A computer-implemented method of partitioning a blockchain network into shards is disclosed. The method comprises the steps of identifying a transaction id of a blockchain transaction and allocating the transaction to a shard based on the transaction id.

A computer-implemented method and system is provided that maintains blocks of a blockchain across nodes of a sharded blockchain network, wherein each node is a member of one or more shards of a plurality of active shards. The method and system employ a given node that is a member of a particular subset of the plurality of active shards to generate data representing a new block of the blockchain and store the data representing the new block. Such data includes i) a list of transaction identifiers for transactions that are part of the new block and associated with the particular subset of the plurality of active shards, and/or ii) a Partial Merkle Tree for the new block.

A computer-implemented method of validating a blockchain transaction is disclosed. The method comprises requesting at least one UTXO referenced by at least one respective input of the transaction from a member node of at least one shard comprising at least one UTXO, obtaining validity data of at least one UTXO from at least one node, and performing a validation check on at least one input using the validity data.

A computer-implemented method for validating a blockchain transaction is disclosed. The method comprises identifying at least one shard comprising at least one UTXO referenced by at least one respective input of the transaction, transmitting the transaction to at least one member node of at least one shard, and performing a validation check on at least one input using validity data of the UTXO.

A computer-implemented method of partitioning a blockchain network into shards is disclosed. The method comprises identifying a parent blockchain transaction, the parent transaction defined by an output which corresponds to an input of a child blockchain transaction, and allocating the parent transaction and the child transaction to the same shard.

A node group management device includes a communication interface managing a first group, to which some nodes belong among nodes that constitute a blockchain network sharing a distributed database, a memory that stores information related to a node of the first group (including a public key of each node of the first group), and a processor connected to the memory. All nodes participating in the blockchain network each include a private key and a public key. The processor operates according to instructions stored in the memory and generates a group private key allowing a transaction to be additionally signed based on said information while the transaction is signed with the private key when the node of the first group generates the transaction and configured to distribute the group private key to the first group so that the nodes of the first group hold the group private key in common.

Disclosed are a payment service apparatus for providing product information to an offline merchant on the basis of location information and supporting payment processing based on a virtual currency and an operating method thereof. The present invention selects offline merchants positioned within a predetermined distance based on current location information of a user terminal and then selects a merchant that transmits a beacon signal having a maximum strength among beacon signals transmitted by beacons provided in the selected merchants and transmits product information for products being sold in the merchant to the user terminal, and when the information on the virtual currency amount of the one predetermined product together with a payment request for one predetermined product from the user terminal are received, completes transfer processing from an electronic wallet account of a user to the electronic wallet account of the merchant for a virtual currency amount of one predetermined product to support the user to easily purchase the product in the offline merchant.

An escrow non-face-to-face cryptocurrency transaction device and method using a phone number is proposed. The device and method includes: providing a phone number wallet that uses a phone number of a user as a login ID; using the phone number wallet having an electronic wallet address of a phone number system so as to remit and deposit cryptocurrency stored in the phone number wallet in an escrow virtual wallet of an escrow virtual wallet address generated for a one-time use in a one-time escrow virtual wallet; transmitting, to a remitter, escrow authentication information that enables a secure connection to the escrow virtual wallet and enables withdrawal authentication; and remitting the cryptocurrency deposited in the escrow virtual wallet address to an electronic wallet address of a recipient who inputs the escrow authentication information directly received from the remitter, so as to withdraw the cryptocurrency.

A computer-implemented method comprises: committing a transaction amount t of a transaction with a commitment scheme to obtain a transaction commitment value T, the commitment scheme comprising at least a transaction blinding factor r_t; encrypting a combination of the transaction blinding factor r_t and the transaction amount t with a second public key PK_2_B of a recipient of the transaction, wherein: the recipient is further associated with a first public key PK_1_B as an address for receiving the transaction amount t; and transmitting the transaction commitment value T and the encrypted combination to a recipient node associated with the recipient for the recipient node to verify the transaction.

Method for managing payment transactions associated with a task completion includes receiving a service assignment and a digital coin value associated with the service assignment over a network from a first computing device associated with a first user, and sending the service assignment over the network for display on a second computing device associated with a second user. The method also includes receiving notification from the second user that the assigned service has been completed, and transferring digital coins equal to the digital coin value of the service assignment from a first digital wallet associated with the first user to a second digital wallet associated with the second user. The method further includes recording the transfer of the one or more digital coins in the digital coin ledger, and applying the one or more digital coins in the second digital wallet to acquire a purchase item.