Nippon Telegraph and Telephone Corporation

Ntt Innovation Institute, Inc.

Hitoshi Fuji

Tetsutaro Kobayashi

Reo Yoshida

Yuto Kawahara

Kazuki Yoneyama

Tomohide Yamamoto

Dai Ikarashi

Go Yamamoto

Akira Nagai

Koki Hamada

Ryo Kikuchi

Koji Chida

Makoto Iwamura

Masaki Hamada

Naoto Kiribuchi

Gen Takahashi

Hiroyoshi Takiguchi

Gembu Morohashi

Tomoaki Washio

Satoshi Tanaka

Asami Miyajima

Tsuyoshi Miyamoto

Teruko Miyata

Shigeru Kayaguchi

Eric Yi-hua Chen

Junya Akiba

A key exchange technique of performing a key exchange among N (≥2) parties, which can conceal metadata on communication, is provided. A key exchange method includes: a first key generation step in which a communication device Ugenerates a first key; a first anonymous broadcast step in which the communication device Uanonymously broadcasts the first key with a set R-{U} being designated for i∈{1, . . . , n} and the communication device Uanonymously broadcasts the first key with φ being designated for i∈{n+1, . . . , N}; a second key generation step in which the communication device Ugenerates a second key; a second anonymous broadcast step in which the communication device Uanonymously broadcasts the second key with the set R-{U} being designated for i∈{1, . . . , n} and the communication device Uanonymously broadcasts the second key with φ being designated for i∈{n+1, . . . , N}; and a session key generation step in which the communication device Ugenerates a session key SK for i∈{1, . . . , n} if a predetermined condition is satisfied.

Anonymous broadcast method, key exchange method, anonymous broadcast system, key exchange system, communication device, and program

A key exchange technique of performing a key exchange among N (≥2) parties, which can conceal metadata on communication, is provided. A key exchange method includes: a first key generation step in which a communication device Ugenerates a first key; a first anonymous broadcast step in which the communication device Uanonymously broadcasts the first key with a set R−{U} being designated for i∈{1, . . . , n} and the communication device Uanonymously broadcasts the first key with φ being designated for i∈{n+1, . . . , N}; a second key generation step in which the communication device Ugenerates a second key; a second anonymous broadcast step in which the communication device Uanonymously broadcasts the second key with the set R−{U} being designated for i∈{1, . . . , n} and the communication device Uanonymously broadcasts the second key with φ being designated for i∈{n+1, . . . , N}; and a session key generation step in which the communication device Ugenerates a session key SK for i∈{1, . . . , n} if a predetermined condition is satisfied.

Provided is a technique for performing statistical processing such as processing for obtaining parameters of logistic regression analysis faster than before. A secure statistical processing system includes a cross tabulation table computing devicethat performs secure computation on a cross tabulation table in which frequencies are in plain texts while keeping each record concealed; and a statistical processing devicethat performs predetermined statistical processing using the cross tabulation table in which frequencies are in plain texts. The cross tabulation table computing devicemay include a plurality of secure computation devicesN that perform secure computation on a cross tabulation table in which frequencies are fragments subjected to secret sharing while keeping each record concealed, and a management devicethat restores the fragments to compute the cross tabulation table in which frequencies are in plain texts.

Secret statistical processing systems, methods, statistical processing apparatus and program

Plurality of users share a common key while permitting change of members sharing the common key and computational complexity required for key exchange is reduced. Rand care computed based on a twisted pseudo-random function in a first key generation step. sid is generated based on a target-collision resistant hash function and (sid, R, R) is transmitted to communication devices Uin a session ID generation step. Tand T' are computed based on a pseudo-random function in a representative second key generation step. Tis computed based on the pseudo-random function in a general second key generation step. k&#x2032; is computed based on the twisted pseudo-random function and T&#x2032;is computed with respect to each j in a third key generation step. Kand kare computed in a first session key generation step. A common key Kis generated based on the pseudo-random function in a second session key generation step.

Key exchange method and key exchange system

To provide a terminal device that can share a session key for use in encryption communication with multiple terminal devices at a certain timing without relying on an existing server device. The terminal device includes: a list/request sending unit that, when the terminal device operates as an owner device, generates a key distribution request, signs the key distribution request, and transmits the key distribution request to a key distribution management device; a participation request sending unit that, when the terminal device operates as a general device, generates a participation request, signs the participation request, and transmits the participation request to the key distribution management device; a session key generating unit that executes an authentication-based multipoint key distribution algorithm of server-client type in cooperation with another terminal device participating in the session and with the key distribution management device to generate a session key; and a post-confirmation unit that, when the session key has been normally generated, transmits a success notice to the key distribution management device and receives a collective notice from the key distribution management device.

Terminal device, key distribution management device, server-client system, communication method, and programs

A communication device includes a signature encryption unit that encrypts input information with a secret key and transmits the information to a server device if the communication device belongs to a group, and a signature decryption unit that downloads, from the server device, encrypted n&#x2212;1 pieces of the input information transmitted from other communication devices and decrypts the encrypted n&#x2212;1 pieces of input information with the secret key if the communication device belongs to a group. The communication device transmits session key generation information to the server device via the signature encryption unit, generates a session key using n&#x2212;1 pieces of session key generation information acquired via the signature decryption unit and session key generation information of the communication device, transmits a cipher text encrypted with the session key via the signature encryption unit to the server device, and decrypts n&#x2212;1 cipher texts acquired via the signature decryption unit with the session key.

