific parameters being the "leading edge sequence number"
and "trailing edge sequence number." See Ans. 11. The Examiner maps
Bleichenbacher' s pointer to be assigned to the next challenge messages to
the "leading edge sequence number." Final Act. 6. Claim 13 similarly
describes the "leading edge sequence number" as the value to be assigned to
the next challenge message ("selecting the leading edge sequence number as
a challenge sequence number").
The Examiner maps the "trailing edge sequence number" to the
pointer for the first entry in the problem solution database. Final Act 6.
Appellants contend this mapping is incorrect because "the 'end of the
sequence' that the Examiner appears to correspond to the last entry in the
database would not be the 'trailing edge sequence number' because the
pointer in Bleichenbacher wraps to the beginning entry after the last entry."
App. Br. 16; see Bleichenbacher col. 9. 11. 33--40. As best, we understand
Appellants' argument to contend that the "leading edge sequence number"
and the "trailing edge sequence number" cannot be the same. Although, as a
general matter of claim construction, different elements of a claim must be
mapped to different elements in the prior art, see Becton, Dickinson & Co. v.
Tyco Healthcare Grp., LP, 616 F.3d 1249, 1254 (Fed. Cir. 2010) ("Where a
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claim lists elements separately, the clear implication of the claim language is
that those elements are distinct components of the patented invention."
(emphasis added)), here Appellants' Specification discloses that under
certain conditions the "leading edge sequence number" and the "trailing
edge sequence number" have the same value. See Spec. i-f 27 ("Initially,
when the server 190 boots up and assigns 0 to SeqNo for the first
ChallengeMessage, the server 190 sets the trailing edge and the leading edge
of the window to O.").
For the foregoing reasons, we are not persuaded the Examiner erred in
finding Bleichenbacher teaches the window limitation of claim 13.
The Sequence Number Discarding Limitation
The Examiner concedes that "Bleichenbacher does not appear to
disclose discarding the response message if the challenge sequence number
is not within the window" (Final Act. 7), but concludes that as a matter of
claim construction the sequence number discarding limitation would never
be performed, and therefore cannot distinguish the claimed invention from
Bleichenbacher' s teaching (id.). We do not rely on the Examiner's claim
construction because, inter alia, it represents only one of two plausible claim
constructions, as discussed in more detail supra. Nonetheless, with regard to
claim 13, we do agree that as a matter of claim construction that the
sequence number discarding limitation cannot distinguish over
Bleichenbacher.
Claim 13 is a "method" or process claim. "Unless the steps of a
method actually recite an order, the steps are not ordinarily construed to
require one. However, such a result can ensue when the method steps
implicitly require that they be performed in the order written." Interactive
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Gift Express, Inc. v. Compuserve Inc., 256 F.3d 1323, 1342-43
(Fed.Cir.2001) (citations omitted).
Interactive Gift recites a two-part test for determining if the
steps of a method claim that do not otherwise recite an order,
must nonetheless be performed in the order in which they are
written. First, we look to the claim language to determine if, as
a matter of logic or grammar, they must be performed in the
order written. If not, we next look to the rest of the
specification to determine whether it "directly or implicitly
requires such a narrow construction."
Altiris, Inc. v. Symantec Corp., 318 F.3d 1363, 1370 (Fed. Cir. 2003) (citing
Interactive Gift at 1343).
Claim 13 recites two "discarding" steps, the step described by the
sequence number discarding limitation, and the step of "discarding the
response message if the solution [to the problem in the challenge message] is
not correct" (the "solution discarding limitation,"). Although claim 13
recites the sequence number discarding limitation before the solution
discarding limitation, and Appellants' disclosed preferred embodiment
performs the steps in that order (see Spec. Fig. 5 (items 570, 575)), nothing
in the logic or grammar of the claim or in Appellants' Specification, requires
that the steps be performed in that order. Indeed, Appellants' Figure 5
would function in exactly the same way if the order of the discarding steps
were reversed. Therefore, claim 13 encompasses a method in which the step
of the solution discarding limitation is performed before the step of the
sequence number discarding limitation.
Both discarding limitations occur only if a condition precedent is met,
and are, therefore conditional limitations, each with two alternative
outcomes (i.e., the message is either discarded or not discarded). According
to our precedent, as a matter of claim construction, the broadest reasonable
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interpretation of a method incorporating a conditional limitation
encompasses a method in which only one of the alternative paths of the
conditional limitation is performed. See Ex parte Schulhauser, Appeal No.
2013-007847, 2016 WL 6277792, at *3-5 (PTAB Apr. 28, 2016)
(precedential).
Therefore, the broadest reasonable interpretation of claim 13
encompasses a method in which the step of the solution discarding limitation
is performed first and determines that the problem solution is not correct,
thereby causing the response message to be discarded. In this event neither
the step of the sequence number discarding limitation or the step of
"performing a session if the response message is not discarded" is required
to meet the limitations of the claim.
