DocuSign Inc v. Clark Paul

1. Case Identification

• Case #: IPR2022-00925
• Patent #: 10,129,214
• 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 ’214 patent discloses a system for secure data transmission between a first domain and a second domain over a public network. The system uses a first logical unit to enhance data with security services and translate its protocol, and a second logical unit to de-enhance, filter, and authorize the data for use in the second domain.

3. Grounds for Unpatentability

Ground 1: Claim 1 is obvious over Duncan

• Prior Art Relied Upon: Duncan (Patent 6,163,844).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Duncan, which discloses a method for granting access to information in a distributed computer system, teaches every limitation of claim 1. Duncan’s client-side components (a proxy browser) were asserted to meet the limitations of the claimed "first logical unit," as it receives user data, enhances it by adding credentials to a request ("[GET][CREDS]"), translates the data from an application protocol (HTTP) to a network protocol, and transmits it over a public network. Petitioner mapped Duncan’s server-side components (a proxy server and web server) to the claimed "second logical unit," arguing it de-enhances the data by extracting the credentials, filters the request by checking an access control list (ACL) to block unauthorized transmissions, and authorizes the request before transmitting it to a node in the second domain (the web server).
  • Key Aspects: Petitioner contended that fundamental functions of the TCP protocol, which Duncan practices, inherently teach the claimed "periodically calculating timestamps and hashes." The argument also asserted that Duncan’s system adds security services without modifying the underlying application, as it operates transparently via proxy components.

Ground 2: Claim 1 is obvious over Grosser in view of Duncan

• Prior Art Relied Upon: Grosser (German Application # DE 19645006A1) and Duncan (Patent 6,163,844).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Grosser teaches most limitations of claim 1 by disclosing a secure client-server communication method. Grosser’s client-side "intermediate process" (Pm) was mapped to the first logical unit, as it receives data from a web form and enhances it with encryption. Grosser's server-side components (intermediate process Pm' and server Ps) were mapped to the second logical unit, as it de-enhances data (by performing cryptographic authentication), filters data using a packet-filtering firewall, and authorizes data based on computer address. To the extent Grosser did not explicitly teach all limitations, Petitioner argued Duncan supplies the remainder. Specifically, Duncan was cited for its explicit teaching of protocol translation and for practicing the TCP protocol, which inherently requires periodically calculating timestamps and hashes.
  • Motivation to Combine: A POSITA would combine Grosser and Duncan because both address the same problem of securing client-server communications over public networks while working with existing firewalls. A POSITA seeking to implement Grosser's secure system would look to a reference like Duncan for specific, well-known techniques for protocol conversion and for implementing reliable data transfer using TCP, thereby improving Grosser's system with predictable results.
  • Expectation of Success: A POSITA would have an expectation of success in combining the references because integrating Duncan’s standard protocol conversion and TCP functionalities into Grosser's security framework was a straightforward application of known networking principles to enhance interoperability.

4. Key Claim Construction Positions

• Petitioner argued for a specific construction of the term "network application level protocol" to mean "a network level protocol and/or an application level protocol." This construction was asserted to be critical because it allows prior art that teaches translation between different protocol layers (e.g., application-to-network) to satisfy the claim limitation. Petitioner supported this construction by pointing to the ’214 patent's specification, which provides examples of conversion involving both application-level protocols (SMTP, X.400) and network-level protocols (X.25, IP), and to the prosecution history of a related application where the applicant provided a similarly broad list of exemplary protocols.

5. Arguments Regarding Discretionary Denial

• §325(d) - Same or Substantially Same Art: Petitioner argued against discretionary denial under §325(d), emphasizing that neither Duncan nor Grosser was before the Examiner during the original prosecution. Petitioner contended the new art is not cumulative because it discloses translation at the application protocol level, a feature the Examiner previously stated was not taught by the art of record.
• §314(a) - Fintiv Factors: Petitioner argued that the Fintiv factors strongly favor institution. The parallel district court litigation was in its earliest stages, with no trial date set and only limited discovery having occurred, making a stay highly likely if IPR is instituted. Petitioner also asserted that the strong merits of the invalidity case, based on new prior art, favor an efficient resolution at the PTAB, which outweighs other factors.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claim 1 of Patent 10,129,214 as unpatentable.