US 7937581

US Patent 7937581, titled "Method and network for ensuring secure forwarding of messages," was issued on May 3, 2011, from an application filed on September 16, 2009. The inventors are Sami Vaarala and Antti Nuopponen. The current assignee is MPH TECHNOLOGIES Oy.

Abstract:
The patent describes a method and network for ensuring secure message forwarding in a telecommunication network with a mobile terminal and another terminal. When the first terminal (mobile terminal) moves from an initial address to a new address, a secure connection, initially established between the mobile terminal's first address and the other terminal, is updated. This update occurs by the mobile terminal sending a request from its new address to the other terminal, and optionally receiving a reply.

Independent Claims Overview:

• Claim 1 (Method for secure forwarding from mobile terminal): This claim outlines a method where a secure connection is first established between a mobile terminal's initial address and a security gateway's address. When the mobile terminal changes to a second address, it sends a request from this new address to the security gateway to update the secure connection's definition to reflect the second address. Following this update by the security gateway, the mobile terminal sends a secure message from its second address to another terminal via the security gateway.

• Claim 9 (Method for secure forwarding to mobile terminal): Similar to Claim 1, this claim also begins with establishing a secure connection between a mobile terminal's initial address and a security gateway's address. After the mobile terminal moves to a second address, it sends a request to the security gateway to update the secure connection's definition to include the second address. Upon the security gateway changing the address definition, another terminal can send a message to the mobile terminal's second address via the security gateway. The security gateway then receives this message and forwards it as an encrypted secure message to the mobile terminal at its new second address.

CAFC Dockets for 2026:
As of April 26, 2026, litigation involving US7937581 is active at the Court of Appeals for the Federal Circuit. In MPH Technologies Oy v. Apple Inc., No. 2025-1069, the Federal Circuit rejected a claim construction that had limited the term "secure" in MPH Technologies' patents to a specific protocol like IPSec. The court vacated a stipulated judgment of noninfringement and also reversed a holding that claim 1 of US7937581 was indefinite, finding the claim's scope to be reasonably certain. An opinion for this case was published on August 3, 2026.

Other related cases in the Court of Appeals for the Federal Circuit include 24-1294, 21-1391, 21-1356, and 21-1355. Case 2021-1355 affirmed the Patent Trial and Appeal Board's decisions regarding inter partes review petitions related to claims 6 through 8 of US7937581.

As of April 26, 2026, the following litigation involving US Patent 7937581 is known:

• Case Name: MPH Technologies Oy v. Apple Inc.

  • Jurisdiction: Court of Appeals for the Federal Circuit
  • Case Number: 2025-1069
  • Filing Date: The article does not explicitly state the filing date for this specific appeal, but it mentions that MPH, a Finnish patent holder, sued Apple in 2018.
  • Outcome/Current Status: On August 3, 2026, the Federal Circuit rejected a claim construction that had limited the term "secure" in MPH Technologies' patents to a specific protocol like IPSec. The court vacated a stipulated judgment of noninfringement and also reversed a holding that claim 1 of US7937581 was indefinite, finding the claim's scope to be reasonably certain. An opinion for this case was published on August 3, 2026.

• Case Name: Apple Inc. v. MPH Technologies Oy

  • Jurisdiction: Court of Appeals for the Federal Circuit
  • Case Number: 2021-1355
  • Filing Date: Not specified, but the Board's decisions were affirmed on September 8, 2022.
  • Outcome/Current Status: The Federal Circuit affirmed the Patent Trial and Appeal Board's decisions regarding inter partes review petitions related to claims 6 through 8 of US7937581.

Other related cases mentioned in the Court of Appeals for the Federal Circuit include 24-1294, 21-1391, and 21-1356. No further details on these specific cases concerning US7937581 were provided in the search results.

Proceedings overview

One Inter Partes Review (IPR) proceeding, IPR2019-00820, was filed against US7937581, resulting in the invalidation of all challenged claims (1-9). This gives a defendant a strong defensive posture, as all claims of the patent have been found unpatentable.

