Court Opinion

ID: 9892057
Source: CourtListenerOpinion
Date Created: 2023-10-20 14:00:44.350148+00
Date Added: 2024-06-11T14:22:03.026145
License: Public Domain

Case: 22-1523   Document: 77     Page: 1    Filed: 10/20/2023

        NOTE: This disposition is nonprecedential.

   United States Court of Appeals
       for the Federal Circuit
                 ______________________

                    VIRNETX INC.,
                       Appellant

                            v.

                      APPLE INC.,
                        Appellee

  KATHERINE K. VIDAL, UNDER SECRETARY OF
  COMMERCE FOR INTELLECTUAL PROPERTY
    AND DIRECTOR OF THE UNITED STATES
      PATENT AND TRADEMARK OFFICE,
                  Intervenor
            ______________________

                       2022-1523
                 ______________________

     Appeal from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in No. 95/001,682.
                   ______________________

                Decided: October 20, 2023
                 ______________________

     IGOR VICTOR TIMOFEYEV, Paul Hastings LLP, Washing-
 ton, DC, argued for appellant. Also represented by
 STEPHEN BLAKE KINNAIRD, NAVEEN MODI, JOSEPH PALYS,
 DANIEL ZEILBERGER.
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 2                                 VIRNETX INC. v. APPLE INC.

     JOSHUA JOHN FOUGERE, Sidley Austin LLP, Washing-
 ton, DC, argued for appellee. Also represented by THOMAS
 ANTHONY BROUGHAN, III, JEFFREY PAUL KUSHAN; SCOTT
 BORDER, Winston & Strawn LLP, Washington, DC.

     SARAH E. CRAVEN, Office of the Solicitor, United States
 Patent and Trademark Office, Alexandria, VA, argued for
 intervenor. Also represented by THOMAS W. KRAUSE,
 MONICA BARNES LATEEF, AMY J. NELSON, FARHEENA
 YASMEEN RASHEED.
                 ______________________

     Before LOURIE, BRYSON, and CHEN, Circuit Judges.
 BRYSON, Circuit Judge.
     In this appeal from an inter partes reexamination
 proceeding before the Patent Trial and Appeal Board, the
 appellant VirnetX Inc. challenges the Board’s decision
 holding that several claims of VirnetX’s U.S. Patent No.
 6,502,135 (“the ’135 patent”) are invalid. We affirm.
                              I
     The ’135 patent is directed to a system and method for
 communicating over the Internet and creating a virtual
 private network following a domain-name server look-up
 function. 1 Claim 18 of the ’135 patent, which is the
 principal focus of VirnetX’s appeal, provides as follows:
     18. A method of transparently creating a virtual
     private network (VPN) between a client computer
     and a target computer, comprising the steps of
     (1) generating from the client computer a Domain
     Name Service (DNS) request that requests an IP

     1   A domain name server uses a look-up table to cor-
 relate human-readable domain names to IP addresses and
 returns the IP address to the user.
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 VIRNETX INC. v. APPLE INC.                                  3

     address corresponding to a domain name associ-
     ated with the target computer;
     (2) determining whether the DNS request trans-
     mitted in step (1) is requesting access to a secure
     web site; and
     (3) in response to determining that the DNS re-
     quest in step (2) is requesting access to a secure
     target web site, automatically initiating the VPN
     between the client computer and the target com-
     puter, wherein:
     steps (2) and (3) are performed at a DNS server sep-
     arate from the client computer, and step (3) com-
     prises the step of, prior to automatically initiating
     the VPN between the client computer and the tar-
     get computer, determining whether the client com-
     puter is authorized to resolve addresses of non
     secure target computers and, if not so authorized,
     returning an error from the DNS request.
     At the conclusion of the reexamination, the examiner
 found claim 18, along with several other claims of the ’135
 patent, to be invalid for anticipation and obviousness over
 several references. The Board reversed some of the exam-
 iner’s rejections but affirmed the rejections of claims 10–14
 and 17–18 on various grounds.
     First, the Board upheld the examiner’s rejection of
 claim 18 for obviousness over a combination of three refer-
 ences—Beser, Kent, and Blum. 2 Second, the Board upheld
 the examiner’s rejection of claim 18 for anticipation based

     2  The Beser reference is U.S. Patent No. 6,496,867;
 the Kent reference is a November 1998 paper entitled “Se-
 curity Architecture for the Internet Protocol”; and the
 Blum reference is U.S. Patent No. 6,182,141.
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 4                                 VIRNETX INC. v. APPLE INC.

