Abstract: A data providing apparatus acquires a plurality of range proof data, generates a digital signature for each of the range proof data, and transmits a data set, a sanitizable signature, the range proof data, and the digital signature to a data processing apparatus. The data processing apparatus performs a process for performing generalizing processing for processing-target data, performs a process for the sanitizable signature, and selects range proof data corresponding to a range of a generalized attribute value. The data processing apparatus transmits the processed data set, the processed sanitizable signature, the selected range proof data, and the digital signature corresponding to this range proof data to a data receiving apparatus. The data receiving apparatus verifies the sanitizable signature, verifies the digital signature corresponding to the range proof data, and verifies the range proof data.

Abstract: A data providing apparatus sets a processing rule, sets predetermined random numbers, calculates a signature hash value corresponding to each of a plurality of data, generates a digital signature using the signature hash value, and transmits a data set, the digital signature, and the random numbers to a data processing apparatus. A data processing apparatus performs a process for processing processing-target data, calculates an after-processing hash value corresponding to each of the processing-target data, and transmits the already-processed data set, the after-processing hash value, and the digital signature to a data receiving apparatus. A data receiving apparatus calculates a verification hash value corresponding to each of the plurality of data by using the already-processed data set and the after-processing hash value, and verifies the verification hash value and the digital signature.

Abstract: A secure computation system comprising secure computation server apparatuses, each of which comprises: a discriminant share generation part that computes discriminant shares configured so that an index relating to an input corresponds to a specific value from shares representing the index relating to the input and possible combinations of index shares of an array; a combination configuration part that configures a combination of shares of an element in the array and the discriminant shares for all possible combinations of indices of the array; a shuffle part that shuffles the combinations; a reconstruction part that reconstructs the discriminant shares in the shuffled combinations; and a selection part that selects shares of an element in the array in the combinations where the reconstructed value is the specific value.

Abstract: An assessment apparatus is able to access a surrogate model generation apparatus that comprises a query generation part that generates a first query causing an assessment target model to make an inference to obtain an inference result; an MIA execution part that executes a membership inference attack using as an input the inference result obtained by sending the first query to the assessment target model and infers virtual training data used to train the assessment target model; and a surrogate model generation part that uses the virtual training data to generate a surrogate model that emulates the behavior of the assessment target model, and the assessment apparatus comprises a security assessment part that transmits a second query to both the surrogate model and the assessment target model to assess the security of the assessment target model using the results therefrom.

Abstract: A distributed re-encryption apparatus comprises: a distributed re-encryption key storage part that stores shares obtained by secret-sharing a re-encryption key that re-encrypts a ciphertext into one encrypted with a different encryption key without decrypting the ciphertext; and a distributed re-encryption part that re-encrypts using the shares of the re-encryption key the ciphertext into one encrypted with a different encryption key without decrypting the ciphertext.

Abstract: An secure computation server apparatus includes: a discriminant computation part that determines, per bit, whether the first bit sequence and a second bit sequence into which the value of the cleartext is converted match each other and that computes a sequence of a discriminant that indicates 0 when the first bit sequence indicates 1 and the second bit sequence indicates 0 at an n-th bit and when the first bit sequence and the second bit sequence match each other at an (n+1)th bit and higher; a shuffle part that shuffles the sequence of the discriminant to conceal information about the digit of the bit for which the discriminant indicates 0; and a comparison and verification part that compares received values with each other, in a communication performed in the shuffling of the discriminant, and adopts the received values that are same at least two received values as an accurate value.

Abstract: Among four secure computation nodes holding first to third shares of data in a secret-shared form, first and second secure computation nodes are selected as resharing nodes, and third and fourth secure computation nodes are selected as receiving nodes. The first and second secure computation nodes perform a mini-shuffle for resharing the shares they each hold by using a permutation that third and fourth receiving nodes do not know. Next, the third and fourth secure computation nodes perform a mini-shuffle for resharing the shares they each hold by using a permutation that first and second receiving nodes do not know.

Abstract: The information processing apparatus comprises a basic operation seed storage part, a reshare value computation part, and a share construction part. The basic operation seed storage part stores a seed for generating a random number used when computation is performed on a share. The reshare value computation part generates a random number using the seed, computes a share reshare value using the generated random number, and transmits data regarding the generated random number to other apparatuses. The share construction part constructs a share for type conversion using the data regarding the generated random number and the share reshare value received from other apparatuses.

Abstract: A learning apparatus according to the present example embodiment includes: a data dividing unit that generates n sets of divided data by dividing first learning data into n (n is an integer of 2 or more); an inference device generation unit that generates n inference devices for learning data generation by machine learning using data excluding one set of divided data from the first learning data; a learning data generation unit that generates second learning data by inputting the one set of the divided data excluded from the machine learning into each of the n inference devices for learning data generation; and a learning unit that generates a second inference device by machine learning using the second learning data.

Abstract: Among four secure computation nodes, one secure computation node is selected as a receiving node. Two of three remaining secure computation nodes among the four secure computation nodes are operated as resharing nodes, and a remaining secure computation node is operated as a verifying node. The resharing node(s) performs a mini-shuffle for resharing share(s) held therein by using a permutation that the receiving node does not know and transmits a result(s) of the mini-shuffle to the receiving node. The verifying node computes data to verify the result(s) of the mini-shuffle performed by the resharing node(s) by using a permutation that the receiving node does not know and transmits the data to the receiving node. Shuffling of shares is achieved by repeatedly performing a round as described above so that each of the four secure computation nodes is selected as the receiving node at least once.

