Intel Corp v. Koninklijke Philips NV

1. Case Identification

• Case #: IPR2021-00370
• Patent #: 9,436,809
• Filed: January 4, 2021
• Petitioner(s): Intel Corporation
• Patent Owner(s): Koninklijke Philips N.V.
• Challenged Claims: 49-54

2. Patent Overview

• Title: Secure authenticated distance measurement
• Brief Description: The ’809 patent discloses methods for securely transferring protected content between two devices. The system combines an authentication protocol with a distance measurement protocol to ensure a receiving device is both compliant and within a limited physical distance before content is transferred.

3. Grounds for Unpatentability

Ground 1: Claims 49-54 are obvious over Menezes in view of Brands-Chaum.

• Prior Art Relied Upon: Menezes (Alfred J. Menezes et al., Handbook of Applied Cryptography, 1997) and Brands-Chaum (Stefan Brands and David Chaum, Distance-Bounding Protocols, 1994).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the challenged claims simply combined two well-known cryptographic techniques in a predictable way. Menezes, a seminal cryptography textbook, taught a complete framework for authenticated key establishment. This included a first device (verifier) receiving a public-key certificate from a second device (prover), using the public key to securely transmit a shared secret (a random number), and then using that secret in a challenge-response protocol to authenticate the second device. Petitioner asserted this Menezes protocol taught nearly all limitations of independent claim 49, including receiving a certificate, determining compliance, providing a secret, sending a first signal (challenge), receiving a second signal (response), and verifying the response was derived from the secret. Brands-Chaum taught a "distance-bounding" technique that could be integrated into existing identification protocols. This technique involved measuring the round-trip time of a challenge-response exchange to determine an upper bound on the physical distance between two parties. Petitioner argued that applying the time-measurement technique of Brands-Chaum to the existing challenge-response step in Menezes's authentication protocol rendered the "predetermined time" limitation of claim 49 obvious. Dependent claims 50-54 were argued to be obvious as they recited additional conventional cryptographic features, such as using the shared secret to create a secure channel (claim 50) or using a specific XOR operation for the challenge-response modification (claim 52), both of which were described as common techniques in Menezes.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Menezes and Brands-Chaum to add a layer of physical proximity verification to a known authentication protocol. Petitioner argued that the content-protection industry had a recognized need to restrict content distribution to a "personal digital network environment" (e.g., a single home). Combining Menezes's robust authentication with Brands-Chaum's distance-limiting directly addressed this need by ensuring a device was not only authenticated but also physically nearby. Brands-Chaum itself expressly stated that its distance-bounding technique could be "integrated into common identification protocols" to prevent fraud and add a locality check, providing an explicit motivation to combine.
  • Expectation of Success: A POSITA would have a high expectation of success. The combination required only a straightforward modification: timing the already-existing challenge-response step in the Menezes protocol. This did not require altering the fundamental operation of either Menezes's authentication or Brands-Chaum's timing method. The result—an authenticated, distance-limited channel—was the predictable sum of its well-understood parts.

4. Key Claim Construction Positions

• Petitioner stated it would assume, for the purposes of the petition, the claim constructions adopted in a related district court case. These constructions were proposed by the Patent Owner, Philips.
  • "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."
• Petitioner argued its obviousness grounds satisfied these constructions, noting that its arguments would also apply to any broader construction the Board might adopt.

5. Arguments Regarding Discretionary Denial

• Petitioner presented extensive arguments that discretionary denial would be inappropriate under both 35 U.S.C. §325(d) and 35 U.S.C. §314(a) (Fintiv factors).
  • Arguments against §325(d) Denial: Petitioner argued the prior art and arguments were new. Menezes is a seminal textbook that was never considered during prosecution. Although Brands-Chaum was cited in an Information Disclosure Statement, the Examiner never substantively addressed it in a rejection or considered it in combination with a comprehensive authentication protocol like the one taught by Menezes.
  • Arguments against Discretionary Denial under Fintiv: Petitioner argued the Fintiv factors favored institution. It noted that the parallel district court action was stayed. While a co-pending International Trade Commission (ITC) investigation was active, Petitioner asserted it filed the IPR expeditiously (less than three months after institution of the ITC investigation). Petitioner argued that the ITC's final determination date was close to the IPR statutory deadline and could be delayed, minimizing efficiency concerns. Furthermore, it contended that investments in the ITC were not duplicative because the invalidity grounds and claim scope would likely differ, and ITC claim construction rulings are not binding on the Patent Trial and Appeal Board.

6. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 49-54 of Patent 9,436,809 as unpatentable.