Trials@uspto.gov
`571-272-7822
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`Paper 11
`Entered: September 1, 2022
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`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`APPLE INC.,
`Petitioner,
`
`v.
`
`TELEFONAKTIEBOLAGET LM ERICSSON,
`Patent Owner.
`
`
`
`
`
`
`IPR2022-00618
`Patent 9,313,178 B2
`
`
`
`
`Before GEORGIANNA W. BRADEN, NATHAN A. ENGELS,
`and NORMAN H. BEAMER, Administrative Patent Judges.
`
`BEAMER, Administrative Patent Judge.
`
`DECISION
`Granting Institution of Inter Partes Review
`35 U.S.C. § 314
`
`
`
`
`
`
`571-272-7822
`
`
`
`
`Paper 11
`Entered: September 1, 2022
`
`
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`APPLE INC.,
`Petitioner,
`
`v.
`
`TELEFONAKTIEBOLAGET LM ERICSSON,
`Patent Owner.
`
`
`
`
`
`
`IPR2022-00618
`Patent 9,313,178 B2
`
`
`
`
`Before GEORGIANNA W. BRADEN, NATHAN A. ENGELS,
`and NORMAN H. BEAMER, Administrative Patent Judges.
`
`BEAMER, Administrative Patent Judge.
`
`DECISION
`Granting Institution of Inter Partes Review
`35 U.S.C. § 314
`
`
`
`
`
`
`
`IPR2022-00618
`Patent 9,313,178 B2
`
`
`INTRODUCTION
`I.
`On February 25, 2022, Apple Inc. (“Petitioner”) filed a Petition
`(“Pet.”) pursuant to 35 U.S.C. §§ 311–319 to institute an inter partes review
`of claims 1–20 of U.S. Patent No. 9,313,178 B2 (“the ’178 patent”).
`Paper 2. On July 8, 2022, Telefonaktiebolaget LM Ericsson (“Patent
`Owner”) filed a Preliminary Response (“Prelim. Resp.”). Paper 9.
`The standard for instituting an inter partes review is set forth in
`35 U.S.C. § 314(a), which provides that an inter partes review may not be
`instituted unless the information presented in the Petition and any
`preliminary response shows that “there is a reasonable likelihood that the
`petitioner would prevail with respect to at least 1 of the claims challenged in
`the petition.”
`For the reasons explained below, we determine that Petitioner has
`established a reasonable likelihood that it would prevail with respect to at
`least one challenged claim. Accordingly, we institute an inter partes review
`as to the challenged claims and grounds raised in the Petition.
`
`II. BACKGROUND
`The ’178 Patent
`A.
`The ’178 patent, titled “Method And System For Secure Over-The-
`Top Live Video Delivery,” was filed on April 30, 2014, issued on April 12,
`2016, and lists a related continuation application filed June 22, 2012, and
`related provisional application filed June 23, 2011.1 Ex. 1001, codes (54),
`(22), (45), (63), (60).
`
`
`1 The effective priority date for the claims is not at issue here.
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`The ’178 patent is directed to managing key rotation (use of a series
`of keys) and secure key distribution in “over-the-top” content delivery,
`which is the delivery of media content over the public Internet. Ex. 1001,
`code (57), 1:15–20. Key rotation is called for when live streaming content
`with long or indefinite durations, because the use of a single encryption key
`for the entire duration increases the probability that the key may be
`compromised. Id. at 1:23–26. As an example, MPEG video content is
`divided into segments of fixed duration, and the segments are encrypted with
`encryption keys. Id. at 2:53–64. Figure 1 is reproduced below.
`
`Figure 1 is a block diagram of a content delivery system. Ex. 1001, 4:39.
`Content management system (CMS) 112 provides high-level control over
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`content ingestion, packaging and delivery. Id. at 5:15–17. Workflow
`manager (WFM) 102 performs more detailed control operations for
`preparation of live content, including generation of content encryption keys.
