DocuSign Inc v. Clark Paul

1. Case Identification

• Case #: IPR2022-00924
• Patent #: 9,391,957
• Filed: April 22, 2022
• Petitioner(s): DocuSign, Inc.
• Patent Owner(s): Paul C. Clark
• Challenged Claims: 1-3

2. Patent Overview

• Title: System and Method for Secure Communication Between Domains
• Brief Description: The ’957 patent discloses a system for securely transmitting data between two domains across a public network. The method involves enhancing data with security services, performing protocol conversion while preserving the enhancements, filtering for unauthorized transmissions, and authorizing the filtered data for use in an application.

3. Grounds for Unpatentability

Ground 1: Claim 1 is obvious over Duncan in view of Gilbrech

• Prior Art Relied Upon: Duncan (Patent 6,163,844) and Gilbrech (Patent 6,173,399).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Duncan taught a method for secure communication between a client and server that included nearly all limitations of claim 1. This included using a proxy browser to add security services (enhancing data), converting protocols (e.g., from HTTP to a network protocol), using an access control unit to filter requests (filtering unauthorized transmissions), and deciding whether to forward requests to a server (authorizing data). Petitioner asserted that Gilbrech was necessary to teach the specific limitation of the first logical unit including a firewall and a protocol gateway that comprise a Virtual Private Network (VPN) server, a feature not explicitly disclosed in Duncan.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) seeking to improve end-to-end security for the client-server system in Duncan would combine it with Gilbrech’s teachings. Petitioner contended that since Duncan already disclosed a firewall-like access control unit, a POSITA would have been motivated to integrate Gilbrech’s known VPN technology to provide an additional, well-understood layer of security for communications over a public network.
  • Expectation of Success: A POSITA would expect success in combining the systems, as Gilbrech explicitly taught that its VPN unit could be configured "in a single box" with a firewall to provide integrated security functions, making it compatible with the architecture described in Duncan.

Ground 2: Claims 2-3 are obvious over Duncan

• Prior Art Relied Upon: Duncan (Patent 6,163,844).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Duncan, by itself, rendered dependent claims 2 and 3 obvious. Claim 2 adds the limitation that the first and second logical units reside on first and second physical platforms, respectively. Petitioner mapped this to Duncan’s disclosure of a client-side browser running on a personal computer (the first physical platform) communicating with a server-side web server running on a host computer (the second physical platform). Claim 3 adds the limitation that the logical units reside on a physical platform, which Petitioner argued was also taught by Duncan’s disclosure of software components running on computer hardware.

Ground 3: Claim 1 is obvious over Grosser in view of Duncan and Gilbrech

• Prior Art Relied Upon: Grosser (German Application # DE 19645006A1), Duncan (Patent 6,163,844), and Gilbrech (Patent 6,173,399).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner used Grosser as the primary reference, arguing it taught a method for secure communication between a client and server over the internet using intermediate processes. Grosser taught enhancing data via encryption, de-enhancing it via authentication, filtering data with a firewall, and authorizing data based on a computer address. Petitioner asserted Duncan was needed to supplement Grosser’s teachings regarding periodically calculating timestamps and hashes (via its use of TCP) and to provide specific examples of protocol translation. Gilbrech was again relied upon to add the specific configuration of a VPN server that includes a firewall and protocol gateway.
  • Motivation to Combine: A POSITA would combine these references to create a robust, multi-faceted security system. The motivation was to take the secure communication framework from Grosser and improve it by incorporating the well-known TCP functionalities from Duncan and the VPN security architecture from Gilbrech. This would result in a predictable and more secure system for communicating over a public network.
• Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground IV) against claims 2-3 based on the combination of Grosser and Duncan.

4. Key Claim Construction Positions

• Term: "network application level protocol"
  • Petitioner’s Proposed Construction: "a network level protocol and/or an application level protocol."
  • Significance: This construction was central to Petitioner's arguments. During prosecution, the Examiner stated that prior art did not teach adding security services "at the application protocol level." Petitioner argued that its broader construction, supported by examples in the ’957 patent’s specification (e.g., conversion involving SMTP, X.25, and IP) and its prosecution history, encompassed both network and application layer protocols. This broader scope allowed Petitioner to apply prior art like Duncan, which discloses protocol translation involving both layers, to meet the claim limitations.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §325(d) was inappropriate because the petition relied on prior art references (Duncan, Grosser, and Gilbrech) that were never presented to or considered by the Examiner during the original prosecution. Petitioner contended the new art was not cumulative and specifically taught the limitation of "translation of data... at the application protocol level," which the Examiner had previously found missing from the cited art.
• Petitioner also argued against discretionary denial under §314(a) based on the Fintiv factors. It asserted that the parallel district court litigation was in its earliest stages, with no trial date set and minimal discovery conducted. Therefore, an IPR would be efficient, and a stay of the district court case would be highly likely upon institution, favoring review by the Board.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-3 of the ’957 patent as unpatentable.