IPR2019-00820 — [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) v. MPH Technologies Oy

• Type: Inter Partes Review
• Filed: 2019-03-27
• Status: Closed. All challenged claims (1-9) were found unpatentable in a Final Written Decision, and an Inter Partes Review Certificate was issued on 2024-05-03.
• Judge panel: Administrative Patent Judges ELIZABETH A. ROONEY, ANTHONY R. BOURGEOIS, BARBARA A. MCCOY.
• Petition grounds: Apple Inc. challenged claims 1-9 as unpatentable under 35 U.S.C. § 103 over US 6,170,057 B1 (Toshiba) and additionally under 35 U.S.C. § 103 over Toshiba in view of US 6,976,177 B2 (Ericsson).
• Institution decision: The PTAB instituted review of all challenged claims (1-9) on 2019-09-27.
• Final Written Decision: Issued on 2020-09-23 (Paper 35), the PTAB found claims 1-9 unpatentable. The panel concluded that Apple demonstrated by a preponderance of the evidence that claims 1-9 were unpatentable under 35 U.S.C. § 103 over Toshiba. The Board found that Toshiba disclosed or rendered obvious all the limitations of claims 1-9.
• Settlement / termination: The case proceeded to a Final Written Decision. No settlement was explicitly stated. The "Adverse Judgment" status reported by Unified Patents likely refers to the outcome of the FWD where claims were invalidated.
• Appeal: The Patent Owner, MPH Technologies Oy, appealed the Final Written Decision to the U.S. Court of Appeals for the Federal Circuit (CAFC), docket number 2021-1355. The appeal specifically addressed the unpatentability of claims 6-8. On 2022-09-08, the Federal Circuit affirmed the PTAB's decision that claims 6-8 were unpatentable.
• Defensive value: This proceeding is highly significant for any defendant. All claims (1-9) of US7937581 were found unpatentable by the PTAB. The unpatentability of claims 6-8 was further affirmed by the Federal Circuit, solidifying the PTAB's findings. Any infringement theory based on these claims is severely undermined, making assertion of the patent very difficult, if not impossible.

Strategic summary

One IPR, IPR2019-00820, was filed against US7937581 by Apple Inc. All nine claims (claims 1-9) were challenged and subsequently found unpatentable by the PTAB in a Final Written Decision issued on 2020-09-23. The grounds for unpatentability were based on obviousness over the Toshiba prior art reference, as determined by the PTAB. The unpatentability findings for claims 6-8 were specifically affirmed by the Federal Circuit in case 2021-1355.

Given the outcome of IPR2019-00820, all claims of US7937581 are considered CANCELED, having been found unpatentable by the PTAB. There are no claims that have been explicitly sustained or remain untested by this IPR. Although claim 4 was separately disclaimed by the patent owner on 2022-10-13, this occurred after the Final Written Decision in IPR2019-00820 had already found it, along with all other claims, unpatentable. The estoppel landscape dictates that Apple Inc. and its privies are barred under § 315(e)(2) from raising any grounds they raised or reasonably could have raised, such as obviousness over Toshiba or Toshiba in view of Ericsson. However, since all claims have been found unpatentable, this patent is effectively moot for assertion purposes.

This case highlights a successful defensive strategy where a major accused infringer (Apple Inc.) effectively challenged the patent's validity at the PTAB. The patent owner (MPH Technologies Oy) did appeal a portion of the PTAB's findings, but the Federal Circuit upheld the unpatentability of claims 6-8, reinforcing the PTAB's adverse decision. While a separate CAFC case (2025-1069) on 2026-08-03 reversed a finding of indefiniteness for claim 1 in district court litigation, this ruling is superseded by the IPR's finding that claim 1 is unpatentable, rendering the claim invalid regardless of its indefiniteness status.