 on a reference the Board referred to as BinGO. 3 Third, the
 Board upheld the examiner’s rejection of claims 10 and 12
 as anticipated by BinGO. Fourth, the Board upheld the
 examiner’s rejection of claim 11 as obvious over a combina-
 tion of BinGO and a reference the Board referred to as
 Reed. 4 The Board also affirmed the examiner’s rejection of
 claims 13, 14, and 17, but VirnetX does not challenge the
 Board’s rulings on those claims.
      We affirm the Board’s decision on appeal with respect
 to claims 10, 12, and 18 based on BinGO and, with respect
 to claim 11, based on the combination of BinGO and Reed.
 In view of our decisions regarding BinGO and the combina-
 tion of BinGO and Reed, we do not find it necessary to ad-
 dress the Board’s reliance on the combination of Beser,
 Kent, and Blum. 5
                             II
                               A
     At the outset of its discussion of BinGO, VirnetX com-
 plains that the Board “recrafted” claim 18, “ignored the
 claim language,” and failed to address the limitations set
 forth in the claim. In particular, VirnetX argues that the
 Board misconstrued the “wherein” clause of claim 18, omit-
 ting the “prior to initiating the VPN” limitation and

     3    The BinGO reference consists of the BinGO! User’s
 Guide and the BinGO! Extended Feature Reference.
      4   The Reed reference is a paper by Michael G. Reed,
 Paul F. Syverson, and David M. Goldschlag entitled Prox-
 ies for Anonymous Routing, presented at the 12th Annual
 Computer Security Applications Conference in December
 1996.
      5   We also find it unnecessary to address the Board’s
 reliance on collateral estoppel with respect to issues con-
 cerning the combination of Beser and Kent. See J.A. 27–
 32.
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 mischaracterizing the “determining” limitation. As such,
 VirnetX argues, the Board analyzed only its own version of
 claim 18, not the actual language of the claim. VirnetX Br.
 30.
      We disagree with VirnetX’s characterization of the
 Board’s treatment of claim 18. To be sure, claim 18 is writ-
 ten in a manner that makes it hard to understand, and the
 Board confessed that it had difficulty in doing so, especially
 in its effort to map claim 18 on any portion of the ’135 writ-
 ten description. 6
     VirnetX’s quarrel with the Board’s treatment of claim
 18 relates to the Board’s statement that it needed to decide
 “whether, as a general matter, the Beser, Kent, and Blum
 references would have rendered obvious determining
 whether a client has permission to access a web site and if
 not, returning an error message.” J.A. 31. That general
 characterization of the thrust of claim 18 does not indicate
 that the Board misunderstood the limitations of the claim,
 and particularly the “wherein” clause on which VirnetX fo-
 cuses. In its discussion of obviousness, the Board accu-
 rately characterized that clause as requiring a
 determination of “whether a client is authorized to access
 a non secure target computer and returning an error if the

     6    We agree with the Board that claim 18, as drafted,
 is not easy to understand. Moreover, the Board was correct
 in stating that the written description of the ’135 patent
 appears to contain nothing that describes the invention re-
 cited in claim 18. VirnetX seems to concede as much. As
 support for the claim, VirnetX points not to the written de-
 scription, but to a canceled claim that was part of the initial
 application that ultimately matured into the ’135 patent.
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 6                                  VIRNETX INC. v. APPLE INC.

 client is not authorized to access a non-secure target.” J.A.
 32. 7
     Later in its decision, when the Board discussed
 whether BinGO anticipates claim 18, the Board again ac-
 curately characterized the requirements of claim 18. In
 that portion of its decision, the Board walked through the
 limitations of claim 18, pointing out how BinGO satisfied
 each of them. The Board explained that if a user enters a
 domain name server request for a website and the destina-
 tion is unknown to the BinGO! Router, the BinGO! Router
 will forward the request to a domain name server for do-
 main name resolution, satisfying steps (1) and (2) of claim
 18. J.A. 44–45. If the request from the client computer is
 for a secure target computer, the Board added, the BinGO!
 Router sets up a virtual private network consistent with
 step (3) of the claimed method. J.A. 45.
     The Board then examined the last limitation of claim
 18, which comprises the step of “determining whether the
 client computer is authorized to resolve addresses of non
 secure target computers and, if not so authorized,
 returning an error from the DNS request.” As to that
 limitation, the Board found that BinGO “discloses
 authentication of the initiating partner, which would
 include situations where the requested web-site is non-
 secure” and that a person of ordinary skill in the art would
 “have immediately understood that such an authentication
 failure would result in an error message being returned.”