Therefore, as to claim 13, Appellants arguments regarding
Bleichenbacher failure to teach the sequence number discarding limitation
are unavailing. See App. Br. 16-17; Reply Br. 10-11.
Summary
For the foregoing reasons, this record does not demonstrate error in
the Examiner's rejection of independent claim 13. Accordingly, we sustain
the rejection under 35 U.S.C. § 103(a) of claim 13 and claims 16-19, which
depend, directly or indirectly, from claim 13, and were not separately argued
with particularity.
CLAIMS 22-27
Issues
Appellants argue the patentability of claims 22 and 25 by relying on
the arguments made for claim 13. App. Br. 18; Reply Br. 11-12. Therefore,
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the issues presented by Appellants' arguments regarding claims 22 and 25
are the same, mutatis mutandis, as presented for claim 13.
Analysis
The Window Limitation
Appellants' arguments regarding the window limitation are
unpersuasive of Examiner error for the same reasons as discussed above
regarding claim 13.
The Sequence Number Discarding Limitation
Claim 22 is directed to a "computer readable storage device" that
embodies "computer code" to perform certain functions including the
sequence number discarding limitation. Claim 25 is directed to a "system
comprising a processor coupled to a non-transitory computer readable
medium storing a computer program" that comprises computer code to
perform certain functions including the sequence number discarding
limitation. As such, but claims are directed to apparatus, i.e., machines, or
articles of manufacture. The broadest reasonable interpretation of an
apparatus claim with structure that performs a function that need only occur
if a condition precedent is met, still requires structure for performing the
function should the condition occur. See Schulhauser, 2016 WL 6277792, at
*3-5. Therefore, our interpretation of apparatus claims 22 and 25 differs
from method claim 13 because the structure, namely the computer code
configured to perform the recited functions, is present in the apparatus
regardless of whether the conditional limitation is met and the function is
actually performed.
The Examiner concedes that "Bleichenbacher does not appear to
disclose discarding the response message if the challenge sequence number
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is not within the window" (Final Act. 7). The Examiner presents two
alternative explanations to fill the gap in Bleichenbacher' s disclosure. First,
the Examiner concludes, as a matter of claim construction, it is not necessary
to show that the sequence number limitation is taught by Bleichenbacher.
Id. We disagree, because in an apparatus claim, such as claims 22 and 25, it
is necessary to show that the all claimed structures (whether or not claimed
functionally) are taught or suggested by the prior art, regardless of whether
the recited structure will be used in a particular instance of operation. See
Schulhauser, 2016 WL 6277792, at *3-5.
In the alternative, the Examiner concludes as follows:
[O]ne of ordinary skill would have recognized that the server of
Bleichenbacher should discard a message from a client that
comprises an invalid index number, such as a number that was
not within the database. This would have been obvious because
one of ordinary skill in the art would have been motivated by
logic to recognize that if the server received invalid data which
could not be used for the server's intended purpose of
establishing a session, then it would be of no value and should
be discarded or ignored.
Final Act. 7-8 (citing Bleichenbacher col. 10, 11. 7-11 ).
Appellants contend the Examiner's reasoning is faulty for the
following reasons:
First, the Examiner offers no definition of a "valid" pointer as
opposed to an "invalid" pointer. Second, as indicated above,
there is no reason in Bleichenbacher to determine whether a
pointer is "valid" because if a solution in the database using the
pointer that the client provides does not match the solution
provided by the client, access will not be granted.
App. Br. 17. We agree with Appellants.
The Examiner's conclusion is based on construing the "window" over
the "sequence number space" to be coextensive with the "sequence number
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space," a claim construction that improperly reads "window" out of the
claim, as discussed supra. We find no teaching in the cited passages of
Bleichenbacher of determining whether or not a returned pointer value falls
within any window of pointer values and no reason why a person of ordinary
skill in the art would find Bleichenbacher's teaching of discarding messages
that fail to correctly solve the challenge problem to be inadequate protection
for the server. We only find this concept in Appellants' Specification.
Thus, we conclude the Examiner's articulated rationale is an exercise in
impermissible hindsight. See KSR Int'! Co. v. Teleflex Inc., 550 U.S. 398,
421 (2007) ("A factfinder should be aware, of course, of the distortion
caused by hindsight bias and must be cautious of arguments reliant upon ex
post reasoning.").
Summary
For the foregoing reasons, Appellants have demonstrated error in the
Examiner's rejection of independent claims 22 and 25. Accordingly, we do
not sustain the rejection under 35 U.S.C. § 103(a) of claims 22 and 25 and
claims 23, 24, 26, and 27, which variously depend, directly or indirectly,
from claims 22 and 25.
CLAIMS 14 AND 15
Issue
The issue presented by Appellants' arguments is whether the
Examiner errs in finding Bleichenbacher teaches or suggests "determining a
challenge message should be sent comprises determining a request count
does not exceed a threshold session count, and wherein the sending the
challenge message comprises incrementing the request count" (the
"threshold limitation"), as recited in claim 14.
