In a recent inter partes review decision invalidating a patent disclosing systems and methods for filtering network data transfers, the Patent Trial and Appeal Board held that a user manual was a publicly available printed publication that qualified as prior art.
Centripetal Networks is the owner of U.S. Patent No. 9,124,552 B2 (“Filtering Network Data Transfers”), which is directed to filtering data packets transmitted between a secured network and an unsecured network. Cisco filed an IPR against Centripetal, contending that the ‘552 patent was invalid as obvious over the user manual titled “Sourcefire 3D System User Guide.”
Cisco asserted that the Sourcefire manual teaches or suggests all of the limitations of the challenged claims and that a skilled artisan would have been motivated to apply the teachings of Sourcefire to achieve certain of the invention’s claimed features. Cisco maintained that the Sourcefire manual was “publicly accessible”—a requirement to qualify as prior art under 35 U.S.C. § 102(b)—because (1) a copy was enclosed on CD-ROM discs included with each Sourcefire 3D System product sold by Sourcefire, Inc., and (2) it was available “for download by persons who had received a login and password from Sourcefire, Inc. to its support website.”
Centripetal argued that Cisco failed to establish that the Sourcefire manual was publicly accessible. In support, Centripetal pointed out that access to the manual was limited by login and password, and the CD-ROM version of the manual was distributed only to approximately 586 customers who purchased the Sourcefire 3D System. Centripetal further argued that Cisco failed to allege why or how a skilled artisan could have found the manual through mere reasonable diligence, nor did Cisco explain how many documentation disks were provided with the product and whether the discs were indexed in any meaningful way. Additionally, there was no evidence that the manual was (or would have been) made available to non-customers upon request. The high cost of the corresponding Sourcefire products also weighed against finding that the manual was publicly accessible.
The PTAB concluded that the Sourcefire manual qualifies as a prior art printed publication and that Cisco proved by a preponderance of the evidence that the manual was publicly accessible through distribution on CD-ROM discs with public sales of the Sourcefire products. The PTAB explained that the Sourcefire 3D System was publicly sold to at least 586 customers (with no restrictions or limits on who could buy it), and a copy of the Sourcefire manual was included on CD-ROM with every system sold. No evidence indicated that the cost of acquiring the Sourcefire system was prohibitively high, or that customers who received the Sourcefire manual had any confidentiality obligations. To the contrary, the manual states that customers “may use, print out, save on a retrieval system, and otherwise copy and distribute the Documentation solely for non-commercial use.”
Additionally, the PTAB noted that the 586 sales of the Sourcefire 3D System, each including a copy of the manual, “far exceeds the number of disclosures recognized under the relevant dissemination law for printed publications.” Further, the evidence established that skilled artisans actually purchased the Sourcefire 3D System. Sourcefire regularly advertised its products for sale, including in a press release announcing the relevant Sourcefire software, and those products were accompanied by manuals. Customers who received the Sourcefire 3D System included entities interested in network security products, including persons of ordinary skill in the art.
The PTAB rejected Centripetal’s argument that limited distribution of the Sourcefire manual to customers of the Sourcefire product was insufficient to demonstrate “public accessibility,” explaining that the Federal Circuit has held that “a limited distribution can make a work publicly accessible under certain circumstances.” And, in this case, the circumstances reflected that the Sourcefire manual was publicly accessible because it was distributed to all purchasers of the Sourcefire 3D system, with no obligations of confidentiality and with the expectation that the Sourcefire manual could be shared for non-commercial use.
Implications for Patent Law Litigation
Given the prevalence of IPR petitions filed by alleged infringers, it is important to consider the potential scope of prior art references used to challenge a patent in patent infringement litigation. This decision demonstrates that the PTAB is willing to construe flexibly, and perhaps broadly, what qualifies as a prior art printed publication.
 Samsung Elecs. Co. v. Infobridge Pte. Ltd., 929 F.3d 1363, 1369 (Fed. Cir. 2019).