DCT
3:18-cv-05597
PersonalWeb Tech LLC v. Intuit Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: PersonalWeb Technologies, LLC (Texas) and Level 3 Communications, LLC (Delaware)
- Defendant: Imgur, Inc. (Delaware)
- Plaintiff’s Counsel: Stubbs, Alderton & Markiles, LLP
- Case Identification: 3:18-cv-05597, N.D. Cal., 09/12/2018
- Venue Allegations: Venue is alleged to be proper because Defendant has 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 associated content delivery infrastructure infringe patents related to using content-based identifiers to manage, distribute, and control access to data across a computer network.
- Technical Context: The technology concerns methods for generating unique identifiers for data files based on their content (e.g., via cryptographic hashing), a foundational concept for modern cloud computing, content delivery networks (CDNs), and data deduplication.
- Key Procedural History: The complaint notes that the patents-in-suit have expired and that the infringement allegations are directed to the time period before expiration. It also states that Plaintiff has previously enforced these patents, resulting in settlements and non-exclusive licenses.
Case Timeline
| Date | Event |
|---|---|
| 1995-04-11 | Earliest Priority Date for ’442, ’310, and ’420 Patents |
| 2005-08-09 | U.S. Patent No. 6,928,442 Issued |
| 2010-09-21 | U.S. Patent No. 7,802,310 Issued |
| 2012-01-17 | U.S. Patent No. 8,099,420 Issued |
| 2018-09-12 | 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"
The Invention Explained
- Problem Addressed: In traditional computer networks, data is identified by name and location (i.e., a pathname), which is inefficient and unreliable in large, distributed systems. The same name can refer to different data in different contexts, and different names can refer to identical data, leading to data duplication and uncertainty about file integrity (Compl. ¶¶12-13; ’442 Patent, col. 1:11-2:46).
- The Patented Solution: The invention proposes replacing location-based naming with content-based identifiers, which the inventors call "True Names." A True Name is a substantially unique identifier generated by applying a cryptographic hash function (such as MD5 or SHA) to the content of a data item. Because this identifier depends only on the data itself, it allows any computer on a network to reliably identify duplicate files, verify data integrity, and manage access to content without regard to file names or storage locations (’442 Patent, Abstract; col. 3:28-36; Compl. ¶¶14-17).
- Technical Importance: This approach provided a system-wide method for reliably identifying and managing data in complex distributed networks, addressing a foundational challenge for the development of cloud computing and efficient content delivery (Compl. ¶11).
Key Claims at a Glance
- The complaint asserts independent claim 10 and dependent claim 11 (Compl. ¶48).
- The essential elements of independent claim 10 are:
- 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 that present copy is an "unauthorized copy or an unlicensed copy" of the file.
U.S. Patent No. 7,802,310 - "Controlling Access to Data in a Data Processing System"
The Invention Explained
- Problem Addressed: The patent addresses the challenge of efficiently controlling the distribution of and access to data in a multi-computer system, building on the same technological foundation as the ’442 Patent (Compl. ¶57).
- The Patented Solution: The invention describes a method where a first computer controls the distribution of content to other computers. This control is exercised in response to a request that includes a "content-dependent name" (e.g., a hash) of the desired data. The first computer uses this content-dependent name to determine if the requesting computer is authorized to access the content and, based on that determination, either permits or denies the provision of that content (’310 Patent, Abstract; Compl. ¶¶58-59).
- Technical Importance: This method enables efficient authorization and cache validation in a distributed network by using content-based identifiers as tokens to grant or deny access, reducing the need to transfer full files for verification (Compl. ¶59).
Key Claims at a Glance
- The complaint asserts independent claim 20 (Compl. ¶56).
- The essential elements of independent claim 20 are:
- A computer-implemented method for controlling content distribution between computers.
- The control is in response to a request that includes a "content-dependent name" of a data item.
- The content-dependent name is based on a hash or message digest function of the data's contents.
- Based on this name, a device permits access if the content is not determined to be unauthorized or unlicensed, and otherwise does not permit access.
U.S. Patent No. 8,099,420 - "Accessing Data in a Data Processing System"
- Technology Synopsis: This patent describes a system comprising hardware and software for managing data access using content-dependent identifiers. The system determines one or more such identifiers for a data item by applying a function to its bits. It then selectively permits the data item to be accessed by computers in a network based on whether the item's identifier corresponds to an entry in one or more databases (’420 Patent, Abstract; Compl. ¶¶66-67).
- Asserted Claims: Claims 25, 26, 27, 29, 30, 32, 34–36, and 166 are asserted, with independent claim 166 detailed in the complaint (Compl. ¶¶63-64).
- Accused Features: The accused features include Defendant’s system of web servers, caches, and software that allegedly control website content distribution. This system is alleged to use content-based ETags associated with URIs, which are stored in databases to manage conditional GET requests and ensure that downstream caches access only authorized file content (Compl. ¶¶64, 68).
III. The Accused Instrumentality
Product Identification
- The imgur.com website and its associated backend infrastructure, including web servers, origin servers, intermediate cache servers, and endpoint caches (Compl. ¶¶29, 49).