     7   VirtnetX’s contention that the Board ignored the
 “prior to automatically initiating the VPN” component of
 the “wherein” limitation overlooks the examiner’s finding,
 upheld by the Board, that the BinGO! Router “discloses re-
 quiring authentication before establishing connections to a
 remote server, by disclosing checking incoming data to de-
 cide whether the connection should be allowed.” J.A. 37–
 38.
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 VIRNETX INC. v. APPLE INC.                               7

 Id. Throughout that analysis, contrary to VirnetX’s
 contention, the Board neither recrafted claim 18 nor
 misconstrued its limitations.
                              B
     VirnetX raises two principal contentions regarding the
 Board’s reliance on BinGO to anticipate claim 18. First,
 VirnetX notes that the Board’s anticipation analysis was
 based not only on the instruction manual known as the
 BinGO! User Guide, but also on the supplemental
 instruction manual known as the BinGO! Extended
 Feature Reference. VirnetX contends that the Board’s
 reliance on two separate references disqualifies
 anticipation as an invalidating theory, because
 anticipation requires that all the limitations of a
 challenged claim be found in a single reference. Second,
 VirnetX argues that the Board committed error when it
 found that a person of ordinary skill in the art would have
 understood that an error message would be returned if the
 client computer is authorized to resolve addresses of non-
 secure target computers.          VirnetX contends that
 anticipation cannot rest on a finding that a person of
 ordinary skill in the art would have envisaged a limitation
 that is, in fact, missing from the purportedly anticipating
 reference. Neither argument is persuasive.
                              1
     As for the argument that the BinGO! User Guide and
 the BinGO! Extended Feature Reference are separate
 references and that they cannot be combined for purposes
 of anticipation, the Board found that the User Guide
 incorporates the Extended Feature Reference and thus the
 two references must be treated as one for anticipation
 purposes. That finding is consistent with the law of
 anticipation. See Advanced Display Sys., Inc. v. Kent State
 Univ., 212 F.3d 1272, 1282 (Fed. Cir. 2000) (material in a
 second document is considered incorporated by reference in
 a host document if the context “makes clear that the
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 8                                   VIRNETX INC. v. APPLE INC.

 material is effectively part of the host document as if it
 were explicitly contained therein”); see also Callaway Golf
 Co. v. Acushnet Co., 576 F.3d 1331, 1346 (Fed. Cir. 2019)
 (incorporation by reference requires that the host
 document “contain language clearly identifying the subject
 matter which is incorporated and where it is to be found”)
 (cleaned up). Whether and to what extent material has
 been incorporated by reference is a question of law that we
 review de novo. Advanced Display, 212 F.3d at 1283;
 Callaway Golf, 576 F.3d at 1346.
     The BinGO! User Guide repeatedly cites to the BinGO!
 Extended Feature Reference, instructing the reader to
 consult the Extended Feature Reference for information
 about how to configure the virtual private network of the
 BinGO! Router.        The evidence shows that the two
 documents were “collectively distributed as a single
 reference document,” and that the User Guide directs users
 to consult specific parts of the Extended Feature Reference
 to implement the VPN features of the BinGO! Router. See
 J.A. 6298 (citing portions of the User Guide). The two
 documents thus serve in effect as two volumes of a single
 instruction manual for using the BinGO system. As such,
 the Board was correct in holding that the BinGO! User
 Guide incorporates the BinGO! Extended Feature
 Reference and that the two references can be considered as
 one for purposes of anticipation.
                               2
     We also reject VirnetX’s argument that the Board
 improperly found anticipation given its acknowledgement
 that “BinGO does not expressly disclose returning an error
 message” as required by claim 18. J.A. 45. This court has
 made clear that a reference can anticipate, even when it
 does not expressly recite a claimed limitation, if a person of
 ordinary skill in the art “would reasonably understand or
 infer from the prior art reference’s teaching that every
 claim [limitation] was disclosed in that single reference.”
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 VIRNETX INC. v. APPLE INC.                                 9

