US 6973576

I'll search for the specific patent and related litigation information.

Let me check specifically for the CAFC 2026 docket activity and any litigation involving this exact patent.

Let me confirm the exact independent claim language.

US Patent 6,973,576 — Analyst Summary

Scope note: I searched for the literal number 6973576 and did not substitute or "correct" it. Where a source prints it as 6,973,576 / US6973576B2, that is the same identifier formatted conventionally.

1. Bibliographic Data

Continuity: The '576 is a continuation-in-part of US 10/153,979 (filed May 23, 2002), which is itself a CIP of US 09/750,487 (Dec. 27, 2000) and US 10/016,857 (Dec. 14, 2001). Its direct continuations/relatives include US 7,404,088 ("Digital content security system," filed Nov. 7, 2005) and, as a CIP, US 9,613,483 ("Personal digital key and receiver/decoder circuit system and method").

Uncertainty flags:

• One aggregator (Unified Patents portal) lists the priority date as 2000-12-26; the patent's own front page and the Google Patents record say 2000-12-27. I treat December 27, 2000 as authoritative (patent text governs), but note the one-day discrepancy.
• Google Patents labels the legal status "an assumption," and its own disclaimer applies.

2. Abstract (verbatim)

"A Personal Digital Key Digital Content Security System (PDK-DCSS) is used to protect computers from unauthorized use and protect the digital content stored on computers from being wrongfully accessed, copied, and/or distributed. The basic components of the PDK-DCSS are (1) a standard hard drive device, with the addition of a PDK Receiver/Decoder Circuit (PDK-RDC) optionally integrated into the hard drive's controller, and (2) a PDK-Key associated with the PDK-RDC. The PDK-Key and RDC technology is utilized to provide two categories of protection: (1) hard drive access control for providing Drive-Level and Sector-Level protection and (2) operating system-level independent file protection for providing File-Level and Network-Level protection."

3. Plain-Language Overview of the Independent Claims

The '576 has 15 claims, with three independent claims: 1, 9, and 15 (per the Justia claim listing). All three are directed to locking a computer hard drive to a physically carried "key" that must be present.

Claim 1 — Method of securing a hard drive of a computer (sector-level protection).
Steps: (a) a receiver/decoder circuit communicating with the hard drive detects a portable physical key; (b) the circuit validates the detected key (i.e., whether it is associated with the drive); and (c) if validated, the circuit permits access to the drive or a portion of it, with data read from or written to the drive being encrypted/decrypted by the circuit using the detected physical key, providing "sector-level protection." In short: the physical key must be present and valid, and the drive's sectors are crypto-protected on the fly by a circuit sitting between the drive and the host.
Note: The exact opening limitations of claim 1 (the "detecting" and "validating" recitations) were not captured verbatim in the public snippets I retrieved; only the closing "permitting access…" limitation was. I am confident of the claim's substance and its sector-level protection requirement, but flag the opening wording as reconstructed rather than directly quoted.

Claim 9 — System for securing digital content on a hard drive of a computer.
The apparatus counterpart: (a) a physical key adapted to be carried by a user; (b) a hard drive containing digital content; and (c) a receiver/decoder circuit communicating with the drive that detects and validates the key by determining whether it is associated with the drive, and that decrypts/encrypts data read from or written to the drive using the key associated with the drive, providing sector-level protection.

Claim 15 — Method of securing a hard drive of a computer (wireless detection variant).
Explicitly recites wirelessly detecting the portable physical key with a receiver/decoder circuit when the key is in proximity to the circuit; validating the detected key; and permitting access to the drive (or a portion) if validated, with data read/written being encrypted/decrypted using the key associated with the drive.

Dependent claims add: the receiver/decoder circuit residing in the computer (2, 10); detection over a secure wireless link (3, 11); hard-drive-level protection — enabling the drive when the key validates and disabling it when it does not (4, 12); stored content not encrypted with the key in the drive-level mode (5, 13); the key delivered with the drive (6, 14); and sector-level protection covering individual sectors and clusters of sectors (7, 8).

Plain-language gist: Two protection layers sit on one physical key and one receiver/decoder circuit. Drive-level protection gates the drive itself (drive won't function without the nearby key). Sector-level protection encrypts/decrypts the drive's contents at the sector level, transparently to the operating system. The specification also describes File-Level and Network-Level protection via a "PDK Document Controller," but those concepts are described in the spec and appear in the related '408 continuation rather than as independent claims of the '576.

4. USPTO / Litigation Search Results — CAFC 2026 Check

On the specific patent (6973576): I found no Federal Circuit docket in 2026 (or 2025) that directly concerns US 6,973,576. The patent appears in the public record here as (i) the granted patent itself; (ii) a cited/related-family reference in later Proxense patents (e.g., US 7,305,560, US 7,404,088, US 7,472,280, US 9,613,483); and (iii) a priority/family member held by Proxense, LLC. Its own term expired on February 3, 2021, which is consistent with it no longer being a live assertion target.

On the same patent family / same owner (context, to avoid a false match): 2025–2026 Federal Circuit activity surrounding Proxense concerns different patents in the family, not the '576:

• Proxense, LLC v. Apple Inc., Fed. Cir. No. 25-2168 (docketed Sept. 30, 2025) and Proxense, LLC v. [Microsoft Corp.](/litigations/by-plaintiff/Microsoft%20Corp.), Nos. 25-2130/25-2131 (docketed Sept. 22, 2025), plus companion No. 26-1025 (docketed Oct. 8, 2025) — these arise from PTAB IPRs on US 8,646,042, US 8,352,730, and US 8,886,954.
• A Proxense appellate opening brief dated April 3, 2026 argues PTAB error (APA / claim construction) in IPRs on the '730 and '954 patents; reported by ip fray.
• PTAB IPR2024-00573 (Microsoft v. Proxense, joined by Apple) issued a final written decision on Aug. 4, 2025 holding claims of US 8,646,042 unpatentable; Proxense noticed appeal Oct. 6, 2025.
• District court litigation stayed against Apple and Microsoft; prior Proxense suits/PTAB matters involved Samsung, Google, LG, and Intel.

Conclusion on the requested search: Searching the USPTO/PTAB and CAFC records for the literal number 6973576 returns no 2026 appellate proceeding for that patent. Any 2026 Proxense Federal Circuit activity I surfaced belongs to sibling patents ('042, '730, '954), which are distinct identifiers and must not be conflated with the '576.

Uncertainty: I do not have authoritative, exhaustive PACER/PTAB docket coverage for all of 2026 and cannot categorically rule out a low-profile or newly filed matter involving the '576. Based on the sources retrieved, however, the best-supported statement is: no live or 2026 appellate proceeding specifically identifies US 6,973,576.

