PTAB

IPR2019-00606

NetApp Inc v. KOM Software Inc

Log In

1. Case Identification

2. Patent Overview

  • Title: Method for Applying an Operation Access Privilege to a Storage Medium
  • Brief Description: The ’477 patent discloses a system and method for providing restricted access to a data storage medium. The method involves intercepting an attempted file system operation, comparing it to an associated access privilege or policy, and then allowing or denying the operation based on that comparison, regardless of the user's identity.

3. Grounds for Unpatentability

Ground 1: Obviousness over Vossen and Denning - Claims 1-5, 18-20, 22-25, 31, 32, 35-39, 43, and 44 are obvious over Vossen in view of Denning.

  • Prior Art Relied Upon: Vossen (Patent 6,026,402) and Denning (a 1982 book titled Cryptography and Data Security).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Vossen, which relates to restricting process access to file systems in Windows NT, teaches the core method of the independent claims. Vossen disclosed a "file system filter driver" that intercepts all I/O requests to a storage medium (the "intercepting" and "trap layer" limitations), compares those requests against data structures defining access restrictions for a given process ("comparing the attempted operation to the access privilege"), and allows or denies the operation based on the comparison. However, Petitioner contended Vossen's data structures do not explicitly teach the claimed "policy." Denning was introduced to supply this element, as it taught a formal "access control policy" implemented via authorization lists that define which subjects (e.g., processes) have what rights (e.g., read, write) to specific objects (e.g., files).
    • Motivation to Combine: A POSITA would combine Denning's formal access control policies with Vossen's filter driver architecture to create a more finely-grained and flexible system for controlling file access. Both references utilized an access control mechanism for a file system and separated the policy (the rules) from the enforcement mechanism (the driver/monitor), making the combination straightforward and predictable.
    • Expectation of Success: A POSITA would have an expectation of success because the combination involved applying a known security technique (Denning's access control policies) to improve a known system (Vossen's filter driver) to achieve the predictable result of more granular access control.

Ground 2: Obviousness over Vossen, Denning, and McGovern - Claims 6-8, 10-12, 14, 17, 21, 45, 48, and 50 are obvious over Vossen in view of Denning and McGovern.

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

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground built upon the Vossen and Denning combination by adding McGovern to teach limitations related to data retention. McGovern disclosed a write-once-read-many (WORM) system that enforces a "retention policy" by preventing modification or deletion of a file until a specified retention period has expired. Petitioner mapped McGovern's teachings to claim limitations requiring enforcement of a "retention policy" (claim 6), using a "secure compliance clock" (claim 21), and denying operations on non-empty directories containing WORM files (claim 17).
    • Motivation to Combine: A POSITA would be motivated to integrate McGovern's retention features into the Vossen/Denning access control framework to add data integrity and compliance functionality. Since Vossen and McGovern were both designed for Windows NT environments, integrating McGovern's WORM logic into Vossen's filter driver was presented as a straightforward extension to provide enhanced data security.

  • Additional Grounds: Petitioner asserted further obviousness challenges, including:

    • Vossen, Denning, and Kung: Adding Kung (Patent 5,265,159) to the base combination to teach secure file erasure by overwriting data, as recited in claims 16 and 46.
    • Vossen, Denning, and Nagar: Adding Nagar (a 1997 book titled Windows NT File System Internals) to teach using filter drivers for virus detection, thereby rendering obvious the claims related to analyzing for and acting on "harmful content" (claims 26, 27, and 54-57).

4. Key Claim Construction Positions

  • "trap layer" (claims 35-37, 44-46, 48, 50): Petitioner argued this term should be construed structurally as a "Windows NT filter driver logically disposed between the application layer and the file system layer." Petitioner contended that the Patent Owner's proposed construction improperly imported functional limitations (e.g., that it "limits operations...to those supported by the read/write device") from the specification into the claim. Petitioner asserted the claims would be unpatentable under either construction but argued its structural construction was correct because the patent specification does not provide a special definition that would overcome the heavy presumption of plain and ordinary meaning.

5. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Challenge: Petitioner argued that the ’477 patent was not entitled to the filing dates of its earlier parent or grandparent applications for certain claim sets. Specifically, it was argued that the term "policy" (claims 1, 22) lacked written description support in the grandparent ’624 patent, and terms like "private personal information" and "harmful content" (claims 26, 27, 54) lacked support in the parent ’524 patent. This argument was critical for establishing that references like McGovern (published 2005) were valid prior art against claims whose effective priority date would be pushed from pre-2005 to 2006 or later.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-8, 10-12, 14, 16-27, 31, 32, 35-39, 43-46, 48, 50, and 54-57 as unpatentable under 35 U.S.C. §103.