`Id. at 5:17–18, 5:21–25, 6:10–13, 6:29–32. License server 106 is
`responsible for storing encryption keys and providing them to the clients 110
`for use during playback. Id. at 5:18–20. The license server registers client
`devices and verifies the right of each client device to view the content. Id.
`at 6:64–67. Packager(s) 104 receive source content from workflow manager
`(WFM) 102 and process the content for delivery to clients 110 via the
`content delivery network (CDN) 108. Id. at 5:11–13, 6:38–40. The
`packagers segment output files into fixed duration segments, and perform
`content encryption using a series of encryption keys. Id. at 5:13–15, 5:40–
`44, 6:2–7. In an exemplary embodiment, each encryption key has a preset
`expiration time, measured by relative wall clock time, segment numbers, or
`number of video key frames. Id. at 6:13–25. However, WFM 102 can push
`a new content encryption key to packager 104 ahead of time when the
`current content encryption key is deemed to be no longer secure (e.g., if the
`content encryption key has been compromised). Id. at 7:17–20.
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`Figure 3 is reproduced below.
`
`
`Figure 3 is a flow diagram showing content downloading and decryption
`using content encryption key rotation. Ex. 1001, 4:42–43. After streaming
`information is requested by and received at client 110 in steps 302 and 304,
`successive segments are retrieved and decrypted in steps 306 and 314. Id.
`at 9:47–56, 10:25–38, 11:32–37. During that process, if an encryption key
`has expired, it is “rotated” — i.e., it is replaced by the next key — in
`steps 310 and 312. Id. at 1:63–65, 11:3–12. Also during the process, at
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`steps 316 and 318, client 110 checks to see if the current content encryption
`key is going to expire within a preset time period, and if so, proactively
`requests a new content encryption key ahead of time to prevent any latency
`in or interruption of decryption services. Id. at 11:38–45. There is also a
`provision, in step 308, to detect the above-mentioned occurrence of a key
`change outside of any fixed duration lifespan for security reasons, in which
`case the client takes that into account. Id. at 10:40–43, 10:65–11:2.
`
`Illustrative Claim
`B.
`Independent claim 1 is reproduced below.
`1. A method for handling secure distribution of content
`comprising:
`initiating a media playback request and receiving a
`playback request response;
`parsing content information from the playback
`request response, the content information
`including content encryption keys, content
`encryption key identifiers, and content
`encryption key expiration times;
`retrieving content and manifest files from a content
`delivery server;
`detecting content encryption key rotation boundaries
`between periods of use of different content
`encryption keys in decrypting retrieved
`content;
`issuing requests to a license server ahead of a key
`rotation boundary to retrieve a second content
`encryption key to be used after a content
`encryption key rotation boundary is reached;
`and
`applying the second key for content decryption after
`the key rotation boundary is reached.
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`Ex. 1001, 12:2–21.
`
`References
`C.
`Petitioner relies on the following references (Pet. ii, 1):
`• Peterka, US 2002/0172368 A1. Ex. 1004 (“Peterka”).
`• Bocharov, et al., US 2010/0235528 A1. Ex. 1005 (“Bocharov”).
`• Chen, et al., EPU 1 418 756 A2. Ex. 1006 (“Chen”).
`• Balraj, et al., US 2009/0254708 A1. Ex. 1007 (“Balraj”).
`• Peterka, et al., US 2008/0270308 A1. Ex. 1009 (“Peterka308”).
`• Kelly, et al., US 2005/0138362 A1. Ex. 1010 (“Kelly”).
`• Eisen, et al., US 2011/0067012 A1. Ex. 1011 (“Eisen”).
`Petitioner also filed the Declaration of Dr. Aviel Rubin in support of the
`Petition. Ex. 1003 (“Rubin Decl.”).
`
`Asserted Challenges to Patentability
`D.
