Hitachi, Ltd.

Renesas Electronics Corporation

Ken Naganuma

Hisayoshi Sato

Masayuki Yoshino

Eriko Ando

Toru Owada

Kenta Takahashi

Yoshinori Sato

Takayuki Suzuki

Dai Watanabe

Yusuke Mishina

Masakazu Fujio

Kunihiko Kido

Takayoshi Fujioka

Yosuke Kaga

Yukie Motomiya

Takayuki Habuchi

Non Kawana

Toshirou Yamayoshi

A first computer, in data registration processing: determines a type of biometric information for encryption with which the data is to be encrypted; acquires the determined type of biometric information for encryption from a user of the first computer; generates, from each piece of the acquired biometric information for encryption, a public key based on a predetermined algorithm; transmits the public key to a second computer; and transmits the data encrypted with the public key to the third computer, the first computer, in data presentation processing: acquires the encrypted data from a third computer; acquires the determined type of biometric information for decryption from the user of the first computer; generates, from each piece of the acquired biometric information for decryption, a private key based on the predetermined algorithm; decrypts the encrypted data with use of the private key; and presents each piece of the decrypted registered data.

Data management system, data management method, and non-transitory computer readable medium

A data comparison device holds first and second encrypted data of first and second plaintext, respectively. The first plaintext is divided into a plurality of blocks and the first encrypted data is generated by executing encryption of each of the plurality of blocks and shuffling of the plurality of blocks. The second plaintext is divided into a plurality of blocks and the second encrypted data is generated by executing encryption of each of the plurality of blocks. In at least one of the first encrypted data and the second encrypted data, a plaintext value is embedded as a value indicating a magnitude comparison result, and the data comparison device compares blocks at the same position before shuffling of the first encrypted data and the second encrypted data based on the embedded value and determines a magnitude relationship between the first plaintext and the second plaintext.

Data comparison device, data comparison system, and data comparison method

Provided is a data processing system having a processor and a storage apparatus coupled to the processor, wherein: the storage apparatus holds a plurality of encrypted data that are generated by encrypting a plurality of plain text data, and a plurality of encrypted queries for retrieving the plurality of encrypted data directly in an encrypted state; and the processor retrieves each of the encrypted data using each of the encrypted queries and thereby calculates the number of appearances of encrypted data that are retrieved using each of the encrypted queries, changes at least two of the plurality of encrypted data on the basis of the number of appearances of encrypted data that are retrieved using each of the encrypted queries so that predetermined anonymity is satisfied, and outputs a plurality of encrypted data.

Data processing system and data processing method

A value comparison server holds a first secret key and a plurality of tags corresponding to values, each of the plurality of tags is a ciphertext obtained by encrypting each of the values with an additive-homomorphic encryption scheme by using secret keys including the first secret key and a first parameter, a plaintext space has remainder operation with a natural number as modulo in the encryption scheme, and the value comparison server generates a value used for comparing two values corresponding to two tags included in the plurality of tags from the first secret key and the two tags by using the additive homomorphism; and determines which of the two values is greater or equal, on the basis of whether a discrete logarithm of the generated value to the first parameter can be calculated within a value of a predetermined range.

Value comparison server, value comparison encryption system, and value comparison method

A data analysis server holds base-point-added information, wherein the base-point-added information includes a value of an explanatory variable encrypted by first high-performance encryption, a value of a response variable encrypted by a predetermined encryption scheme, and a base point based on frequencies of the value of the explanatory variable in information for learning are associated with one another, wherein the data analysis server: executes decision tree generation processing for generating a decision tree having a leaf node associated with the value of the response variable encrypted by the predetermined encryption scheme, which is included in the base-point-added information; and execute branching rule determine processing in decision tree generation processing without decrypting the value of the explanatory variable and the base point corresponding.

Data analysis server, data analysis system, and data analysis method

Provided is a signature verification system comprising: a signature terminal including a biometric information acquisition unit for acquiring biometric information of a user, a public template certificate generation unit for generating a public template certificate by subjecting the biometric information to predetermined processing, a key pair generation unit for generating a pair of a secret key and a public key, and a public key certificate generation unit for generating a public key certificate by providing a biometric signature to the public key with the biometric information used as a key; and a verification terminal including a public key certificate verification unit for receiving a transaction including the public template certificate, the public key certificate, and a signature to verify the validity of the public key certificate using the public template certificate, and a signature verification unit for verifying the signature using the public key certificate.

Signature verification system, signature verification method, and storage medium

A searchable encryption processing system includes a server including: a communication device to communicate with another device; a storage device configured to store as search target data, secret data obtained by concealing plaintext data, and a secret index obtained by concealing a plaintext index to classify the plaintext data; and an arithmetic device to execute a process including receiving, from a search client, a secret data query obtained by concealing a plaintext query, and a secret index query obtained by concealing a plaintext index, searching the storage device for a secret index matching the secret index query based on a predetermined searchable encryption technique, searching a secret data group classified by the matching secret index for secret data matching the secret data query, and returning the searched secret data to the search client.

