DETAILED ACTION
Notice of AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election with traverse of Invention III (claims 1, 3-4, 7, 10, 12-13, and 16) in the reply filed on 2026-06-01 is acknowledged. The traversal is on the grounds that the identified inventions are “interrelated design conditions within a single threshold secret recovery framework using first and second share generation structures, rather than separately patentable inventions” and that the stated utilities “are not independent functionalities” but are instead “tightly coupled, simultaneous optimization parameters required to solve a single technical problem”. This is not found persuasive.
Although the restricted claims in the various inventive groups may be “interrelated design conditions” (i.e., different design parts that are usable together in a larger tightly coupled system), such description supports the appropriateness of the restriction requirement. Note that a restriction requirement of “subcombinations usable together” covers exactly what applicant describes as their claimed inventions – distinct portions of a system operating together to solve a problem, but where the utility of each subcombination addresses a different aspect of the invention as a combination.
In this instance, the restriction requirement for related but distinct inventions analyzes whether the differences between the respective inventive groups cause them to be patentably distinct. More particularly, if, among any set of identified inventions, each identified invention has at least one distinct element that is not an “obvious variation” of the other inventions (regardless of how much overlap or interconnection the inventions share), then the inventions are mutually-exclusive and hence demonstrate two-way distinction; (“Related inventions in the same statutory class are considered mutually exclusive, or not overlapping in scope, if a first invention would not infringe a second invention, and the second invention would not infringe the first invention”, MPEP § 806.05). Further, Applicant has merely provided allegations that the features of the sub-combinations cannot be practiced in isolation, but such argument is not germane to the restriction and more particularly, Applicant did not amend the claims to similar scope or make a clear admission on the record that the inventions are not patentably distinct because they are all “obvious variations”, which would have been sufficient to successfully traverse the restriction requirement; See MPEP § 1504.05(III).
Applicant further alleges that because “the inventions are within a single framework, separating them into divisional applications would result in a duplication of effort for both the Office and the Applicant without a meaningful distinction in the field of search or the applicable prior art”; however, as the Examiner noted at the end of the restriction requirement (¶7), because these identified subcombinations are linked by a common independent claim, they would be rejoined upon a finding of allowability of the independent claim, rendering applicant’s point moot.
The requirement is still deemed proper and is therefore made FINAL.
Priority
Receipt is acknowledged of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d) and of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 2024-12-05, 2025-08-06, and 2026-02-25 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements are being considered by the examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Claims 1, 3-4, 7, 10, 12-13, and 16 are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement. The claims contain subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor at the time the application was filed, had possession of the claimed invention. In particular, claim 1 recites the limitation “(e) recovering a secret using the obtained first shares and the obtained second shares, wherein a critical share set is determined so that a number of shares of the critical share set, which is a subset of an intersection of a first share set generated by the first share generation structure and a second share set generated by the second share generation structure, is greater than or equal to a critical threshold value (r) that is less than the first threshold value”, and the specification does not describe the claimed feature in sufficient detail that one skilled in the art can reasonably conclude that the inventor had possession of the claimed invention at the time of filing.
It is first noted that original claims lack adequate written description when the claims define the invention in functional language specifying a desired result but the specification does not sufficiently describe how the function is performed or the result is achieved; See MPEP § 2161.01(I). That is, “the algorithm or steps/procedure taken to perform the function must be described with sufficient detail so that one of ordinary skill in the art would understand how the inventor intended the function to be performed”. In this instance, the claims generally recite recovering a secret using a combination of shares from two different share generation structures. The specification does provide antecedent basis for this feature (e.g. pp. 14-18); however, the specification does not adequately describe how to recover a secret from two secret generation structures. More critically, the specification even recites that the “second share generation structure must be different from the first share generation structure and must be able to have the shares of the critical share set and the shares of the duplication share set as shares” (p. 16), and the Examiner notes that shares from one generation structure should not applicable to a different generation structure, as cryptographic secret recovery isn’t a fill-in-the-gap situation.
Cryptographic secret splitting schemes are and all-or-nothing operation. If you need t shares in a particular generation scheme but fall even one share short, nothing is recoverable. It should not be possible to use shares from another generation scheme without designing the scheme in a particular fashion to be compatible with the other scheme, but the specification provides no such description for creating the necessary compatibility between schemes. Instead, the specification merely describes which parties should receive “critical” shares, and then makes the statement that “a second share generation structure is generated that can generate all shares of Sc ∪ Sdup while having a threshold value greater than |Sc ∪ Sdup|” (p. 17) and that the “fallback case secret recovery module 154 recovers a secret by aggregating r shares among the shares belonging to the critical share set Sc, (|Sdup| + α) shares among the shares belonging to the duplication share set and the shares Sadd belonging to the additional share set. The total number of aggregated shares is (r + |Sdup| + α), which is the minimum number of shares required to recover a secret in the threshold secret sharing of (r + |Sdup| + α, |Sc| + |Sdup| + α + δ)” (pp. 19-20). However, as previously noted, shares from different systems don’t simply function as plug-and-play entities where shares between schemes just work together such that the shared secret is recoverable. More so, the specification must describe how the second share generation structure is generated such that it can generate shares that meet the function and describe how they’re combined with the first set of shares to recover the secret; however, no such description is present.