`Petitioner challenges the patentability of claims 1–20 of the ’178
`patent on the following basis (Pet. 1):
`
`Claims Challenged
`1–4, 6–7, 12–13, 16–
`20
`7–9, 14–15, 19
`
`5
`10
`11
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`35 U.S.C. §2
`103
`
`References
`Peterka, Bocharov
`
`103
`
`103
`103
`103
`
`Peterka, Bocharov, Peterka308,
`Chen
`Peterka, Bocharov, Balraj
`Peterka, Bocharov, Kelly
`Peterka, Bocharov, Kelly,
`Eisen
`
`
`2 The Leahy-Smith America Invents Act, Pub. L. No. 112-29, 125 Stat. 284
`(2011) (“AIA”), included amendments to 35 U.S.C. §§ 102 and 103 that
`became effective after the original filing of the application for the ’178
`patent. Therefore, we apply the pre-AIA versions of these sections.
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`Real Parties in Interest
`E.
`Petitioner identifies itself as the real party in interest. Pet. 66. Patent
`Owner identifies Ericsson AB and Ericsson Inc. as the real parties in
`interest. Paper 6 (Patent Owner’s Mandatory Disclosures), 1.
`Related Proceedings
`F.
`The parties do not identify any related matters. Pet. 66; Paper 6, 1.
`
`III. ANALYSIS
`A. Obviousness: Legal Standards
`A claim is unpatentable for obviousness if, to one of ordinary skill in
`the pertinent art, “the differences between the subject matter sought to be
`patented and the prior art are such that the subject matter as a whole would
`have been obvious at the time the invention was made.” KSR Int’l Co. v.
`Teleflex Inc., 550 U.S. 398, 406 (2007) (quoting 35 U.S.C. § 103). The
`question of obviousness is resolved on the basis of underlying factual
`determinations, including “the scope and content of the prior art”;
`“differences between the prior art and the claims at issue”; and “the level of
`ordinary skill in the pertinent art.” Graham v. John Deere Co., 383 U.S. 1,
`17–18 (1966).
`Additionally, objective indicia of non-obviousness, such as
`“commercial success, long felt but unsolved needs, failure of others, etc.,
`might be utilized to give light to the circumstances surrounding the origin of
`the subject matter sought to be patented. As indicia of obviousness or
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`nonobviousness, these inquiries may have relevancy.”3 Graham, 383 U.S. at
`17–18.
`A patent claim “is not proved obvious merely by demonstrating that
`each of its elements was, independently, known in the prior art.” KSR,
`550 U.S. at 418. Rather, an obviousness determination requires finding
`“both ‘that a skilled artisan would have been motivated to combine the
`teachings of the prior art references to achieve the claimed invention, and
`that the skilled artisan would have had a reasonable expectation of success in
`doing so.’” Intelligent Bio-Sys., Inc. v. Illumina Cambridge Ltd., 821 F.3d
`1359, 1367–68 (Fed. Cir. 2016) (citation omitted); see KSR, 550 U.S. at 418
`(for an obviousness analysis, “it can be important to identify a reason that
`would have prompted a person of ordinary skill in the relevant field to
`combine the elements [in the way the claimed] new invention does”).
`“Although the KSR test is flexible, the Board ‘must still be careful not to
`allow hindsight reconstruction of references . . . without any explanation as
`to how or why the references would be combined to produce the claimed
`invention.’” TriVascular, Inc. v. Samuels, 812 F.3d 1056, 1066 (Fed. Cir.
`2016) (citation omitted).
`Furthermore, an assertion of obviousness “cannot be sustained by
`mere conclusory statements; instead, there must be some articulated
`reasoning with some rational underpinning to support the legal conclusion of
`obviousness.” KSR, 550 U.S. at 418 (quoting In re Kahn, 441 F.3d 977, 988
`(Fed. Cir. 2006)); accord In re NuVasive, Inc., 842 F.3d 1376, 1383 (Fed.
`Cir. 2016) (stating that “‘conclusory statements’” amount to an “insufficient
`
`
`3 At this stage, no issues of objective indicia of non-obviousness are
`presented.
