On a second appeal from an inter partes review (IPR) proceeding, the US Court of Appeals for the Federal Circuit reversed the Patent Trial and Appeal Board (PTAB) determination that a patent directed to creating a substantially unique identifier for each data item in a data processing system was invalid as obvious, finding that the PTAB’s decision was not supported by substantial evidence. PersonalWeb Technologies, LLC v. Apple, Inc., Case No. 18-1599 (Fed. Cir. Mar. 8, 2019) (Chen, J).

PersonalWeb owns a patent directed to a method and apparatus for creating a substantially unique identifier for each data item in the data processing system that is independent of the data item’s user-defined name and location, and is dependent only on the content of the data item itself. The identifier for a particular data item is created by applying a cryptographic hash function to the data item. The output of the hash function is the content-based identifier or “True Name,” which is “virtually guaranteed” to be unique to the data item. The system uses the content-based identifier alone to determine whether a particular data item is present on the system. When the data item’s contents are changed, the content-based identifier of the data item also changes.

Apple filed an IPR petition arguing that PersonalWeb’s patent was invalid because a Woodhill patent inherently discloses a reference index/lookup feature, and it would be obvious to a person skilled in the art to combine Woodhill with a patent to Stefik, which discloses an authentication system for controlling access to digital works. In Stefik, each digital work’s unique identifier and associated usage rights, among other information, are stored in a repository. A user accesses a digital work over a network using a “digital ticket,” which entitles the ticket holder to exercise usage rights associated with the work because, for example, the user has paid for access.

At the PTAB, Apple argued that in Woodhill, “referencing necessarily must be accomplished” using “the remote backup fileserver,” which “maintains some sort of file system or other mapping (i.e., a database) that allows the Binary Object Identification Record to serve as a lookup for the requisite file data that is to be restored.” Apple argued that a skilled artisan would have combined the backup and restore system in Woodhill and Stefik with the repository in Stefik to add an authorization layer to prevent unauthorized users from accessing a different user’s backup files. The PTAB agreed with Apple and found PersonalWeb’s patent claims invalid. PersonalWeb appealed.

PersonalWeb argued that the PTAB erred because Woodhill does not necessarily require a lookup table to locate the current or previous version of the file because Woodhill’s system “obtains from the user the identities of the current and previous versions of the file (comprised of binary objects) which needs to be restored.” PersonalWeb argued that this was an alternative method to achieve the same result, and thus referencing would not necessarily be accomplished using the remote backup fileserver, as found by the PTAB. The Federal Circuit agreed with PersonalWeb, finding that the PTAB’s determination that the “compared to a plurality of values” limitation was inherent in prior art was not supported by substantial evidence. The Court noted that Woodhill only disclosed a method of locating a current or previous file by searching for the file using standard file block information, including the file name and location, but the Woodhill reference did not disclose searching for a file based on a content-based identifier. The Court thus reversed the PTAB’s obviousness finding.

Practice Note: Before making inherency arguments to support invalidity, practitioners should consult with experts to carefully rule out alternative solutions or explanations.