Abstract: A secret hash table construction apparatus constructs a secret hash table capable of storing up to Z items of data in B kinds of address values by secret computation from a real data stream including items of data each having a key and a flag indicating whether or not the data is dummy data. The secret hash table construction apparatus executes generating a first array in which a storage destination data array is connected with another storage destination data array as dummy data; generating a second array in which the real data stream is connected with a dummy data stream; sorting each of the first and second arrays based on a ranking operations; extracting address values of lower ranks to generate a third array; and sorting the second array using a fourth array, and outputting BZ elements in the sorted second array as the secret hash table.

Abstract: A server determines an array [[addr]] indicating a storage destination of each piece of data, generates an array of concealed values, and connects the generated array to the array [[addr]] to determine an array [[addr?]]. The server generates a sort permutation [[?1]] for the array, applies the sort permutation [[?1]] to the array [[addr?]], and converts the array [[addr?]] into an array with a sequence composed of first Z elements set to [[i]] followed by ?i elements set to [[B]]. The server generates a sort permutation [[?2]] for the converted array [[addr?]], generates dummy data, imparts the generated dummy data to the concealed data sequence, applies the sort permutations [[?1]] and [[?2]] to the data array imparted with the dummy data, and generates, as a secret hash table, a data sequence obtained by deleting the last N pieces of data from the sorted data array.

Abstract: A secure random number that follows a binomial distribution is generated without performing successive communication. A secure computation apparatus (1i) generates a share [r]i of a random number r that follows a binomial distribution. A parameter storage unit (10) stores a pseudorandom function PRF, at least one set of a key kA and a polynomial fA. A pseudorandom number generating unit (11) obtains a pseudorandom number pA for each of the keys kA by computing the pseudorandom function PRF(kA, a) using the keys kA. A bit counting unit (12) counts the number rA of 1s included in each pseudorandom number pA. A random number share generating unit (13) obtains the sum of products of the number rA of 1s and an output of the polynomial fA(i) corresponding to the number rA of 1s as the share [r]i of the random number r.

Abstract: A computation apparatus, a method of the same, and a program which perform a secure computation using fixed-point arithmetic, and overflow is unlikely to occur and the occurrence of division by zero can be detected when an odds ratio is calculated. The computation apparatus includes an odds ratio computation unit for obtaining an odds ratio between a first group (a+b) and a second group (c+d) based on four plaintext values a, b, c, and d, by means of secure computation; a zero-division detection unit for determining, by means of secure computation, whether or not at least one of the plaintext values b and c is not zero, and detecting division by zero; and a selection unit for selecting the odds ratio if division by zero is not detected, by means of secure computation.

Abstract: A secure computation apparatus (1i) generates a concealed value [r] of a random number r following a discrete Laplace distribution with parameter ?. A bit stream generating unit (11) generates a concealed value stream [b0], [b1], . . . , [bN] that is constituted by a concealed value [b0] of a random number bit bo following a Bernoulli distribution with probability (1??)/(1+?) and concealed values [b1], . . . , [bN] of random number bits b1, . . . , bN each following a Bernoulli distribution with probability (1??). An absolute value determining unit (12) obtains a concealed value [L] of a position L at which 1 is first set from the head of the random number bits b0, b1, . . . , bN. A sign determining unit (13) obtains a result [L·s] obtained by multiplying the concealed value [L] by a concealed value [s] of a random sign s, as a concealed value [r] of the random number r.

Abstract: The present invention provides techniques to calculate the number of surviving and the number of deaths while still concealing survival time data. The present invention includes: a group data position calculation means configured to calculate a share [[gA]] of a sequence gA and a share [[gB]] of a sequence gB represented by predetermined equations from a share [[g]] of a sequence g of values of group of survival time data included in a survival time data set D; a group data number calculation means configured to calculate a share [[sA]] and a share [[sB]] from a share [[t]] of a sequence t of values of time of survival time data included in the survival time data set D, the share [[gA]], and the share [[gB]], by [[sA]]=GroupSum ([[gA]], [[t]]), [[sB]]=GroupSum ([[gB]], [[t]]); and a survival number calculation means.

Abstract: A search key is generated (S20). A key relationship array is transmitted (S11). If an element matching the key relationship array is present, the found search key is held (S21). A key relationship index is transmitted (S22). A record read out using the key relationship index is transmitted (S12). If the record matches the search key, the found search key is held (S23). The found search key is set for an empty element of the key relationship array and is transmitted (S24). A data array is transmitted (S13). If an element matching the data array is present, the found data is held (S25). A data index is transmitted (S26). A record read out using the data index is transmitted (S14). If the record matches the search key, the found data is held (S27). Desired data is set for an empty element of the data array and is transmitted (S28).

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.

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.