DCT

5:18-md-02834

In re: PersonalWeb Technologies, LLC

Log In
Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 5:18-cv-00409, N.D. Cal., 10/04/2018
  • Venue Allegations: Venue is based on allegations that Defendant maintains a regular and established place of business in the Northern District of California and has committed acts of infringement within the district.
  • Core Dispute: Plaintiff alleges that Defendant’s website and its underlying content delivery architecture infringe four patents related to the use of content-based identifiers to manage, distribute, and control access to data in computer networks.
  • Technical Context: The technology involves generating unique identifiers for data based on the data's own content (e.g., via cryptographic hashing), a foundational technique for modern content delivery networks (CDNs), cloud storage, and data deduplication.
  • Key Procedural History: This Second Amended Complaint is part of a multi-district litigation (MDL) proceeding. Plaintiff notes that the patents-in-suit have expired and that it has previously enforced these patents against other parties, resulting in settlements and non-exclusive licenses. The litigation is therefore focused on recovering monetary damages for past infringement.

Case Timeline

Date Event
1995-04-11 Earliest Priority Date for all Patents-in-Suit
2005-08-09 U.S. Patent No. 6,928,442 Issued
2010-09-21 U.S. Patent No. 7,802,310 Issued
2011-05-17 U.S. Patent No. 7,945,544 Issued
2012-01-17 U.S. Patent No. 8,099,420 Issued
2018-10-04 Second Amended Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 6,928,442 - "Enforcement and Policing of Licensed Content Using Content-Based Identifiers" (Issued Aug. 9, 2005)

The Invention Explained

  • Problem Addressed: Traditional data processing systems identify data by names and locations (e.g., file paths) that are dependent on context, leading to difficulties in managing duplicate data, verifying data integrity, and controlling access across distributed networks (Compl. ¶¶ 12-13; ’442 Patent, col. 1:49-2:27).
  • The Patented Solution: The invention proposes a system where each "data item" (e.g., a file, a block of data) is assigned a "substantially unique" identifier, called a "True Name," derived from the content of the data item itself, typically through a cryptographic hash function like MD5 or SHA (’442 Patent, Abstract; col. 2:30-36). This allows any data item to be identified, managed, and verified based on what it is, rather than where it is stored, creating a context-independent naming system (Compl. ¶¶ 14-15; ’442 Patent, col. 3:7-12).
  • Technical Importance: This content-based addressing approach is a foundational element for data deduplication and efficient content delivery, as it allows systems to avoid storing or transmitting redundant data (Compl. ¶11).

Key Claims at a Glance

  • The complaint asserts independent claim 10 (Compl. ¶53).
  • Essential elements of claim 10 include:
    • A method in a system with files distributed across multiple computers.
    • Obtaining a name for a data file based on a function of the file's contents.
    • Using that name to determine if a copy of the file is present on one of the computers.
    • Determining if a present copy of the file is an "unauthorized copy or an unlicensed copy."
  • The complaint also asserts dependent claim 11 (Compl. ¶53).

U.S. Patent No. 7,802,310 - "Controlling Access to Data in a Data Processing System" (Issued Sep. 21, 2010)

The Invention Explained

  • Problem Addressed: In a distributed network with caching, it is difficult to ensure that only authorized or current versions of data are accessed, as multiple copies may exist at different locations (’310 Patent, col. 1:50-67).
  • The Patented Solution: The invention uses the content-dependent name of a data item as the basis for an access control decision. A first computer (e.g., an origin server) receives a request from a second computer (e.g., a browser or cache) that includes the content-dependent name. The first computer then uses this name to determine if the content is "unauthorized or unlicensed" and, based on that determination, either permits or denies the second computer from accessing or using the content (’310 Patent, Abstract; col. 2:20-51).
  • Technical Importance: This method links cache validation directly to an authorization framework, providing a mechanism to control the distribution and use of specific versions of content across a network (Compl. ¶¶ 13, 17).

Key Claims at a Glance

  • The complaint asserts independent claims 20 and 69 (Compl. ¶61).
  • Essential elements of independent claim 20 (a method claim) include:
    • Controlling distribution of content from a first computer to another in response to a request from a second device.
    • The request includes a "content-dependent name" of a data item, generated using a hash function.
    • Based on this name, the first computer either (A) permits the content to be provided or accessed if it is not determined to be unauthorized/unlicensed, or (B) does not permit the content to be provided or accessed if it is determined to be unauthorized/unlicensed.