Abstract: Each of a secure computation server apparatuses includes a random number generation part that generates random numbers using a pseudo random number generator shared among the secure computation server apparatuses; a seed storage part that shares and stores a seed(s) used for generating random numbers in the random number generation part; a pre-generated random number storage part that stores random numbers generated by the random number generation part; a share value storage part that stores a share(s) to be a target of processing; a logical operation part that computes a carry to be transmitted and received among the secure computation server apparatuses using the random numbers and the share(s) to be a target of processing; an inner product calculation part that removes a mask from the carry; and an arithmetic operation part that performs a processing of erasing the carry to obtain a processing result.

Abstract: An individual secure computation server apparatus in a secure computation system computes, by using a cyclic permutation shared by secure computation server apparatuses except one of the secure computation server apparatuses, a value of a cyclic permutation for the one secure computation server apparatus, performs a fraud detection by performing an equality check on values of cyclic permutations computed by the other secure computation server apparatuses, constitutes a random cyclic permutation by synthesizing the cyclic permutations, applies the random cyclic permutation to the share in the sequence, computes a share which indicates an index and to which the random cyclic permutation has been applied by adding a share having a shift amount of the cyclic permutation to the share which indicates the index, reconstructs the share which indicates the index and to which the random cyclic permutation has been applied, and selects a share corresponding to the reconstructed index.

Abstract: In a secret computation system, each of the three or more secret computation servers is configured to transmit, to the auxiliary server, carry computation information for computing a carry indicating whether or not digit carry occurs when a share of arithmetic operation is added as a binary number. The auxiliary server is configured to compute the carry based on the carry computation information received and compute an adjustment value used for computing the share of the arithmetic operation from a share of logical operation by using the computed carry. The auxiliary server distributes the computed adjustment value to the three or more secret computation servers. Each of the three or more secret computation servers is configured to convert the share of the logical operation to the share of the arithmetic operation by using a distributed value of the adjustment value.

Abstract: An secure computation server apparatus in a secure computation system includes: a local shuffle part that computes, by using a shared permutation shared by four of the five secure computation server apparatuses, permuted values of a share for a remaining one of the five secure computation server apparatuses and sends the permuted values of the share to the remaining secure computation server apparatus; a comparison and verification part that compares values with each other, which are received from at least three of the four secure computation server apparatuses and which are supposed to be a same value, and adopts the values that are same at least two values as an accurate permutation; and a shuffle synthesis part that synthesizes mini-shuffles, by using a shared permutation shared by a corresponding combination of four secure computation server apparatuses and a permutation adopted by a corresponding one of the comparison and verification parts.

Abstract: A secure computation server apparatus in a secure computation system includes: a table storage part that stores a table of secret shares of the product of a first value and a second value for combinations of shares of possible values of the first value and shares of possible values of the second value; a table shuffle part that shuffles indices of possible values of the first value and indices of possible values of the second value in the table; a multiplication part that selects an element in the table whose indices in the shuffled table match the first and the second values; and a comparative verification part that accepts data that a majority of other secure computation server apparatuses agrees on as a correct value out of a plurality of data received from the other secure computation server apparatuses.

Abstract: A verification apparatus acquires a source code for multiparty computation, while changing a combination of options settable to a multiparty computation compiler, compiles the source code for each combination of options to generate a plurality of multiparty computation executable codes, selects at least one multiparty computation executable code from the plurality of multiparty computation executable codes as a verification code and provides the at least one verification code to a verification environment of multiparty computation, generates an evaluation index with respect to an execution result of at least one verification code in the verification environment, and selects at least one recommended code from the plurality of multiparty computation executable codes, based on the evaluation index corresponding to at least one verification code and outputs the selected recommended code.

Abstract: A federated learning apparatus in a federated learning system includes: a model storage part that replicates and stores a shared model as a local model; a local training part that trains the local model by using data held by the federated learning apparatus; a secret sharing part that decomposes a local update parameter indicating a training result of the local model into shares based on an additive secret sharing scheme and distributes the shares to other federated learning apparatuses; an aggregation and secure computation part that performs a secure computation for shares of a global update parameter by performing addition of the shares of the local update parameters and multiplication of the shares by cleartext constants; and a global training part that reconstructs the shares of the global update parameter and updates the shared model by the global update parameter.

Abstract: An individual one of secure computation server apparatuses in a secure computation system includes: a local reshare part that computes an arithmetic share from a logic share without communicating with the other secure computation server apparatuses by setting a sub-share not held thereby to zero; a secure computation part that performs a secure computation with communications by using the arithmetic share acquired by the local reshare part, to acquire an arithmetic share from the logic share through a bit conversion; and a comparison and verification part that compares received values with each other, which are received from at least three of the secure computation server apparatuses and which are supposed to be a same value, and adopts the received values that are same at least two received values as an accurate value. The comparison and verification part verifies the received values acquired in the secure computation with communications.

Abstract: In IaaS (Infrastructure as a Service), when it is desirable to delegate the authority to a user outside a system, a recipient of an access token is designated, thereby preventing illegal distribution of the access token. There is provided an access token system including a generator and a verifier. The generator generates, using secret information of a recipient, a recipient-designated access token for which the recipient is designated, and provides the recipient-designated access token to a user. The verifier verifies that the user who makes access using the recipient-designated access token is the designated recipient.

Abstract: When an absolute value of a difference value between a first share and a second share which are secret-shared is less than or equal to a natural number t, the information processing apparatus calculates the difference value between the first share and the second share. Furthermore, the information processing apparatus performs a comparison in magnitude of the first share and the second share using bit-decomposition from a least significant bit to an m-th bit (m being a natural number) of the difference value.