Patents by Inventor Koki Hamada

Koki Hamada has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11316674
    Abstract: An aggregate median is efficiently obtained while confidentiality is kept. An order computing part generates ascending order a and descending order d within a group when a table which has been stably sorted based on a desired value attribute and a key attribute is grouped based on the key attribute. A subtracting part generates shares {a-d}, {d-a} of a-d, d-a. A bit deleting part generates shares {a?}, {d?} of a?, d? obtained by excluding least significant bits from {a-d}, {d-a}. An equality determining part generates shares {a?}, {d?} of {a?}:={|a?=0|}, {d?}:={|d?=0|}. A format converting part (15) converts {a?}, {d?} into [a?], [d?]. A flag applying part generates shares [va], [vd] of [va]:=[v1a?], [vd]:=[v1d?]. A permutation generating part generates shares {{?a}}, {{?d}} of permutations ?a, ?d which sort ¬a?, ¬d?. A median computing part generates a share [x] of a vector x.
    Type: Grant
    Filed: April 22, 2019
    Date of Patent: April 26, 2022
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai Ikarashi, Koki Hamada
  • Publication number: 20220114110
    Abstract: Access to an array is efficiently performed without reveling an accessed position. A storage 10 stores an array of concealed values [x??] of an array x?? and an array of addresses a?? corresponding to respective elements of the array of concealed values [x??]. A refresh unit 11 determines a concealed value [F] of a random parameter F, an array of concealed values [x?] of an array x? generated by permutating the array x?? with random permutation ?, and an array of public tags b? calculated from respective elements of the array of addresses a? with the function TagF. An access unit 12 performs a desired access to an element of the array of concealed values [x?] corresponding to a tag that is calculated from a concealed value [j] of an access position j with the function Tag and the concealed value [F] of the parameter.
    Type: Application
    Filed: January 9, 2020
    Publication date: April 14, 2022
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Koki HAMADA, Atsunori ICHIKAWA
  • Patent number: 11294633
    Abstract: A secure computation system calculates concealed text of a difference x?r from concealed text by using concealed text and generates concealed text and of an integer portion e and a decimal fraction portion f (0?f<1) of the difference x?r from the concealed text; reconstructs the decimal fraction portion f from the concealed text; generates, from the decimal fraction portion f and the concealed text, concealed text of a left shift value y obtained by shifting 2f, which is 2 raised to the power f which is the decimal fraction portion f, to the left by e bit; and calculates, as concealed text, concealed text of a value 2r×y obtained by multiplying 2r, which is a power of 2, by the left shift value y from the concealed text by using the concealed text.
    Type: Grant
    Filed: January 18, 2018
    Date of Patent: April 5, 2022
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventor: Koki Hamada
  • Patent number: 11265155
    Abstract: An agreement apparatus P(i) (where i=0, . . . , n?1) which executes a consensus protocol generates an opinion value with a signature Xij=(xi, sig_i(xi)) including an opinion value xi indicating an opinion and a signature sig_i(xi) on the opinion value xi or information different from the opinion value with the signature Xij as an opinion value with a signature X?ij=(x?ij, e?ij) and outputs the opinion value with the signature X?ij to an agreement apparatus P(j) (where j=0, . . . , n?1, i?j). The agreement apparatus P(j) accepts the opinion value with the signature X?ij and outputs the opinion value with the signature X?ij or information different from the opinion value with the signature X?ij to an agreement apparatus P(m) (where m=0, . . . , n?1, m?i, m?j) as an opinion value with a signature X?ij.
    Type: Grant
    Filed: August 16, 2018
    Date of Patent: March 1, 2022
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai Ikarashi, Koki Hamada
  • Publication number: 20220058290
    Abstract: An analysis query response system comprises a user terminal 1 that generates and transmits an analysis query, and a database apparatus 2 including an analysis query verification apparatus 22 that includes a verification execution part 222 that performs a first verification of whether the analysis query satisfies a predetermined privacy preservation indicator, and an analysis query execution apparatus 21 that includes a personal data storage part 211 that stores personal data and an analysis query execution and preservation part 214 that, in a case where the first verification is successful, performs an analysis corresponding to the analysis query on the personal data read from the personal data storage part to acquire an analysis result, and applies a predetermined privacy-preserving mechanism to the acquired analysis result.