Functionality and Market Context
- The complaint alleges the accused instrumentality operates a system for efficiently delivering webpage content. It allegedly uses the standard HTTP "ETag" mechanism to manage caching. When a browser or intermediate cache requests a web asset (like an image), the server provides the asset along with an ETag value, which the complaint alleges is a content-based hash of that asset (Compl. ¶¶31, 35). On subsequent requests for the same asset, the browser sends the ETag value in an "If-None-Match" header. If the server determines the ETag matches its current version, it responds with an HTTP 304 (Not Modified) message, instructing the browser to use its local cached copy. If the content has changed, the ETags will not match, and the server sends the new asset along with a new ETag (Compl. ¶¶39-42). This process is alleged to reduce bandwidth and server load by avoiding the re-transmission of unchanged files (Compl. ¶33).
No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
U.S. Patent No. 6,928,442 Infringement Allegations
| Claim Element (from Independent Claim 10) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| 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’s system generates or obtains ETag values for its webpage and asset files using a hash function, where the ETags are based on the contents of the files. | ¶50 | col. 13:5-15 |
| determining, using at least the name, whether a copy of the data file is present on at least one of said computers | Defendant’s origin and intermediate cache servers respond to a conditional GET request by using the ETag and URI to determine if they have a copy of the content having that ETag. | ¶51 | col. 19:20-25 |
| 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 ETag from a downstream cache/browser matches the server's ETag, the server determines the copy is "authorized." If there is no match, it determines the copy is "unauthorized." | ¶52 | Abstract |
U.S. Patent No. 7,802,310 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...from a second device... | Defendant’s upstream origin or cache servers (first computer) control distribution of webpage files to downstream intermediate caches or user browsers (second device) in response to conditional GET requests. | ¶¶57-58 | Abstract |
| the request including at least a content-dependent name of a particular data item, the content-dependent name being based at least in part on a function...which comprises a message digest function or a hash function... | The conditional GET request includes an ETag in an "If-None-Match" header. The complaint alleges this ETag is a content-dependent name generated by hashing the file's contents. | ¶58 | col. 4:13-27 |
| based at least in part on said content-dependent name...the first device (A) permitting the content to be provided...if it is not determined that the content is unauthorized or unlicensed, otherwise, (B)...not permitting the content... | The server compares the ETag in the request to its stored ETag. If they match, it sends an HTTP 304 response, permitting the downstream device to use its cached content. If they do not match, it sends an HTTP 200 response with new content, not permitting use of the older, cached version. | ¶59 | col. 24:1-20 |
Identified Points of Contention
- Scope Questions: A primary point of contention may be the interpretation of "unauthorized copy or an unlicensed copy." The complaint equates this with a stale or out-of-date cached file. A defendant, however, could argue that the patent's language, including its title ("Enforcement and Policing of Licensed Content"), limits this term to a digital rights management context concerning pirated or illegally distributed content, not standard cache validation.
- Technical Questions: The complaint alleges "on information and belief" that the ETags used by Imgur are generated via a hash of the file's content. A key factual dispute will be what evidence exists to support this. A defendant might argue its ETags are generated differently (e.g., from timestamps or version numbers) and are therefore not "content-dependent" in the manner required by the claims.
V. Key Claim Terms for Construction
The Term: "unauthorized copy or an unlicensed copy" (’442 Patent, Claim 10)
- Context and Importance: This term's definition is critical. If construed broadly to mean any "out-of-date" or "stale" version of a file in a cache, it supports the plaintiff's infringement theory. If construed narrowly to mean a pirated or rights-infringed copy, the infringement case may be significantly weakened. Practitioners may focus on this term because its interpretation could determine whether standard internet caching protocols fall within the patent's scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification discusses using the invention for cache synchronization, which involves identifying and replacing outdated data items, a process that does not inherently involve licensing status (’442 Patent, col. 3:5-11, col. 35:9-24).
- Evidence for a Narrower Interpretation: The patent's title is "Enforcement and Policing of Licensed Content." The abstract explicitly states, "A copy of a requested file is only provided to licensed (or authorized) parties." This language strongly supports a narrower construction related to digital rights management (’442 Patent, Title; Abstract).
The Term: "controlling distribution of content" (’310 Patent, Claim 20)
- Context and Importance: The plaintiff alleges that responding to an HTTP request with either a "304 Not Modified" or a "200 OK" message constitutes "controlling distribution." A defendant may argue that this is merely a standard, passive response mechanism inherent to the HTTP protocol, whereas the patent claims a more active system of control and authorization. The case may turn on whether this standard protocol behavior meets the claim's "controlling" limitation.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is broad, and the act of deciding whether to send a full file or a simple "not modified" header could be framed as a form of "control" over what data is distributed over the network.
- Evidence for a Narrower Interpretation: The specification describes a system for managing access and permissions, suggesting a more robust gatekeeping function than the automatic cache-validation responses built into HTTP (’310 Patent, Abstract).
VI. Other Allegations
Indirect Infringement
- While not pleaded as a separate count, the complaint contains language that may support a theory of induced infringement. It alleges that Defendant "caused" downstream cache servers and endpoint browsers to perform certain claimed steps, such as obtaining ETags and sending conditional GET requests (Compl. ¶¶50, 58). This allegation of causation is a required element for inducement.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the patent term "unauthorized copy," rooted in the context of policing licensed content, be construed to cover a technically "out-of-date" file in a standard web caching system?
- A key evidentiary question will be whether the "ETag" values used by the accused system are, in fact, "content-dependent names" generated from a hash of file contents, as required by the claims, or if they are simply version identifiers generated by another method.
- A central question for the litigation, potentially impacting both infringement and validity, will be whether the patents' claims, when applied to the standard HTTP ETag cache-validation protocol, are distinguishable from conventional and widely practiced methods for efficient content delivery on the internet.