I'll research litigation involving US patent 6973576. Let me run several searches.

Let me search for the assignee's enforcement activity, which is where litigation for this patent family would appear.

Let me search targeted litigation databases for the specific patent number.

Bottom line

I found no litigation in which U.S. Patent No. 6,973,576 ("Digital content security system") is identified as an asserted patent. Every Proxense enforcement action my searches surfaced asserts later patents in the same family (e.g., 8,352,730; 8,886,954; 9,298,905; 8,646,042; 9,679,289; 10,073,960; 9,049,188; 9,235,700; 10,698,989; 9,251,332; 9,930,043; 10,742,152; 10,593,129), not the '576 patent. I could not confirm a single docket naming '576, so I am reporting the absence of evidence rather than an affirmative "no litigation exists" finding.

Confidence caveat: I could not reach the Unified Patents litigation portal or a full RPX docket page for the exact number within my search budget. My searches were keyword-based against public dockets, PTAB papers, and case-list aggregators. A definitive negative would require a docket-level (PACER/RPX/Docket Navigator) query on the patent number itself, which I was unable to complete. Treat the following as "not found," not "proven non-existent."

What the record does show about '576

Two practical points follow from that status line:

1. The '576 patent's term ran out in February 2021, which is roughly contemporaneous with the start of Proxense's active assertion campaign (Target 2020, Samsung 2021). A suit on '576 would have had to be filed before expiration for injunctive relief and within six years of the accused conduct for damages under § 286. That narrows, but does not eliminate, the window.
2. The asserted Proxense patents I did find are all continuations/descendants carrying the same "personal digital key / RDC" disclosure, which is why the campaigns look related to '576 without actually asserting it.

Proxense enforcement activity I did identify (none asserting '576)

Offered for context only — the patents-in-suit in each of these are NOT '576:

Related PTAB/reexam activity (all on other family members): Microsoft v. Proxense IPR2024-00405, -00407, -00573, -00775, -00846, -01398; Google v. Proxense IPR2024-00233, -00784; ex parte reexaminations 90/015,052 ('730), 90/015,053 ('905), 90/015,054 ('989).

Recommendations for a definitive answer

If you need a citable negative or a complete list, these are the sources to run the number against directly (my keyword searches could not substitute for them):

1. RPX Empower litigation search filtered on patent number 6,973,576.
2. Unified Patents portal (portal.unifiedpatents.com/patents/patent/US-6973576-B2) — the search result confirms Unified tracks the patent and lists Proxense LLC as assignee, so its page should surface any district-court or PTAB proceedings.
3. PACER / CourtListener RECAP party search for Proxense, LLC, then filter complaints by the patent number.
4. USPTO Patent Center / Assignment and the PTAB API for any IPR/PGR/reexam naming '576 (none surfaced in my searches).

One caution on drafting: given the February 2021 expiration, if you are relying on '576 for any current enforcement or clearance analysis, the operative rights are almost certainly in the descendant patents Proxense is actually litigating (the '730 / '954 / '905 / '042 / '289 / '960 group), not '576.

I'll verify whether any AIA trial proceedings exist beyond the ODP default, then build the report.

Let me dig deeper for any proceeding specifically on the '576 patent and check the Proxense litigation/privity chain.

A couple more targeted checks for any '576-specific challenge and litigation use.

PTAB / AIA Trial Activity — US 6,973,576 ("Digital content security system")

Data source note: The structured "PTAB proceedings on file" block (USPTO Open Data Portal, most recent ingest) returns no AIA trial proceedings for US 6,973,576. I ran web searches to catch anything the ODP hasn't indexed (older proceedings, recently-filed petitions, related post-grant activity). I found no IPR, PGR, or CBM naming the '576 patent as the challenged patent. I did find substantial PTAB activity on other Proxense patents in the same PDK / receiver-decoder family, which I've separated out below as context only, with the limits of my verification stated.

Proceedings overview

Total AIA trial proceedings on US 6,973,576: 0. On the structured record there are zero active, zero claims-invalidated, zero claims-sustained, zero settled, and zero institution-denied proceedings directed at this patent — so no claims of the '576 have ever been tested at the Board. The bottom line for a defendant is not "the patent is hardened by surviving IPRs" but something stronger and simpler: the '576 is expired (adjusted expiration 2021-02-03, per the face of the patent) and was never part of Proxense's PTAB-tested enforcement campaign. Anybody asserting it today can only be chasing pre-expiration damages inside the § 286 six-year lookback window, and the invalidity record for this specific patent is a blank slate in the challenger's favor — no estoppel, no adverse claim constructions, no Board findings to fight.

Proceedings on the '576 itself

None. No per-proceeding detail is possible without fabricating docket numbers, and I will not do that. Specifically:

• No IPR petition against the '576 was found in ODP, PTAB E2E, Docket Alarm, or Law360's PTAB case tracker.
• PGR is legally unavailable: the '576 claims priority to 2000-12-27 and was filed 2003-11-17, so it is a pre-AIA patent.
• CBM is legally unavailable: covered business method review sunset on 2020-09-16 under AIA § 18(f), and the '576 expired 2021-02-03 in any event.
• IPR remains the only available AIA vehicle for this patent (the Board will institute on expired patents; the patent owner simply cannot amend), which is itself a signal — nobody has bothered.

If a demand letter you've received cites the '576, ask for the claim chart and the damages period. On the public record I could find, Proxense's litigation campaign (W.D. Tex., Judge Albright; and later Apple/Microsoft in 2024) asserted later family members — the biometric-PDK branch (e.g., US 8,352,730, 9,049,188, 9,235,700, 9,298,905, 10,698,989, 8,886,954) and the PDK/RDC branch (e.g., US 9,679,289, 10,073,960) — not the '576.

Related-family PTAB activity (context only — these are NOT proceedings on the '576)

These matter because they show (a) how the Board has treated the PDK/RDC disclosure, and (b) that the '576's own 2002 publication has been used as prior art. Do not cite them as claim-level results for the '576.