Searchable encryption processing system and searchable encryption processing method

A communication system () includes a certificate authority () for performing authentication, a roadside device (), a vehicle-mounted terminal (), a first server (), and a second server (). The vehicle-mounted terminal transmits its position information to the first server. The certificate authority acquires information about a vehicle-mounted terminal likely to appear according to place and time from the first server. The certificate authority allows the second server to verify validity of a certificate for a vehicle-mounted terminal acquired from the first server. The certificate authority generates a first list of vehicle-mounted terminals having valid certificates and a second list of vehicle-mounted terminals having invalid certificates according to place and time based on a verification result. The certificate authority transmits the first and second lists to the roadside device and the vehicle-mounted terminal. The roadside device and the vehicle-mounted terminal verify a certificate using the first and second lists.

Communication system, vehicle-mounted terminal, roadside device

An authentication method is provided which is capable of performing message authentication within an allowable time regardless of the magnitude of the number of messages and performing message authentication high in accuracy within a range for which the allowable time allows. Upon transmission by wireless communications with another mobile or a fixed station, a message authentication code of communication data and a digital signature are generated (Sand S). The generated message authentication cod and digital signature are transmitted with being added to the communication data. Upon reception, whether authentication should be done using either one of the message authentication code and the digital signature included in received information is determined according to its own state for the authentication (Sand S). This state includes, for example, a load state of a central processing unit or the like that performs an authentication process.

Wireless communications device and authentication processing method

A client executes processing for data encryption by adding an error vector to plaintext, the error vector being not larger than a predetermined criterion and processing for sending limitation information to a server, the limitation information being formed from a sublattice basis of a lattice generated by a secret key. The server executes processing for receiving the limitation information and storing it in a storage device and in the homomorphic computation processing on the encrypted data received from the client, processing for, when a bit length of ciphertext which is a result of the homomorphic computation processing is equal to or larger than a predetermined value, reducing the bit length of the ciphertext to a value not larger than a predetermined threshold by translating a vector of the ciphertext to an inside of a region formed from the sublattice basis corresponding to the stored limitation information.

Confidential computation system, confidential computation method, and confidential computation program

In the searchable encryption processing system, a data base server retaining data, a registration client which deposits the data into the data base server, and a search client which causes the data base server to search the data collaborate across a network, wherein the registration client, using a probabilistic encryption method which uses a mask using a homomorphic function and a hash value, deposits the encrypted data into the server, whereupon the search client, using probabilistic encryption which uses the mask which uses the homomorphic function for encryption of the search query, outputs the search query and non-corresponding data as search results without causing the data base server to unmask the mask and without allowing the frequency of occurrences of the data corresponding to the search to leak to the data base server.

Searchable encryption processing system

There is a need to reduce the certificate verification time in a communication system. A communication system () includes a certificate authority () for performing authentication, a roadside device (), a vehicle-mounted terminal (), a first server (), and a second server (). The vehicle-mounted terminal transmits its own position information to the first server. The certificate authority acquires information about a vehicle-mounted terminal highly likely to appear according to place and time from the first server. The certificate authority allows the second server to verify validity of a certificate for a vehicle-mounted terminal acquired from the first server. The certificate authority generates a first list of vehicle-mounted terminals having valid certificates and a second list of vehicle-mounted terminals having invalid certificates according to place and time based on a verification result. The certificate authority transmits the first list and the second list to the roadside device and the vehicle-mounted terminal. The roadside device and the vehicle-mounted terminal verify a certificate using the received first and second lists. Thus, the certificate verification time is reduced.

A communication system includes a certificate authority for performing authentication, a roadside device, a vehicle-mounted terminal, a first server, and a second server. The vehicle-mounted terminal transmits position information to the first server. The certificate authority acquires information about a vehicle-mounted terminal likely to appear according to place and time from the first server. The certificate authority allows the second server to verify validity of a certificate for a vehicle-mounted terminal acquired from the first server. The certificate authority generates a first list of vehicle-mounted terminals having valid certificates and a second list of vehicle-mounted terminals having invalid certificates according to place and time based on a verification result. The certificate authority transmits the first and second lists to the roadside device and the vehicle-mounted terminal. The roadside device and the vehicle-mounted terminal verify a certificate using the received first and second lists thereby reducing the certificate verification time.

In an indoor positioning system, for establishment of a cost sharing system, the positioning information transmission device does not directly transmit positional information but performs concealment and variablization on the device ID and transmits the concealed and variablized device ID. The positioning information management server stores and manages correspondence between the device IDs and positional information, and performs conversion from the device ID to the positional information in accordance with the correspondence. Further, the problem of conflict between concealed IDs upon concealment of positioning identification information by the positioning information transmission devices, which occurs when all the positioning information transmission devices use the same secret key, can be prevented. The system can be operated even when the bit length of the device ID is short.

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Tokyo, Japan

Ken Naganuma