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`articulation [] of motivation to combine”; “instead, the finding must be
`supported by a ‘reasoned explanation’” (citation omitted)); In re Magnum
`Oil Tools Int’l, Ltd., 829 F.3d 1364, 1380 (Fed. Cir. 2016) (“To satisfy its
`burden of proving obviousness, a petitioner cannot employ mere conclusory
`statements. The petitioner must instead articulate specific reasoning, based
`on evidence of record, to support the legal conclusion of obviousness.”).
`A reason to combine must be “accompanied by a reasonable
`expectation of achieving what is claimed in the patent-at-issue.” Intelligent
`Bio-Sys, 821 F.3d at 1367. “The reasonable expectation of success
`requirement refers to the likelihood of success in combining references to
`meet the limitations of the claimed invention.” Id.
`
`Level of Skill in the Art
`
`B.
`Petitioner asserts:
`[A] person of ordinary skill in the art at the time of the
`alleged invention (“POSITA”) would have had a Bachelor’s
`degree in computer science, computer engineering, or a related
`field, and 2-3 years of practical engineering experience,
`including experience designing or researching information
`security systems that employ cryptographic keys to
`encrypt/decrypt digital data . . . . Additional education could
`substitute for professional experience, or significant experience
`in the field could substitute for formal education.
`Pet. 5 (citing Rubin Decl. ¶¶ 23–26).
`Patent Owner does not dispute Petitioner’s proposal at this stage of
`the proceeding. Prelim. Resp. 5.
`Petitioner’s proposal is consistent with the level of ordinary skill in
`the art reflected by the prior art. See Okajima v. Bourdeau, 261 F.3d 1350,
`1355 (Fed. Cir. 2001); In re GPAC Inc., 57 F.3d 1573, 1579 (Fed. Cir.
`
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`1995). On this record, the level of ordinary skill is neither in dispute nor
`dispositive of any challenge. For purposes of this Decision, we apply
`Petitioner’s articulation.
`
`Claim Construction
`C.
`The Petition was accorded a filing date of February 25, 2022.
`Paper 5, 1. In an inter partes review for a petition filed on or after
`November 13, 2018, a claim “shall be construed using the same claim
`construction standard that would be used to construe the claim in a civil
`action under 35 U.S.C. 282(b).” 37 C.F.R. § 42.100(b) (2019). We apply
`the claim construction standard from Phillips v. AWH Corp., 415 F.3d 1303,
`1312–13 (Fed. Cir. 2005) (en banc).
`Claim terms need only be construed to the extent necessary to resolve
`the controversy. Nidec Motor Corp. v. Zhongshan Broad Ocean Motor Co.,
`868 F.3d 1013, 1017 (Fed. Cir. 2017).
`Petitioner states that “no formal claim constructions are presently
`necessary.” Pet. 5. Patent Owner states that it “does not believe the Board
`need resolve any claim construction issues at this stage.” Prelim. Resp. 6.
`However, Patent Owner’s arguments with respect to claim 1 of
`the ’178 patent do raise claim construction issues, which we discuss in
`Section III.D.4.b) below.
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`D.
`
`Alleged Obviousness of Claims 1–4, 6–7, 12–13, and 16–20 over
`Peterka and Bocharov
`Petitioner challenges claims 1–4, 6–7, 12–13, and 16–20 as obvious
`over the combination of Peterka and Bocharov. Pet. 12–44.
`
`1. Peterka
`Peterka, titled “Intial [sic] Free Preview For Multimedia Multicast
`Content,” was filed October 26, 2001, and published November 21, 2002.
`Ex. 1004, codes (54), (22), (43). Peterka is directed to providing free
`preview of a program to client computers in a multicasting system, allowing
`for the opportunity to decide whether to order the program content, and
`using encryption keys to distribute additional program content. Id. at code
`(57). A content distribution system is made up of servers that download
`streaming media to clients. Id. at Fig. 1, ¶ 38. In disclosed embodiments,
`the content is divided into purchasable segments and encrypted with separate
`keys. Id. ¶ 99. Disclosed embodiments provide for a “pull model,” in which
`“each client keeps track of the keys and their expiration times and actively
`requests new keys before the current keys expire so as to avoid service
`interruptions.” Id. ¶ 105.