U.S. Patent No. 7,945,544 - "Similarity-Based Access Control of Data in a Data Processing System" (Issued May 17, 2011)

  • Technology Synopsis: This patent describes generating a "digital key" for a data file by first generating "part values" (e.g., hashes) for its constituent parts, and then applying a second function to those part values. This hierarchical hashing allows for efficient comparison of composite data items, like webpages composed of multiple asset files (’544 Patent, Abstract).
  • Asserted Claims: Independent claim 46 is asserted (Compl. ¶71).
  • Accused Features: The complaint alleges that Defendant's ETag value for a webpage base file is a "digital key" generated by a hash function operating on the base file's contents. These contents include URIs of asset files, and those URIs contain "fingerprints" (hashes) which are the alleged "part values" of the asset files (Compl. ¶¶ 73-74).

U.S. Patent No. 8,099,420 - "Accessing Data in a Data Processing System" (Issued Jan. 17, 2012)

  • Technology Synopsis: This patent discloses a system for selectively permitting access to data. It involves determining a content-dependent identifier for a data item and checking whether that identifier corresponds to an entry in one or more databases of authorized identifiers to resolve whether access should be granted (’420 Patent, Abstract).
  • Asserted Claims: Independent claim 166 is asserted (Compl. ¶82).
  • Accused Features: The complaint alleges Defendant's web servers maintain databases of ETag values for webpage files. When a conditional GET request is received containing an ETag, the system compares the received ETag with the database entries to determine whether the requesting cache is authorized to access the content it already holds or must fetch new content (Compl. ¶¶ 86-87).

III. The Accused Instrumentality

Product Identification

  • Defendant Merkle, Inc.'s website, located at "500friends.com", and the associated system and method for providing and controlling its webpage content (Compl. ¶¶ 29, 31).

Functionality and Market Context

  • The accused system employs a content distribution and caching method to reduce bandwidth and improve efficiency (Compl. ¶34). The complaint alleges two key technical features:
    1. Content-Based ETags: For a given webpage base file (e.g., the primary HTML document), the system generates an ETag value by applying a hash function to the file's content. This ETag is used in HTTP "If-None-Match" headers to allow browsers and intermediate caches to verify if their cached version is still valid (Compl. ¶¶ 31, 40).
    2. Asset File Fingerprinting: For asset files (e.g., images, scripts, stylesheets), the system generates a "fingerprint" from the file's content using a hash function and embeds this fingerprint into the asset's filename and URI. When an asset's content changes, its fingerprint and URI change. This change in the URI within the webpage base file subsequently causes the base file's content to change, resulting in a new ETag (Compl. ¶¶ 32, 36-37, 39).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

6,928,442 Patent Infringement Allegations

Claim Element (from Independent Claim 10) Alleged Infringing Functionality Complaint Citation Patent Citation
a method, in a system in which a plurality of files are distributed across a plurality of computers, Defendant distributes files for its webpages across production servers, origin servers, intermediate cache servers, and endpoint browser caches (Compl. ¶54). ¶54 col. 1:21-25
obtaining a name for a data file, the name being based at least in part on a given function of the data, wherein the data used by the function comprises the contents of the particular file Defendant generates or obtains ETags for its webpage base files using a hash function, where the ETags are based on the files' contents (Compl. ¶55). ¶55 col. 2:30-34
determining, using at least the name, whether a copy of the data file is present on at least one of said computers Defendant's servers, upon receiving a conditional GET request with an ETag, compare the ETag to the stored ETag for the requested URI to determine if a copy of the content is present (Compl. ¶56). ¶56 col. 7:38-44
determining whether a copy of the data file that is present on a at least one of said computers is an unauthorized copy or an unlicensed copy of the data file If the received ETag matches the server's ETag, the downstream cached copy is determined to be authorized. If there is no match, the copy is determined to be unauthorized (Compl. ¶57). ¶57 col. 2:1-4

