IP Law Daily, PATENT—Fed. Cir.: PTAB properly found internet security dispute claims obvious, (Jul 25, 2025)

By Kevin M. Finson, J.D.

Claims relating to a method of improving internet security were unpatentable as obvious because a prior art reference’s “converting” of information between protocols was essentially identical to the claimed “translating” of information between protocols.

DocuSign successfully showed the obviousness of three patents related to internet security, the U.S. Court of Appeals for the Federal Circuit has held. The Patent Trial and Appeal Board (PTAB) decision to that effect was supported by substantial evidence in the form of expert testimony and the plain language of a prior art reference (Clark v. DocuSign, Inc., No. 24-1301, 24-1302, 24-1308 (Fed. Cir. July 25, 2025)).

Dr. Paul C. Clark was the owner of U.S. Patents Nos. 8,695,066 (the ’066 patent), 9,391,957 (the ’957 patent), 10,129,214 (the ’214 patent), each of which shared a specification and claimed improvements to security mechanisms for business-to-business or business-to-consumer transactions on the internet. Specifically, the claimed method used “one or more conventional security services to enhance data from a first domain, ‘translated’ the data to a target protocol, de-enhanced the translated data, filtered out unauthorized data, and transmitted the filtered data to a second domain.”

DocuSign, Inc. (DocuSign) petitioned for inter partes review (IPR) of all three patents on the ground of obviousness. During the IPR proceeding Clark argued only against DocuSign’s claim mapping and the “translating” limitation, conceding all of the other claim limitation were obvious in light of the prior art. The PTAB instituted review and found all of the challenged claims unpatentable as obvious. Clark appealed.

Claim construction. Clark argued that the Board erred either by failing to resolve an express claim construction dispute or by implicitly construing a claim incorrectly, in that the Board did not determine whether the “target” and “first” protocols referred to in the “translating” step could be the same protocol. The court found that the Board had properly declined to resolve this claim construction dispute because the challenged claims were obvious under either construction, and therefore there was no need for either an express or implicit claim construction.

Obviousness. Clark argued that the prior art reference relied upon by DocuSign did not disclose the “translating” limitation. The court found that the Board had properly relied upon the language of the prior art reference itself as well as expert testimony in finding that the reference’s “protocol converters” were interchangeable with the patent’s claimed “translation.” Clark also argued that the reference was limited to only one protocol, HTTP, but the court found that this was used only as an example and that the reference expressly allowed for different protocols.

The court affirmed the decision of the Board.

The Case is Nos. 24-1301, 24-1302, 24-1308.

Judge: Clevenger, R.

Attorneys: Frederick Ngosi Samuels (Cahn & Samuels, LLP) for Paul C. Clark. Michael John Sacksteder (Fenwick & West LLP) for DocuSign, Inc.

Companies: DocuSign, Inc.

Cases: Patent FedCirNews USPTO