Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Hitachi Solutions, Ltd.

Chuo University

Tokyo, Japan

Shinko Kigyo Corp.

Chiyoda Gravure Corp.

Educational Foundation Chuo University

Hisayoshi Sato

Masayuki Yoshino

Ken Naganuma

Dai Watanabe

Masashi Takahashi

Kazuo Takaragi

Kunihiko Miyazaki

Hiroyuki Kurumatani

Soichi Furuya

Takayuki Suzuki

Yoshinori Sato

Isao Ishikawa

Keisei Fujiwara

Yoshiaki Isobe

Kunihiko Kido

Yasuhiro Tani

Kazunori Umeda

Kosuke Anzai

Suguru Iwasaki

Hisashi Osumi

Naruhiro Irino

Takuya Semba

Toshirou Yamayoshi

An connection apparatus receives a purchase desire notification including a public key from another connection apparatus via a blockchain network and transmits an encrypted content key acquired by encrypting a content key using the public key to the other connection apparatus via the blockchain network. The other connection apparatus transmits the purchase desire notification to the one connection apparatus and transmits transmission source information representing a transfer destination of the content to the blockchain network. In addition, the other connection apparatus decrypts the encrypted content key from the one connection apparatus using the stored secret key. In a case in which the encrypted content key is received, the blockchain network changes an owner represented in owner management information to the transfer destination.

Content protection system

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

A first terminal holds first encrypted data encrypted by using a first key by a first encryption scheme having deterministic and commutativity, a second terminal holds second encrypted data encrypted by using a second key by the first encryption scheme, the first terminal transmits the first encrypted data to the second terminal, the second terminal transmits the second encrypted data to the first terminal, the first terminal generates third encrypted data by encrypting the second encrypted data by using the first key by the first encryption scheme, the third encrypted data is transmitted to the second terminal, the second terminal decrypts the third encrypted data with the second key, and calculates a common part between the second encrypted data and the decrypted third encrypted data, and transmits the common part to the first terminal, and the first terminal decrypts the common part with the first key.

Information processing system and information processing method

In the confidential information processing server, when the processing query execution unit receives a processing request, the TEE trusted part processing unit generates a confidential extraction query for extracting data that matches with a condition of a processing target in the processing request by confidential extraction based on the processing request and an encryption key that can be used only in a TEE trusted part, the confidential extraction processing unit instructs execution of the confidential extraction query so as to extract encrypted data of the processing target while the data is kept encrypted from the encryption DB unit, the TEE trusted part processing unit decrypts the encrypted data of the processing target extracted by the confidential extraction processing unit with an encryption key, and executes data processing requested by the processing request, and the processing query execution unit returns an execution result of the data processing to a transmission source of the processing request.

Confidential information processing system and confidential information processing 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

Provided is a data processing system in which data are uploaded from a user terminal A to data storage server, and data are accessed from a user terminal B. User terminal A and B have a key KA and KB, respectively. Data storage server has a replacement key KA&#x2192;B. User terminal A generates an authenticator tag with data M and temporary key R, generated by user terminal A, and generates a key k with temporary key R and key KA. User terminal A transmits data M, key k, and authenticator tag to the data storage server. Data storage server generates a key k' from key k and replacement key KA&#x2192;B, and transmits data M, key k&#x2032;, and the message authenticator tag to user terminal B. User terminal B generates temporary key R with key k&#x2032; and key KB and generates an authenticator tag&#x2032; to compare with the received authenticator tag.

Data processing system

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

In this searchable encryption processing system in which a registered client and a management server are connected via a network, the registered client is provided with a registered client processing unit that generates, on the basis of the difference between a first secret key for encrypting plaintext data and a second secret key for newly encrypting the plaintext data, a difference key mask for updating, by using the second secret key, confidential data encrypted by the first secret key.

Searchable encryption processing system

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

In a searchable cipher system, the security of ciphertext, the optimization of the size of ciphertext and the optimization of the network traffic are not examined enough. A registration client deposits encrypted data acquired by compressing the size of a search tag created for a search by a stochastic encryption using a mask by a hash value and an output value of a homomorphic function in a server, a search client similarly stochastically encrypts a search keyword and transmits it to the management server as a search keyword acquired by encrypting only a part of the encrypted data, the search client requests the management server to search data to be searched without making the management server release a mask by random numbers of the encrypted data and the encrypted keyword, the search client detects a wrong search in a search result, and decrypts the search result.

Searchable code processing system and method

A storage count verification system is provided in which a client can verify the number of identical data items stored by a server without the server being notified of the results. A storage count verification system verifies whether a user device and a server device have identical data where search data requested by a user device is used to search data to be searched on a server device. The server device generates a public parameter for searching the data to be searched and transmits the generated public parameter to the user device. The user device is provided with a user generation unit for generating, on the basis of the public parameter received from the server device, a secret parameter that is for the search data and corresponds to the public parameter and a user encryption unit for encrypting the search data on the basis of the generated secret parameter.

Storage count verification system

With a portal server, a request for information from a terminal of a second user that is an agent for a first user is received, and an encrypted data directed to a terminal of the first user, stored in an encrypted-data memory unit, is re-encrypted using a re-encryption key for the second user, stored in a first encryption-key memory unit, and is transmitted to the terminal of the second user, with the terminal of the second user, the re-encrypted data received is decrypted using an encryption key for the second user, stored in a second encryption-key memory unit, and time keys specified by the terminal of the first user, related to a time-period during which browsing of the information is permitted.

Method, information service system and program for information encryption/decryption

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.

To achieve high safety, large-sized nonlinear permutation is employed; however, the larger permutation processing is, the more the period of time required for the processing is, which hence is not efficient. There is provided a hash value generation method or a hash value generator which has the following aspects and which is highly safe and is capable of executing processing at a high speed.

Growing community of inventors

Tokyo, Japan

Hisayoshi Sato