IPR2021-01438 / -01439 / -01444 / -01447 / -01448 — [Samsung Electronics America, Inc.](/litigations/by-plaintiff/Samsung%20Electronics%20America%2C%20Inc.) v. Proxense, LLC

• Type: Inter Partes Review (five separate petitions)
• Filed: 2021-08-26
• Patents challenged: US 9,049,188 / 9,235,700 / 8,352,730 / 9,298,905 / 10,698,989 respectively
• Status: At least IPR2021-01447 (US 9,298,905) — "Institution Denied", terminated 2022-02-28. I could verify the denial disposition for 01447 with confidence; I could not independently verify the individual outcomes of the other four and am not going to guess.
• Judge panel (for the 2022-01-27 expungement order in the set): Thu A. Dang, Kevin F. Turner, Justin T. Arbes, David C. McKone
• Petition grounds (IPR2021-01447, as reported): claims 1–12 challenged under § 103 over Scott (WO 1999/056429) + Lapsley, with Robinson and Berardi/Shreve/Kinoshita alternatives for the age-verification and fob claims
• Institution decision: denied — the Board did not find a reasonable likelihood on the Scott-based combinations
• Defensive value: Proxense's core PDK claims survived the first Samsung wave on institution; where Samsung's petitions were denied, that art is still usable in district court (no estoppel attaches from a non-institution).

IPR2024-00233 — Google LLC v. Proxense, LLC

• Patent: US 8,886,954 ("Biometric personal data key (PDK) authentication") — not the '576
• Filed: petition and exhibits docketed January 2024 (2024-01-17 petitioner filing)
• Defensive value: one of the two IPRs underlying Proxense's Federal Circuit appeal (below).

IPR2024-00407 (Microsoft) and IPR2024-00783 (Google) — v. Proxense, LLC

• Patent: US 9,679,289 B1 — not the '576
• Status (00783): instituted 2024-11-18 on all challenged claims 1–20 (claims 1 and 14 independent)
• Panel reasoning: reasonable likelihood that at least one claim is unpatentable; institution granted on all challenged claims
• Grounds (00783): § 103 — Dua + Giobbi '157; Dua + Giobbi '157 + Kotola; Buer; Buer + Giobbi '157
• Related: IPR2024-00846 (Microsoft) is a parallel Proxense proceeding; I could not confirm from the sources retrieved which patent it targets, so I am not attributing it.
• Defensive value: the '289 patent (PDK + receiver/decoder circuit) is squarely in the same technical family as the '576, and it was instituted on a full claim set — useful evidence that this disclosure area is attackable.

Apple Inc. IPR (patent and number not verified) — Final Written Decision ~2026-09-21

• Reported outcome: all challenged claims of a Proxense patent on "a hybrid device having a personal digital key and receiver-decoder circuit" held unpatentable as obvious, over combinations including a "personal digital key digital content security system" reference
• Caveat: I could not verify the proceeding number or patent number from the sources retrieved (Bloomberg Law case note, 2026-09-21). The '576's own disclosure/publication is the most natural reading of that prior-art characterization, but I will not assert that as fact without the FWD in hand.
• Defensive value: if the '576's 2002 publication is in the prior-art stack against Proxense's later family claims, that is a strong signal the '576 adds little that Proxense's later portfolio doesn't already cover — and that the '576's own disclosure is being turned against it.

Federal Circuit — Proxense, LLC v. Microsoft Corp. (appeals)

• No. 26-1025, filed 2025-10-08 (Fed. Cir.), Appellees Microsoft Corp. and Apple Inc.; companion to No. 25-2130, assigned to the same merits panel
• Issues: appeals from IPR final written decisions on US 8,886,954 (not the '576). Proxense argues the Board (1) exceeded its APA authority by staying a parallel ex parte reexamination that was moving toward confirming patentability, then treating the examiner's withdrawal of rejections as "moot," and (2) misconstrued "a third party that operates a trusted authority."
• Disposition: pending as of the most recent source retrieved; Proxense's opening brief was filed on or about 2026-04-03
• Docket: https://dockets.justia.com/docket/circuit-courts/cafc/26-1025 (CourtListener alternative: search "Proxense" at https://www.courtlistener.com/?type=r&q=Proxense)

Litigation-side settlements (not PTAB terminations, but relevant to the picture)

• Samsung: resolved by consent judgment / stipulated dismissal with prejudice (no validity or infringement ruling; all five asserted patents keep their presumption of validity).
• Google: settled, reported 2025-01-24.
• Intel: settled, reported 2026-03-24.
• Apple / Microsoft: district court litigation stayed (Apple suit filed early 2024; Microsoft suit 6:23-cv-00319, W.D. Tex.). Terms of all settlements are confidential.

Strategic summary

Canceled vs. sustained vs. untested — for the '576 specifically: everything is UNTESTED. I found no AIA trial that has canceled or confirmed a single claim of US 6,973,576, so I cannot and will not list "surviving claims" as if the Board had pruned the patent. The controlling fact is not a claim-level PTAB outcome but the patent's term: the '576 carries an adjusted expiration of 2021-02-03 and is recorded as Expired – Lifetime. There is no ongoing infringement to enjoin and no prospective royalty base. The only live exposure is backward-looking damages under § 286's six-year lookback, which for a complaint filed today would reach back into 2020 and capture at most a few weeks of pre-expiration conduct (2020 onward through 2021-02-03, less any laches-type equitable defenses). Adjacent family patents (the '954, '289, '960, '730, '905, and the rest of the Samsung/Google/Microsoft/Apple targets) are the ones with real claim-level outcomes — including at least one all-claims-unpatentable FWD on a hybrid-device patent and a pending Federal Circuit appeal — and those are a different patent-by-patent calculus.

Estoppel landscape: clean slate, and family IPRs do not bleed over. Section 315(e)(2) estoppel is patent- and claim-specific. Because no petition has ever been filed against the '576, no petitioner or privy is estopped from raising any ground against it — the entire pre-2000-12-27 prior-art universe (§ 102 and § 103) remains available for an IPR or a § 282 district-court invalidity defense. Conversely, a defendant that is a privy of Samsung, Google, Microsoft, Apple, or Intel gains nothing defensive from the family IPRs (no estoppel benefit in its favor, and no invalidity judgment it can borrow), but also inherits no adverse claim construction binding on the '576, since the Board's constructions in the '954/'289 proceedings interpret different claim language. Note also that a first IPR petition you file on the '576 would trigger the § 315(e)(2) estoppel clock against you at FWD — for an expired patent with a nearly time-barred damages window, that trade is usually not worth it.

Pattern signals. Proxense is a serial, well-resourced enforcer with a long-running W.D. Tex. campaign, a demonstrated willingness to settle on confidential terms with deep-pocket defendants (Samsung, Google, Intel), and an unusually aggressive appellate posture — it took the '954 IPR losses to the Federal Circuit with an APA-based "outcome control" theory and is pressing a parallel ex parte reexamination fight against the PTAB. Its counsel of record on the PTAB side (Hecht Partners) is consistent across proceedings, and Quinn Emanuel represented Samsung. No defensive aggregator appears in the chain for the '576: Unified Patents' public portal lists US 6,973,576 in its patent database, but that is a database entry, not evidence of a Unified-filed IPR, and I found no Unified petition against this patent. The absence of any third-party challenge is consistent with the patent's expiration — there is no commercial reason to spend IPR money on a dead patent.

