Nippon Telegraph and Telephone Corporation

Nippon Telegraph and Telephone Corporatioin

Hiroki Watanabe

Atsushi Nakadaira

Shigeru Fujimura

Shigenori Ohashi

Tatsuro Ishida

Junichi Kishigami

Akihito Akutsu

Yasuhiko Miyazaki

Kota Hidaka

Masayoshi Chikada

Satoshi Sakuma

Koutarou Suzuki

Masaya Taguchi

Tsunekazu Saito

Kentarou Yamada

Yuudai Hirai

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

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 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.

Blockchain system, registration terminal, approval terminal, smart contract registration method, and smart contract registration program

An objective is to manage contract data registered in a distributed ledger with part of the contract data flexibly concealed without a centralized concealment server and without bothering the user with complicated procedures or the key management. A data registration method performed by a computer includes: generating a common key for encrypting and decrypting an item included in data that is registered in a distributed ledger; acquiring a public key for each account of a user having access authority to the item; encrypting the common key with the public key for each account; and registering the common key encrypted for each account in the distributed ledger via a transaction.

Data registration method, data decryption method, data structure, computer, and program

The blockchain generation apparatusincludes: a parameter calculatorthat identifies a parameter type to be used for linkage of the new block, based on block approval method data, and calculates a value for the identified parameter type based on transaction datasets which are related to an identifier of a generating party; a block generation condition checkerthat determines whether the generating party is qualified to generate the new blockchain data, based on the value calculated by the parameter calculator; and a blockchain generatorthat tries to generate the new blockchain by referring to the shared data when the block generation condition checkerdetermines that the generating party is qualified. An identifier of the blend pattern included in the block approval method dataspecifies a combination of the plurality of parameter types that conflict with each other.

Blockchain generation apparatus, blockchain verification apparatus, and program

A key exchange system method safely conceal secret information recorded on a blockchain. A first terminal includes a license issuing unit that generates a first transaction including a first public key, a first key storage region that retains a first secret key, and a first encrypting and decrypting unit that generates a common key using deal-specific information, a second public key, and the first secret key, and a second terminal includes a license requesting unit that generates a second transaction including the second public key, a second key storage region that retains a second secret key, and a second encrypting and decrypting unit that generates the common key using deal-specific information, the first public key, and the second secret key. The first encrypting and decrypting unit encrypts secret information using the common key. The second encrypting and decrypting unit decrypts the encrypted secret information using the common key.

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Yokosuka, Japan

Hiroki Watanabe