Thus, the specification does not disclose, let alone adequately describe with sufficient detail, the algorithm (e.g., the necessary steps and/or flowcharts) that performs the claimed function of enabling shares from one generation scheme to work in another generation scheme for secret recovery in sufficient detail such that one of ordinary skill in the art can reasonably conclude that the inventor possessed the claimed subject matter at the time of filing as required by the written description requirement.
Claim 10 is rejected under a similar rationale. The dependent claims included in the statement of rejection but not specifically addressed in the body of the rejection have inherited the deficiencies of their parent claim and have not resolved the deficiencies. Therefore, they are rejected based on the same rationale as applied to their parent claims above.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 3-4, 7, 10, 12-13, and 16 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Nadooshan et al. (US Pre-Grant Publication No. 20030147535-A1, hereinafter “Nadooshan”).
With respect to independent claim 1, Nadooshan discloses a method for recovering threshold secret, the method comprising the steps of:
(a) obtaining first shares generated by a first share generation structure from participants {paras. 0015-0016, 0022-0028, and 0054-0057: “determine if, collectively, the group has (i) any k or more pieces of Ri”}.
(b) determining whether a number of the obtained first shares is greater than or equal to a first threshold value (t) {paras. 0015-0016, 0022-0028, and 0054-0057: “determine if, collectively, the group has (i) any k or more pieces of Ri”}.
(c) recovering a secret by a (t,n) threshold secret recovery method when the number of the obtained first shares is greater than or equal to the first threshold value (t) {paras. 0015-0016, 0022-0028, and 0054-0057: “with (i) any k or more pieces of Ri …, then equation (1) can be solved for R”; note that the limitation is a contingent limitation that has an optional precedent (i.e., “when the number” meets a threshold), and the broadest reasonable interpretation does not require the limitation (at least for the method/process claims); See MPEP § 2111.04(II)}.
(d) obtaining second shares generated by a second share generation structure from participants when the number of the obtained first shares is less than the first threshold value (t) {paras. 0015-0016, 0022-0028, and 0054-0057: “determine if, collectively, the group has … (ii) knowledge of S and any one of Ri”; one or two shares is less than any k > 2; and/or “a multiple threshold secret sharing scheme is disclosed that assigns various users in a group into one of a number of classes”; note that the limitation is a contingent limitation that has an optional precedent (i.e., “when the number” is less than a threshold), and the broadest reasonable interpretation does not require the limitation (at least for the method/process claims); See MPEP § 2111.04(II)}.
(e) recovering a secret using the obtained first shares and the obtained second shares, wherein a critical share set is determined so that a number of shares of the critical share set, which is a subset of an intersection of a first share set generated by the first share generation structure and a second share set generated by the second share generation structure, is greater than or equal to a critical threshold value (r) that is less than the first threshold value {paras. 0015-0016, 0022-0028, and 0054-0057: “with … (ii) knowledge of S and any one of Ri, then equation (1) can be solved for R”; and/or each “user class has a corresponding threshold level” (i.e., some thresholds are lower than others); note that both generation schemes share the same cryptographic center point, and thus don’t suffer the same § 112(a) deficiency as the instant application}.
With respect to dependent claim 3, Nadooshan discloses wherein a duplication share set is determined, which is a subset of the intersection of the first share set generated by the first share generation structure and the second share set generated by the second share generation structure, and an intersection of the duplication share set and the critical share set is an empty set, and a union of the duplication share set and the critical share set is the intersection of the first share set and the second share set {para. 0014: “any k-1 or fewer components, Ri, leaves R undetermined”, i.e., an empty set, which is a subset of all sets, is empty when intersected with anything, and when joined with a set that is the intersection of “super component value, S” is the intersection of the center of the sphere (which is the intersection of the center of the points on the sphere surface)}.
With respect to dependent claim 4, Nadooshan discloses wherein the second share set includes the critical share set, the duplication share set, and an additional share set determined by the second share generation structure {paras. 0014-0022: each threshold scheme relies on the definition of the sphere, which includes central point (S), an empty set, and all points on its surface (each “key component, Ri”)}.
With respect to dependent claim 7, Nadooshan discloses wherein the second share generation structure is determined to have a different structure from the first share generation structure by using the critical share set and the duplication share set included in the first share {paras. 0014-0022: “build a (4, 7)-threshold scheme on top of this (3, 5)-threshold scheme, equation (1) is populated with (k-1=3) elements to establish a three-dimensional surface (a sphere)”, which uses the same “super secret component, S, is at the center of a sphere 100”}.
With respect to claims 10, 12-13, and 16, a corresponding reasoning as given earlier in this section with respect to claims 1, 3-4, and 7 applies, mutatis mutandis, to the subject matter of claims 10, 12-13, and 16; therefore, claims 10, 12-13, and 16 are rejected, for similar reasons, under the grounds as set forth for claims 1, 3-4, and 7.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant’s disclosure.
The reference Ryu (US Pre-Grant Publication No. 20240340165-A1) discloses a hierarchical share generation method of a share hardening method for multi-factor threshold secret sharing.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Kevin Bechtel whose telephone number is 571-270-5436. The examiner can normally be reached Monday - Friday, 09:00 - 17:00 ET.
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/Kevin Bechtel/
Primary Examiner, Art Unit 2491
Prosecution Insights