This specification describes a system and method that enables bitcoin signed transactions to be accepted as a payment for goods and services instantly and off-line, without the need to wait for confirmation that the transaction is included in a valid block, or even for confirmation that a transaction has been received by the network. Building on the concept of a one-time signature implemented within bitcoin script, this method involves a payer providing the payee with a special compensation key at the point-of-sale which can be used to claim a time-locked deposit output when combined with a ‘revealed’ private key, if (and only if) a double-spend is perpetrated by the payee. The validity of this compensation key is guaranteed via a novel type of zero-knowledge -proof, which is highly efficient: the proof can be generated in ˜5 milliseconds and can be verified in −30 milliseconds. The use of this system in a retail setting would allow vendors to accept instant ciyptocurrency payments off-line for high value items without aggregated risk of loss, and without the need to trust a third party service.

Parking lots can provide parking services to users for fees, and the user needs to pay a corresponding amount of fees to the parking lot based on parking duration of a vehicle in a parking environment. Parking information of a vehicle in a parking environment can be detected by using an IoT device associated with the parking fee collection system; parking fee payment information of the vehicle is determined when the parking information indicates that the vehicle exits the parking environment; and when the parking fee payment information indicates that fee payment for the vehicle is uncompleted, an overdue fee record related to the vehicle is published to a blockchain network by using a first blockchain node corresponding to the parking fee collection system in the blockchain network.

A method for indexing a domain to a digital asset by a registrar server includes the steps of: (a) receiving, by the registrar server, a request for registration of a domain entity from a client of an owner or an expectant owner of a domain; and (b) requesting, by the registrar server, registration of the whole or part of the domain entity to a registry server, wherein, in step (a), the domain entity includes an address of the domain or information on a digital asset held by the owner or the expectant owner of the domain, and the information on the digital asset is cryptocurrency holding information in which trading records of digital tokens are encrypted and connected to node servers through a network having a blockchain structure. Therefore, a user of a website can easily recognize the actual asset size of an operator of the website.

A computer method and system for automated storage and retrieval of data utilizes blockchain technology to enhance security and efficiency of data storage and access. When a data object is stored in a data storage system, a corresponding storage address is written onto a blockchain. When the data object is to be retrieved, the storage address is read from the blockchain and the data object is retrieved from the storage location.

Disclosed herein is a method of facilitating transactions between users using a transaction processor, the transaction processor being configured to facilitate at least one transaction between a first and second user, the method comprising: providing a transaction user interface configured to receive currency and identification information from the users; facilitating transfer of at least one currency payment between the first and second users, wherein the at least one currency payment is based on the currency information; verifying the at least one currency payment has been transferred correctly; and indicating to the users that the transfer has been made.

Provided is a method for efficiently enabling access to a past transaction in a blockchain network. A first node 101 generates a new block from one or more transactions accumulated by using, as a memory pool, the storage unit 101C or a storage device or a storage medium accessible from the first node 101 (S201). When an adoption of the generated block is agreed upon in the blockchain network (100), the generated block is added to the blockchain at each node (S202). In an embodiment of the present invention, various consensus algorithms can be used, but it is required that the algorithm has finality. Each node generates and stores an identifier for uniquely identifying each transaction based on the height of the added block and the order within the block (S203).

A computer implemented method includes receiving, by a trusted execution environment (TEE) application, a cross-chain data request from a first blockchain node of a first blockchain; obtaining, by the TEE application, cross-chain data corresponding to the cross-chain data request from a second blockchain node of a second blockchain; verifying, by the TEE application, the cross-chain data; generating, by the TEE application, a signature using a private key of the TEE application, where a public key corresponding to the private key is stored in the first blockchain; and returning, by the TEE application, the cross-chain data and the signature to the first blockchain node.

A method of transaction between a first cryptocurrency transacted based on a first blockchain and a second cryptocurrency transacted based on a second blockchain includes obtaining first transaction information with respect to a first transaction in which a first user transmits the first cryptocurrency to a second user, and second transaction information with respect to a second transaction accompanying the first transaction and in which the first user receives the second cryptocurrency from the second user; if the first transaction information satisfies terms of agreement between the first user and the second user, adding, to the first transaction information, first condition information depending on validity of the second transaction information and activating the first transaction of the first cryptocurrency; and digitally signing the first transaction information to which the first condition information is added, to prove the terms of agreement, and transmitting the first transaction information to a node on a network of the first blockchain.

A computer-implemented method includes receiving, by a node in a blockchain network from a client node, a service initiation transaction broadcasted to the blockchain network, wherein each node of blockchain network comprises a blockchain virtual machine, an instruction set of the blockchain virtual machine comprises an XML processing instruction, and XML processing logic corresponding to the XML processing instruction is deployed in the blockchain virtual machine, an instruction set of a smart contract compiler comprises the XML processing instruction, and a service smart contract compiled by the smart contract compiler comprises the XML processing instruction, and is deployed in the blockchain network; invoking, using the blockchain virtual machine, the service smart contract; and triggering, using the blockchain virtual machine, execution of the XML processing logic based on the XML processing instruction in the service smart contract to perform an XML processing operation on data to be processed.

A method of controlling operation of an electronic wallet executed in an electronic device includes executing an electronic wallet of a first user managing cryptocurrency convertible with each game cash used in at least one game application executed on the electronic device; obtaining first transaction information used to perform a transaction of cryptocurrency between the first user and a second user based on a first event generated within the at least one game application; and based on a blockchain that distributes and manages a ledger recording transactions of the cryptocurrency, performing the transaction of the cryptocurrency corresponding to the first transaction information between the electronic wallet of the first user and an electronic wallet of the second user.