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`
`Figure 7A is reproduced below.
`
`
`
`Figure 7A is a graph showing distribution of cryptographic keys during
`portions of a program. Ex. 1004 ¶ 21. During the “Free Preview” period,
`the content is encrypted with “Content Key 0,” which is freely distributed.
`Id. ¶¶ 91–92. Subsequent keys are required to decrypt the remainder of the
`program content, delivered only to those clients that purchased the content.
`Id. ¶¶ 92–93.
`
`2. Bocharov
`Bocharov, titled “Delivering Cacheable Streaming Media
`Presentations,” was filed March 6, 209, and published September 16, 2010.
`Ex. 1005, codes (54), (22), (43). Bocharov is directed to streaming media
`fragments from a server to clients, including providing manifest files
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`containing metadata information about the fragments. Id. at code (57), Fig.
`5, ¶¶ 30–31, 53. The manifest can provide timestamps for each fragment
`archived up to the point of the request, and the client uses the timestamp to
`compose a URL for requesting the fragment from the server. Id. at ¶¶ 30–
`31.
`
`3. The Combination of Peterka and Bocharov
`Petitioner argues that one of ordinary skill would have had reason to
`combine the teachings of Peterka and Bocharov, resulting in a combination
`that would have rendered obvious, for example, independent claim 1. Pet.
`12–18. Petitioner argues that Peterka indicates that video content can be
`streamed using various protocols and bit rates, but does not provide
`implementation details. Id. at 13 (citing Rubin Decl. ¶ 69). However,
`argues Petitioner, one of ordinary skill in the art would have had reason to
`use manifest files to provide the necessary information to handle different
`protocols and bit rates, because that technique was well known as evidenced
`by the teachings of Bocharov. Id. at 13–18 (citing Rubin Decl. ¶¶ 70–75).
`Petitioner argues that one of ordinary skill in the art would have been so
`motivated because both Peterka and Bocharov are directed to highly similar
`systems for live streaming of media content, and provide solutions for
`managing heavy loads resulting from many users. Id.
`Patent Owner does not specifically address the merits of combining
`Peterka and Bocharov. See generally Prelim. Resp. Nonetheless the burden
`remains on Petitioner to demonstrate unpatentability. See Dynamic
`Drinkware, LLC v. Nat’l Graphics, Inc., 800 F.3d 1375, 1378 (Fed.
`Cir. 2015). For purposes of this Decision, we determine that Petitioner has
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`provided sufficiently articulated reasoning with rational underpinnings for
`the proffered combined teachings of Peterka and Bocharov.
`
`4. Independent Claims 1 and 16
`a) Petitioner’s Challenge
`For the preamble of claim 1, Petitioner relies on the disclosure in
`Peterka of supplying encrypted video content to clients. Pet. 18 (citing
`Ex. 1004, Figs. 1, 3, ¶¶ 12, 83, 94; Rubin Decl. ¶¶ 76–77).4
`For the claim 1 requirement, “initiating a media playback request and
`receiving a playback request response,” Petitioner relies on the disclosure in
`Peterka of the ability of clients to purchase content and request encryption
`keys, and the response of servers in the form of Entitlement Management
`Messages (EMMs) or Entitlement Control Messages (ECMs). Pet. 19–21
`(citing Ex. 1004, Figs. 7A, 7B, 8, 18–20, ¶¶ 38, 55–56, 91, 101, 104–106,
`110, 121–125, 131, 137; Rubin Decl. ¶¶ 78–81).