 Genentech, Inc. v. Hospira, Inc., 946 F.3d 1333, 1340–41
 (Fed. Cir. 2020) (quoting CRFD Research, Inc. v. Matal, 876
 F.3d 1330, 1338 (Fed. Cir. 2017)). On the other hand, a
 reference that is missing a limitation does not anticipate
 just because “a skilled artisan would ‘at once envisage’ the
 missing limitation.” Id. at 1340 (quoting Nidec Motor Corp.
 v. Zhongshan Board Ocean Motor Co., 851 F.3d 1270,
 1274–75 (Fed. Cir. 2017). The core inquiry is whether a
 person of ordinary skill in the art would understand the
 reference to disclose the limitation in question, rather than
 merely “envisage” a limitation that is in fact missing from
 the reference.
     In this case, the Board concluded that one of ordinary
 skill in the art “would have immediately understood” that
 an authentication failure in the BinGO system “would
 result in an error message being returned.” J.A. 45 (citing
 Apple’s Comments Pursuant to 37 C.F.R. § 1.947, J.A.
 6299). That is, the limitation in question—returning an
 error message upon determining that the client computer
 is not permitted to resolve addresses of non secure target
 computers—would be understood to be disclosed by the
 BinGO reference, even though not expressly stated as such
 in the reference itself. That finding is supported by
 substantial evidence and is sufficient to satisfy the
 requirements of anticipation under Genentech.
                              3
     Apart from those two principal challenges to the
 Board’s use of BinGO as an anticipating reference, VirnetX
 asserts in passing that BinGO “operates differently than
 claim 18.” VirnetX Br. 32. The evidence on which VirnetX
 relies in making that argument consists of statements from
 its expert’s declaration to the effect that BinGO does not
 disclose “determining if the user’s PC is authorized to
 resolve addresses not located” on the network and does not
 disclose “performing such a determination with respect to
 ‘non secure target computers.’” Id. (citing J.A. 4122–23).
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 10                                  VIRNETX INC. v. APPLE INC.

     Apple offered contrary evidence, which the examiner
 credited, and the Board upheld the examiner’s findings on
 that issue. J.A. 44–45. In particular, Apple offered
 evidence that in one configuration BinGO requires
 authentication before the DNS request is resolved, without
 regard to whether the request specifies a secure or non-
 secure destination; Apple’s evidence also showed that
 BinGO discloses routers that establish and maintain
 connections to multiple networks based on the destination
 specified in a DNS request. See J.A. 351–52, 6296–97;
 Right of Appeal Notice pp. 25–26 (Nov. 6, 2019). That is,
 because BinGO discloses authentication based on target
 computer security, a person of ordinary skill in the art
 would understand that BinGO discloses determining
 whether a user’s computer is authorized to resolve
 addresses not located on the network, including those of
 non secure target computers. We conclude that substantial
 evidence supports the Board’s determination on that issue.
     For those reasons, we sustain the Board’s ruling that
 BinGO anticipates claim 18 of the ’135 patent. Because we
 have upheld the use of the BinGO! User Guide and the
 BinGO! Extended Feature Reference as a single reference,
 and because VirnetX has not challenged the rejections of
 claims 10 and 12 on other grounds in this appeal, we
 uphold those rejections as well.
                              III
     VirnetX makes a brief reference to claim 11, arguing
 that the obviousness rejection of claim 11 based on BinGO
 and Reed “fails for the same reason” as the rejections of
 claims 10, 12, and 18 based on BinGO. VirnetX Br. 36.
 With respect to claim 11, VirnetX makes the same
 argument that the two BinGO references cannot be
 considered as one. Because that argument has been
 rejected for anticipation purposes, it fails a fortiori in the
 obviousness context.
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 VIRNETX INC. v. APPLE INC.                                11

                              IV
                              A
     VirnetX’s final point on appeal relates to the way the
 Patent and Trademark Office (“PTO”) handled VirnetX’s
 request for rehearing of the Board’s decision. In its six-
 page request for rehearing, VirnetX sought reconsideration
 of various aspects of the Board’s ruling, including a single
 paragraph devoted to the Board’s reliance on BinGO as an
 anticipating reference for claim 18.
      In the concluding paragraph of the request for
 rehearing, VirnetX stated that “reconsideration of all of
 VirnetX’s prior arguments, which VirnetX continues to
 maintain, is also appropriate here given imminent
 guidance from the Supreme Court regarding the proper
 remedy for decisions rendered by Board panels whose
 appointments did not comport with the requirements of the
 Appointments Clause.” J.A. 7055. Citing this court’s
 decision in Arthrex, Inc. v. Smith & Nephew, Inc., 941 F.3d
 1320 (Fed. Cir. 2019), VirnetX noted that the court had
 held that the Board’s structure “did not comply with the
 constitutional requirements because [Board judges] were
 principal officers of the United States not appointed in
 conformity with the Appointments Clause’s provisions.”
 J.A. 7055. VirnetX then pointed out that the Supreme
 Court “may agree that the remedy [discussed by the
 Federal Circuit in its Arthrex decision] did not cure the
 Appointments Clause violation and/or may order a
 different remedy.” Id. at 7056. In its conclusion, VirnetX
 stated that “whatever remedy is provided by the Supreme
 Court should be provided in the present examination.” Id.
     A week after VirnetX filed its request for rehearing, the
 Supreme Court issued its decision in Arthrex, in which it
 agreed with the Federal Circuit that the unreviewable
 authority wielded by Board judges in inter partes review
 proceedings is incompatible with the Appointments
 Clause, but held that an appropriate remedy was to render
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 12                                VIRNETX INC. v. APPLE INC.

