Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset management. One of the methods includes: obtaining a request for creating a digital asset corresponding to a tangible asset, wherein the request comprises one or more characteristics of the digital asset; generating a blockchain contract corresponding to the tangible asset based on the one or more characteristics of the digital asset; and deploying the generated blockchain contract on a blockchain, wherein the deployed blockchain contract is executable to issue the digital asset corresponding to the tangible asset.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset buyback. One of the methods includes: obtaining a request for buying back a digital asset from a first blockchain account, the request comprising a quantity of the digital asset; identifying, based on the request, a blockchain contract that is deployed on the blockchain and that corresponds to the digital asset; generating a blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to a second blockchain account associated with digital asset buyback, wherein the blockchain contract comprises a restriction prohibiting transfer of the digital asset out of the second blockchain account; and sending, to a blockchain node for adding to the blockchain, the blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to the second blockchain account.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable sub-states in blockchain are provided. One of the methods includes: obtaining a request for registering one or more sub-states of a state, wherein a registered workflow comprises the state; generating a blockchain contract comprising the one or more sub-states; and deploying the blockchain contract in a blockchain. The deployed blockchain contract is executable to update a current sub-state of the state corresponding to the workflow among the one or more sub-states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable sub-states in blockchain are provided. One of the methods includes: obtaining a request for registering one or more sub-states of a state, wherein a registered workflow comprises the state; generating a blockchain contract comprising the one or more sub-states; and deploying the blockchain contract in a blockchain. The deployed blockchain contract is executable to update a current sub-state of the state corresponding to the workflow among the one or more sub-states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset management. One of the methods includes: obtaining a request for creating a digital asset corresponding to a tangible asset, wherein the request comprises one or more characteristics of the digital asset; generating a blockchain contract corresponding to the tangible asset based on the one or more characteristics of the digital asset; and deploying the generated blockchain contract on a blockchain, wherein the deployed blockchain contract is executable to issue the digital asset corresponding to the tangible asset.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable sub-states in blockchain are provided. One of the methods includes: obtaining a request for registering one or more sub-states of a state, wherein a registered workflow comprises the state; generating a blockchain contract comprising the one or more sub-states; and deploying the blockchain contract in a blockchain. The deployed blockchain contract is executable to update a current sub-state of the state corresponding to the workflow among the one or more sub-states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset management. One of the methods includes: obtaining a request for creating a digital asset corresponding to a tangible asset, wherein the request comprises one or more characteristics of the digital asset; generating a blockchain contract corresponding to the tangible asset based on the one or more characteristics of the digital asset; and deploying the generated blockchain contract on a blockchain, wherein the deployed blockchain contract is executable to issue the digital asset corresponding to the tangible asset.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable states in blockchain are provided. One of the methods includes: obtaining a request for registering a workflow comprising one or more states; generating a blockchain contract comprising the workflow; and deploying the blockchain contract in a blockchain, wherein the deployed blockchain contract is executable to update a current state of the workflow among the one or more states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset buyback. One of the methods includes: obtaining a request for buying back a digital asset from a first blockchain account, the request comprising a quantity of the digital asset; identifying, based on the request, a blockchain contract that is deployed on the blockchain and that corresponds to the digital asset; generating a blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to a second blockchain account associated with digital asset buyback, wherein the blockchain contract comprises a restriction prohibiting transfer of the digital asset out of the second blockchain account; and sending, to a blockchain node for adding to the blockchain, the blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to the second blockchain account.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for blockchain-based notification are provided. One of the methods includes: obtaining information in a block of a blockchain to determine a current state of a workflow, wherein a blockchain contract deployed in the blockchain is executable to update the current state among one or more states of the workflow; updating a locally-maintained state machine based on the determined current state; and in response to determining that the updated state machine corresponds to one of the one or more states, transmitting a notification message to one or more subscribers subscribing to the one state.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for blockchain-based notification are provided. One of the methods includes: obtaining, from a computing device, a notification message indicating that a current state of a workflow is one of one or more states of the workflow, wherein a blockchain contract deployed in a blockchain is executable to update the current state among the one or more states of the workflow; executing a function associated with the one state in response to the notification message; and in response to completion of the execution of the function, transmitting, to the computing device, a reply message indicating completion of the execution of the function associated with the one state.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable states in blockchain are provided. One of the methods includes: obtaining a request for registering a workflow comprising one or more states; generating a blockchain contract comprising the workflow; and deploying the blockchain contract in a blockchain, wherein the deployed blockchain contract is executable to update a current state of the workflow among the one or more states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable sub-states in blockchain are provided. One of the methods includes: obtaining a request for registering one or more sub-states of a state, wherein a registered workflow comprises the state; generating a blockchain contract comprising the one or more sub-states; and deploying the blockchain contract in a blockchain. The deployed blockchain contract is executable to update a current sub-state of the state corresponding to the workflow among the one or more sub-states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for digital asset buyback. One of the methods includes: obtaining a request for buying back a digital asset from a first blockchain account, the request comprising a quantity of the digital asset; identifying, based on the request, a blockchain contract that is deployed on the blockchain and that corresponds to the digital asset; generating a blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to a second blockchain account associated with digital asset buyback, wherein the blockchain contract comprises a restriction prohibiting transfer of the digital asset out of the second blockchain account; and sending, to a blockchain node for adding to the blockchain, the blockchain transaction for transferring the quantity of the digital asset from the first blockchain account to the second blockchain account.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for blockchain-based notification are provided. One of the methods includes: obtaining, from a computing device, a notification message indicating that a current state of a workflow is one of one or more states of the workflow, wherein a blockchain contract deployed in a blockchain is executable to update the current state among the one or more states of the workflow; executing a function associated with the one state in response to the notification message; and in response to completion of the execution of the function, transmitting, to the computing device, a reply message indicating completion of the execution of the function associated with the one state.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable sub-states in blockchain are provided. One of the methods includes: obtaining a request for registering one or more sub-states of a state, wherein a registered workflow comprises the state; generating a blockchain contract comprising the one or more sub-states; and deploying the blockchain contract in a blockchain. The deployed blockchain contract is executable to update a current sub-state of the state corresponding to the workflow among the one or more sub-states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable states in blockchain are provided. One of the methods includes: obtaining a request for registering a workflow comprising one or more states; generating a blockchain contract comprising the workflow; and deploying the blockchain contract in a blockchain, wherein the deployed blockchain contract is executable to update a current state of the workflow among the one or more states.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for controlling restrictions on digital asset. One of the methods includes: detecting a triggering event for derestricting a quantity of a digital asset associated with a tangible asset, wherein the tangible asset corresponds to a blockchain contract deployed on a blockchain; generating a blockchain transaction for transferring the quantity of the digital asset from a restricted blockchain account associated with the blockchain to an unrestricted blockchain account associated with the blockchain, wherein the blockchain transaction invokes the blockchain contract corresponding to the tangible asset; and sending the blockchain transaction to a blockchain node for adding to the blockchain.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for blockchain-based notification are provided. One of the methods includes: obtaining, from a computing device, a notification message indicating that a current state of a workflow is one of one or more states of the workflow, wherein a blockchain contract deployed in a blockchain is executable to update the current state among the one or more states of the workflow; executing a function associated with the one state in response to the notification message; and in response to completion of the execution of the function, transmitting, to the computing device, a reply message indicating completion of the execution of the function associated with the one state.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for registering subscribable states in blockchain are provided. One of the methods includes: obtaining a request for registering a workflow comprising one or more states; generating a blockchain contract comprising the workflow; and deploying the blockchain contract in a blockchain, wherein the deployed blockchain contract is executable to update a current state of the workflow among the one or more states.