DocuSign Inc v. Clark Paul

1. Case Identification

• Case #: IPR2022-00923
• Patent #: 8,695,066
• Filed: April 22, 2022
• Petitioner(s): DocuSign, Inc.
• Patent Owner(s): Paul C. Clark
• Challenged Claims: 1

2. Patent Overview

• Title: System and Method for Secure Communication Between Domains
• Brief Description: The ’066 patent describes methods for securing data communications that traverse a public network between two private domains. The claimed method involves adding security services to data in a first domain, translating the data's protocol, transmitting it across a public network, and then filtering, authorizing, and de-enhancing the data in a second domain.

3. Grounds for Unpatentability

Ground 1: Claim 1 is obvious over Duncan, RFC 793, and RFC 1323.

• Prior Art Relied Upon: Duncan (Patent 6,163,844), RFC 793 ("Transmission Control Protocol"), and RFC 1323 ("TCP Extensions for High Performance").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Duncan, which describes a method for granting secure access to information in a distributed computer system like the World Wide Web, taught nearly every limitation of claim 1. Duncan’s system used a client-side proxy browser and a server-side proxy server to manage secure communications. Petitioner asserted that Duncan disclosed enhancing data with security credentials, transmitting user data from a web form, translating the data from an application protocol (HTTP) to a network protocol, and transmitting it over a public network. On the server side, Duncan’s access control unit was alleged to de-enhance (decrypt), filter, and authorize the data before passing it to a web server application. Petitioner contended that while Duncan did not explicitly detail the calculation of timestamps and hashes, it specified the use of the TCP protocol. The well-known RFC 793 and RFC 1323 standards, which define the TCP protocol, explicitly taught the use of checksums (hashes) and timestamps for every data segment.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) implementing the TCP protocol as taught by Duncan would have naturally referred to the defining standards for that protocol, RFC 793 and RFC 1323, to understand its fundamental operations, including the standard use of timestamps and hashes for reliability and performance measurement.
  • Expectation of Success: Since RFC 793 and RFC 1323 are the authoritative standards for the TCP protocol used in Duncan, a POSITA would have had a high expectation of success in implementing the protocol’s standard timestamp and hashing functions as part of Duncan’s system.

Ground 2: Claim 1 is obvious over Grosser, Duncan, RFC 793, and RFC 1323.

• Prior Art Relied Upon: Grosser (German Application No. DE 19645006A1), Duncan (Patent 6,163,844), RFC 793, and RFC 1323.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Grosser taught a secure client-server communication method using intermediate processes that transparently add security, such as encryption, to the data stream. Grosser allegedly disclosed using web forms, enhancing data with encryption, transmitting it over the internet, de-enhancing it via authentication, and filtering it with a firewall that authorizes access based on a computer address. Petitioner asserted that Grosser’s disclosure of "logging" data inherently taught the use of timestamps and its disclosure of creating a "checksum" taught hashing, with the RFCs providing further detail as in Ground 1. While Grosser taught "protocol...adaptation," Petitioner relied on Duncan to explicitly teach the claimed step of translating data from a first network application level protocol to another while preserving security enhancements.
  • Motivation to Combine: A POSITA seeking to implement the general "protocol adaptation" taught by Grosser would combine its teachings with a specific, well-documented implementation like that in Duncan. Both references addressed the same problem of securing client-server communications over a public network, making it obvious to look to Duncan’s specific protocol translation method to supplement Grosser’s security framework.
  • Expectation of Success: A POSITA would have reasonably expected success in combining the references because it involved integrating a known protocol translation technique (from Duncan) into a system designed for secure communication (Grosser), a predictable and common task in network engineering.

4. Key Claim Construction Positions

• "network application level protocol": Petitioner proposed construing this term to mean "a network level protocol or an application level protocol." This construction was argued to be supported by the patent’s specification, which provided examples of both protocol types (e.g., X.25, a network protocol, and SMTP, an application protocol). This broader construction was critical to Petitioner’s argument that Duncan, which taught translating from an application protocol (HTTP) to a network protocol, met the claim limitation.

5. Arguments Regarding Discretionary Denial

• §325(d) Arguments: Petitioner argued against discretionary denial under §325(d), emphasizing that the primary prior art references (Duncan and Grosser) and the RFCs were never presented to or considered by the examiner during prosecution. Petitioner asserted that this new art was stronger than the art of record, as it specifically taught the protocol translation at the application level that the examiner previously found lacking in the cited references.
• §314(a) Fintiv Arguments: Petitioner argued that the Fintiv factors strongly favored institution. The parallel district court litigation was in its infancy, with no trial date set and minimal discovery having occurred. Petitioner stated its intent to file a motion to stay the litigation pending the outcome of the IPR, a motion that is frequently granted in such circumstances. Therefore, Petitioner contended that instituting the IPR would promote efficiency and not be an inefficient use of Board resources.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claim 1 of the ’066 patent as unpatentable under 35 U.S.C. §103.