    Type: Application
    Filed: December 19, 2019
    Publication date: February 24, 2022
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Atsunori ICHIKAWA, Koki HAMADA
  • Patent number: 11250004
    Abstract: A secure equijoin technique of generating one table from two tables while curbing the volume of communications traffic is provided. The technique includes: a first permutation generating means 110 that generates a permutation <?> from an element sequence which is generated from the first column of a table L and the first column of a table R; a first column generating means 120 that generates, for j=2, . . . , a, by using the permutation <?>, a prefix sum, and an inverse permutation <??1>, the j-th column of a table J from an element sequence which is generated from the to j-th column of the table L; a join-result element sequence generating means 130 that generates a join-result element sequence from an element sequence ([[1]], . . . , [[1]], [[0]], . . . , [[0]], [[?1]], . . . , [[?1]]) by using the permutation <?>, the prefix sum, and the inverse permutation <??1>; a second column generating means 140 that generates, for j=a+1, . . .
    Type: Grant
    Filed: September 14, 2017
    Date of Patent: February 15, 2022
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai Ikarashi, Naoto Kiribuchi, Koki Hamada, Gembu Morohashi
  • Publication number: 20220006614
    Abstract: A technique for performing secure computation of a sigmoid function with high speed and precision is provided. A secret sigmoid function calculation system is a system, in which g(x) is assumed to be a secure computable function, which calculates, from a share [[x]] of an input value x, a share [[??(x)]] of a value of a sigmoid function for the input value x, and includes: a first comparing means that generates a first comparison result [[c]]=less_than([[x]], t1); a second comparing means that generates a second comparison result [[d]]=greater_than([[x]], t0); a first logical computation means that generates a first logical computation result [[e]]=not([[c]]); a second logical computation means that generates a second logical computation result [[k]]=and([[c]], [[d]]) or [[k]]=mul([[c]], [[d]]); and a function value calculating means that calculates the share [[??(x)]]=mul([[k]], [[g(x)]])+[[e]].
    Type: Application
    Filed: September 25, 2019
    Publication date: January 6, 2022
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Ibuki MISHINA, Dai IKARASHI, Koki HAMADA, Ryo KIKUCHI
  • Patent number: 11200346
    Abstract: Multiple elements are efficiently read from a secured array. A secure text array <a>=(<a[0]>, . . . , <a[n?1]>) where an array a=(a[0], . . . , a[n?1]) having a size of n is secured, secure text <x> of an integer x that is equal to or higher than 0 and less than n, and in integers i0, . . . , im-1 that are equal to or higher than 0 and less than n are input into an input part 11. A secure shift part 12 secure-shifts the secure text array <a> by <x> to obtain a secure text array <a?>=(<a?[0]>, . . . , <a?[n?1]>) where an array a?=(a?[0], . . . , a?[n?1]) obtained by shifting leftward the array a by x is secured. An array generation part 13 generates a secure text array <b>=(<a?[i0]>, . . . , <a?[im-1]>) from the secure text array <a?>.
    Type: Grant
    Filed: June 30, 2017
    Date of Patent: December 14, 2021
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventor: Koki Hamada
  • Publication number: 20210377005
    Abstract: An aggregate median is efficiently obtained while confidentiality is kept. An order computing part generates ascending order a and descending order d within a group when a table which has been stably sorted based on a desired value attribute and a key attribute is grouped based on the key attribute. A subtracting part generates shares {a?d}, {d?a} of a?d, d?a. A bit deleting part generates shares {a?}, {d?} of a?, d? obtained by excluding least significant bits from {a?d}, {d?a}. An equality determining part generates shares {a?}, {d?} of {a?}:={|a?=0|}, {d?}:={|d?=0|}. A format converting part (15) converts {a?}, {d?} into [a?], [d?]. A flag applying part generates shares [va], [vd] of [va]:=[v1a?], [vd]:=[v1d?]. A permutation generating part generates shares {{?a}}, {{?d}} of permutations ?a, ?d which sort ¬a?, ¬d?. A median computing part generates a share [x] of a vector x.
    Type: Application
    Filed: April 22, 2019
    Publication date: December 2, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA
  • Publication number: 20210358332
    Abstract: A secure sigmoid function calculation system is a system in which map? is assumed to be secure batch mapping defined by parameters (a0, . . . , ak-1) representing the domain of definition of a sigmoid function ?(x) and parameters (?(a0), . . . , ?(ak-1)) representing the range of the sigmoid function ?(x) (a0, . . . , ak-1 are real numbers that satisfy a0< . . . <ak-1) and which is configured with three or more secure sigmoid function calculation apparatuses and calculates, from a share [[x?]] of an input vector x?, a share [[y?]] of a value y? of a sigmoid function for the input vector x?, the system including a secure batch mapping calculating means that calculates the share [[y?]] by [[y?]]=map?([[x?]])=([[?(af(0))]], . . . , [[?(af(m-1)]]) (where f(i) (0?i?m?1) is j that makes aj?xi<aj+1 hold).
