Nippon Telegraph and Telephone Corporation

Yokogawa Electric Corporation

Nippon Telegraph and Telephone Corporatioin

Shigeru Fujimura

Atsushi Nakadaira

Hiroki Watanabe

Shigenori Ohashi

Tatsuro Ishida

Junichi Kishigami

Akihito Akutsu

Yasuhiko Miyazaki

Masayoshi Chikada

Kota Hidaka

Tomokazu Yamada

Satoshi Sakuma

Koutarou Suzuki

Kimikazu Takahashi

Tsunekazu Saito

Haruko Mitake

HIroki Watanabe

An identifier change management apparatus according to an embodiment includes: a distributed ledger in which an identifier change program holding a public key and a first hash value; an identifier change key input unit that receives a secret key; a hash chain management unit that holds a seed value of a hash value used in the identifier change; a transaction issuing unit that issues an identifier change transaction including a signature value of an electronic signature that has been performed using the secret key and a second hash value generated using the seed value; and a program control management unit that changes the identifier, by the identifier change program, on condition that the signature value included in the identifier change transaction is verifiable by using the public key and a value obtained by applying a hash function to the second hash value becomes the first hash value.

Identifier change management apparatus, identifier change management method, and identifier change management program

A blockchain is used to distribute a right to content data. A right holder terminal, an assignee terminal, and a blockchain control terminal stores a blockchain that is synchronized among the right holder terminal, the assignee terminal, and the blockchain control terminal. The blockchain includes a transaction set with a smart contract program for distributing the right. The blockchain control terminal includes a token issuance unit generating token data that includes match information for the content data and a type of right to be distributed, is set with an address of a right holder as owner information, and is identified by a token identifier, and registering the token data corresponding to the token identifier with the blockchain.

Content contract system, content contract method, and control terminal

An identifier change management apparatus according to one embodiment includes: a key management unit configured to manage a group of private keys including a first private key; a message input unit configured to receive a message; a transaction issuing unit configured to issue an identifier change transaction including a hash value of the message and a first signature value generated from the first private key; a distributed ledger in which an identifier change program is registered, the identifier change program holding a pairing public key used when the identifier is changed and a second signature value; and a program control management unit configured to calculate a pairing signature value by the first and second signature values by the identifier change program and change the identifier on condition that the pairing signature value, the pairing public key, and the hash value satisfy an equation using a predetermined pairing function.

Upon receiving a usage request that includes a file identifier and a version identifier from a user terminal, a control servertransmits a file request that is based on the usage request to a file management system, and transmits a permission information request that is based on the usage request to a distributed ledger system. Upon receiving the file request, the file management system acquires the file that corresponds to the combination of the file identifier and the version identifier and transmits the file to the control server. Upon receiving the permission information request, the distributed ledger system acquires permission information that corresponds to the combination of the file identifier and the version identifier from a distributed ledger, and transmits the permission information to the control server. The control servertransmits the file to the user terminalif the user of the user terminal has viewing permission based on the permission information.

Control server for sharing data using distributed ledger, data sharing system with distributed ledger, and control program for sharing data with distributed ledger

Content data is registered in a file management system, an identifier of a user in the file management system is registered in blockchain data, and a right-holder terminal includes a permission request receiving unit that receives, from the file management system, permission request data for the content including an identifier of the user, a verification unit that verifies that the identifier of the user registered in the blockchain data corresponds to the identifier of the user included in the permission request data, and an permission issuing unit that transmits, to the file management system, permission data for permitting a use of the content by the user.

Right-holder terminal, user terminal, and content usage method

Pieces of information on multiple file management systems are managed by one contract in a distributed ledger. An administrator terminal includes: a file management system generation unit that issues a contract generation transaction for generating, in blockchain data, a contract in which a network identifier that identifies a file management system is associated with an identifier of a participant terminal in a blockchain system, and notifying the participant terminal of the network identifier and an identifier of the contract; and a file management control unit that issues a registration transaction for registering, in the contract, connection information of the administrator terminal in the file management system, acquires connection information of the participant terminal in the file management system from the contract, and establishes a P2P connection with the participant terminal based on the acquired connection information.

