Abstract: A blockchain based data management method performed by a computing device according to an embodiment of the present disclosure includes recording a deletion event for off-chain data and time information of the deletion event in a blockchain network, and selectively deleting the off-chain data based on a validity verification result calculated for the time information, wherein the validity verification result is calculated using a time-consensus algorithm of the blockchain network.

Abstract: A blockchain data recording method includes determining a recording type as one of an on-chain type and an off-chain type according to a target data to be recorded in a blockchain, transmitting a first transaction proposal for recording the target data in a blockchain node configured to store an on-chain data on a blockchain to the blockchain node when the recording type is an on-chain type, and recording the target data in a storage node provided to store an off-chain data, and transmitting a second transaction proposal for storing recording information of the target data in the blockchain to the blockchain node when the recording type is an off-chain type.

Abstract: A blockchain based data management method performed by a computing device according to an embodiment of the present disclosure includes recording a deletion event for off-chain data and time information of the deletion event in a blockchain network, and selectively deleting the off-chain data based on a validity verification result calculated for the time information, wherein the validity verification result is calculated using a time-consensus algorithm of the blockchain network.

Abstract: An off-chain data sharing system according to an embodiment of the present invention includes a first storage node to store off-chain data, a blockchain node to store a ledger that records permission information of the off-chain data, and a data stream hub to relay data transmission and reception between the first storage node and a second storage node requesting the off-chain data by referring to the permission information.

Abstract: A blockchain data recording method includes determining a recording type as one of an on-chain type and an off-chain type according to a target data to be recorded in a blockchain, transmitting a first transaction proposal for recording the target data in a blockchain node configured to store an on-chain data on a blockchain to the blockchain node when the recording type is an on-chain type, and recording the target data in a storage node provided to store an off-chain data, and transmitting a second transaction proposal for storing recording information of the target data in the blockchain to the blockchain node when the recording type is an off-chain type.

Abstract: A file transmission method includes storing each chunk of a target file by public cloud, receiving, by the first node, a file transmission request including an encrypted chunk order sheet of the target file, information on the target file and recipient information, wherein the chunk order sheet includes connection order information of each chunk necessary for restoring the target file, and the encrypted chunk order sheet is encrypted with a public key of a recipient, storing a first transaction including information included in the file transmission request and chunk storage location information in a ledger stored in the first node, storing, by the second node, the first transaction in a ledger of the second node according to synchronization of the ledger, storing a chunk in the internal storage using the chunk storage location information when the recipient information included in the first transaction includes a user belonging to the intranet.

Abstract: A file transmission method includes storing each chunk of a target file by public cloud, receiving, by the first node, a file transmission request including an encrypted chunk order sheet of the target file, information on the target file and recipient information, wherein the chunk order sheet includes connection order information of each chunk necessary for restoring the target file, and the encrypted chunk order sheet is encrypted with a public key of a recipient, storing a first transaction including information included in the file transmission request and chunk storage location information in a ledger stored in the first node, storing, by the second node, the first transaction in a ledger of the second node according to synchronization of the ledger, storing a chunk in the internal storage using the chunk storage location information when the recipient information included in the first transaction includes a user belonging to the intranet.

Abstract: A system for supporting reflection of transactions between blockchain networks. includes a first bridge node which receives transaction data as to a first transaction within a source blockchain network, generates a transaction reflection message based on the received transaction data, and sends the generated transaction reflection message to a second bridge node related to a target blockchain network, and the second bridge node which generates a second transaction corresponding to the first transaction based on the generated transaction reflection message and processes the generated second transaction within the target blockchain network.