PTAB

IPR2014-01532

Amazon.com Inc v. Personalized Media Communications LLC

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Encryption and Decryption of Computer Programming
  • Brief Description: The ’304 patent relates to methods for controlling the decryption of digital television or computer programming at a subscriber station. The invention uses a transmitted information stream containing both encrypted programming and an encrypted control signal, where the control signal is used to enable decryption of the programming.

3. Grounds for Unpatentability

Ground 1: Obviousness over Guillou - Claims 1, 11, 18, 23, and 24 are obvious over Guillou.

  • Prior Art Relied Upon: Guillou (Patent 4,337,483).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Guillou, which discloses an access-control system for video transmissions, taught the core elements of the challenged claims. Guillou’s system uses a two-layer "double-key" encryption scheme: an operating key (K) encrypts the primary data, and this key K is itself encrypted using a subscriber-specific key (Ci) to create a control message (Mi). A receiver uses its stored key Ci to decrypt the control message Mi to obtain key K, and then uses key K to decrypt the primary data. Petitioner mapped the encrypted control message Mi to the claimed "first encrypted digital control signal portion" and the encrypted primary data to the "encrypted digital information portion."
    • Motivation to Combine: Although asserted as an obviousness challenge, Petitioner noted a belief that Guillou actually anticipates the claims. A key contention addressed the "said decryptor" limitation of claim 1, which implies a single decryptor performs multiple steps. Petitioner argued that while Guillou describes two distinct decryption circuits (a K-restoring circuit and an automatic decryption circuit), it would have been an obvious design choice for a person of ordinary skill in the art (POSITA) to combine their functions into a single logical or physical multipurpose decryptor.
    • Expectation of Success: A POSITA would expect success in implementing the decryption functions in a single logical unit as it represented a simple design tradeoff between cost and signal processing requirements with predictable results.

Ground 2: Obviousness over Guillou, Block, and Guillou '011 - Claim 22 is obvious over Guillou in view of Block and Guillou '011.

  • Prior Art Relied Upon: Guillou (Patent 4,337,483), Block (Patent 4,225,884), and Guillou '011 (Patent 4,352,011).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targeted claim 22, which recites a method of providing "digital enabling information" to a receiver from a remote source in response to a "query" from the receiver. Petitioner asserted that Guillou provided the fundamental encryption system but lacked the query-response feature. Block supplied this missing element by teaching a subscription-television system with a remote billing computer that communicates with a subscriber station over telephone lines. Block explicitly disclosed the subscriber station initiating a call (a "query") to the remote computer to receive updated scramble codes ("digital enabling information"). Guillou '011 was cited to provide further detail on the Guillou system and demonstrate its inherent compatibility with Block's architecture.
    • Motivation to Combine: A POSITA would combine Guillou and Block because both relate to access-control systems for television and address similar technical challenges. The motivation was to improve Guillou's system by incorporating Block's automated, remote subscription-management subsystem. This would enhance user convenience by automating billing and access, eliminating the need for a user to physically visit a charging station.
    • Expectation of Success: The integration was presented as a predictable combination of known systems. A POSITA would expect success in replacing Guillou's manual subscription management with Block's telephone-based automated system.

Ground 3: Anticipation of Claims 1, 16, and 18 by FIPS PUB 81

  • Prior Art Relied Upon: FIPS PUB 81 (DES Modes of Operation, Federal Information Processing Standards Publication 81, Dec. 2, 1980).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that FIPS PUB 81, which describes the Cipher Block Chaining (CBC) mode of operation for the Data Encryption Standard (DES), anticipated every limitation of claim 1. In the CBC decryption process, a block of cipher text from a preceding time step is used to decrypt the current block of cipher text. Petitioner mapped the preceding cipher text block to the claimed "first encrypted digital control signal portion" and the current cipher text block to the "encrypted digital information portion." The standard's description of the CBC decryption algorithm was alleged to teach every step of claim 1. FIPS PUB 81 was also argued to anticipate dependent claim 16 by disclosing the temporary storage of intermediate values (the decrypted block) and claim 18 by explicitly stating its applicability to computer data.

  • Additional Grounds: Petitioner asserted that claims 11 and 16 would have been obvious over Guillou in view of Block, leveraging the same motivation to combine a remote, telephone-based subscription management system with a broadcast encryption system.

4. Key Claim Construction Positions

  • "Digital Programming/Mass Medium Presentation Signal/Television": Petitioner argued that under the broadest reasonable interpretation, these terms should encompass broadcast transmissions that contain digital signals embedded within traditional analog television signals, as described in the specification.
  • "Said Decryptor": Petitioner proposed that this term should be construed to mean a single logical decryptor, which could be implemented as a single physical circuit or as multiple distinct circuits that collectively perform the claimed decryption functions. This construction was central to the argument that Guillou’s two separate decryption circuits met the limitation.
  • "A Processor": Petitioner argued this term should not be limited to a general-purpose microprocessor but should refer more broadly to any decryptor, decoder, or other circuitry capable of performing the claimed functions of "identifying or locating," "processing," and "decrypting."

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1, 11, 16, 18, and 22-24 of the ’304 patent as unpatentable.