Right holder terminal, user terminal, and non-transitory computer-readable medium

A history of data can be easily traced on a blockchain. A blockchain system includes a user terminaland an approval terminal. The user terminalincludes a transaction issuing unitthat issues a transaction for updating a value of a variable of a smart contract. The approval terminalincludes a block generation unitthat generates a block including the transaction and updates the value of the variable, and reflects the block and an update block number of the block in which the value of the variable is updated to a distributed ledgerof a terminal of the blockchain system.

Blockchain system, approval terminal, user terminal, history management method, and history management program

Content use system

A permission terminal generates access information for content using a content public key of the content and a user public key of a browser of the content, and registers the access information in a blockchain. The access information includes an aggregate public key generated by aggregating the content public key and the user public key, a message for the content, and a content signature obtained by signing the message with a content private key corresponding to the content public key. A browsing terminal acquires access information of requested content from a blockchain and verifies, with the aggregate public key, an aggregate signature where a user signature in which a message of the access information is signed with a user private key and the content signature of the access information are aggregated, and transmits a content request including the user signature or the aggregate signature if the verification succeeds.

Content use system, permission terminal, browsing terminal, distribution terminal, and content use program

A digital watermark is applied to a video to be distributed without re-encoding. A content distribution devicereceives a content acquisition request to request video content, distributes the video content based on the content acquisition request, generates and distributes a watermark video with a watermark ID embedded, and causes watermark-video-related information including the watermark ID to be recorded, and a content playback devicetransmits the content acquisition request, receives the video content and the watermark video, plays back and displays the video content, and superimposes the watermark video on the video content for playback and display.

Video distribution method, distribution device, and inspection device

A proprietor terminal stores state data in which an identifier of a contract executed in a blockchain system, a hash value of control target file data that specifies content data managed by the contract, and an identifier of a proprietor and an identifier of a user of the content data in the file management system are associated with one another, and includes a route object generation unit that generates reference destination data having the identifier of the contract and generates route object data having the reference destination data and a link name and the hash value of the control target file data.

Proprietor terminal, user terminal, and new proprietor terminal

When an updated file that is an updated version of an original file is registered in a distributed file management system, a difference creation unitcreates a difference file between the original file and the updated file, a route object creation unitcreates a route object that includes an ID of the original file and an ID of the difference file, and a distributed file management clientcauses the difference file and the route object to be registered in the distributed file management system

Data update device, data update method, data update program, and data structure

A user terminal generates a first key pair and a second key pair, transmits a permission request including a public encryption key of the second key pair after electronically signing the permission request with a secret encryption key, and acquires, from permission information transmitted from a right-holder terminal, a content decryption key by using a secret decryption key of the second key pair and uses the content. The right-holder terminal stores a third key pair and the content decryption key, verifies the permission request received, and encrypts the content decryption key by using the public encryption key of the second key pair included in the permission request and transmits the permission information including the encrypted content decryption key after electronically signing the permission information with a secret encryption key of the third key pair. The permission request and the permission information are transmitted and received via a blockchain.

User terminal, permission information management method, and permission information management program

A settlement system includes a service provider devicewhich transmits a template information transaction including a template of a transaction to a networkof a first blockchain, a user device which transmits, to the networkof the first blockchain, a payment information transaction that includes an electronic signature generated by using the template of the transaction and a payment amount, and a smart contract, wherein the smart contractverifies the electronic signature by using the payment amount and the template of the transaction, the service provider devicegenerates a settlement transaction by using the template of the transaction, the electronic signature and the payment amount, and transmits the settlement transaction to a networkof a second blockchain, a plurality of output conditions are set to the template of the transaction, and the settlement transaction becomes usable when any one of the plurality of output conditions is satisfied.

Settlement system, settlement method, user device, and settlement program

The present invention prevents falsification of ABI information and makes it possible for the users to safely read data on a blockchain. A registration terminalincludes an extraction unitthat extracts from a smart contract, ABI information used to access the smart contract and a transaction issuing unitthat issues a transaction including bytecode generated by compiling the smart contract and the ABI information, and an approval terminalincludes a verification unitthat verifies whether it is possible to access the bytecode included in the transaction by using the ABI information included in the transaction and a block generation unitthat, if it is possible to access the bytecode, generates a block including the transaction and makes the block and the ABI information reflected on a distributed ledgerof each terminal in the blockchain system.

Growing community of inventors

Yokosuka, Japan

Shigeru Fujimura