`For the claim 1 requirement, “parsing content information from the
`playback request response, the content information including content
`encryption keys, content encryption key identifiers, and content encryption
`key expiration times,” Petitioner relies on the disclosure in Peterka of the
`content of the EMMs and ECMs, which messages, according to Petitioner’s
`expert Dr. Rubin, one of ordinary skill would have known would have been
`parsed by clients to extract the content. Pet. 22–23 (citing Ex. 1004,
`Fig. 7B, ¶¶ 104, 121–125; Rubin Decl. ¶¶ 82–91). In particular, Petitioner
`argues that the messages include the required content encryption keys,
`
`
`4 Based on the present record, we make no determination at this stage of the
`proceeding that the preamble of claim 1 is limiting.
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`content encryption key identifiers, and content encryption key expiration
`times. Id. at 23–26 (citing Ex. 1004, ¶¶ 105–106, 114, 117–121; Rubin
`Decl. ¶¶ 83–86). As to the required encryption key and expiration time
`items, we note that Peterka explicitly discloses that the messages contain
`encryption keys and “the time remaining in the lifetime of the key.”
`Ex. 1004 ¶ 1121. For the encryption key identifier requirement, Petitioner
`relies on additional items contained in the messages: the “type of key,” a
`“parity” value, “a sequence number or a time stamp,” and a “keyed message
`authentication code (MAC), or a public key digital signature for
`authentication,” and argues that from the vantage point of one of ordinary
`skill, these items would have corresponded to, or made obvious, content
`encryption key identifiers. Pet. 24–26 (citing Rubin Decl. ¶ 85).
`For the claim 1 requirement, “retrieving content and manifest files
`from a content delivery server,” Petitioner relies on the disclosures in
`Peterka and Bocharov of clients receiving content from servers, and in
`addition the disclosures in Bocharov of receiving manifest files from a sever,
`and, as discussed above, argues that it would have been obvious to combine
`the teachings of Peterka and Bocharov such that the client device would
`retrieve content and manifest files from a content delivery server. Pet. 32–
`34 (citing Ex. 1004, Fig. 1, ¶¶ 38, 39, 40, 60, 71, 83, 135; Ex. 1005, Fig. 5,
`¶¶ 7, 15, 22–25, 30–35, 49–53; Rubin Decl. ¶¶ 92–94).
`For the claim 1 requirement, “detecting content encryption key
`rotation boundaries between periods of use of different content encryption
`keys in decrypting retrieved content,” Petitioner relies on the disclosure in
`Peterka of methods for signaling to the client information for the client to
`detect content encryption key rotation boundaries, such as including
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`predetermined bit in the header of a packet sent from the server. Pet. 34
`(citing Ex. 1004 ¶¶ 116–121; Rubin Decl. ¶ 95). Petitioner also relies on the
`disclosure in Peterka of a “pull model,” in which “each client keeps track of
`the keys and their expiration times and actively requests new keys before the
`current keys expire so as to avoid service interruptions.” Id. at 34–35 (citing
`Ex. 1004 ¶¶ 105–106, 114; Rubin Decl. ¶¶ 96–97).
`For the claim 1 requirement, “issuing requests to a license server
`ahead of a key rotation boundary to retrieve a second content encryption key
`to be used after a content encryption key rotation boundary is reached,”
`Petitioner relies on the above-referenced disclosure in Peterka of the a “pull
`model.” Pet. 35–36 (citing Ex. 1004, Fig. 8, ¶¶ 82, 105–106, 114; Rubin
`Decl. ¶ 98).
`For the claim 1 requirement, “applying the second key for content
`decryption after the key rotation boundary is reached,” Petitioner relies on
`the disclosure in Peterka of receiving a new content encryption key and
`using that key to decrypt further content. Pet. 36–37 (citing Ex. 1004 ¶¶ 90,
`92, 108, 116; Rubin Decl. ¶¶ 101–102).
`Independent claim 16 is a device counterpart to method claim 1, and
`Petitioner’s arguments and reliance on the combination of Peterka and
`Bocharov for this claim are in substance the same as for claim 1. Pet. 43–
`44.
