PTAB

IPR2014-00614

Microsoft Corp v. VirnetX Inc

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1. Case Identification

2. Patent Overview

  • Title: Agile Network Protocol for Secure Communications Using Secure Domain Names
  • Brief Description: The ’504 patent describes a domain name service for establishing a secure communication link. The system is configured to connect to a network, store domain names and corresponding network addresses, receive a query for a network address, and provide an indication that the system supports establishing a secure link.

3. Grounds for Unpatentability

Ground 1: Anticipation over Kiuchi - Claims 1, 2, 6, 14-17, 19-23, 26-31, 33-41, 43-47, 50-55, and 57-60 are anticipated under 35 U.S.C. §102 by [Kiuchi](https://ai-lab.exparte.com/case/ptab/IPR2014-00614/doc/1018).

  • Prior Art Relied Upon: Kiuchi et al., “C-HTTP – The Development of a Secure, Closed HTTP-based Network on the Internet,” (published by IEEE 1996).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kiuchi disclosed every limitation of the challenged claims. Kiuchi described a secure "C-HTTP" protocol and system that provided secure communication for a closed group of institutions over the public Internet. This system, comprising client-side and server-side proxies and a C-HTTP name server, constituted the claimed "domain name service system." Petitioner asserted this system was connected to the Internet (the "communication network"), stored hostnames (claimed "domain names") and corresponding IP addresses, and received queries for network addresses to resolve hostnames. The "indication" of supporting a secure link was met by the C-HTTP name server's response: returning an IP address and public key for a secure destination (indicating success) versus an error code for a non-secure one.
    • Key Aspects: Petitioner contended that Kiuchi’s C-HTTP name server, in conjunction with standard DNS servers for external requests, performed all functions of the claimed system, including transparently establishing an encrypted, secure communication link between proxies.

Ground 2: Obviousness over Kiuchi and RFC 1034 - Claims 20, 21, 35, 44, 45, and 59 are obvious over Kiuchi in view of [RFC 1034](https://ai-lab.exparte.com/case/ptab/IPR2014-00614/doc/1010).

  • Prior Art Relied Upon: Kiuchi and RFC 1034, “Domain Names - Concepts and Facilities,” (Nov. 1987).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims requiring a "domain name database." Petitioner argued that while Kiuchi’s name server inherently stored domain names and IP addresses, RFC 1034 explicitly disclosed the structure of a formal domain name database used by name servers in the Domain Name System (DNS). RFC 1034 described name servers as repositories of information that make up the domain database, which is divided into zones.
    • Motivation to Combine: A POSITA would have been motivated to implement the name storage function in Kiuchi's C-HTTP name server using a structured domain name database as taught by RFC 1034. This was because databases provide fast, efficient, and structured storage and retrieval, which is necessary for timely responses when resolving a large number of domain names and IP addresses, a well-known problem in network design.
    • Expectation of Success: The combination was a straightforward application of a standard, well-understood data storage solution (a DNS database) to a known system (Kiuchi's name server), and therefore a POSITA would have had a high expectation of success.

Ground 3: Obviousness over Kiuchi and RFC 2660 - Claims 16, 27, 33, 40, 51, and 57 are obvious over Kiuchi in view of [RFC 2660](https://ai-lab.exparte.com/case/ptab/IPR2014-00614/doc/1012).

  • Prior Art Relied Upon: Kiuchi and RFC 2660, “The Secure HyperText Transfer Protocol,” (Feb. 1996).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed claims requiring the establishment of a secure communication link "between" a first location and a second location, which Petitioner argued could be interpreted to require true end-to-end security (e.g., from user agent to origin server). Kiuchi’s primary security was between intermediate proxies. RFC 2660 disclosed Secure HTTP (S-HTTP), a protocol providing security mechanisms directly between HTTP clients and servers for end-to-end secure transactions.
    • Motivation to Combine: Petitioner argued that Kiuchi itself provided the motivation to combine. Kiuchi explicitly stated that its C-HTTP protocol could "co-exist with" other secure HTTP proposals and that developing C-HTTP proxies compatible with other secure agents and servers was possible to "assure end-to-end or individual security." Kiuchi specifically referenced RFC 2660 as an example of such a protocol.
    • Expectation of Success: A POSITA would have been capable of integrating S-HTTP (from RFC 2660) into Kiuchi’s framework to achieve the stated goal of end-to-end security, as this involved using a known security protocol for its intended purpose.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground 3) for claims 32 and 56 based on Kiuchi in view of Lindblad (Patent 6,225,993). This combination argued that it would have been obvious to add multimedia (audio/video) services, as taught by Lindblad, to the secure communication system of Kiuchi.

4. Key Claim Construction Positions

  • "domain name service system": Petitioner argued this term should encompass any system with the claimed characteristics, which could include one or more discrete computers or devices. This construction was important because Kiuchi's system comprised multiple components (proxies, C-HTTP name server, standard DNS server) that worked together to provide the service.
  • "indication that the domain name service system supports establishing a secure communication link": Petitioner argued for a broad construction to include any visible or non-visible message or signal. This was critical to the anticipation argument, as the "indication" in Kiuchi was the successful return of an IP address and cryptographic data, as opposed to an error message, which itself signaled that a secure connection was supported and could be established.
  • "transparently": Petitioner asserted this meant the user need not be involved in creating the secure link. This supported the argument that Kiuchi's automated proxy-based system, which did not require user intervention to establish the secure C-HTTP connection, met this limitation.

5. Key Technical Contentions (Beyond Claim Construction)

  • Effective Priority Date: Petitioner contended that the effective filing date for the challenged claims was no earlier than February 15, 2000. It was argued that key claim terms like "domain name service" lacked written description support in any application filed before that date. This was a foundational argument for establishing that Kiuchi (1996), RFC 1034 (1987), and RFC 2660 (1996) were all valid prior art references under §102(b).

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 2, 6, 14-17, 19-23, 26-41, 43-47, and 50-60 of the ’504 patent as unpatentable.