Mitsubishi Electric Corporation

Mitsubishi Electric Research Laboratories, Inc.

The University of Electro-communications

Mitsuhiro Hattori

Nori Matsuda

Takashi Ito

Takato Hirano

Takumi Mori

Takeshi Yoneda

Yoichi Shibata

Rina Shimizu

Yusuke Sakai

Yutaka Kawai

Katsuyuki Takashima

Ye Wang

Yoshihiro Koseki

Sachihiro Ichikawa

Tsutomu Sakagami

Kazuo Ota

A random-number generation unit generates a plurality of random numbers from a plurality of seeds. A data scrambling unit conceals concealment target data which is a concealment target by using the plurality of random numbers generated by the random-number generation unit. A transmission unit transmits concealed data which is the concealment target data concealed by the data scrambling unit to a data analysis device, and transmits any seed among the plurality of seeds to the data analysis device, after transmission of the concealed data to the data analysis device.

Concealment device, data analysis device, and computer readable medium

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

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

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 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

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.

Data processing apparatus and data storage apparatus

A certification deviceencrypts a feature vector for registration by using a random number and a public key which is set to correspond to a secret key in a decryption device. The encrypted feature vector for registration is registered in an authentication device. In authentication, the certification device encrypts a feature vector for authentication by using the public key and a random number. With the two encrypted feature vectors being kept encrypted, the authentication device generates encrypted similarity degree information from which the decryption device can derive the similarity degree between the two feature vectors by a decryption process using the secret key. The decryption devicedecrypts the encrypted similarity degree information to derive the similarity degree of the plaintext. The authentication device, if the similarity degree is equal to or larger than a threshold, determines that the user is the correct user. The similarity degree can be derived without using the feature vector of the plaintext. Thus, secure identity authentication with a lower possibility of plaintext theft can be realized.

Data processing device

A confidential search that can flexibly control searchable data depending on a role or authority of a user when the data is shared in a group. When the inner product of an attribute vector and a predicate vector is a predetermined value, the confidential search system conducts pairing computation of decrypted data generated based on the attribute vector and a decryption key generated based on the predicate vector, so as to realize confidential search by utilizing an inner-product predicate encryption process that can decrypt the encrypted data. In particular, the confidential search system enables flexible control of searchable data depending on the role or authority of the user, by devising a method of generating the attribute vector and the predicate vector.

Confidential search system and cryptographic processing system

Secret key backup is safely implemented even if a role base access structure in which the access structure is specified using roles is used. An all combination generating unitobtains a backup participating user listwhich is a list of backup participating users and a list of validated roles validated by the users, and a role base access structurewhich is a combination of specified roles by which a secret keycan be restored, and generates an all combination extracted result which is all combinations of restoration enabling users of the secret key by applying users described in the backup participating user listto the specified role. A same user/role deleting unit, etc. deletes a combination showing the same user redundantly, etc. from the all combination extracted result, a general access structure secret distributing unitgenerates fragments of secret key from the secret key, and distributes the fragments of secret key to the combinations of users from which the redundancy is removed.

Secret information management apparatus, information processing apparatus, and secret information management system

A tamper resistant apparatusis mounted inside of a PCand stores confidential information A through C. The tamper resistant apparatusreceives data from an applicationwhich operates on the PC, processes the data using the confidential information A through C, and returns processed data to the application. To the tamper resistant apparatus, plural external sensorsprovided to the PCare connected. The plural external sensorsdetect opening/closing of a case of the PCor movement of the body of the PCand send a detection signal to the tamper resistant apparatus. On inputting the detection signal from the plural external sensors, the tamper resistant apparatusselects and erases confidential information to be erased from the confidential information A through C according to the tamper resistant policy stored previously.

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Tokyo, Japan

Mitsuhiro Hattori