`
`b) Patent Owner’s Response
`Patent Owner’s response primarily relies on its construction of the
`claim 1 requirement, “detecting content encryption key rotation boundaries
`between periods of use of different content encryption keys in decrypting
`retrieved content” (hereafter, the “detecting requirement”), asserting that the
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`requirement is limited to “the scenario in which the client receives a
`notification instructing it to rotate a key before the normal period-based
`expiration (i.e., “between periods of use”) associated with that key.” Prelim.
`Resp. 12. Patent Owner argues that this requirement is not met by detecting
`“the normal period-based expiration of the current key while decrypting
`content.” Id. at 15.
`Patent Owner’s interpretation of the detecting requirement is premised
`on a specific grammatical construction of the wording of the requirement in
`which “detecting” refers to detecting rotation boundaries that occur between
`normal key expiration boundaries:
`[The limitation] requires “detecting content encryption key
`rotation boundaries between periods of use of different content
`encryption keys in decrypting retrieved content.” The terms
`“detecting” and “between periods of use of different content
`encryption keys” refer to the scenario in which the client
`receives a notification instructing it to rotate a key before the
`normal period-based expiration (i.e., “between periods of use”)
`associated with that key.
`Prelim. Resp. 12. Patent Owner points to the above-discussed provision in
`the ’178 patent, illustrated as step 308 of Figure 3, for providing a new
`content encryption key before normal expiration of the current encryption
`key when the current key is deemed to be no longer secure (e.g., if the
`content encryption key has been compromised), and to detect such a
`premature key change. Prelim. Resp. 8–11; Ex. 1001, Fig. 3 (step 308),
`7:11–20, 10:39–43, 10:65–11:2. Patent Owner in particular relies on the
`statement in the ’178 patent, when describing the process of changing the
`key outside of any fixed duration lifespan, that “[i]f a content encryption key
`change request is detected, the client notes the need to expire the current
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`content encryption key and the content encryption key identifier of the new
`key to be used.” Id. at 12 (citing Ex. 1001, 10:65–11:1). Patent Owner
`argues that the occurrence of the word “detected” in this passage aligns with
`“detecting content encryption key rotation boundaries” in the claim. Id.
`Patent Owner also relies on dependent claims 12–15, which specify various
`ways to detect key rotation boundaries, and which Patent Owner argues can
`only apply to the premature key changes, not to the normal period-based
`expiration of the current key. Id. at 13–15 (citing Ex. 1001, 12:65–13:13).
`Patent Owner argues that, given this construction, Petitioner’s reliance
`on the disclosure in Peterka of methods for signaling to the client
`information for the client to detect content encryption key rotation
`boundaries cannot satisfy the detecting requirement, because it only applies
`to the normal period-based expiration of the current key. Prelim. Resp. 17–
`19. Patent Owner also argues that the disclosure in Peterka of a “pull
`model,” in which “each client keeps track of the keys and their expiration
`times and actively requests new keys before the current keys expire so as to
`avoid service interruptions,” cannot satisfy the detecting requirement,
`because it also only applies to the normal period-based expiration of the
`current key. Prelim. Resp. 20–21.
`Patent Owner also argues that the claim 1 limitation, “issuing requests
`to a license server ahead of a key rotation boundary to retrieve a second
`content encryption key to be used after a content encryption key rotation
`boundary is reached,” is not obvious in light of the combination of Peterka
`and Bocharov. Prelim. Resp. 19, 21–22. For Petitioner’s reliance on the
`disclosure in Peterka of using a predetermined bit to signal encryption key
`rotation boundaries, Patent Owner argues that the new keys being signaled
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`are not received in response to request from the client for a new key.
`Id. at 19. Also, argues Patent Owner, neither the use of the predetermined
`bit, nor the “pull model” operations, satisfy the above discussed detecting
`requirement, which as discussed Patent Owner would limit to key changes
`ahead of the known expiry time of the current key. Id. at 21–22.
`Patent Owner makes the same arguments discussed above for the
`corresponding requirements of independent claim 16. Prelim. Resp. 7, n. 1.
`Patent Owner does not specifically respond to any of Petitioner’s arguments
`regarding the other requirements of claims 1 or 16. See generally Prelim.
