Mitsubishi Electric Corporation

Mitsubishi Electric Research Laboratories, Inc.

The University of Electro-communications

Mitsubishi Space Software Co., Ltd.

Nori Matsuda

Mitsuhiro Hattori

Takashi Ito

Takato Hirano

Takumi Mori

Takeshi Yoneda

Yutaka Kawai

Katsuyuki Takashima

Yoichi Shibata

Yusuke Sakai

Ye Wang

Yoshihiro Koseki

Atsushi Kohno

Akihiro Miura

Takehiko Koyasu

Rina Shimizu

Sachihiro Ichikawa

Tsutomu Sakagami

Kimihiko Izaki

Shigeki Tanishima

Kazuhiro Kusunoki

Kazuo Ota

Tadakazu Yamanaka

Tatsuya Tsurukawa

A registration destination determination device () determines which data management device, among a plurality of data management devices (A,B), is to manage registration data, such that, with a data type constituting the registration data as a target type, an appearance frequency distribution of values set for the target type of the registration data managed by each of the plurality of data management devices (A,B) is different from an appearance frequency distribution of values set for the target type of the registration data managed by the whole of the plurality of data management devices (A,B).

Registration destination determination device, searchable encryption system, destination determination method, and computer readable medium

A data search server stores a system ciphertext including a data ciphertext and a keyword ciphertext in each category-specific DB unit for each data category, and stores each category-determination secret key being associated with each category-specific DB unit. A search request receiving unit receives from a data search terminal a search request including a search trapdoor and an index tag. A data searching unit searches for a category-determination secret key with which the index tag is decrypted to the same value as a key-determination value. Using the search trapdoor, the data searching unit performs a search of a Public-key Encryption with Keyword Search scheme on system ciphertexts in a category-specific DB unit associated with this category-determination secret key. A search result transmitting unit transmits to the data search terminal a data ciphertext included in a system ciphertext which has been found as a hit in the search.

Data search device, data search method, computer readable medium storing data search program, data registration device, data registration method, computer readable medium storing data registration program, and information processing device

An encrypted data receiving unit () receives encrypted data which has been encrypted, in which a decryption condition to define a user attribute of a decryption-permission user who is permitted to decrypt the encrypted data is embedded. A data storage unit () stores the encrypted data received by the encrypted data receiving unit () in an encrypted state. A revocation processing unit () adds revocation information in which a user attribute of a revoked user who is no longer the decryption-permission user is indicated, to an embedded decryption condition that is embedded in the encrypted data, while the encrypted data remains in an encrypted state.

Data storage apparatus, data processing method, and computer readable medium adding a user attribute of a revoked user to an embedded decryption condition while encrypted data remains in an encrypted state

In a server apparatus, a data storage part stores a plurality of pieces of encrypted data. An index storage part stores, as an index I, a data structure which is for performing search with using a function H that outputs a unique numeric value in response to an inputted keyword, the data structure having a plurality of storage areas corresponding, in one-to-one relation, to numeric values outputted from the function H, and storing, for a plurality of keywords corresponding to plaintext data, an identifier of encrypted data being post-encryption data of the plaintext data to which each keyword corresponds, in a storage area corresponding to the numeric value outputted from the function H when each keyword is inputted. A search part inputs one of the plurality of keywords to the function H, identifies a storage area corresponding to the numeric value outputted from the function H, from the index I, and acquires encrypted data corresponding to the identifier stored in the identified storage area, from the data storage part.

Server apparatus, search system, terminal apparatus, search method, non-transitory computer readable medium storing server program, and non-transitory computer readable medium storing terminal program

An object is to enable to search genetic information in an encrypted state. An encryption apparatus () encrypts a target gene which is genetic information to be stored in a storage apparatus and generates an encrypted gene, as well compares a reference gene which is predefined genetic information with the target gene to generate differential information, and generates an encrypted tag which is encrypted by embedding the generated differential information. A data center () stores the encrypted gene with related to the encrypted tag in the storage apparatus. A search apparatus () generates a search query which is encrypted by embedding the differential information as a search keyword, and sends the generated search query to a data center (). The data center () specifies the encrypted tag including the differential information specified in the search query, extracts the related encrypted gene, and sends the encrypted gene to the search apparatus ().

