Dolby Laboratories Inc v. Intertrust Technologies Corp

1. Case Identification

• Case #: IPR2020-01123
• Patent #: 6,157,721
• Filed: June 24, 2020
• Petitioner(s): Dolby Laboratories, Inc.
• Patent Owner(s): Intertrust Technologies Corporation
• Challenged Claims: 5, 9, and 29

2. Patent Overview

• Title: Secure Distribution of Data
• Brief Description: The ’721 patent discloses methods for protecting computing environments from unauthorized load modules (e.g., executable programs). One method involves a certifying authority testing a load module against a specification and issuing a digital certificate. Another method involves a receiving device authenticating a digital signature associated with a load module using a public key secured in a tamper-resistant barrier before conditionally executing the module.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claim 5 over Stefik in view of Jobber

• Prior Art Relied Upon: Stefik (Patent 5,715,403) and Jobber (a March 1989 article in MIS Quarterly).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Stefik taught a method for controlling software distribution by requiring software to be certified with a digital certificate, which attests that the software has been tested by an authorized organization and "does what it is supposed to do." This disclosed the core "software verifying method" of claim 5. However, Petitioner contended that Stefik did not explicitly teach testing the software against a predefined "specification describing one or more functions." Jobber was introduced to supply this missing element, as it taught the desirability and feasibility of a software quality assurance certificate where software is tested to confirm it operates "as claimed" in one or more specifications.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Jobber's teachings with Stefik's system as a straightforward and well-known way to implement Stefik’s step of determining if software "does what it is supposed to do." Verifying software against a functional specification was, per Jobber, a known method to achieve this goal.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because combining a known software testing methodology (testing against a specification, from Jobber) with a known software certification framework (Stefik) was a predictable combination of familiar elements to improve the reliability of the certification.

Ground 2: Anticipation of Claims 9 and 29 by Arnold

• Prior Art Relied Upon: Arnold (European Patent Application EP 0706275).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Arnold disclosed every element of claims 9 and 29. Arnold taught a method for the secure distribution of data, including executable software (the "load module" or "executable"), to a receiving device. The method involved: (a) receiving the software, which has (b) an associated digital signature; (c) authenticating the signature using a public key housed within a "tamper-resistant" and "secured area" of an adapter card, thus being hidden from the user; and (d) conditionally executing the software only if the signature is verified. Petitioner argued Arnold's "secured area... protected from physical and direct electrical access" met the "tamper resistant barrier" limitation.
  • Key Aspects: This ground asserted that Arnold, as a single reference, described a complete, integrated system that performed all steps of the methods recited in independent claims 9 and 29.

Ground 3: Obviousness of Claims 9 and 29 over Chang in view of Stefik

• Prior Art Relied Upon: Chang (Patent 5,724,425) and Stefik (Patent 5,715,403).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Chang disclosed a method for distributing secure software using a "software passport" system. This system performed most steps of claims 9 and 29: receiving software, determining if it has a platform builder's digital signature, authenticating that signature using a public key embedded in the hardware platform, and conditionally executing the code. However, Petitioner contended that Chang did not explicitly describe its embedded public key as being "secured behind a tamper resistant barrier and therefore hidden from the user." Stefik was introduced to teach this specific element, as it disclosed enclosing cryptographic keys in a "secure housing" or "tamper-resistant master repository" to protect them.
  • Motivation to Combine: A POSITA would be motivated to apply Stefik’s teaching of a tamper-resistant barrier to Chang's system to enhance security. Since Stefik taught that key management and security are instrumental to a public key system's success, adding a tamper-resistant barrier to protect the public key in Chang's hardware platform was an obvious improvement to further Chang's stated goal of allowing only authorized code to be executed.
  • Expectation of Success: A POSITA would expect success in this combination because it involved applying a known security feature (tamper-resistant key storage from Stefik) to a known software authentication system (Chang) to achieve the predictable result of enhanced security.

• Additional Grounds: Petitioner asserted an additional obviousness challenge against claim 5 based on Dan (Patent 5,825,877) and against claims 9 and 29 as obvious over Arnold (as a fallback to the anticipation ground).

4. Key Claim Construction Positions

• "load module": Petitioner proposed this term be construed to mean "executable code, such as a computer program or an applet, plus any associated data required for code execution." This construction was argued to be consistent with the ’721 patent’s description of "load modules" as entities that are "tested," "execut[ed]," and can contain algorithms, data, and keys. This broad definition was important for applying prior art that referred to "software," "executable code," or "data" containing executable fragments.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial of institution under 35 U.S.C. §314(a) and the Fintiv factors. Key arguments included:
  • Petitioner intended to seek a stay in the co-pending N.D. Cal. litigation, favoring institution.
  • The district court had not set a trial date, and any trial would likely occur after the Final Written Decision (FWD) in the inter partes review (IPR).
  • The court had not issued any substantive orders or invested significant resources in the case, and the invalidity grounds in the IPR differed from other grounds raised in the litigation.
  • The petition's merits were strong, including anticipation and obviousness grounds based on single references, which weighs heavily in favor of institution.

6. Relief Requested

• Petitioner requested institution of an IPR and cancellation of claims 5, 9, and 29 of Patent 6,157,721 as unpatentable.