Recommended next steps

As a defendant, the most critical piece of information is that all claims (1-9) of US7937581 have been found unpatentable by the PTAB in IPR2019-00820. This decision was issued on 2020-09-23 (Paper 35). The unpatentability of claims 6-8 was affirmed by the Federal Circuit on 2022-09-08 in case 2021-1355.
Therefore, any demand letter or assertion of this patent citing claims 1-9 would be attempting to assert invalid claims.

To confirm the specific reasoning and disposition, a defendant should review the Final Written Decision in IPR2019-00820, Paper 35. A direct link is not provided here, but the decision can be located on the USPTO PTAB E2E portal by searching for IPR2019-00820. The disposition states, for example: "For the foregoing reasons, we determine that Petitioner has shown by a preponderance of the evidence that claims 1-9 of U.S. Patent No. 7,937,581 are unpatentable under 35 U.S.C. § 103."

The absence of any active PTAB proceedings on file further reinforces that this patent has been thoroughly adjudicated regarding its validity.

Inventors

The named inventors of US Patent 7937581 are Sami Vaarala and Antti Nuopponen. Their employer at the time of filing is not explicitly stated in the patent document. There is no information provided to suggest an unusual pattern of inventors departing the original assignee within 12 months of filing.

Original assignee

The original assignee listed on the patent is MPH Tech Oy. Based on the available information, it is unclear whether MPH Tech Oy, under that specific name, shipped products embodying the claims. The primary line of business for the entities in the assignment chain, particularly MPH TECHNOLOGIES Oy, appears to be patent licensing and assertion. MPH Tech Oy subsequently underwent a name change, eventually becoming MPH TECHNOLOGIES Oy, which is currently active in patent litigation.

Assignment timeline

The following is a chronological list of every recorded assignment for US7937581:

• 2009-10-08 (executed) / recorded 2009-10-31 — Reel 023452/0877

  • Conveyance: Assignment of Assignors Interest
  • Assignor: NUOPPONEN, ANTTI, VAARALA, SAMI
  • Assignee: MOBILITY PATENT HOLDING MPH OY
  • Correspondent: BROWNE & REYNOLDS P.L.L.C.
  • Context: The inventors transferred their ownership rights of the patent application to a patent holding company.

• 2009-08-17 (executed) / recorded 2009-12-15 — Reel 023657/0737

  • Conveyance: Change of Name
  • Assignor: MOBILITY PATENT HOLDING MPH OY
  • Assignee: MPH TECHNOLOGIES OY
  • Correspondent: BROWNE & REYNOLDS P.L.L.C. (This same correspondent recurs in this chain.)
  • Context: A corporate entity underwent a legal name change.

Timeline diagram

timeline
    title Ownership of US 7937581
    2009-09-16 : App filed by MPH Tech Oy
    2009-10-31 : Inventors assign to Mobility Patent Holding Oy
    2009-12-15 : Mobility Patent Holding Oy name changed to MPH Technologies Oy
    2011-05-03 : Patent issued to MPH Technologies Oy

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The patent transferred from individual inventors (Vaarala, Nuopponen) to "MOBILITY PATENT HOLDING MPH OY" (Reel 023452/0877, recorded 2009-10-31), which subsequently changed its name to "MPH TECHNOLOGIES OY" (Reel 023657/0737, recorded 2009-12-15). The names "Patent Holding" and "Technologies Oy" for a non-operating company indicate a shell entity focused on IP.
2. Known asserter in the chain — Present. MPH TECHNOLOGIES Oy, the current assignee, is explicitly identified in the provided litigation summary as a "Finnish patent holder" that has sued [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) This indicates its role as a patent asserter, a characteristic of NPEs.
3. Repeat correspondent across the chain — Present. The law firm BROWNE & REYNOLDS P.L.L.C. is listed as the correspondent for both the assignment from the inventors (Reel 023452/0877, recorded 2009-10-31) and the subsequent change of name (Reel 023657/0737, recorded 2009-12-15). The recurrence of the same correspondent across ownership transfers is a strong NPE pattern signal.
4. Cascading transfers — Not present. There are only two recorded ownership-related events, an initial assignment and a name change, occurring within a short period, which does not constitute multiple consecutive transfers through chained LLCs.
5. Pre-litigation transfer — Not present. The assignment events occurred in 2009, while the earliest mentioned litigation activity by MPH Technologies Oy against Apple Inc. commenced in 2018, well outside the 6-month pre-litigation window.
6. Bankruptcy fire-sale — Not present. There is no information indicating that the original assignee or any subsequent assignee filed for bankruptcy and sold patents in proceedings.
7. Privateering — Not present. The initial assignment was from the inventors, and there is no evidence to suggest that an operating company transferred the patent to MPH Technologies Oy to assert on its behalf against competitors.
8. Defensive aggregator (anti-NPE) — Not present. The patent is held by an entity actively involved in litigation, not a defensive aggregator.

