PTAB

IPR2014-00403

Microsoft Corp v. VirnetX Inc

Key Events

Petition

petition

Title: Method For Establishing Secure Communication Link Between Computers Of Virtual Private Network
Brief Description: The ’274 patent discloses a method for establishing a secure communication link, such as a Virtual Private Network (VPN), between computers. The method involves a client computer querying a specialized "secure domain name service" to resolve a non-standard "secure domain name" into a secure network address, and then using that address to establish a VPN communication link with a second computer.

Prior Art Relied Upon: Provino (Patent 6,557,037).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Provino disclosed every limitation of the challenged claims. Provino described a system where an external client device establishes a secure tunnel to a private network's firewall. To access a server within the private network, the client queried a nameserver located inside the private network (nameserver 32) to resolve a human-readable address into an integer IP address. Petitioner contended this internal nameserver is the claimed "secure domain name service" because it resolves non-standard names that a conventional, external nameserver cannot. After receiving the IP address (the "secure network address") from the internal nameserver through the secure tunnel, the client used it to send an access request to the server, establishing the claimed "virtual private network communication link."

Prior Art Relied Upon: Provino (Patent 6,557,037) and Kosiur (Dave Kosiur, Building and Managing Virtual Private Networks (1998)).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that while Provino taught the core method of establishing the secure link, dependent claims 2-5 add limitations requiring support for a "plurality of services" and application programs (e.g., video conferencing, e-mail, audio, video) over that link. Kosiur, a textbook on VPN technology, explicitly taught that VPNs were commonly configured to support a wide variety of such applications, including interactive multimedia, file transfers, web browsing, e-mail, and IP telephony.
- Motivation to Combine: A POSITA would combine Provino's secure access method with Kosiur's teachings on VPN applications to increase the productivity and mobility of remote employees. Since Provino's system was designed for remote access by employees of a company or government agency, it would have been a natural and obvious improvement to ensure it supported the standard business applications described by Kosiur.
- Expectation of Success: Combining the references involved implementing well-known applications over a known type of network (a VPN), which presented no technical hurdles and would have been a predictable implementation with a high expectation of success.

Prior Art Relied Upon: Provino (Patent 6,557,037) and Xu (Patent 6,151,628).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that claim 18 adds the limitation of performing the method of claim 1 on a "mobile device connected...through a cellular network." While Provino described a generic client computer, Xu explicitly disclosed connecting mobile devices, such as a laptop with a "cellular telephone modem" or a PDA, to a corporate private network using a tunneling protocol over a wireless/cellular network to access a VPN.
- Motivation to Combine: A POSITA would be motivated to modify Provino's system to incorporate Xu's teaching of cellular access. Doing so would advantageously extend the utility of Provino's secure access method to the growing number of mobile users, which was an obvious and desirable goal. Both references addressed the same field of secure remote access, making the combination a predictable convergence of known technologies to enhance system capabilities.
- Expectation of Success: The modification involved using a known method of network connectivity (cellular) for a client device in a known type of secure access system, ensuring a high expectation of success.

"secure domain name service": Petitioner proposed construing this term as "a service that can resolve secure computer network addresses for a secure domain name for which a conventional domain name service cannot resolve addresses." This construction was central to mapping Provino’s internal nameserver, which resolves addresses unresolvable by external DNS, to the claimed service.
"secure domain name": Petitioner proposed this term means "a non-standard domain name that corresponds to a secure computer network address and cannot be resolved by a conventional DNS." This was critical for arguing that the human-readable addresses for internal servers in Provino met the claim limitation.

Priority Date Challenge: A central contention was that the challenged claims were not entitled to their earliest claimed priority date. Petitioner argued that the subject matter of independent claim 1 first received written description support on April 26, 2000, in a continuation-in-part application. It was further argued that claim 18, which recites a "mobile device" and "cellular network," lacked support in any parent application and was therefore only entitled to a priority date of the patent's filing date, August 16, 2007. This technical-legal argument was crucial for establishing that Provino (filed May 1998) qualified as prior art under 35 U.S.C. §102(e) for claims 1-17 and under 35 U.S.C. §102(b) for claim 18.

Petitioner requested institution of an inter partes review and cancellation of claims 1-5, 7, 8, 10, 12, 13, 15, 17, and 18 as unpatentable.