    Type: Application
    Filed: October 2, 2019
    Publication date: November 18, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Ibuki MISHINA, Dai IKARASHI, Koki HAMADA, Ryo KIKUCHI
  • Publication number: 20210342476
    Abstract: Provided is a technique for performing statistical processing such as processing for obtaining parameters of logistic regression analysis faster than before. A secure statistical processing system includes a cross tabulation table computing device 2 that performs secure computation on a cross tabulation table in which frequencies are in plain texts while keeping each record concealed; and a statistical processing device 3 that performs predetermined statistical processing using the cross tabulation table in which frequencies are in plain texts. The cross tabulation table computing device 2 may include a plurality of secure computation devices 221, . . . , 22N that perform secure computation on a cross tabulation table in which frequencies are fragments subjected to secret sharing while keeping each record concealed, and a management device 21 that restores the fragments to compute the cross tabulation table in which frequencies are in plain texts.
    Type: Application
    Filed: August 28, 2019
    Publication date: November 4, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Satoshi TANAKA, Asami MIYAJIMA, Gen TAKAHASHI, Dai IKARASHI, Koki HAMADA, Ryo KIKUCHI, Hitoshi FUJI
  • Patent number: 11164484
    Abstract: A secure computation technique of calculating a polynomial in a shorter calculation time is provided. A secure computation system generates concealed text [[u]] of u, which is the result of magnitude comparison between a value x and a random number r, from concealed text [[x]] by using concealed text [[r]]; generates concealed text [[c]] of a mask c from the concealed text [[x]], [[r]], and [[u]]; reconstructs the mask c from the concealed text [[c]]; calculates, for i=0, . . . , n, a coefficient bi from an order n, coefficients a0, a1, . . . , an, and the mask c; generates, for i=1, . . . , n, concealed text [[si]] of a selected value si, which is determined in accordance with the result u of magnitude comparison, from the concealed text; [[u]]; and calculates a linear combination b0+b1[[s1]]+ . . . +bn[[sn]] of the coefficient bi and the concealed text [[si]] as concealed text [[a0+a1x1+ . . . +anxn]].
    Type: Grant
    Filed: January 18, 2018
    Date of Patent: November 2, 2021
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventor: Koki Hamada
  • Publication number: 20210314145
    Abstract: A secure joining system is a secure joining system including a plurality of secure computing apparatuses. The plurality of secure computing apparatuses include a first vector joining unit, a first permutation calculation unit, a first vector generation unit, a second vector joining unit, a first permutation application unit, a second vector generation unit, a first inverse permutation application unit, a first vector extraction unit, a second permutation application unit, a third vector generation unit, a second inverse permutation application unit, a second vector extraction unit, a modified second table generation unit, a third permutation application unit, a fourth vector generation unit, a shifting unit, a third inverse permutation application unit, a bit inversion unit, a third vector extraction unit, a modified first table generation unit, a first table joining unit, and a first table formatting unit.
    Type: Application
    Filed: August 8, 2019
    Publication date: October 7, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA, Ryo KIKUCHI, Naoto KIRIBUCHI
  • Publication number: 20210287573
    Abstract: Calculation time is reduced without degrading approximation accuracy in calculation of a complicated function through secure computation. A secret batch approximation system calculates a concealed text [z] of an approximate value z for a function value y satisfying yj=f(xj) by using a concealed text [x] of a value x as input. g is defined as a polynomial for approximating each section of m sections into which the function f is divided. A parameter acquisition unit acquires a concealed text [a] of a parameter a corresponding to the value x for each integer j that is not less than 1 and not more than n, where aj is defined as a parameter pi corresponding to a section Ri including a value xj. A polynomial calculation unit calculates a polynomial g([x], [a]) by using the concealed text [x] of the value x as input based on the concealed text [a].
    Type: Application
    Filed: May 20, 2019
    Publication date: September 16, 2021
    Applicant: Nippon Telegraph and Telephone Corporation
    Inventor: Koki HAMADA
  • Patent number: 11121868
    Abstract: Fisher's exact test is efficiently computed through secure computation. A computation range determination part determines i0, i1, x0, x1. A preliminary computation part computes f(x0), . . . , f(x1), and generates an array M=(f(x0), . . . , f(x1)). A securing part secures the array M, and generates a secure text array <M>=(<f(x0)>, . . . , <f(x1)>). A batch-reading part generates a function value secure text (<f(ai)>, <f(bi)>, <f(ci)>, <f(di)>) (i0?i?i1).