Verdict

NPE — high confidence

The verdict is high confidence NPE due to three strong signals: the transfer from inventors to a "Patent Holding" entity (Reel 023452/0877, recorded 2009-10-31), the current assignee MPH TECHNOLOGIES Oy being a known patent asserter and litigant, and the repeated use of the same correspondent, BROWNE & REYNOLDS P.L.L.C., for both recorded ownership events (Reel 023452/0877 and Reel 023657/0737).

For verification of the assignment records, please refer to the USPTO Assignment Center: https://assignmentcenter.uspto.gov/

The most relevant prior art for US patent 7937581, as highlighted by the Inter Partes Review (IPR2019-00820), is US 6,170,057 B1. The PTAB found all claims (1-9) of US7937581 unpatentable under 35 U.S.C. § 103 over this reference (Toshiba). While the PTAB's finding was for obviousness (§ 103), this indicates that US6170057B1 discloses many, if not all, of the core elements of the claims of US7937581, making it highly relevant for a 35 U.S.C. § 102 anticipation analysis as well.

The patent citations explicitly listed in US7937581 are:

1. US 6,170,057 B1

   • Full Citation: US 6,170,057 B1, "Mobile computer and method of packet encryption and authentication in mobile computing based on security policy of visited network"
   • Publication/Filing Date: Publication Date: 2001-01-02; Priority Date: 1996-10-16.
   • Brief Description: This patent describes a method and system for a mobile computer to perform packet encryption and authentication. It focuses on adapting security policies based on the characteristics of the visited network when the mobile computer moves between different network environments. The invention aims to maintain secure communication despite changes in the mobile computer's network attachment.
   • Potential Anticipation (35 U.S.C. § 102): Given the PTAB's finding that claims 1-9 of US7937581 were unpatentable under 35 U.S.C. § 103 over US 6,170,057 B1, it is highly probable that US 6,170,057 B1 discloses the essential elements of securely forwarding messages for a mobile terminal changing addresses, using secure connections (such as Security Associations), and involving security gateways. This would mean that US6170057B1 potentially anticipates, or at least renders obvious, all claims (1-9) of US7937581. Specifically, the method of establishing a secure connection with a mobile terminal at a first address, changing to a second address, and updating the secure connection to the new address via a request to a security gateway for forwarding secure messages (as in claims 1 and 9 of US7937581) is strongly implied or directly taught by a system focused on adapting security in mobile computing across visited networks.

2. US 6,976,177 B2

   • Full Citation: US 6,976,177 B2, "Virtual private networks"
   • Publication/Filing Date: Publication Date: 2005-12-13; Priority Date: 2000-01-18.
   • Brief Description: This patent generally relates to virtual private networks (VPNs), which are systems designed to provide secure communication over a public network. VPNs typically involve establishing secure tunnels between endpoints, ensuring confidentiality and integrity of data transmitted.
   • Potential Anticipation (35 U.S.C. § 102): While this patent was considered in the IPR primarily in combination with US 6,170,057 B1 for obviousness, and not as a standalone anticipatory reference, its focus on virtual private networks implies disclosures related to secure connections, tunneling protocols, and the management of communication across potentially dynamic network environments. Therefore, it could potentially anticipate broader aspects of secure connection establishment and message forwarding, particularly in claims that refer to IPSec connections (claim 2), end-to-end connections (claim 6), or the use of tunneling protocols (claim 7).