Genetic information storage apparatus, genetic information search apparatus, genetic information storage program, genetic information search program, genetic information storage method, genetic information search method, and genetic information search system

A server devicecomprises a communication part, a search history storage region, a data storage part, and a checking part. The communication part receives a set of a trapdoor and a deterministic encrypted keyword from a search device. The search history storage regionstores the set of the trapdoor and the deterministic encrypted keyword. The data storage partstores keyword information in which search target data and an encrypted keyword are associated with each other. If the deterministic encrypted keyword is obvious, a deterministic encrypted keyword corresponding to the encrypted keyword is additionally associated with the search target data and the encrypted keyword in the keyword information. The checking partchecks whether or not a deterministic encrypted keyword which matches the received deterministic encrypted keyword exists in the search history storage region. If the deterministic encrypted keyword exists, the checking partexecutes a concealed search targeting the data storage part, based on a deterministic encryption scheme using the deterministic encrypted keyword existing in the search history storage region. If the deterministic encrypted keyword does not exist, the checking partexecutes the concealed search targeting the data storage part, based on a probabilistic encryption scheme using the received trapdoor and the encrypted keyword stored in the data storage part

Server device, recording medium, and concealed search system

Methods and systems for transmitting user aggregate data to a third party, such that a privacy of the aggregated data is protected, while analytical usefulness of the aggregated data is preserved. The method including receiving, using a transceiver, aggregated data including time-series data collected over a period of time. Selecting, from a memory, a mapping for transforming a segment of the aggregated data of a predetermined size. Partitioning the aggregated data into a multiple data segments, each data segment is of the predetermined size. Transforming each data segment using the mapping to produce multiple transformed data segments, wherein each data segment is transformed by the mapping independently from other data segments. Finally, transmitting, using the transceiver, the multiple transformed data segments to a third party over a communication channel, wherein steps of the method are performed by a processor operatively connected with the memory and the transceiver.

Method and systems using privacy-preserving analytics for aggregate data

A data storage unit () stores encrypted data while remaining in an encrypted state, and stores decryption conditions to define a user attribute of a decryption-permission user who is permitted to decrypt the encrypted data. In a case wherein revocation information to indicate a user attribute of a revoked user who is no longer the decryption-permission user has been added to the decryption condition when update timing arrives, a revocation information removing unit () removes the revocation information from the decryption condition while the encrypted data remains in the encrypted state. Further, the revocation information removing unit () transmits the encrypted data and the decryption conditions from which the revocation information has been removed to a re-encryption apparatus that performs re-encryption in a proxy re-encryption scheme, and receives, from the re-encryption apparatus, the encrypted data that has be re-encrypted in the proxy re-encryption scheme using the decryption condition from which the revocation information has been removed. A refresh processing unit () updates the encrypted data that has been re-encrypted and the decryption condition from which the revocation information has been removed.

Data storage apparatus, data updating system, data processing method, and computer readable medium

A data generation devicetransmits communication data bound for a data receiving devicefrom a transmission unit, and a monitoring devicereceives the communication data. The monitoring devicerequests retransmission of the communication data to the data generation device, and the data generation deviceretransmits the communication data from a retransmission unit being different from the transmission unit. The monitoring devicereceives retransmission data retransmitted from the retransmission unit, compares the communication data with the retransmission data. If the communication data and the retransmission data are identical, the monitoring devicetransmits the communication data to the data receiving device. If the communication data and the retransmission data are not identical, the monitoring devicetransmits a message which notifies that the communication data and the retransmission data are not identical to the data generation device

Retransmission data processing device, retransmission data communication device, retransmission data communication system, retransmission data processing method, retransmission data communication method, and non-transitory computer readable medium for detecting abnormality by comparing retransmission data to transmission data