    Type: Grant
    Filed: June 30, 2017
    Date of Patent: September 14, 2021
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventor: Koki Hamada
  • Publication number: 20210263921
    Abstract: A secure joining system is a secure joining system comprising a plurality of secure computation apparatuses; and the plurality of secure computation apparatuses are provided with vector joining parts 11n, first permutation calculating parts 12n, first permutation applying parts 13n, first vector generating parts 14n, second vector generating parts 15n, bit-flipping parts 16n, second permutation calculating parts 17n, second permutation applying parts 18n, third vector generating parts 19n, inverse permutation applying parts 110n, vector separating parts 111n, third permutation applying parts 112n, attribute value permutating parts 113n and fourth vector generating parts 114n.
    Type: Application
    Filed: June 13, 2019
    Publication date: August 26, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA
  • Patent number: 11081024
    Abstract: Fisher's exact test is efficiently computed through secure computation. It is assumed that a, b, c and d are frequencies of a 2×2 contingency table, [a], [b], [c] and [d] are secure texts of the respective frequencies a, b, c and d, and N is an upper bound satisfying a+b+c+dN. A reference frequency computation part computes a secure text ([a0], [b0], [c0], [d0]) of a combination of reference frequencies (a0, b0, c0, d0) which are integers satisfying a0+b0=a+b, c0+d0=c+d, a0+c0=a+c, and b0+d0=b+d. A number-of-patterns determination part determines integers h0 and h1 satisfying h0?h1. A pattern computation part computes [ai]=[a0]+i, [bi]=[b0]?i, [ci]=[c0]?i and [di]=[d0]+i for i=h0, . . . , h1, and obtains a set S={([ai], [bi], [ci], [di])}i of secure texts of combinations of frequencies (ai, bi, ci, di).
    Type: Grant
    Filed: June 30, 2017
    Date of Patent: August 3, 2021
    Assignees: NIPPON TELEGRAPH AND TELEPHONE CORPORATION, TOHOKU UNIVERSITY
    Inventors: Koki Hamada, Koji Chida, Satoshi Hasegawa, Masao Nagasaki, Kazuharu Misawa
  • Publication number: 20210191927
    Abstract: To efficiently determine intermediate data for use with an aggregate function while keeping confidentiality, a bit decomposition unit generates a share of a bit string by bit decomposition and concatenation of key attributes. A group sort generation unit generates a share of a first permutation, which performs a stable sort of the bit string in ascending order. A bit string sorting unit generates a share of a sorted bit string obtained by sorting the bit string with the first permutation. A flag generation unit generates a share of a flag indicating a boundary between groups. A key aggregate sort generation unit generates a share of a second permutation, which performs a stable sort of the negation of the flag in ascending order. A de-duplication unit generates shares of de-duplicated key attributes. A key sorting unit generates shares of sorted key attributes by sorting the de-duplicated key attributes.
    Type: Application
    Filed: May 14, 2019
    Publication date: June 24, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA
  • Publication number: 20210182419
    Abstract: A secure joining system is a secure joining system including a plurality of secure computing apparatuses. The plurality of secure computing apparatuses include a vector joining unit 11n, a first vector generation unit 12n, a first permutation calculation unit 13n, a first permutation application unit 14n, a second vector generation unit 15n, a third vector generation unit 16n, a second permutation calculation unit 17n, a second permutation application unit 18n, a fourth vector generation unit 19n, a fifth vector generation unit 110n, a first inverse permutation application unit 111n, a first vector separation unit 112n, a second inverse permutation application unit 113n and a second vector separation unit 114n, a third permutation application unit 115n, a fourth permutation application unit 116n, and a first joined table generation unit 117n.
    Type: Application
    Filed: August 8, 2019
    Publication date: June 17, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA
  • Publication number: 20210182062
    Abstract: A secure strong mapping computing system is a secure joining system including a plurality of secure computing apparatuses. The plurality of secure computing apparatuses include a first vector joining unit 11n, a first permutation calculation unit 12n, a first vector generation unit 13n, a second vector joining unit 14n, a first permutation application unit 15n, a second vector generation unit 16n, a first inverse permutation application unit 17n, and a first vector extraction unit 18n.
    Type: Application
    Filed: August 8, 2019
    Publication date: June 17, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Dai IKARASHI, Koki HAMADA