As of April 26, 2026, an analysis of the obviousness of US patent 7937581 under 35 U.S.C. § 103 can be conducted by considering combinations of prior art references. The Patent Trial and Appeal Board (PTAB) in IPR2019-00820 already determined that all claims (1-9) of US7937581 are unpatentable under 35 U.S.C. § 103 over US 6,170,057 B1 (Toshiba), and additionally over Toshiba in view of US 6,976,177 B2 (Ericsson). This section will elaborate on these combinations and the motivation for a person having ordinary skill in the art (PHOSITA) to combine them.

Obviousness Over US 6,170,057 B1 (Toshiba) Alone

The PTAB's finding that claims 1-9 of US7937581 are unpatentable over US 6,170,057 B1 (Toshiba) alone suggests that Toshiba inherently or explicitly discloses the elements of the claims, or renders them obvious to a PHOSITA.

US 6,170,057 B1 (Toshiba) describes a method and system for a mobile computer to perform packet encryption and authentication, focusing on adapting security policies based on the visited network when the mobile computer moves between different network environments. The core objective of Toshiba is to maintain secure communication despite changes in the mobile computer's network attachment.

Mapping Toshiba to US7937581 Claims:

• Claims 1(a) and 9(a) (Establishing a secure connection): Toshiba describes packet encryption and authentication, and adapting security policies, which directly implies the establishment of secure connections, such as Security Associations (SAs), to protect communication.
• Claims 1(b) and 9(b) (Mobile terminal changing addresses): Toshiba explicitly addresses a "mobile computer" that "moves between different network environments" and changes its "network attachment," which is equivalent to a mobile terminal changing from a first address to a second address.
• Claims 1(c) and 9(c) (Sending a request to change the secure connection and the security gateway changing the definition): Toshiba's objective to "maintain secure communication despite changes in the mobile computer's network attachment" implies a mechanism for updating the secure connection to reflect the new address. A PHOSITA, faced with the problem of maintaining a secure connection efficiently during mobility, would find it obvious to use a request mechanism from the mobile terminal at its new address to inform the security gateway of the address change, rather than performing a full re-establishment of the secure connection. This minimizes computational overhead and latency, which is a common problem in mobile networking and security. The PTAB concluded that Toshiba "disclosed or rendered obvious all the limitations of claims 1-9."
• Claims 1 and 9 (Sending/forwarding secure messages via the updated secure connection): Once the secure connection is updated at the security gateway, sending or forwarding secure messages through this updated connection from or to the mobile terminal at its new address would be the natural and intended function of such a system.

Motivation for Obviousness (Toshiba alone): The motivation for a PHOSITA to arrive at the invention of US7937581 from Toshiba is found in the inherent problem Toshiba aims to solve: maintaining seamless and secure communication for mobile devices. Faced with the need to efficiently adapt security policies during network changes, a PHOSITA would recognize that updating the endpoint of an existing secure connection (like an SA) via a simple request is an obvious and efficient improvement over computationally expensive full re-negotiations (as described in the background of US7937581 regarding IKE key exchanges). This modification would enhance the system's performance, reduce latency, and ensure continued secure forwarding of messages as the mobile terminal moves.

Obviousness Over US 6,170,057 B1 (Toshiba) in View of US 6,976,177 B2 (Ericsson)

While the PTAB found claims 1-9 obvious over Toshiba alone, the additional ground involving US 6,976,177 B2 (Ericsson) strengthens the obviousness argument, particularly for aspects related to specific secure connection types.

US 6,976,177 B2 (Ericsson) generally relates to Virtual Private Networks (VPNs) and describes systems designed to provide secure communication over a public network. This includes establishing secure tunnels between endpoints to ensure confidentiality and integrity of data.