A searchable encryption resistant to frequency analysis. A conversion rule management device generates a conversion rule table associating a search keyword with a conversion keyword group. Based on the conversion rule table, a data registration device generates registration data associating encrypted data with an encrypted keyword, and registers the registration data in a server device. An information processing device obtains from the conversion rule table a conversion keyword group associated with a specified search keyword, generates an encrypted keyword group, and requests a data search by specifying the encrypted keyword group. Using as a search key an encrypted keyword included in the encrypted keyword group, the server device searches for encrypted data associated with the search key, and returns searched encrypted data. The information processing device decrypts the searched encrypted data, and outputs as a search result search data obtained by decryption.

Search system, search method of search system, and information processing device

Data search device, data search method, data search program, data registration device, data registration method, data registration program, and information processing device

In a wildcard-applicable anonymous hierarchical identity-based encryption system, it is aimed to make the number of pairing operations a fixed number. A user identifier ID and a pattern P are used. The user identifier ID includes k number of hierarchy identifiers. The pattern P includes either of a hierarchy identifier, a wildcard value and a blank value for each hierarchy. An encryption deviceextracts a key value H corresponding to a hierarchy of the wildcard value and a key value H corresponding to a hierarchy of a pattern value from a public key PK, calculates a cipher value Cand a cipher value C, and outputs ciphertext data CT including plaintext cipher value C, the cipher value C, and the cipher value C. A decryption deviceextracts the hierarchy identifier of the hierarchy corresponding to the wildcard value from the user identifier ID, decrypts the plaintext cipher value Cincluded in the ciphertext data CT using the extracted hierarchy identifier, the cipher value Cand the cipher value Cwhich are included in the ciphertext data CT, and outputs plaintext data M.

Encryption system, encryption processing method of encryption system, encryption device, decryption device, setup device, key generation device, and key delegation device using a user identifier for a user who belongs to a k-th hierarchy in an organization

An invalidation scheme of a secret key is implemented, which is usable for a functional encryption scheme. In a cryptographic processing systememploying an encryption scheme with which if attribute information and key information set in encrypted data do not correspond to attribute information and key information set in a secret key, the encrypted data cannot be decrypted using the secret key, an encrypted data management deviceis provided, which carries out a relay between a user terminalcarrying out encryption and decryption of data and an encrypted data storage devicestoring encrypted data. The encrypted data management devicedetermines whether or not a user whose secret key is invalid is included in users having attribute information set in the encrypted data acquired from the encrypted data storage device, and sets a different value as key information in the encrypted data based on the determination result. Then, the encrypted data management devicesends the encrypted data in which the key information is set to the user terminal

Encrypted data management device, encrypted data management method, and encrypted data management program

A public parameter PK is key information used in a secret search system having: a transmission device generating and sending an encryption tag which is an encrypted keyword; a server receiving and storing the encryption tag and conducting a secret search in response to a request for the secret search; and a reception device generating a trapdoor which corresponds to a digital signature of the keyword and as well data requesting the secret search, sending the trapdoor to the server, and receiving a search result. The public parameter PK includes a true public parameter PP and a protection key PK'. The transmission device and the reception device require both the true public parameter PP and the protection key PK&#x2032;; however, the server does not require the protection key PK&#x2032;. The key generation device generates separately the true public parameter PP and the protection key PK&#x2032; included in the public parameter PK.

Key generation device, key generation program, secret search system, and key distribution method

An access terminal apparatus provides a group determination key being a decryption key to a data center apparatus previously, and then transmits grouping information generated from a keyword of storage target data and having been encrypted to the data center apparatus, with encrypted data of the storage target data and tag data of the encrypted data of the storage target data. The data center apparatus stores the encrypted data relating it to the tag data, decrypts a part of the grouping information with the group determination key, derives an index value from a bit value obtained by the decryption, and stores the derived index value and the tag data relating them with each other.

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Tokyo, Japan

Nori Matsuda