Intel Corp v. Koninklijke Philips NV

1. Case Identification

• Case #: IPR2021-00328
• Patent #: 10091186
• Filed: December 31, 2020
• Petitioner(s): Intel Corporation
• Patent Owner(s): Koninklijke Philips N.V.
• Challenged Claims: 1-16 and 18

2. Patent Overview

• Title: Secure authenticated distance measurement
• Brief Description: The ’186 patent discloses a method for controlling the transfer of protected content between two devices by combining a cryptographic authentication protocol with a distance measurement protocol. The system first authenticates a second device and establishes a shared secret, then performs a timed challenge-response exchange using the secret to ensure the device is within a predetermined physical distance before transferring the content.

3. Grounds for Unpatentability

Ground 1: Claims 1-16 and 18 are obvious over Menezes in view of Brands-Chaum.

• Prior Art Relied Upon: Menezes (a 1997 cryptography textbook) and Brands-Chaum (a 1994 paper on distance-bounding protocols).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Menezes, a seminal textbook, taught all elements of a standard authenticated key exchange protocol as claimed. This included a first device (verifier) receiving a public-key certificate from a second device (prover), verifying the certificate against compliance rules (e.g., validity, signature), and then using the authenticated public key to securely transport a secret to the second device. Menezes also taught using this secret in a subsequent challenge-response exchange to provide entity authentication. Brands-Chaum taught the missing element: measuring the round-trip time of a challenge-response exchange to determine an upper bound on the physical distance between two parties. Petitioner asserted that adding the time measurement from Brands-Chaum to the challenge-response step already present in the Menezes protocol renders the claims obvious.
  • Motivation to Combine: A POSITA would combine these references to solve the well-known industry problem of restricting protected content distribution to a personal or local network. Menezes provided the standard security framework, and Brands-Chaum provided a known technique to add a physical proximity check. Brands-Chaum itself suggested its distance-bounding technique could be integrated into common identification protocols, providing an express motivation. The combination was a straightforward application of a known technique (distance-bounding) to an existing system (authenticated key exchange) to achieve a predictable result (secure, proximity-limited content transfer).
  • Expectation of Success: A POSITA would have a high expectation of success, as the combination only required timing an existing challenge-response step and comparing the result to a threshold, a simple and well-understood process.

Ground 2: Claims 1, 2, 10, 11, and 13-15 are obvious over the OCPS Documents in view of Brands-Chaum.

• Prior Art Relied Upon: OCPS-Proposal and OCPS-Rules (the "OCPS Documents," Philips' own 2002 publications) and Brands-Chaum (a 1994 paper).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that the Patent Owner’s own prior art Open Copy Protection System (OCPS) disclosed a nearly complete embodiment of the invention. The OCPS Documents described a system for securely transferring protected content between a "source" and "sink" device. This system included an authentication phase where the source validates the sink's public-key certificate against a set of compliance rules. Following successful authentication, the devices perform a key exchange protocol that functions as a challenge-response, which OCPS explicitly stated was timed against a 1ms threshold to forbid "non-local" transmissions. Petitioner argued the only element OCPS lacked was the explicit teaching that this predetermined time threshold corresponds to a desired physical distance limit.
  • Motivation to Combine: A POSITA would be motivated to apply the teachings of Brands-Chaum to the OCPS protocol. Brands-Chaum expressly taught how to translate a desired physical distance limit into a maximum round-trip time for a challenge-response exchange. Since OCPS already performed a timed exchange to prevent "non-local" communication, it would have been obvious for a POSITA to apply the principle from Brands-Chaum to select the time threshold in OCPS for the specific purpose of enforcing a physical distance limit. This would have been a minor, predictable improvement to the existing OCPS framework.
  • Expectation of Success: A POSITA would have an absolute expectation of success because the underlying mechanism—a timed challenge-response—was already present in OCPS. The combination merely involved applying a known design principle from Brands-Chaum to an existing, compatible system.

4. Key Claim Construction Positions

• Petitioner argued for adopting constructions from a related district court case for key terms central to its obviousness arguments.
• "certificate": "information containing at least the entity's distinguishing identifier and public key, and signed by a certification authority to guard against forgery."
• "[provide/providing] the secret to the second device": "securely [transmits/transmitting] the common secret with the second device according to a key transport protocol or a key agreement protocol."
• "predetermined time": "a time interval selected to ensure that the first and second communication devices are sufficiently near one another to permit access to the protected content." This construction, tying the time value to physical proximity, was noted as critical.

5. Arguments Regarding Discretionary Denial

• Petitioner presented arguments that discretionary denial under §325(d) and §314(a) (Fintiv) would be inappropriate.
• §325(d): Petitioner argued denial is improper because the primary references (Menezes and the OCPS Documents) were never considered by the Examiner during prosecution. While Brands-Chaum was disclosed in an IDS, it was never substantively addressed in combination with the other references.
• §314(a) (Fintiv): Petitioner argued the Fintiv factors favor institution. The parallel district court case is stayed. While a co-pending ITC investigation exists, Petitioner filed this IPR expeditiously. Furthermore, the issues do not fully overlap, as claims 8 and 18 are challenged in the IPR but not asserted in the ITC. Petitioner also stated that its invalidity grounds and claim construction positions in the ITC would differ from those in the IPR.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-16 and 18 of the ’186 patent as unpatentable.