CAFC confirms PTAB findings that Centripetal’s Network Security Patent Claims Are Obvious
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“Although the CAFC conceded that the PTAB misstated the legal standard from Syntex (U.S.A.) v. Apotex, incorrectly raising a sufficient condition for teaching away into a necessary condition, the error was harmless in context.”
Today, the U.S. Court of Appeals for the Federal Circuit (CAFC) issued a pair of rulings on appeals filed by cybersecurity developer Centripetal Networks, following decisions by the Patent Trial and Appeal Board (PTAB) that invalidated its patent claims to network threat detection technologies. Affirming the PTAB’s obviousness findings in both rulings, the Federal Circuit found substantial evidence supporting the Board’s claim constructions underlying those obviousness determinations, despite a sometimes-unclear separation between the Board’s claim construction and analysis.
‘Responsive To’ Limitation Not Satisfied by Threat Indicator Alone
In one ruling, the Federal Circuit affirmed the PTAB in a pair of inter partes review (IPR) proceedings challenging claims of Centripetal’s U.S. Patent No. The ‘Responsive To’ limitation is not satisfied by the threat indicator alone
In one ruling, the Federal Circuit affirmed the PTAB in a pair of inter partes review (IPR) proceedings challenging claims of Centripetal’s U.S. Patent no. The patents’ common specification discloses the use of a packet-filtering device for receiving data packets and determining whether each packet satisfies criteria specified by a packet-filtering rule corresponding to network threat indicators. The patents’ common specification discloses the use of a packet-filtering device for receiving data packets and determining whether each packet satisfies criteria specified by a packet-filtering rule corresponding to network-threat indicators.
In IPR proceedings petitioned by Palo Alto Networks challenging these patents, the Board construed the meaning of the claim term “responsive to,” a limitation indicating that the claimed method communicates threat indicators and applies operators following the determination that a packet satisfies the packet-filtering rule. The Board found this limitation disclosed by user guides for the Sourcefire 3D System, an enterprise threat management system that analyzes network traffic according to intrusion rules that can trigger different intrusion actions.[ness]Centripetal appealed the PTAB’s IPR determinations, arguing that the Board impermissibly failed to construe the “responsive to” limitation. The Federal Circuit acknowledged the Board’s confusion of claim construction with application made it more difficult to determine the proper standard for agency review. The appellate court, however, found that the PTAB discussion of the Sourcefire prior arts established that the claimed invention is “responsive
to” sources indicating that network threats include an action taken based upon source information in conjunction with other criteria. This finding nixed Centripetal’s argument that the communicating and applying steps should be triggered by a determination based on network-threat indicators alone.
Affirming this construction led the Federal Circuit to uphold the rest of the PTAB’s obviousness determinations in these IPRs. The Board determined that Sourcefire intrusion rules are triggered when Internet protocol (IP), “which are undisputedly “network-threat indicator”,” and other optional criteria, are satisfied. The Federal Circuit found Centripetal’s remaining arguments, including that intrusion rules can be triggered by an IP address alone, to be duplicative of its failed claim construction arguments.
‘Boundary’ Limitation Met Even Under Centripetal’s Narrow Claim Construction
In the second ruling issued today, the Federal Circuit affirmed the PTAB’s obviousness finding in a separate IPR petitioned by Palo Alto Networks to challenge the validity of Centripetal’s U.S. Patent No. The same title as the patents ‘028’ and ‘126’ is 10567413. In that IPR the PTAB found that the challenged claims were invalid in relation to the Sourcefire user manual combined with U.S. Patent Application No. 20150207809 (“Macaulay”), which discloses a real-time system for information sharing on threat agents that assigns reputation scores reflecting the extent to which network traffic has been compromised.
Centripetal appealed the PTAB’s construction of claim terms limiting a packet-filtering device to a location “at a boundary” between protected and unprotected networks. Centripetal argued the “boundary’ limitation was meant to be interpreted as requiring that the claimed device is the first point of contact between a user’s network and unprotected Internet. The Federal Circuit found that Sourcefire’s disclosures of the “boundary limitation” were supported by the fact that installation guides for Sourcefire’s threat management system discussed the placement of network sensors between a firewall and border router to analyze all traffic. Even under Centripetal’s proposed construction, the appellate court found language in Sourcefire’s installation guide that could be reasonably interpreted as showing the traffic sensor as the first interface between a protected network device and an unprotected network.
Centripetal also challenged the sufficiency of the analysis set out by Palo Alto Network’s IPR petition, arguing that a cross-reference label used by the petition limited the patentability challenge to Macaulay alone. However, the Federal Circuit found that the petition was cross-referencing relevant arguments made on independent claims with limitations related to those challenged under the combination of Sourcefire and Macaulay.
Finally, the Federal Circuit dismissed Centripetal’s argument that the PTAB improperly rejected evidence that prior art taught away from combining the references. The court acknowledged that the PTAB misrepresented the legal standard in Syntex (U.S.A. v. Apotex (2005) by incorrectly converting a sufficient condition of teaching away into a necessity condition, but the error was harmless when viewed in context. The PTAB applied the correct legal rule when finding that there is no teaching away, the Federal Circuit concluded, and reasonably found that the inability to bodily incorporate Macaulay into the Sourcefire system did not mean that Sourcefire taught away from the combination.
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Author billperry
Steve Brachmann
Steve Brachmann graduated from the University at Buffalo School of Law in May 2022, earning his Juris Doctor. He served as the president of the Intellectual […see more]