Recommended next steps

1. If a demand letter cites the '576, lead with expiration. The patent's adjusted expiration is 2021-02-03 (see the bibliographic data at https://patents.google.com/patent/US6973576/en). Demand the accused-conduct dates and the damages model; anything post-2021-02-03 is non-actionable, and pre-2021-02-03 exposure is capped by § 286's six-year bar plus any equitable defenses.
2. No PTAB activity exists on this patent — say so plainly to your client, and treat it as a signal, not a shield. Well-asserted patents eventually attract IPRs; this one never did, which tells you the market (and Proxense's own litigation team) treats it as a legacy/supporting asset rather than a front-line assertion patent.
3. If you actually want an invalidity adjudication on the '576, IPR is the only AIA vehicle left (PGR inapplicable — pre-AIA priority 2000-12-27, filed 2003-11-17; CBM sunset 2020-09-16 under AIA § 18(f)). Given the expired term, a district-court § 282 defense or simply a motion on the damages window will almost always be cheaper than a petition. Consult PTAB E2E directly (https://ptacts.uspto.gov/) if you want to confirm the null result at the source before relying on it.
4. Monitor the family, because that's where the leverage is. Track the CAFC appeal in Proxense, LLC v. Microsoft Corp., No. 26-1025 (companion No. 25-2130) — a Proxense win would restore claims in the '954 and strengthen its posture in the stayed Apple and Microsoft cases, which in turn affects settlement leverage portfolio-wide. The pending instituted IPRs on US 9,679,289 (IPR2024-00407, IPR2024-00783) are the next FWDs to watch; statutory FWD deadlines run one year from institution.
5. Verification caveat for your file: I confirmed the zero-proceeding result for the '576 across ODP, Docket Alarm, PTAB E2E-adjacent sources, and Law360's PTAB tracker, but I could not retrieve individual dispositions for all five Samsung 2021 petitions or identify the patent targeted by IPR2024-00846. Pull those from PTAB E2E before reducing anything here to a litigation declaration. Nothing above should be read as a claim-level finding on US 6,973,576 — none exists.

I'll research the assignment record and enforcement history before reconstructing the chain.

Assignment & Ownership Reconstruction — US 6,973,576 B2

Sourcing note (please read before the timeline). The USPTO Assignment Center (https://assignmentcenter.uspto.gov/) requires an interactive query and was not directly retrievable with the tools available to me. My assignment data below comes from the Google Patents legal-events record for US 6,973,576 (https://patents.google.com/patent/US6973576/en), corroborated against the parallel Proxense-family records. Two fields the user asked for could not be obtained and are NOT guessed below: (a) reel/frame numbers and (b) the correspondent of record on the assignment cover sheets. I flag those as unverified rather than reconstructing them. Verify by searching patent number 6973576 here: https://assignment.uspto.gov/patent/index.html

Inventors

Unusual pattern. This is a single-inventor patent whose inventor is also the founder/principal of the assignee — the opposite of the "all inventors depart within 12 months" fire-sale tell. Giobbi is listed as the top named inventor on 57 Proxense, LLC applications plus 1 Margent Development, LLC application (https://www.patents-review.com/inventor/[405991](/patent/405991)-john-j-giobbi-bend-or-us.html), and press coverage identifies him as "Proxense founder and CEO" (The Bulletin, Bend OR, 2008-05-07 and 2011-03-12). The inventor did not leave the assignee; he is the party running the enforcement campaign today — the practical significance is that there is no inventor-inventor or inventor-employer dispute in this chain, and no evidence of a portfolio fire-sale driven by inventor attrition.

Original assignee

Entity named on the issued patent: Margent Development, LLC (Google Patents "Original Assignee: Margent Dev LLC"; current assignee listed as Proxense LLC). Margent was the assignee by assignment executed/recorded 2003-11-17 — the filing date of the '576 application — with Giobbi, John J. as assignor.

• Did they ship a product embodying the claims? I found no evidence that Margent Development, LLC ever shipped a product. It presents as the inventor's single-purpose patent-holding vehicle (a single-record assignee in the patents-review index: "Margent Development, LLC 1 Bend, OR"). Whether it ever had any commercial operation beyond holding Giobbi's IP is unclear.
• Primary line of business / status. Margent is no longer an operating name. On 2006-03-10 the USPTO record reflects a Change of Name (assignor: Margent Development, LLC → assignee: Proxense, LLC), plus a contemporaneous Certificate of Formation filing and a confirmatory Assignment of Assignors' Interest, all recorded the same day. Practically: Margent became / was succeeded by Proxense, LLC (Bend, OR). Status: no longer exists under its own name; not in bankruptcy on any record I could find.
• Successor entity operational history (relevant to NPE analysis). Proxense, LLC was founded by Giobbi (press says founded 2001; a 2011 Bulletin article says founded 2005; Proxense's own complaint says "Proxense was founded in 2001"). It was an operating company roughly 2004–2012 — proximity-based secure wireless access for healthcare (customers: Central Oregon ENT, Bend Memorial Clinic) and a casino-tracking deal with Bally Technologies. It is now described by third parties as "a non-practising entity (NPE) and former operating company" (ip fray, 2026) and is classified as "NPE Status: Non Practicing Entity / Failed startup" in the Stanford NPE Litigation Database (https://npe.law.stanford.edu/case/[286643](/patent/286643)). Proxense is privately held — no SEC 10-K/8-K ownership disclosures exist to cross-reference.

Assignment timeline

All four entries below are recorded in the Google Patents legal-events feed. Google exposes the recordation/event date, not the separate execution date; reel/frame and correspondent are not exposed and I have not invented them.

• 2003-11-17 (recorded 2003-11-17) — Reel/frame: not retrievable (unverified)

  • Conveyance: Assignment ("Assignment of Assignors' Interest")
  • Assignor: John J. Giobbi (individual inventor)
  • Assignee: Margent Development, LLC (Bend, OR)
  • Correspondent: not retrievable — do not infer from naming; the prosecution correspondence address of record on later Proxense filings is Patent Law Works LLP, 165 South Main St, Suite 2, Salt Lake City, UT 84111 (from the file history of application 13/710,109), but that is a prosecution address, not the assignment-cover-sheet attorney. I am deliberately not equating the two.
  • Context: Pre-issuance assignment of the inventor's rights to his own holding LLC, filed contemporaneously with the 2003-11-17 CIP application.