Communication device, server device, concealed communication system, methods for the same, and program

A key distribution system includes a representative user terminal, a server apparatus, and an (n+1)-th user terminal. The representative user terminaluses a public key for the (n+1)-th user terminaland information for identifying the (n+1)-th user terminalto encrypt key information with a predetermined encryption function in Certificate-less Encryption to obtain ciphertext. The server apparatussends the ciphertext to the (n+1)-th user terminalwhen the (n+1)-th user terminalis added. The (n+1)-th user terminaluses a complete secret key for the (n+1)-th user terminaland the information for identifying the (n+1)-th user terminalto decrypt the ciphertext with a predetermined decryption function to obtain the key information.

Key distribution system and method, key generation apparatus, representative user terminal, server apparatus, user terminal, and program

A client apparatus converts second input authentication information having a data content compliant with a second authentication method different from a first authentication method into authentication target information in a data format compliant with the first authentication method and transmits information corresponding to the authentication target information to a communication server apparatus. A server apparatus is capable of carrying out both a first process of providing a first authentication server apparatus that carries out an authentication process compliant with the first authentication method with first information corresponding to the authentication target information and a second process of providing a second authentication server apparatus that carries out an authentication process compliant with the second authentication method with second information corresponding to the authentication target information. The server apparatus transmits authentication result information based on at least one of a result of the authentication performed by the first authentication server apparatus based on the first information and a result of the authentication performed by the second authentication server apparatus based on the second information to the communication server apparatus.

Authentication control system, server apparatus, client apparatus, authentication control method, authentication method, and program

A server sends a key update request for requesting updating of the key, to a client terminal. The client terminal sends, to a key delivery server, a key delivery request for requesting the delivery of a key to the client terminal. The key delivery server delivers a key to the client terminal. The client terminal sends, to the server, a key reception notice indicating that the delivered key was received. The server sends, to the client terminal, a key-use start notice indicating that the client terminal starts data transmission and reception by using the delivered key with a different client terminal from the aforementioned client terminal. The client terminal performs data transmission and reception with the different client terminal by using the delivered key.

Data transmission and reception method and system

Plurality of users share a common key while permitting dynamic member change and computational complexity required for key exchange is reduced. The first key generation unitof the communication devices Ucomputes Rand c, or cbased on a twisted pseudo-random function. A session ID generation unitof a key distribution device S generates sid based on a target-collision resistant hash function and transmits sid to the communication devices U. A second key generation unitof the communication devices Ucomputes Tbased on a pseudo-random function. A third key generation unitof the key distribution device S computes k' and T&#x2032;based on the twisted pseudo-random function. A session key generation unitof the communication devices Ugenerates the common key Kbased on a pseudo-random function.

Key exchange method, key exchange system, communication device and storage medium therefore

A leakage prevention apparatus stores an assumed use permission range, stores an information asset caused to be in an unavailable state by encryption, stores an information asset caused to be in an available state by decryption, and stores an information asset caused to be in a leakage-concerned state. When use of an information asset in the unavailable state is requested by an application corresponding to the use permission range, the information asset is decrypted to cause the information asset to be in the available state. When the use of the information asset in the available state by the application ends, the information asset is encrypted to cause the information asset to be in the unavailable state. When use of an information asset in the unavailable state is requested by an application not corresponding to the use permission range, the information asset is caused to be in the leakage-concerned state.

Leakage prevention apparatus, leakage prevention method and program

Plurality of users share a common key while permitting dynamic member change and computational complexity required for key exchange is reduced. The first key generation unit computes Rand cbased on a twisted pseudo-random function. A session ID generation unit generates sid based on a target-collision resistant hash function and transmits (sid, R, R) to communication devices U. A second key generation unit of a representative communication device Ucomputes Tbased on a pseudo-random function. A second key generation unit of general communication devices Ucomputes Tbased on the pseudo-random function. A third key generation unit computes k' based on the twisted pseudo-random function and computes T&#x2032;with respect to each j. A session key generation unit of the general communication devices Ucomputes Kand k. The session key generation unit generates a common key Kbased on the pseudo-random function.

Key exchange method, key exchange system, key distribution device, communication device, and program

At the time of setting authority, a management apparatus stores a database in which authority information corresponding to authority to physically drive a drive apparatus, which is a tangible object, using a terminal apparatus, and registration identification information corresponding to a subject that is given the authority are associated, and outputs information representing any of the registration identification information; and a permission apparatus receives and stores the information. At the time of exercising the authority, the terminal apparatus outputs information representing identification information, and the permission apparatus receives the information and, when the identification information corresponds to registration identification information comprised in setting information, outputs information representing authority exercise information required to exercise the authority. The terminal apparatus receives the information representing the authority exercise information and outputs a drive signal corresponding to the authority exercise information. By this drive signal, a drive apparatus, which is a tangible object, is physically driven.

Security system, management apparatus, permission apparatus, terminal apparatus, security method and program

Data processing is performed while personal information is kept concealed. A registrant terminal splits a registration input password and allocates the split pieces to secure computation servers. The secure computation servers verify whether the password matches. The registrant terminal splits target data and allocates the data shared values to the secure computation servers. The secure computation servers store the data shared values. A user terminal splits a utilization input password and allocates the split pieces to the secure computation servers. The secure computation servers verify whether the password matches. The user terminal sends a data processing request to the secure computation servers. The secure computation servers execute secure computation of the data shared values to generate processing result shared values. The user terminal recovers the processing result from the processing result shared values.

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Musashino, Japan

Hitoshi Fuji