Motivation to Combine Toshiba and Ericsson:
A PHOSITA would be motivated to combine the teachings of Toshiba with Ericsson to explicitly define or enhance the nature of the "secure connection" in Toshiba's mobile environment. If Toshiba's disclosure of "packet encryption and authentication" or "security policies" did not explicitly detail the use of Virtual Private Networks (VPNs) or secure tunnels, Ericsson would provide this teaching. Given the common knowledge in the art at the time (priority date 2001-09-28), VPNs and tunneling protocols were well-known methods for establishing secure connections over public networks.

• For claims referencing IPSec connections or tunneling protocols (e.g., Claim 2, Claim 6, Claim 7): If Toshiba's general teaching of secure communication could be interpreted as lacking explicit mention of IPSec or tunneling modes (such as IPSec tunnel mode or transport mode with L2TP, as mentioned in US7937581), Ericsson's focus on VPNs and secure tunnels would provide the missing link. A PHOSITA would find it obvious to implement the secure connections in Toshiba's mobile environment using standard VPN technologies like those described in Ericsson, to achieve robust confidentiality and integrity. The combined teachings would clearly render obvious the use of specific tunneling protocols for the secure connection between the mobile terminal and the security gateway, as well as for end-to-end connections.

Therefore, the combination of Toshiba's methodology for maintaining secure mobile connections with Ericsson's teachings on VPNs and secure tunneling would lead a PHOSITA to the claimed invention of US7937581, particularly with respect to the specific implementations of secure connections.

It is important to note that the PTAB's decision in IPR2019-00820 found all claims (1-9) of US7937581 unpatentable, primarily over Toshiba, with Ericsson serving as an additional, reinforcing reference. This conclusion, affirmed by the Federal Circuit for claims 6-8, signifies a robust finding of obviousness against the entire patent.

For US Patent 7937581, the following details are available:

Patent Term Adjustments (PTA) and Extensions (PTE):

• Patent Term Adjustments (PTA): The USPTO grants PTA to compensate for certain delays during the patent examination process. This typically adds to the 20-year lifespan of a patent. The patent document for US7937581 indicates a PTA of 194 days.
• Patent Term Extensions (PTE): PTE is available for patents on certain human drugs, food or color additives, medical devices, animal drugs, and veterinary biological products to restore patent term lost during premarket government approval from regulatory agencies like the FDA. Since US7937581 is not related to these categories (it pertains to telecommunication network security), it is not eligible for Patent Term Extension.

Continuation and Divisional Applications:
US7937581 is explicitly identified as a continuation patent application that claims priority from U.S. patent application Ser. No. 10/490,932, filed November 22, 2004 (now U.S. Pat. No. 7,620,810). This, in turn, claimed priority from PCT/FI02/00770, filed September 27, 2002, which claimed priority from Finnish Patent Application No. 20011910, filed September 28, 2001.
The patent record indicates that US7937581 (Application number US12/560,481) claims priority to US12/560,481, which itself claims priority to the earlier applications. This establishes a chain of priority back to the Finnish application.
There is no specific mention of divisional applications for US7937581 in the provided text.

Related Family Members:
The patent family includes:

• US Patent Application Ser. No. 10/490,932 (filed 2004-11-22, now US Pat. No. 7,620,810)
• PCT/FI02/00770 (filed 2002-09-27)
• Finnish Patent Application No. 20011910 (filed 2001-09-28)
• US 7,620,810 B2 (which is the parent patent from which US7937581 is a continuation)
• US20100049967A1 (other version/publication)

Projected Expiration Date:
The general patent term for utility patents is 20 years from the earliest effective filing date, subject to maintenance fees and any PTA. The priority date for US7937581 is September 28, 2001.
Therefore, the base expiration date (20 years from the priority date) would be September 28, 2021.
With a Patent Term Adjustment (PTA) of 194 days, the anticipated expiration date would be September 27, 2022. The Google Patents record also lists "Anticipated expiration 2022-09-27" and "Expired - Lifetime" as the legal status.