Prosecution Insights
Last updated: April 19, 2026
Application No. 18/135,922

LOW-ENTROPY MASKING FOR CRYPTOGRAPHY

Non-Final OA §101§102
Filed
Apr 18, 2023
Examiner
ALMAMUN, ABDULLAH
Art Unit
2431
Tech Center
2400 — Computer Networks
Assignee
Nxp B V
OA Round
3 (Non-Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
3y 5m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
317 granted / 405 resolved
+20.3% vs TC avg
Strong +26% interview lift
Without
With
+25.6%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
29 currently pending
Career history
434
Total Applications
across all art units

Statute-Specific Performance

§101
18.4%
-21.6% vs TC avg
§103
43.3%
+3.3% vs TC avg
§102
18.1%
-21.9% vs TC avg
§112
13.4%
-26.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 405 resolved cases

Office Action

§101 §102
DETAILED ACTION Notice of Pre-AIA or 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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 08, 2026 has been entered. Remarks Pending claims for reconsideration are claims 1-20. Applicant has Amended claims 1-2, 11, and 18. Response to Arguments Applicant’s arguments filed on December 10, 2025 have been fully considered but they are not persuasive. In the remarks, applicant argues in substance: In response to argument (Page 12, Para: last) - Examiner respectfully disagrees with applicant’s argument that Poeppelmann failed to discloses masking with a low entropy masking in regard to independent claims 1, 11 and 18. Poeppelmann discloses Number Theoretic Transform (NTT) operation which is a masking operation (Poeppelmann, Col 16: lines 57-67, NTT is performed). Applicant provided specification details the process of masking using NTT operation similar fashion that of Poeppelmann (see, applicant specification, Para 0066-0067). Claim Rejections - 35 USC § 101 Applicant amended independent claims 1, 1l, and 18; therefore, the rejection under 35 U.S.C. 101 (abstract) is withdrawn. 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 1-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Thomas Poeppelmann (U.S. Patent No.: US 11,265,163 B2 / or “Poeppelmann” hereinafter). Regarding claim 1, Poeppelmann discloses “A computer-implemented method for masking secret polynomials for cryptography, the method comprising” (Col 1: lines 42-55, method masking secret polynomials based on disguised polynomials): “receiving, at a processor of a computing device, a secret polynomial function in a polynomial ring” (Fig. 4: Step 401; and Col 19: lines 32-34, a secret polynomial is obtained; and Col 8: lines 1-11: where the polynomial are ring of integer polynomials); “masking, by the processor, the secret polynomial function with one or more masking polynomials including at least one low-entropy mask [i.e., performing NTT operation, see applicant specification (Para 0066)]in which at least some coefficients are equal” ( Fig. 4: Step 402; Col 19: lines 35-35, the secret polynomial is masked with a blinding polynomial i.e., “masking polynomials”; and Col 16: lines 57-67, NTT is performed); “performing, by the processor, an arithmetic operation on coefficients of the masking polynomials with repeated coefficients to produce an output having integer values” (Fig. 4: Step 403; Col 19: lines 38-40, a product is obtained; and Col 8: lines 1-11: where the polynomial are ring of integer polynomials); “and performing, by the processor, a cryptographic operation with the output of the arithmetic operation to produce a cryptographic output, the cryptographic output comprises one of a ciphertext or a verification of a ciphertext” (Fig. 4: Step 404; and Col 21: lines 22-27, prevent physical attacks; and Col 12: lines 29-32, cipher text is produced). Regarding claim 2, in view claim 1, Poeppelmann discloses “wherein n coefficients of a masked version of the secret polynomial function include k unique coefficients” (Col 21: lines 45-49, polynomials with coefficients). Regarding claim 3, in view claim 2, Poeppelmann discloses “further comprising generating k uniformly random coefficients ri for the masked version of the secret polynomial function for each of the masking polynomials, where k is a positive integer and less than the n coefficients” (Col 8: lines 17-19; and Col 14: lines 25-29, uniformly random coefficients). Regarding claim 4, in view claim 3, Poeppelmann discloses “wherein performing the arithmetic operation includes executing a Number Theoretic Transform (NTT) on the masking polynomials with the repeated coefficients in registers of a processor” (Col 9: lines 58-67, NTT is performed). PNG media_image1.png 21 41 media_image1.png Greyscale Regarding claim 5, in view claim 4, Poeppelmann discloses “further comprising computing a small NTT sj= r-i ζ- ji with the random coefficients ri for all k primitive 2k-th roots of unity ζ-j” (Col 9: lines 39-67, roots of unity) . Regarding claim 6, in view claim 5, Poeppelmann discloses “wherein performing the arithmetic operation includes computing sj NTTn/k(1+…+Xn/k-1) for all j= 0, …, k-1” (Col 9: lines 39-67, performing NTT). Regarding claim 7, in view claim 2, Poeppelmann discloses “wherein performing the arithmetic