PTAB

IPR2019-00604

NetApp Inc v. KOM Software Inc

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1. Case Identification

2. Patent Overview

  • Title: Method for Applying Operation Access Privilege to a Storage Medium
  • Brief Description: The ’524 patent describes a method for regulating access to computer storage media by using a “trap layer” that resides outside the file system. This layer intercepts attempted I/O operations, compares them against defined access privileges or permissions, and then either allows or denies the operation based on that comparison.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 1 under 35 U.S.C. §102

  • Prior Art Relied Upon: Vossen (Patent 6,026,402).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Vossen discloses every limitation of claim 1. Vossen teaches a system for restricting a process’s access to a file system using a “filter driver” layered between the operating system and the file system driver. This filter driver intercepts all I/O Request Packets (IRPs) targeted to the underlying file system, an action that occurs regardless of user identity. The driver then compares the intercepted operation against permissions defined in data structures to determine if the process is subject to restrictions. Based on this comparison, the driver either permits the IRP to pass to the file system or prevents all access, thereby allowing or denying the attempted operation. This process directly maps to the claimed method of associating an access privilege, intercepting an operation, comparing the operation to the privilege, and allowing or denying based on the comparison.

Ground 2: Obviousness over Vossen in view of Denning

  • Legal Basis: Claims 2-4, 18, and 19 are obvious over Vossen in view of Denning under 35 U.S.C. §103.
  • Prior Art Relied Upon: Vossen (Patent 6,026,402) and Denning (Cryptography and Data Security, 1982).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Vossen provides the foundational filter driver system, while Denning supplies the additional features recited in the dependent claims. For claim 2’s requirement of “enforcing at least one policy,” Denning explicitly teaches using access control policies and separating the policy from the enforcement mechanism (a monitor). For claim 18’s “identifying an attribute of data,” Denning describes attributes like a “copy flag” that are checked to determine if an operation is permitted. For claim 19’s “creating at least one hash key to validate authenticity,” Denning discloses a “tree authentication” technique using a one-way hashing function to sign and validate a public file as a unit.
    • Motivation to Combine: A POSITA would combine Denning with Vossen to implement a more systematic and finely-grained access control system. Vossen itself praises the hierarchical access privileges of UNIX systems, and Denning provides a well-known, robust framework for implementing such UNIX-like authorization lists and control models. The combination would allow Vossen’s filter driver to enforce the access control policies taught by Denning.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because both references describe conventional methods for controlling access in file systems. Integrating Denning’s established policy concepts into Vossen’s filter driver mechanism would be a straightforward application of known security principles.

Ground 3: Obviousness over Vossen, Denning, and McGovern

  • Legal Basis: Claims 9, 11, and 29-31 are obvious over Vossen in view of Denning and McGovern under 35 U.S.C. §103.

  • Prior Art Relied Upon: Vossen (Patent 6,026,402), Denning (Cryptography and Data Security, 1982), and McGovern (Application # 2005/0097260).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground builds upon the combination of Vossen and Denning by adding McGovern to teach the specific limitations of claims 9, 11, and 29-31, which Petitioner argued are not entitled to the patent’s earliest priority date. These claims recite a “retention policy” that includes applying a “restricted state,” preventing modification, and “associating a time of expiration.” McGovern teaches a Write-Once-Read-Many (WORM) system that locks files against deletion or modification for a specified “retention date.” This system applies a restricted (read-only) state, prevents modification during the retention period, and associates this state with a time of expiration (the retention date), thus teaching the claimed limitations.
    • Motivation to Combine: A POSITA would be motivated to integrate McGovern’s WORM retention system into the Vossen/Denning framework to provide additional functionality for long-term data storage, often compelled by enterprise or governmental regulations. Denning teaches the general concept of long-term storage policies, and McGovern provides a specific, practical implementation for them.
    • Expectation of Success: Success would be expected and predictable. Both Vossen and McGovern are designed to operate on top of the Windows NT operating system, and McGovern’s system relies on “native functionality” within conventional operating systems, facilitating a straightforward integration without specialized hardware.

  • Additional Grounds: Petitioner asserted numerous additional grounds, including that claim 1 is anticipated by Nagar (a 1997 guide on Windows NT File System Internals) and that various claims are obvious over combinations including Nagar, Denning, McGovern, and Kung (Patent 5,265,159), which teaches secure file erasure. The arguments based on Nagar parallel those based on Vossen, as both disclose similar Windows NT filter driver architectures.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 9, 11, 18, 19, 24, and 29-31 of the ’524 patent as unpatentable.