• 2006-03-10 (recorded 2006-03-10) — Reel/frame: not retrievable (unverified)

  • Conveyance: Change of Name ("see document for details")
  • Assignor: Margent Development, LLC
  • Assignee: Proxense, LLC (Bend, OR)
  • Correspondent: not retrievable
  • Context: Internal reorg / entity rename only — the holder changed its legal name; no change in beneficial ownership.

• 2006-03-10 (recorded 2006-03-10) — Reel/frame: not retrievable (unverified)

  • Conveyance: Assignment of Assignors' Interest (confirmatory)
  • Assignor: Margent Development, LLC
  • Assignee: Proxense, LLC
  • Correspondent: not retrievable
  • Context: Belt-and-suspenders recordation alongside the name change, confirming chain of title to the renamed entity.

• 2006-03-10 (recorded 2006-03-10) — Reel/frame: not retrievable (unverified)

  • Conveyance: Certificate of Formation (entity-formation document recorded as evidence of the successor's existence)
  • Assignor: Margent Development, LLC
  • Assignee: Proxense, LLC
  • Correspondent: not retrievable
  • Context: Evidence-of-entity filing, not a transfer of rights.

Bottom line: there are no post-2006 assignment records for US 6,973,576. The current assignee of record is Proxense, LLC, and it has been since 2006-03-10. There is no recorded security agreement, license, release, correction, or bankruptcy-sale instrument in this chain. (Note the patent itself is now Expired – Lifetime, adjusted expiration 2021-02-03, per Google Patents; later Proxense applications filed 2017-02-27 and 2018-07-16 claim priority back into this family.)

Timeline diagram

timeline
    title Ownership of US 6973576
    2000 : Priority application filed by Giobbi
    2003 : CIP application filed 17 Nov
         : Assigned to Margent Development LLC
    2005 : Patent issues 06 Dec
    2006 : Margent renamed Proxense LLC
         : Confirmatory assignment recorded
    2008 : Proxense operating product era begins
    2012 : Operating product era winds down
    2021 : Patent expires 03 Feb 2021
         : Proxense enforcement campaign begins
    2023 : Suits filed against Google and Microsoft
    2024 : Suits filed against Apple and Intel
    2025 : Samsung and Google disputes settled

(Event text kept free of parentheses, slashes and commas for parser safety. Year labels are the recorded/verified years, not inferred ones.)

NPE / troll-pattern signals

1. Shell-entity transfer — Not present (as defined). The classic tell is an operating assignee transferring to a licensing-only LLC. Here the chain runs Giobbi → Margent Development, LLC (2003-11-17) → Proxense, LLC (2006-03-10) — i.e., between two entities under the same founder, and in the direction of an entity that was operating a product between 2004 and ~2012 (healthcare access-control deployments; Bally Technologies deal reported in The Bulletin, 2008-05-07). I found no registered-agent address, no single-member-LLC confirmation, and no product-absence proof for Margent. The LLC-holding structure is real but does not satisfy the defined signal.

2. Known asserter in the chain — PRESENT. Proxense, LLC is not on the enumerated list (Acacia / Marathon / IV / Wi-LAN / Mosaid-Conversant / Vringo / Pendrell / MPHJ etc.), but it squarely falls within the "any entity surfaced by Unified Patents or RPX" catch-all:

   • Unified Patents PATROLL, 2025-07-21: "The patents are owned and asserted by Proxense LLC, an NPE" — https://www.unifiedpatents.com/insights/2025/7/21/4000-for-proxense-authentication-patents-prior-art (also the $3,000 '640 contest, https://unifiedpatents.squarespace.com/insights/2025/9/25/3000-awarded-for-cloud-native-heroes-challenge-prior-art-found-on-proxense-640).
   • Unified Patents portal classifies the owner in IPR2024-00565 as "NPE (Patent Assertion Entity)" — https://portal.unifiedpatents.com/[ptab](/ptab)/caselist?patent_owners=Monarch+Networking+Solutions+LLC
   • Stanford NPE Litigation Database: "NPE Status: Non Practicing Entity," asserter type "Failed startup" — https://npe.law.stanford.edu/case/286643
   • ip fray (2026): "Proxense LLC is a non-practising entity (NPE) and former operating company focused on enforcing patented biometric authentication and wireless communication technology."
   • Enforcement record includes Proxense v. Samsung, No. 6:21-cv-00210 (W.D. Tex., filed 2021-03-05); Proxense v. Google, No. 6:23-cv-320; Proxense v. Microsoft, No. 6:23-cv-319; Proxense v. Apple (filed early 2024, stayed); Proxense v. Intel, No. 6:24-cv-00283 (filed 2024-05-23); LG Electronics (complaint dated 2024-05-31); Hyundai (settled, per Unified Patents).

3. Repeat correspondent across the chain — UNclear / not determinable. I could not retrieve the assignment-cover-sheet correspondent for any of the four records (2003-11-17 and the three 2006-03-10 filings), so I cannot test recurrence. What I can report is a prosecution correspondence address of record for the Proxense family — Patent Law Works LLP, 165 South Main St, Suite 2, Salt Lake City, UT 84111 (USPTO file history of application 13/710,109, cited in Google IPR2024-00233 Exhibit 1002) — but a single prosecution-firm appearance is not the signal, and I am not asserting it appears on any reel/frame.

4. Cascading transfers — Not present. Only two ownership events exist (2003-11-17 and 2006-03-10), ~27 months apart, and both move between entities of the same enterprise. There is no chain of sequentially created LLCs, no shared correspondent address across unrelated LLC names, and no common-principal hopscotch.

5. Pre-litigation transfer — Not present. The last recorded transfer is 2006-03-10; the first Proxense enforcement action I verified was filed 2021-03-05 (6:21-cv-00210). That is a ~15-year gap, the opposite of a pre-suit venue-shopping flip. Separately, I could not confirm that US 6,973,576 itself was ever asserted — the Proxense patents I saw in pleadings were different numbers (e.g., 8,035,152; 8,219,129; 8,352,730; 8,457,672; 9,265,043; 9,235,700; 9,679,289; 10,073,960; 8,886,954; 11,095,640). Treat "was the '576 asserted?" as unclear.

6. Bankruptcy fire-sale — Not present on available evidence. No Chapter 7/11 proceeding for Margent Development, LLC or Proxense, LLC surfaced, and there is no recorded sale instrument against the '576. Third parties characterize Proxense as a "failed startup" (Stanford NPE database) and a "former operating company" (ip fray), which describes a commercial wind-down, not a judicially supervised patent sale.

7. Privateering — Not present. Privateering requires an operating company transferring to an NPE that asserts on the operating company's behalf. Here the last recorded assignee is the enforcer, and it is led by the named inventor. There is no separate operating-company beneficiary in this chain, and no SEC filing exists (Proxense is private).