 inoperative the statutory restrictions that prevented the
 Director of the PTO from reviewing final decisions issued
 by Board judges during such proceedings. United States v.
 Arthrex, Inc., 141 S. Ct. 1970 (2021).
     Considering VirnetX’s express reference to the
 challenge to the constitutionality of the Board’s structure
 and VirnetX’s request that it be accorded whatever remedy
 the Supreme Court provided in its Arthrex decision, the
 Board treated VirnetX’s request for rehearing as a request
 for Director review. The Commissioner of Patents, Andrew
 Hirshfeld, acting on behalf of the Director, then reviewed
 the request and on January 10, 2022, denied it. J.A. 55–
 57.
     VirnetX now contends that it was improper for the
 Board to treat the request for rehearing as a request for
 Director review, and that the Board should itself have
 ruled on the request for rehearing. As a result, VirnetX
 argues, this court should remand the case to the Board for
 a further review of the request for rehearing.
     Shortly after the Supreme Court’s decision in Arthrex,
 the PTO issued interim guidance for Director review of
 Board decisions in inter partes review or post-grant review
 cases. The guidance explained that in seeking rehearing,
 a party must choose between asking for rehearing from the
 Board panel or from the Director and would not be
 permitted to request both. See Arthrex Q&As, A3, found at
 https://uspto.gov/patents/patent-trial-and-appeal-board/
 procedures/arthrex-qas (“[A] party may request either
 Director review or rehearing by the original PTAB panel,
 but may not request both.”). Following the issuance of that
 guidance, VirnetX did not specify whether it was seeking
 Director review, Board review, or both.
                             B
    VirnetX raises several arguments regarding the
 Board’s handling of the request for rehearing. First,
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 VIRNETX INC. v. APPLE INC.                               13

 VirnetX argues that the Board’s failure to render a decision
 itself on the request for rehearing violated 37 C.F.R.
 § 41.79(d), which provides that the Board “shall render a
 decision on the request for rehearing.” Second, VirnetX
 points to the requirement of the Administrative Procedure
 Act (“APA”) that an agency “fully and particularly set out
 the bases upon which it reached [its] decision,” Power
 Integrations, Inc. v. Lee, 797 F.3d 1318, 1323 (Fed. Cir.
 2015), and argues that Commissioner Hirshfeld’s denial
 order did not adequately explain the basis for his denial of
 the request for rehearing. VirnetX Br. 38. Third, VirnetX
 contends that it is unclear whether Commissioner
 Hirshfeld reviewed the request for rehearing on the merits
 rather than simply concluding that Director review is
 unavailable in inter partes reexamination proceedings.
 VirnetX Br. 41–42. 8
     As Apple points out, the subtext of VirnetX’s complaint
 seems to be that VirnetX should have been permitted to
 seek both rehearing by the Board and Director review,
 rather than having to elect one form of review or the other.
 In the interim guidance provided by the PTO following the
 Supreme Court’s decision in Arthrex, however, the PTO
 made clear that a party could choose which form of review
 to request, but would not be entitled to have a petition for
 rehearing reviewed by both the Board and the Director.
 While it is true that the PTO issued its interim guidance

     8   VirnetX’s fourth argument is that Commissioner
 Hirshfeld was not properly appointed as a principal officer
 of the United States and thus was not qualified to act on
 behalf of the Director in conducting Director review in this
 case. Br. 43–44. VirnetX acknowledges that its argument
 on that issue is foreclosed by this court’s decision in Ar-
 threx, Inc. v. Smith & Nephew, Inc., 35 F.4th 1328 (Fed.
 Cir. 2022), and is being raised simply to preserve the issue
 for en banc or Supreme Court review.
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 14                                  VIRNETX INC. v. APPLE INC.