7,802,310 Patent Infringement Allegations

| Claim Element (from Independent Claim 20) | Alleged Infringing Functionality - | Complaint Citation | Patent Citation |
|:----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |:-----------------------|:--------------------|
| controlling distribution of content from a first computer to at least one other computer, in response to a request obtained by a first device in the system from a second device in the system, . . . the request including at least a content-dependent name of a particular data item... | An upstream server ("first computer") receives a conditional GET request from a downstream cache or browser ("second device"). The request includes a content-dependent name (the ETag) in the If-None-Match header (Compl. ¶63). | ¶63 | col. 2:20-31 |
| based at least in part on said content-dependent name . . . the first device (A) permitting the content to be provided to or accessed by the at least one other computer if it is not determined that the content is unauthorized or unlicensed, otherwise, (B) if it is determined that the content is unauthorized or unlicensed, not permitting the content to be provided to or accessed by the at least one other computer | The upstream server compares the received ETag to its stored ETag. If they match, it sends an HTTP 304 (Not Modified) response, permitting the use of the cached content. If they do not match, it sends an HTTP 200 response with new content, indicating the cached content is no longer authorized (Compl. ¶64). | ¶64 | col. 2:42-51 |

Identified Points of Contention

  • Scope Questions: A central dispute may arise over whether standard HTTP mechanisms like ETags and fingerprinted URIs fall within the scope of the patents' "content-dependent name" or "True Name." A defendant could argue that the patents describe a comprehensive, system-wide, context-independent naming architecture, whereas ETags are a specific feature of the HTTP protocol used for cache validation alongside traditional location-based URIs.
  • Technical Questions: The infringement theory equates a stale file (indicated by a non-matching ETag) with an "unauthorized or unlicensed" file (Compl. ¶57). A key technical and legal question will be whether determining a file is out-of-date is the same as determining it is "unauthorized." A defendant may contend that an ETag mismatch is a technical signal for cache coherency, not a determination of intellectual property rights or license status as contemplated by the patent specifications.

V. Key Claim Terms for Construction

  • The Term: "a name for a data file" / "content-dependent name"

    • Context and Importance: This term is the foundation of the asserted claims. The viability of the infringement case depends on whether the accused ETags and URI fingerprints can be construed as this "name." Practitioners may focus on this term because its construction will determine if standard web caching technologies read on the patents.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification of the ’442 Patent states the name is based on a "message digest function or hash function" to produce a "substantially unique data identifier" (’442 Patent, col. 6:8-12). This functional description could be argued to encompass any content-based hash used for identification, including an ETag.
      • Evidence for a Narrower Interpretation: The specifications often describe the "True Name" as part of a holistic file system that provides "transparent access to any data item by reference only to its identity and independent of its present location" (’442 Patent, col. 4:55-58). A defendant could argue this implies a replacement for, not a supplement to, traditional naming conventions, and that ETags do not function this way.

  • The Term: "unauthorized copy or an unlicensed copy"

    • Context and Importance: This term connects the technical act of file comparison to the patents' stated purpose of content control and enforcement. The infringement allegation hinges on construing a file with a non-matching ETag as "unauthorized."
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The complaint alleges that when content changes, the website operator no longer authorizes use of the old version, and the ETag mismatch is the mechanism for communicating this revocation of authorization (Compl. ¶¶ 27, 33).
      • Evidence for a Narrower Interpretation: The ’442 Patent's title is "Enforcement and Policing of Licensed Content", and its specification discusses tracking file uses for "accounting purposes" and "licensing purposes" (’442 Patent, col. 4:29-35). A defendant may argue that "unauthorized" must be interpreted in this context of legal rights management, not merely as a synonym for "stale" or "out-of-date."

VI. Other Allegations

The complaint does not provide sufficient detail for analysis of indirect or willful infringement.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of definitional scope: Can standard, protocol-specific web caching identifiers like HTTP ETags and fingerprinted filenames be construed as the fundamental, context-independent "content-dependent name" system described and claimed in the patents-in-suit?
  • A key evidentiary question will be one of functional equivalence: Does the accused system's process of identifying a cached file as stale via an ETag mismatch perform the claimed function of determining that the file is unauthorized or unlicensed in the intellectual property enforcement sense described in the patents, or is there a fundamental mismatch in technical and legal function?