8. Defensive aggregator — Not present. The chain terminates at Proxense, LLC, an active plaintiff (2021–2026 litigation record above). There is no RPX / AST / LOT / Unified / OIN link anywhere in the record; Unified's only involvement is as a challenger (PATROLL + IPRs, e.g., Google IPR2024-00233/-00234/-00784), which is the inverse signal.

Verdict

NPE — moderate confidence.

The decisive evidence is signal 2: the current and only post-2006 assignee, Proxense, LLC, is independently identified as an NPE/patent-assertion entity by Unified Patents (PATROLL entry dated 2025-07-21 and portal classification "NPE (Patent Assertion Entity)") and by the Stanford NPE Litigation Database ("Non Practicing Entity"), with a documented multi-defendant campaign running from 2021-03-05 (6:21-cv-00210) through the 2024 Intel, Apple and LG actions. That is one strong signal, which caps the call at moderate rather than high confidence. The chain itself — Giobbi → Margent Development, LLC (2003-11-17) → Proxense, LLC (2006-03-10) — shows no third-party shell cascade, no pre-litigation transfer (the last flip predates the first suit by ~15 years), and no bankruptcy sale, so I am not elevating it to high confidence. Note also that US 6,973,576 is recorded as expired as of 2021-02-03, so the enforcement value today sits in the continuation family, not in this patent.

Verify at: https://assignment.uspto.gov/patent/index.html (search patent number 6973576). If reel/frame and correspondent data matter to your chain-of-title opinion, that query is the only clean source, and it is the one field set I could not complete here.

I'll research US patent 6973576 and its cited prior art references.

Let me get the specific prior art citations listed in US6973576 itself.

Let me get the exact citation list from the 6973576 front page.

Prior-Art Analysis — US Patent No. 6973576

1. Patent identification (verified)

Because the application was filed before March 16, 2013, pre‑AIA 35 U.S.C. § 102 governs. Any reference dated before Dec 27, 2000 (the earliest priority) is potential § 102(a)/(b) art; references filed before but published after that date are potential § 102(e) art.

Methodology / limitation flag: I could not retrieve the complete printed "References Cited" front‑page section for 6973576 from a single source. The list below is the portion of the 6973576 "Referenced Cited" record that I was able to confirm (US patent documents through US 6,088,730, plus the NPL cited). The remaining entries after 6,088,730 were truncated in the available records, and the authoritative source would be the patched front page in USPTO PatentCenter / Google Patents "References Cited" tab for US 10/715,035. Some bibliographic descriptions below rely on my training knowledge of those references; where I am not fully certain of a reference's substance I say so rather than assert it.

2. The claims that must be mapped

From the granted claims (Justia/Google Patents record):

• Claim 1 — Method of securing digital content on a hard drive of a computer: detecting a portable physical key with a receiver/decoder circuit (RDC) communicating with the hard drive; validating that the key is associated with the hard drive; permitting access if validated, with read/written data encrypted/decrypted by the RDC using the key to provide sector-level protection.
• Claim 2 — RDC resides in the computer.
• Claim 3 — key detected over a secure wireless link.
• Claim 4 — RDC enables the hard drive if validated and disables it if not (hard‑drive–level protection).
• Claim 5 — stored data not encrypted with the key.
• Claim 6 — key initially delivered with the hard drive.
• Claim 7 — each sector encrypted/decrypted with the key associated with the corresponding drive.
• Claim 9 — System counterpart (physical key + hard drive + RDC).
• Claims 10–11 — RDC in the computer; access-permission variants.

The invention's two protective tiers are: (A) drive‑level lock/unlock of the hard drive based on key proximity (claims 1, 4, 5, 6), and (B) sector‑level transparent encryption bound to the key (claims 1, 7). This is the axis along which the cited art should be evaluated.

3. Confirmably cited US patent references for 6973576

(The list continues beyond 6,088,730 in the printed record; those entries were not retrievable in full and are not represented above. Additional late‑1990s/2000–2003 references in the record would be evaluated as § 102(a)/(b) or § 102(e) art depending on their dates.)

Non‑patent literature cited in the 6973576 family record includes: "Digital Rights Management May Solve the Napster 'Problem'," Technology Investor, Oct. 2000, pp. 24–27 (also discussed at length in the 6973576 specification); and the Paget "Secure Extranets" article (Enterprise System Journal, Dec. 1999). The Napster/DRM article is § 102(b) printed‑publication art but is cited as general background, not as anticipating the disk‑control claims.

4. Most relevant prior art (assessment)

Ranked by proximity to the actual claimed subject matter — the hard‑drive key‑bound control and sector‑level encryption:

1. US 5,892,825 (Mages et al.) and US 6,035,329 (Mages et al.) — most on point for claims 1, 4, 5, 9: both concern preventing unauthorized use of a computer and controlling access to a computer's resources, i.e., the "enable/disable the storage device based on a credential" concept of claim 4.
2. US 5,392,433 (Hammersley et al.) — computer anti‑unauthorized‑use, relevant to claims 1/4/9.
3. US 5,784,464 (Akiyama et al.) and US 5,991,399 (Graunke et al.) — key‑based encryption/access control of stored data, relevant to claims 1/7.
4. US 5,629,980 (Stefik et al.) — the foundational DRM reference for the key‑bound‑to‑content concept underpinning claims 1/3/9.
5. US 5,187,352 (Blair et al.), US 5,666,412 (Handelman et al.), US 5,825,876 / 5,857,020 (Peterson) — portable credential + key delivery for software/content, relevant to claims 1/3/9.

Analytical conclusion: No single one of the cited references appears to disclose the complete combination recited in claim 1 — a portable physical key detected by a receiver/decoder circuit communicating with the hard drive, validating key‑to‑drive association, with sector‑level encryption performed by that circuit binding content to the key. The cited art is strongest against the broader "computer‑access‑control" and "key‑based content encryption" concepts (claims 1, 4, 9) and weaker against the sector‑level, OS‑transparent limitation of claims 1/7 and the key‑shipped‑with‑drive limitation of claim 6. This is consistent with the fact that the patent issued over these references. (This is my analytical assessment, not a legal conclusion.)

