PTAB

IPR2020-00660

Dolby Laboratories Inc v. Intertrust Technologies Corp

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: System and Method for Protecting Data
  • Brief Description: The ’815 patent relates to methods for managing the use of electronic data files by ensuring their integrity before access is granted. The disclosed method involves creating a digital signature from one or more hash values ("check values") that are themselves derived from portions of the electronic data file. When a user requests to use the file (e.g., copy it), the system retrieves the signature and the check values, uses the signature to authenticate the check values, and then uses the authenticated check values to verify the integrity of the data file itself. If the data is authentic, the user's request is granted.

3. Grounds for Unpatentability

Ground 1: Obviousness over Hanna in view of Stefik - Claims 42 and 43 are obvious over Hanna in view of Stefik.

  • Prior Art Relied Upon: Hanna (International Publication No. WO 1999040702), Stefik (Patent 5,629,980).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hanna teaches the core data verification method claimed in the ’815 patent. Hanna describes a system for "efficient authentication and integrity checking" where a data set is divided into packets, each packet is hashed, and the resulting sequence of hashes forms a "hash block." This entire hash block (analogous to the claimed "check value(s)") is then signed with a single digital signature and transmitted to a receiver as a "top level hash block." The receiver first verifies the digital signature to authenticate the hash block, and then uses the individual verified hashes to authenticate the corresponding data packets. This maps directly to the claimed steps of retrieving a signature and check values, verifying the check values with the signature, and verifying the data with the check values.
    • Motivation to Combine: Petitioner contended that Stefik supplies the "request/grant" framework that Hanna only implies. Stefik is directed to controlling the distribution and use of digital works and explicitly discloses a system where a user makes a request to use a file in a predefined manner, such as an "Install transaction" to install software. The system grants this request only after verifying the authenticity of the digital work. A POSITA, addressing the common problem of secure data transfer and use, would have been motivated to combine Hanna's robust and efficient hierarchical hashing method with Stefik's well-understood access control framework. This combination would create a more secure system by ensuring data integrity at the moment of requested use, a clear improvement for applications like remote software installation or secure file backup mentioned in the references.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination because both references operate in the same field of digital security and address the same fundamental problems. Furthermore, the computer system described in Hanna already included the necessary network communication capabilities to readily implement the request/grant protocol taught by Stefik.

Ground 2: Obviousness over Gennaro - Claims 42 and 43 are obvious over Gennaro.

  • Prior Art Relied Upon: Gennaro (Patent 6,009,176).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Gennaro, a single reference, renders the challenged claims obvious. Gennaro describes signing and authenticating digital data streams to allow a receiver to "authenticate and consume the stream" in real-time. In its primary embodiment, Gennaro teaches creating "initial authentication data" which contains a digital signature and a hash of the first combined data block (the "check value"). This initial data is sent to the receiver first. When a receiver "asks for the authenticated stream" (the claimed "request"), it verifies the signature to authenticate the hash value. It then computes its own hash of the first incoming data block and compares it to the now-authenticated hash from the initial data. If they match, the block is verified, and the request to "play or consume the block" is granted. This process directly maps to every step of the challenged claims.

4. Key Technical Contentions (Beyond Claim Construction)

  • Deficient Priority Claim: A central contention of the petition is that challenged claims 42 and 43 are not entitled to the June 8, 1999, priority date of the patent's provisional application. Petitioner argued the provisional application fails to provide adequate written description support for two key limitations: (1) "retrieving at least one digital signature and at least one check value associated with the file"; and (2) "verifying the authenticity of the at least one check value using the digital signature." The petition noted that key embodiments illustrating these steps in the issued patent, specifically Figures 13 and 14 and their corresponding descriptions, are absent from the provisional application. This alleged deficiency pushes the critical date for the claims to the non-provisional filing date of June 7, 2000, thereby making Hanna (1999) and Gennaro (1999) available as prior art.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion under 35 U.S.C. §314(a) to deny institution based on co-pending district court litigation. The petition asserted that the parallel court case involves different invalidity grounds, including challenges under §§101 and 112, as well as distinct prior art combinations under §§102 and 103. Therefore, Petitioner contended that the IPR would not be duplicative and would serve to simplify the issues before the district court.

6. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 42 and 43 of Patent 6,785,815 as unpatentable.