operation includes multiplying the masked version of the secret polynomial function and a second polynomial function fi” (Col 19: lines 45-49, multiplying polynomials). PNG media_image2.png 33 442 media_image2.png Greyscale Regarding claim 8, in view claim 7, Poeppelmann discloses “wherein performing the arithmetic operation includes computing to derive the product of the masked version of the secret polynomial function and the second polynomial function fi” (Col 19: lines 45-49, multiplying polynomials to generate blinding or masking polynomials). Regarding claim 9, in view claim 1, Poeppelmann discloses “further comprising: generating coefficients of a masked version of a second secret polynomial function such that at least some of the coefficients of the masked version of the second secret polynomial function are equal” (Col 19: lines 45-63, coefficients are zero and non-zero). PNG media_image3.png 19 38 media_image3.png Greyscale Regarding claim 10, in view claim 1, Poeppelmann discloses “wherein the secret polynomial function fiXi in a ring Rq = Fq[X]/(Xn + 1) or in a ring Rq = Fq[X]/(Xn-1)” (Col 12: lines 1-4, describes polynomial on the ring). Regarding claim 11, claim 11 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 1. Claim 11 is similar in scope to claim 1, and is therefore, rejected under similar rationale. Regarding claim 12, claim 13 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 2. Claim 12 is similar in scope to claim 2, and is therefore, rejected under similar rationale. Regarding claim 13, claim 13 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 3. Claim 13 is similar in scope to claim 3, and is therefore, rejected under similar rationale. Regarding claim 14, claim 14 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 4. Claim 14 is similar in scope to claim 4, and is therefore, rejected under similar rationale. Regarding claim 15, claim 15 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 5. Claim 15 is similar in scope to claim 5, and is therefore, rejected under similar rationale. Regarding claim 16, claim 16 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 7. Claim 16 is similar in scope to claim 7, and is therefore, rejected under similar rationale. Regarding claim 17, claim 17 is directed to a non-transitory computer-readable storage medium corresponding to the method recited in claim 9. Claim 17 is similar in scope to claim 9, and is therefore, rejected under similar rationale. Regarding claim 18, claim 18 is directed to an electronic device corresponding to the method recited in claim 1. Claim 18 is similar in scope to claim 1, and is therefore, rejected under similar rationale. Regarding claim 19, claim 19 is directed to an electronic device corresponding to the method recited in claim 4. Claim 19 is similar in scope to claim 4, and is therefore, rejected under similar rationale. Regarding claim 20, claim 20 is directed to an electronic device corresponding to the method recited in claim 7. Claim 20 is similar in scope to claim 7, and is therefore, rejected under similar rationale. Relevant Prior Arts The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Son et al. (US 2023/0269067 Al) discloses “…The homomorphic encryption operation accelerator according to some example embodiments may efficiently accelerate the homomorphic encryption operation through a method of performing the iNTT/NTT operation and the BaseConv operation in parallel and a memory structure specialized therefor” (Para 0047: lines 9-14). Valencia et al. (NPL: The Design Space of the Number Theoretic Transform: a Survey) discloses “The most common techniques for improving the throughput and the performance are in pre-calculating all possible constants and saving them in memory, and taking advantage of the NTT recursive structure for parallelizing the computation. This approach of pre-calculating all constants (the twiddle factors) boosts the performance, however this adds a storage overhead.” (Page 274: Col 1: Para 3). Contact Information Any inquiry concerning this communication or earlier communications from the examiner should be directed to ABDULLAH ALMAMUN whose telephone number is (571) 270-3392. The examiner can normally be reached on 8 AM - 5 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Lynn Feild can be reached on (571) 272-2092. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ABDULLAH ALMAMUN/Examiner, Art Unit 2431 /TRANG T DOAN/Primary Examiner, Art Unit 2431
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Prosecution Timeline

Apr 18, 2023
Application Filed
Feb 22, 2025
Non-Final Rejection — §101, §102
May 28, 2025
Response Filed
Sep 02, 2025
Final Rejection — §101, §102
Dec 10, 2025
Response after Non-Final Action
Jan 08, 2026
Request for Continued Examination
Jan 25, 2026
Response after Non-Final Action
Feb 07, 2026
Non-Final Rejection — §101, §102 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
78%
Grant Probability
99%
With Interview (+25.6%)
3y 5m
Median Time to Grant
High
PTA Risk
Based on 405 resolved cases by this examiner. Grant probability derived from career allow rate.

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