5. Caveats you should weigh

• Record completeness: The front‑page "References Cited" list is longer than what was retrievable here; the authoritative complete list must be pulled from the USPTO PatentCenter file wrapper for application 10/715,035 (Form PTO‑892 / IDS) or Google Patents' "References Cited" tab. Do not treat the table above as the exhaustive citation list.
• "References Cited" ≠ "Cited By": Many results surfaced by search are later patents that cite 6973576 (e.g., US 7,404,088, US 8,886,954, US 9,613,483 — all Giobbi/Proxense continuations). Those are not prior art against 6973576 and have been excluded.
• Dates: All dates above are taken from the printed record; I did not independently verify each reference's content beyond its title/subject as commonly understood. Where a description is drawn from my training knowledge rather than a fetched abstract, verify against the reference document before relying on it in a § 102 chart.
• Legal status: The patent is expired (as of 2021‑02‑03), so any § 102 analysis is historical/defensive rather than enforcement‑oriented.

I'll gather the prior-art references associated with US 6,973,576 before analyzing.

Obviousness Analysis — US 6,973,576 B2 (Giobbi, "Digital content security system") under 35 U.S.C. § 103

Analyst note on the record used, and a scope limitation I must flag up front

The instruction was to "use the results from the Prior Art section of this page." The authoritative text supplied for this patent contains a Prior Art metadata block but not an enumerated reference list. The Prior Art section as fetched states, verbatim:

"Prior art keywords — key / hard drive / digital content / content / receiver"
"Prior art date — 2000-12-27"

The page text I was given is truncated mid-sentence in the Description (it ends in §"The 'system remote' circuitry in the remote control 316 is for establishing a first wireless"), and it contains no "References Cited," "Citations," or "Similar Documents" listing. Google Patents does render such lists (I retrieved the forward-facing "Cited By (68)" list, which is not prior art — it is later art citing the '576), but I could not retrieve the '576's own backward citation list or the examiner's cited references. I therefore do not claim to have the '576's actual cited-art set. I ground the analysis below on (a) the page's stated prior-art date and keywords, (b) the admitted prior art in the '576 specification itself, and (c) the applicant's own earlier family publications, which are of-record art against the CIP-added claims. Each is flagged. I have deliberately not invented patent numbers or reference names to fill the gap.

One collision to flag immediately (do not conflate): my searches surfaced heavy prior-art activity around US 7,269,576 (ContentGuard/Stefik) — e.g., IPR2013-00139, IPR2015-00049, and the Linn / Shear / Dyad / ABYSS / Denning / EP‑306 exhibits. That is a different patent with a coincidentally similar number. Per the strict no-auto-correction rule, I treat 6,973,576 and 7,269,576 as distinct identifiers, and none of those ContentGuard references are used below as the '576's prior art.

1. Threshold issue: the effective filing date controls everything

The page lists the prior-art date as 2000‑12‑27, consistent with the '576's earliest priority (US 09/750,487). But the '576 (App. 10/715,035, filed 2003‑11‑17) is a continuation-in-part. Per the previously generated summary (authoritative here), the chain is:

• 09/750,487 (2000‑12‑27) → 10/016,857 (2001‑12‑14) → 10/153,979 (2002‑05‑23) → 10/715,035 ('576, 2003‑11‑17).

The hard-drive / sector-level subject matter (FIGS. 11–15, on which independent claims 1, 9, and 15 and dependents 4–8, 12–14 rest) does not appear in the earlier '979 disclosure. The published '979 is US 2002/0144116 A1, "Digital rights management," published Oct. 3, 2002 (FPO record: https://www.freepatentsonline.com/y2002/0144116.html), and it discloses only the content acquisition/playback embodiment (FIGS. 1–10): physical key with activation code, playing device reading key + content, comparison, and enablement of playback. It says nothing about locking a hard drive, disabling a drive, or sector-level encryption.

Consequence: the drive-level/sector-level claims of the '576 are almost certainly entitled only to the 2003‑11‑17 filing date (the new matter date), not the 2000‑12‑27 date. That is decisive, because it converts the applicant's own earlier publication — US 2002/0144116 A1 (Oct. 3, 2002, more than one year before 2003‑11‑17) — into a pre-AIA § 102(b) statutory bar against those claims. Under pre-AIA § 102(b), a printed publication describing the invention more than one year before the effective filing date is a bar even if the author is the inventor (In re Katz); § 102(b) contains no "by another" requirement (unlike § 102(a)/(e)). Combined with § 103, this makes the '979 publication the most powerful single item of prior art against the '576's head-line claims.

(Caveat: I could not inspect the '979's as-filed disclosure to rule out unclaimed hard-drive support. If the '576's claims were ever shown to be supported by the '979, the effective date would move earlier and this ground would weaken. I flag this as the single most important factual predicate to verify from the file wrapper.)

2. Available prior art and why each qualifies

I want to be explicit: F is characterized at the level of a known class, not a verified reference, because I could not retrieve the '576's cited-art list or examiner citations. Any actual ground of rejection built on F must be re-grounded on specific pre-2003 references pulled from the file wrapper (or from an IPR/reexam record, if one exists). Prior sections found no 2026 (or 2025) appellate proceeding identifying US 6,973,576, and its term expired 2021‑02‑03 — so there is likely no PTAB/district invalidity record that already assembled this art for us.

3. Claim element breakdown (building on § 3 of the summary; no repetition of the verbatim claim text)

Key observation for § 103: the independent claims contain no recitation of (i) a network, (ii) content distribution, (iii) the key provider/validation-site architecture, or (iv) OS/driver modifications. They are, in substance, two known building blocks stacked: (1) a proximity/physical-key authentication scheme and (2) a protected hard drive (access-gated and/or transparently encrypted below the OS). That narrowness is what makes the claims vulnerable.

4. Grounds of rejection

Ground 1 — Claims 1, 9, 15 obvious over A (US 2002/0144116 A1) in view of F (hard-drive access-control art)

Teaching of A: A discloses every "key-side" element of the independent claims: a portable physical electronic key carrying an activation code; a receiver/decoder (transceiver) circuit that wirelessly retrieves the key's code over a secure RF link; logic that determines whether the key's code is associated with a second code; and, conditioned on a match, enabling a device to decrypt and use protected digital content. A further discloses the key being a smart card/magnetic card and the link being wired (serial) — presaging the exact "detect / validate / enable" chain recited in claims 1, 9, and 15.

Teaching of F: Hard-drive access control was notoriously old: drives and BIOSes could be password-locked, and peripherals/storage could be gated by a hardware token ("dongle") that must be present for the device to function.

The only gap A leaves is the substitution of the protected object: A gates content playback/decryption; the '576 gates a hard drive's access and encrypts its sectors. The proposed combination supplies that: apply A's key-holder-presence check to the drive itself.

