PTAB

IPR2019-01093

PayPal, Inc. v. PersonalWeb Technologies, LLC

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1. Case Identification

2. Patent Overview

  • Title: Similarity-Based Access Control Of Data In A Data Processing System
  • Brief Description: The ’544 patent describes a system for identifying data files using names derived from the file's own contents, rather than its location or user-assigned name. This content-based identifier, termed a "True Name" or "digital key," is generated using a hash function, allowing the system to uniquely identify and manage files, such as locating duplicates, regardless of their context in a data processing system.

3. Grounds for Unpatentability

Ground 1: Anticipation and/or Obviousness over Kantor - Claims 46, 48, 52, and 55 are anticipated by Kantor under 35 U.S.C. §102 and/or obvious over Kantor under 35 U.S.C. §103.

  • Prior Art Relied Upon: Kantor (“The Frederick W. Kantor Contents-Signature System Version 1.22,” a 1993 printed publication).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kantor, which described a software tool (FWKCS) to prevent duplicate file uploads on Bulletin Board Systems (BBS), disclosed every element of the challenged claims. Independent claim 46, for example, requires determining a "digital key" for a file based on "part values" derived from the file's internal parts. Petitioner asserted that Kantor's "zipfile contents signature" is the claimed "digital key," a zipfile is the "particular file," its internal files are the "parts," and the 32-bit CRCs calculated for each internal file are the "part values." Kantor then added these signatures to a database file (CSLIST.SRT) and used a "Lookup" command to check for matches, satisfying the claim steps of adding a key to a database, determining a search key, matching keys, and providing information about a match. Arguments for claims 48, 52, and 55 followed similar logic, with Kantor's disclosure of operating on networked BBSs teaching the limitations of dependent claim 48.
    • Motivation to Combine (for §103 grounds): The petition presented an alternative obviousness argument. If the Board found Kantor’s signature calculation, which also used file length as an input, was not based "only" on the part values as potentially required by a narrow construction, Petitioner argued it would have been obvious to a POSITA to modify it. A POSITA would have known to use other well-known hash algorithms of the time (like SHA or MD5, which the ’544 patent admits are prior art) that operate solely on the part values to achieve the same, or better, uniqueness, representing a predictable design trade-off between uniqueness and processing power.
    • Expectation of Success: A POSITA would have had a high expectation of success in applying a standard hash function like SHA or MD5 to the part values to create a unique file signature, as this was a well-understood and common use for such functions.

Ground 2: Obviousness over Kantor and Woodhill - Claims 46, 48, 52, and 55 are obvious over Kantor in view of Woodhill.

  • Prior Art Relied Upon: Kantor (1993 printed publication) and Woodhill (Patent 5,649,196).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented as an alternative in the event the Board determined that Kantor's flat file (CSLIST.SRT) did not meet the "database" limitation of claims 46 and 52. Petitioner argued that Woodhill, which discloses a distributed storage manager for file backups, explicitly taught the missing element. Woodhill described maintaining a structured "File Database" to store unique, content-based "Binary Object Identifiers" for file parts to manage data and avoid duplicate storage.
    • Motivation to Combine (for §103 grounds): A POSITA implementing Kantor’s system would have been motivated to combine it with Woodhill’s database teachings to improve efficiency and scalability. Kantor described a need to search and manage its content signatures but did not detail a robust structure, creating a known problem. Woodhill provided an explicit solution, teaching a hierarchical database for managing content-based identifiers. A POSITA would have recognized that replacing Kantor's simple list with Woodhill's structured database would improve search speeds and better handle the large-scale data storage anticipated on growing network systems.
    • Expectation of Success: Integrating a known database management technique (from Woodhill) into a content-signature system (from Kantor) to improve performance was a straightforward application of conventional computer science principles with a high likelihood of success.

4. Key Claim Construction Positions

  • Petitioner argued that while no terms required explicit construction, the Board should not adopt narrow constructions from a related district court case.
  • Petitioner contended that terms in the challenged claims like "digital key" and "part value" were distinguishable from previously construed terms like "data identifier." The challenged claims recite a key based on "part values," not a key based on the entire contents of a data file, making prior constructions inapplicable.
  • Furthermore, Petitioner noted that the Board itself, in a prior reexamination of a related patent, had rejected a patent owner's attempt to import a narrow "only" limitation (i.e., that an identifier is based only on the data). The Board found that open-ended claim language like "comprises" and "based on" did not exclude the use of additional information, such as file length, in calculating an identifier.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate because the petition raised new, substantial questions of patentability.
  • The primary prior art reference, Kantor, was not considered by the examiner during the original prosecution of the ’544 patent. The invalidity theory based on Kantor's content-signature system was therefore never before the Patent Office.
  • Petitioner also argued that the instant petition was not an improper "follow-on" or "second bite at the apple" relative to a prior inter partes review (IPR) on the ’544 patent (the "EMC IPR"). The Petitioners here were not parties to the EMC IPR, were not sued for infringement until after that proceeding had terminated, and thus had no opportunity to join. Furthermore, the EMC IPR challenged only claim 1, whereas this petition challenges a different set of claims (46, 48, 52, and 55).

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 46, 48, 52, and 55 of the ’544 patent as unpatentable.