Nippon Telegraph and Telephone Corporation

Koha Kinjo

Tetsuya Okuda

Yuki Okano

Ryo Kikuchi

Ryohei Suzuki

Tsunekazu Saito

A signature verification system includes a signature generation server, a signature verification server, and a verification key management server that are connected to one another via a communication network. The signature generation server includes: reporting means for, when a signing key and a verification key are generated by a publisher, reporting the verification key and publisher identification information that identifies the publisher to the verification key management server; and signature generation means for signing a bid request issued by the publisher with use of the signing key. The verification key management server includes: registration means for registering the publisher identification information and the verification key that were reported by the reporting means in a storage unit in association with information that enables specifying a version of the verification key.

Signature verification system, verification key management apparatus, verification key management method and program

A service providing system providing services to a plurality of users includes a transmitting unit configured to transmit, to a user terminal of each user, an authentication request requesting authentication for executing a predetermined process, a receiving unit configured to receive, from the user terminal of each user, an authentication response affixed with a user signature, and an executing unit configured to execute the predetermined process with respect to each user upon successful signature verification for all the plurality of users.

Service providing system, service providing device, service providing method, and service providing program

In a voting system including a vote broadcasting server and a plurality of client terminals, the vote broadcasting server generates a plurality of pieces of vote information that is data in which secret information is shared and transmits the vote information to each client terminal, each client terminal generates voting information by encrypting vote information such that the vote information can be decrypted when predetermined conditions are satisfied and transmits the voting information to the vote broadcasting server, the vote broadcasting server transmits a voting information group composed of voting information received from respective client terminals to the respective client terminals, and each client terminal ascertains a vote result according to the number of pieces of vote information decrypted from the voting information group and executes processing based on the vote result.

Voting system, vote relay server, client terminal, voting method, advertisement distribution system, and program

A communication system includes a transmitting device configured to transmit information, and a receiving device configured to receive the information, the receiving device includes a determination unit configured to determine whether or not an electronic certificate of the transmitting device used for a communication with the transmitting device is an EV certificate, and a process that is performed is varied according to a determination result of the determination unit.

Communication system, communication apparatus, communication method, program and advertisement communication system

In Round1, each terminal device transmits a key encryption key which conforms to post-quantum cryptography to a neighboring terminal device; in Round2, each terminal device generates a key capsule of a key-shared-between-two-parties using the received key encryption key and returns the key capsule to a terminal device which is a source of the key encryption key; in Round3, each terminal device generates information based on the key-shared-between-two-parties and transmits the information to a key distribution management device and the key distribution management device distributes information, which is obtained based on these pieces of information, to the terminal devices. Each terminal device calculates a shared key based on the distributed information.

Quantum-proof multiparty key exchange system, quantum-proof multiparty terminal device, quantum-proof multiparty key exchange method, program, and recording medium

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Tokyo, Japan

Koha Kinjo