*Why a POSITA would combine (motivation, KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007)):*

1. Same field, same problem, same inventor. A and the '576 are by the same inventor and target the identical stated problem: the '576 Background expressly frames the hard-drive work as an associated extension — "the present inventor has discovered an associated digital content security system for protecting computers from unauthorized use and protecting the digital content stored on computers from being wrongfully accessed, copied, and/or distributed." When a specification describes its own system as the extension of an earlier concept, the combination is effectively conceded as within the inventor's own design trajectory.
2. Known technique to improve a similar device in the same way. Gating a resource on presentation of an authorized token is a known technique (A itself; F generally). Applying it to a storage device yields the predictable result that the device is unusable without the token — no new interaction of elements; each element performs exactly its known function.
3. Recognized need. Portable-PC theft and unauthorized use were well-recognized problems (the '576 Background notes the disorganized/盗-prone content market), motivating "key-present" protection at the drive level.
4. Design incentive / market parity (KSR "design choice"). A distributor who already ships key-enabled players (A) has a direct incentive to make the storage key-enabled so that the protected content cannot be pulled off the drive by a non-key-holder.

Reasonable expectation of success: high and predictable — both references are electrical/software systems in the same art, combined by conventional engineering.

Ground 2 — Claims 1, 9, 15 obvious over A in view of the known transparent on-the-fly sector encryption technique

Beyond mere drive gating, claims 1/9/15 require that the circuit encrypt/decrypt data read from or written to the drive using the key ("sector-level protection"). Transparent, block/sector-level encryption performed below the file system (in a controller, driver, or dedicated crypto circuit) so that the OS is unaware is a classic, well-understood technique.

• Motivation to combine: the '576's own stated rationale supplies it — drive-level gating alone fails "if the drive access is in some way defeated," whereas sector encryption preserves protection of the file contents. A POSITA seeking defense in depth would plainly add on-the-fly encryption to a gated drive. The reference A already reposes confidence in cryptographic enablement (software encryption/decryption keys), so using that same key material to encrypt the drive's sectors is the use of a known technique to improve a similar device in the same way.
• Predictable result: encryption at the sector level (rather than file level) is a routine design choice serving the admitted goal of OS-transparency.

Ground 3 (alternative) — Claim 15 specifically

Claim 15's only additional recitation is that detection is wireless. A expressly discloses the key↔device link as Bluetooth (2.4 GHz ISM), Wi‑Fi/IEEE 802.11b, and even describes a wired alternative. Wireless detection in claim 15 is therefore squarely disclosed by A, if A is available as prior art for claim 15's subject matter (same CIP-date analysis as above). If A is not available for a given claim, the same disclosure is available in the family's earlier publication B (US 2002/0080969 A1).

Ground 4 — The admitted prior art (C + D + E) as the "content" backdrop

The '576 Background admits that DRM (watermarking, encryption, transaction and rights management) and its delivery mechanisms were known (C), that short-range RF links were known (D), and that copy-protection schemes and SDMI copy flags were known (E). These admissions corroborate that the environment into which the '576 added its hard-drive layer was fully developed — supporting the conclusion that the invention is an improvement, not a pioneer, and is judged under ordinary § 103 standards.

5. Dependent claims

Following the numbering in the summary (dependents 2–8 off claim 1; 10–14 off claim 9):

• Claims 2 / 10 (receiver/decoder circuit resides in the computer) — design choice; no patentable weight beyond placement.
• Claims 3 / 11 (secure wireless link) — A discloses.
• Claims 4 / 12 (enable the drive when the key validates; disable when it does not) — the core of class F; driving the drive controller's enable/disable line is conventional.
• Claims 5 / 13 (stored content not encrypted with the key in drive-level mode) — simply the alternative mode to sector-level encryption; obvious in view of the two options the spec presents.
• Claims 6 / 14 (key delivered with the drive) — obvious packaging/kit expedient (pairing a token with the device it unlocks).
• Claims 7 / 8 (sector-level protection over individual sectors and clusters of sectors) — mere granularity choice; clusters vs. individual sectors is a predictable design variation with no unexpected result.

Each dependent claim adds only a known expedient or obvious design choice, so all fall with the independent claims under § 103 (In re Keller).

6. Anticipated rebuttals and secondary considerations

• Teaching away: unlikely. Nothing in A or F discourages combining token-based enablement with a locked/encrypted drive; A's whole premise is that portability of the key is desirable, which encourages extending the key's reach to more devices.
• Unexpected results: the claims recite none; the specification asserts advantages that are the natural consequence of the combination (transparency to the OS; content protected if drive access is defeated). Natural consequences are not unexpected results.
• Secondary considerations / nexus: none of record. The patent expired 2021‑02‑03 and (per the previously generated section) never became a live 2025–2026 appellate target; I found no evidence of commercial-success, licensing-due-to-merit, or long-felt-need evidence tied to these claims. Any such evidence would need a nexus to the claimed hard-drive/key combination.
• Priority argument (the real battleground): the patent owner's strongest response is that the claims are entitled to the 2000‑12‑27 date because the drive subject matter is somehow supported in the '487/'979 chain. If sustained, A (published 2002) drops out as § 102(b) art. This is why the file wrapper must be checked; it is the pivotal fact.

7. Bottom line

• Most likely path to invalidity: an § 103 rejection of claims 1, 9, 15 over the applicant's own earlier publication US 2002/0144116 A1 in view of a hard-drive access-control reference, optionally further in view of the known transparent sector-encryption technique — with all dependents following.
• The pivot: effective filing date. If the drive-level/sector-level claims get only the 2003‑11‑17 CIP date, the '979 publication is a § 102(b) bar and the combination is strong. If they get the 2000‑12‑27 date, the '979 publication cannot be used and the analysis must rest on third-party hard-drive-lock and transparent-encryption art (which I could not verify from this record).
• Confidence: moderate on legal structure, low-to-moderate on the specific reference set, because — as flagged in § 1 — the supplied page text did not include the '576's enumerated Prior Art/References Cited list, and I could not retrieve it. No "Prior Art" reference list is fabricated here; the two built-in groundings from the page's own Prior Art section (keywords: key, hard drive, digital content, content, receiver; prior-art date 2000‑12‑27) are used as the frame, and the substantive art is drawn from admitted prior art and the applicant's own earlier family publications.

Sources used for grounding (retrieved this session):

• https://patents.google.com/patent/US6973576/en (Prior-art keywords/date; forward "Cited By (68)")
• https://www.freepatentsonline.com/y2002/0144116.html (US 2002/0144116 A1 — Giobbi '979 publication)
• https://patents.justia.com/patent/[7404088](/patent/7404088) (child '088 claims/storage-medium language, confirming '576's claim cluster)
• IPR2024-00405 and IPR2024-00784 records (Proxense-family prior-art usage of the family's own Giobbi publications — not the '576's own cited art)
• ContentGuard/Stefik IPR materials (explicitly excluded as belonging to US 7,269,576, a different patent)