`Resp. Nonetheless the burden remains on Petitioner to demonstrate
`unpatentability. See Dynamic Drinkware, 800 F.3d at 1378.
`c) Analysis
`We are not persuaded by Patent Owner’s interpretation of the
`detecting requirement. As discussed above, that interpretation hinges on
`the assumption that “detecting” in the claim limitation at issue only refers
`to detecting rotation boundaries that occur between normal rotation
`boundaries — i.e., key rotations triggered by security issues or other
`specific events, rather than normal key rotations due to expiration of the
`current key. Patent Owner’s rationale for this construction is illustrated by
`the emphasis that Patent Owner applies when quoting the claim language:
`“detecting content encryption key rotation boundaries between
`periods of use of different content encryption keys in decrypting
`retrieved content.”
`Prelim. Resp. 12.
`However, this construction improperly limits the scope of the claim to
`one aspect of the disclosed embodiment of the ’178 patent that deals with the
`special case of key changes requested for security reasons outside of any
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`fixed duration lifespan. Ex. 1001, 10:40–42. Considering, as we must, the
`disclosure of the ’178 patent as a whole, the scope of the disclosure is
`directed broadly to key rotation in general, whether due to scheduled key
`expiration times or otherwise. Id. at code (57), Fig. 3, 1:63–65, 2:23–25,
`3:26–28, 9:47–49; see also Superguide Corp. v. DirecTV Enter., Inc., 358
`F.3d 870, 875 (Fed. Cir. 2004) (“Though understanding the claim language
`may be aided by explanations contained in the written description, it is
`important not to import into a claim limitations that are not part of the claim.
`For example, a particular embodiment appearing in the written description
`may not be read into a claim when the claim language is broader than the
`embodiment”).
`The basic error in Patent Owner’s approach is revealed by its choice
`of emphasis in the above quotation of the claim limitation at issue —
`“detecting” and “between periods of use.” Properly construed, it is the
`“boundaries” that are “between periods of use of different content
`encryption keys,” not the “detecting.” In other words, the phrase “between
`periods of use . . .” modifies “boundaries,” not “detecting.”5 The
`“detecting” limitation refers to all boundaries between key rotations,
`whether caused by normal expiration of a key or by forced rotation due to
`security issues. The “detecting” part of the limitation refers to detecting any
`key rotation boundary. In terms of Figure 3 of the ’178 patent, the detecting
`limitation corresponds to step 316, not step 308:
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`5 See The Chicago Manual of Style Online, 17th Edition, § 5.178 (“Placement
`of prepositional phrases: A prepositional phrase with an adverbial or
`adjectival function should be as close as possible to the word it modifies to
`avoid awkwardness, ambiguity, or unintended meanings.”)
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`In step 316, the client 110 checks to see if the current content
`encryption key is going to expire in the near future or if a
`content encryption key change request for a future segment was
`detected in step 308.
`Ex. 1001, 11:38–41 (emphasis supplied). As stated in this description of
`step 316, normal expiration key boundaries are “check[ed]” — i.e.
`“detected.” We are not persuaded that the use of the word “checks” in this
`description, rather than “detects,” is somehow a disavowal of the broader
`construction of the detecting requirement that we adopt.
`Patent Owner is correct that the detecting requirement covers
`detecting key rotation boundaries that are triggered by security issues, and
`that dependent claims 12–15 refer to specific methods for detecting such key
`changes. But Patent Owner erroneously excludes from claim coverage the
`detection of rotation boundaries due to normal key expiration.
`Thus, we determine that Petitioner’s reliance on the disclosure in
`Peterka of a “pull model,” in which “each client keeps track of the keys and
`their expiration times and actively requests new keys before the current keys
`expire so as to avoid service interruptions,” is reasonably likely to meet the
`detecting requirement of claim 1.6 Based on this, and on our further review
`of Petitioner’s reliance on the combination of Peterka and Bocharov in
`challenging the remaining requirements
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