PTAB

IPR2015-01046

Mangrove Partners Master Fund Ltd v. VirnetX Inc

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Agile Network Protocol for Secure Communications with Assured System Availability
  • Brief Description: The ’135 patent describes a system and method for secure communication over the Internet. The challenged claims specifically relate to a Domain Name Service (DNS) proxy server that transparently creates a virtual private network (VPN) in response to a domain name inquiry for a secure website.

3. Grounds for Unpatentability

Ground 1: Anticipation by Kiuchi - Claims 1, 3, 4, 7, 8, 10, and 12 are anticipated by Kiuchi under 35 U.S.C. §102(b).

  • Prior Art Relied Upon: Kiuchi (Takahiro Kiuchi and Shigekoto Kaihara, "C-HTTP - The Development of a Secure, Closed HTTP-based Network on the Internet," IEEE Proceedings of SNDSS 1996).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kiuchi discloses every limitation of the challenged claims. Kiuchi describes a "C-HTTP" system that creates a secure, closed virtual network over the public internet using client-side and server-side proxies. This system functions as the claimed VPN. The method starts when a user agent (client computer) sends a request for a URL to a client-side proxy. This proxy then queries a C-HTTP name server to resolve the hostname, which Petitioner contended is equivalent to the claimed "DNS request." The C-HTTP name server determines if the request is for a destination within the secure, closed network ("a secure web site"). If authorized, the server returns the IP address of the server-side proxy, and the proxies automatically establish a secure, encrypted connection, which constitutes the "automatically initiating the VPN." For non-secure sites, Kiuchi's client-side proxy receives an error and then performs a lookup with a standard DNS server, which Petitioner asserted meets the limitations of dependent claim 3.

Ground 2: Obviousness over Kiuchi and RFC 1034 - Claim 8 is obvious over Kiuchi in view of RFC 1034 under 35 U.S.C. §103.

  • Prior Art Relied Upon: Kiuchi and RFC 1034 (Mockapetris, P., "Domain Names-Concepts and Facilities," Nov. 1987).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative to the anticipation argument for claim 8. Claim 8 requires that the determination of whether a site is secure is performed in a "DNS proxy server," which then passes the request to a DNS server if the site is not secure. In Kiuchi, this function is distributed between the client-side proxy and the C-HTTP name server.
    • Motivation to Combine: Petitioner argued that a person of ordinary skill in the art (POSITA) would find it an obvious design choice to consolidate this functionality into the C-HTTP name server. Instead of the C-HTTP name server returning an error code to the client-side proxy for non-secure requests (requiring the proxy to initiate a second, separate DNS query), a POSITA would combine the steps to streamline the system. Based on the standard DNS functionalities described in RFC 1034, the C-HTTP name server could be modified to directly query the conventional DNS server itself upon determining a request is for a non-secure site.
    • Expectation of Success: A POSITA would have a high expectation of success because the C-HTTP name server already performs name service functions. Integrating a conventional DNS lookup for non-secure requests would be a simple and predictable rearrangement of known functions to improve efficiency.

4. Key Claim Construction Positions

Petitioner argued for specific constructions crucial to its unpatentability arguments, asserting they align with the broadest reasonable interpretation standard.

  • "Virtual Private Network (VPN)" (Claims 1, 10): Petitioner proposed the construction "a secure network that includes portions of a public network." This construction was central to the petition, as Petitioner argued against the Patent Owner's narrower interpretations from prior litigations.

    • No Encryption Requirement: Petitioner contended that a VPN, under the broadest reasonable interpretation, does not strictly require encryption. The ’135 patent specification itself describes security being achieved through alternative methods like "IP address hopping," suggesting encryption is a common but not mandatory feature.
    • No "Direct Communication" Requirement: Petitioner argued that the term VPN does not require that the client and target computers communicate directly without intermediaries. The presence of proxies, routers, and firewalls is typical in network communication, and Kiuchi's use of client-side and server-side proxies to establish the secure channel falls within the scope of a VPN. Petitioner asserted that any disclaimers made by the Patent Owner during district court litigation regarding "direct communication" are not controlling in an inter partes review (IPR).

  • "Client Computer" (Claims 1, 10): Petitioner proposed construing this term as "a computer from which a data request to a server is generated." This broader construction was argued to be consistent with the specification and PTAB precedent, pushing back against the Patent Owner's attempt to narrow the term to a "user's computer," which Petitioner characterized as improperly reading limitations from an embodiment into the claims.

5. Relief Requested

  • Petitioner requested the institution of an IPR and the cancellation of claims 1, 3, 4, 7, 8, 10, and 12 of the ’135 patent as unpatentable.