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Analysis
The Examiner finds Bleichenbacher teaches or suggests the threshold
limitation. Final Act 8 (citing Bleichenbacher col. 1, 11. 56----67, col. 9, 11. 49-
55, col. 11, 11. 27-33.) The Examiner explains as follows:
[T]he determination to send a specific challenge message is
based on whether an incremented request number ("request
count") exceeds a threshold (a "threshold session count").
Specifically, Bleichenbacher clearly teaches that adjusting the
complexity enables the server to regulate (i.e. place a limit
upon) the number of connections by a single client. The
examiner notes that the stated purpose of Bleichenbacher is to
prevent a client from overloading a server with illegitimate
requests, thus it would have been obvious to one of skill in the
art to logically recognize that if a single client did not yet solve
his/her initial problem, then the sever should not send him/her
another one to solve.
Id. (citations omitted).
Appellants contend as follows:
Bleichenbacher appears to disclose that the problems in
Bleichenbacher may be dynamically adjusted with respect to
computation time based on the number and interval of requests.
(Bleichenbacher, column 9, lines 47-58). Thus, Bleichenbacher
does not disclose determining a challenge should be sent based
on a request count not exceeding a threshold session count. To
the contrary, Bleichenbacher appears to disclose that a
challenge is always sent, just the level of computation required
for a response can vary.
App. Br. 19. We agree with Appellants for the reasons stated by Appellants.
The Examiner mistakenly conflates the selection of a problem to be
sent in a challenge message, i.e., determining the content of a challenge
message to be sent, with "determining a challenge message should be sent,"
i.e. determining whether to send a message at all. We find no teaching or
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suggestion in the cited passages of Bleichenbacher of any use of a threshold
to "determin[e] a challenge message should be sent."
Appellants have demonstrated error in the Examiner's rejection of
claim 14. Accordingly, we do not sustain the rejection under 35 U.S.C. §
103(a) of claim 14 and claim 15, which depends from claim 14.
CLAIMS 20 AND 21
Issue
The issue presented by Appellants' arguments is whether the
Examiner errs in finding Bleichenbacher teaches or suggests "computing an
index based on a number of entries in a problem-solution table and the
challenge sequence number; and selecting the problem based on the index"
(the "computing limitation"), as recited in claim 20.
Analysis
The Examiner finds Bleichenbacher teaches the computing limitation.
Final Act. 10 (citing Bleichenbacher col. 9, 11. 25-27, col. 10, 11. 38--40).
Appellants contend "Bleichenbacher uses a pointer to select a problem from
a database, and then the pointer gets incremented to the next value.
Bleichenbacher does not disclose, nor would it be obvious to so modify
Bleichenbacher, computing an index based on a number of entries in a
problem-solution table for selecting a problem from the table." App. Br. 19.
We disagree with Appellants' argument.
Bleichenbacher teaches using a pointer to select a problem from
Bleichenbacher's database. Bleichenbacher col. 9, 11. 25-27. We conclude
that Bleichenbacher' s pointer is encompassed within the broadest reasonable
interpretation of an index used as a basis for selecting a problem. In
explaining how Bleichenbacher's pointer is determined, Bleichenbacher
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teaches that the pointer is incremented with each problem sent.
Bleichenbacher col. 9, 11. 35-37 (cited at Final Act. 5). In other words, the
pointer (i.e. "index") is computed based on the challenge sequence number.
We note that equating the index to the challenge sequence number falls
within the broadest reasonable interpretation of "computing" the index based
on the challenge sequence number. As acknowledged by Appellants,
Bleichenbacher further explains that "[i]f the pointer exceeds the number of
entries in the database, the pointer wraps back to the beginning entry of the
database." Bleichenbacher col. 9, ll.38--40; see App. Br. 15. In other words,
Bleichenbacher teaches that the pointer (i.e., "index") is computed based on
the number of entries in Bleichenbacher's database (i.e., the "problem
solution table.").
This record does not demonstrate error in the Examiner's rejection of
claim 20. Accordingly, we sustain the rejection under 35 U.S.C. § 103(a) of
claim 20 and claim 21, which depends from claim 20 and was not separately
argued with particularity
DECISION
The rejection of claims 13-27 under 35 U.S.C. § 112, second
paragraph is affirmed.
The rejection of claims 13-21under35 U.S.C. § 101 is reversed.
The rejection of claims 13 and 16-21 under 35 U.S.C. § 103(a) is
affirmed.
The rejection of claims 14, 15, and 22-27 is reversed.
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Because the rejection of every pending claim is affirmed on at least
one ground of rejection, the Examiner's decision to reject claims 13-27 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). See 37 C.F.R.
§§ 41.50(±), 41.52(b).
AFFIRMED
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