 after VirnetX filed its request for rehearing, VirnetX could
 have made clear, following the issuance of that interim
 guidance, that it wished to have the Board rule on its
 request for rehearing rather than seeking Director review,
 but it did not.
     Contrary to the implications of VirnetX’s position, we
 do not read section 41.79(d) of the PTO’s regulations to
 require the PTO to grant the right to two successive
 reviews of a request for rehearing, one by the Board and
 the other by the Director. VirnetX cites no authority
 indicating that such a two-stage review process is required.
 Nor is the PTO’s position that a party seeking rehearing
 must choose one or the other of those paths at odds with
 the text of section 41.79(d), because the PTO could
 reasonably conclude that a party that elects Director
 review has waived its right to rehearing by the Board.
     As for VirnetX’s second argument, neither the PTO
 regulations (including the PTO’s interim guidance) nor the
 APA required Commissioner Hirshfeld or the Board to
 provide an explanation for his decision to deny VirnetX’s
 request for rehearing. The regulation and the interim
 guidance do not require such an explanation, 9 and the
 pertinent portion of the APA, 5 U.S.C. § 555(e), likewise
 does not require agencies to explain rehearing denials.
 Rather, the statute expressly states that the requirement
 of an explanation for agency action does not apply to an
 agency decision “affirming a prior denial.” See ICC v. Bhd.

      9  The regulation provides that the agency’s decision
 on the request for rehearing “is deemed to incorporate the
 earlier opinion reflecting its decision for appeal, except for
 those portions specifically withdrawn . . . .” 37 C.F.R.
 § 41.79(d). That provision makes it clear that if the agency
 does not alter the initial decision on rehearing, the expla-
 nation given in the initial decision will serve as the
 agency’s final word on the matter.
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 VIRNETX INC. v. APPLE INC.                                15

 of Locomotive Eng’rs, 482 U.S. 270, 283 (1987) (“The vast
 majority of denials of reconsideration . . . are made without
 statement of reasons, since 5 U.S.C. § 555(e) exempts from
 the normal APA requirement of ‘a brief statement of the
 grounds for denial’ agency action that consists of ‘affirming
 a prior denial.’”).
     There is also no force to VirnetX’s third argument—
 that Commissioner Hirshfeld’s decision following Director
 review may not have been based on the merits. If VirnetX
 can be viewed as having elected Director review, it must be
 regarded as having accepted the possibility that the
 Commissioner might decide the request for rehearing on
 procedural grounds rather than on the merits.
      Even assuming the PTO erred in treating VirnetX’s
 request for rehearing as a request for Director review, we
 conclude that the error was harmless. The bulk of
 VirnetX’s request for review is addressed to issues not
 germane to VirnetX’s appeal in this case. The only portion
 of the request for review that is pertinent here is a single
 paragraph dealing with claim 18. J.A. 7054–55. In that
 paragraph, VirnetX argued that the Board erred in holding
 that the error message limitation could be found in BinGO
 because a person of ordinary skill in the art would have
 immediately understood from the BinGO reference that an
 authentication failure would result in an error message
 being returned. J.A. 7055. VirnetX does not challenge the
 Board’s factual finding on that issue, and we have held
 above that the Board’s legal conclusion flowing from that
 finding was consistent with our decision in Genentech. It
 is therefore highly unlikely that the Board’s decision on the
 request for review would have resulted in relief based on
 that claim of error.
     The other ground on which VirnetX challenged the
 Board’s ruling on claim 18 was VirnetX’s assertion, without
 elaboration, that the Board “misapprehended” VirnetX’s
 argument that BinGO does not disclose limitation (3) of
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 16                                VIRNETX INC. v. APPLE INC.

 claim 18 and the following “wherein” clause of the claim.
 In our discussion of the Board’s interpretation of claim 18
 above, we analyzed and rejected VirnetX’s argument that
 the Board misunderstood claim 18. For the same reasons,
 there is no substantial likelihood that the arguments made
 in VirnetX’s request for rehearing would have led the
 Board to alter its ruling as to claim 18. We therefore
 conclude that the PTO’s decision to direct VirnetX’s request
 for rehearing to Commissioner Hirshfeld rather than the
 Board was, at most, harmless error, and that a remand for
 Board consideration of the request is not required.
                        AFFIRMED