Digital asset processing methods on blockchain, computer systems, and storage media

Abstract

This specification provides a method for processing digital assets on a blockchain, a computer system, and a storage medium. The blockchain issues privacy-protected encrypted digital assets, and among the multiple participants managing the encrypted digital assets is a target participant. The target participant holds a target device and manages the target digital assets. The method includes: the target device performing a preset operation to invalidate any changes to the target digital assets after a target block; the target device obtaining a target key to be updated and requesting a data reset operation from a node of the blockchain based on the target key, causing the blockchain node to receive at least one transaction invoking a target contract; and the blockchain node executing the transaction by running the target contract to perform the data reset operation.

Description

Specification 1 Method, Computer System, and Storage Medium for Digital Asset Processing on Blockchain Technical Field This specification relates to the field of blockchain technology, and particularly to a method, computer system, and storage medium for digital asset processing on blockchain. Background Technology Blockchain has advantages such as decentralization, traceability, and high security. In recent years, due to the rapid development of blockchain technology, various digital assets managed based on blockchain have gradually emerged. Some institutions or organizations can issue digital assets with certain value and functions to users through blockchain. In order to improve data security, protect personal privacy, and prevent the leakage of personal financial information and the leakage of the issuer's reserve funds, advanced cryptographic technology can be used to realize the circulation of privacy-protecting encrypted digital assets (such as privacy tokens) on the blockchain. Encrypted digital assets can hide the account balance of their holders, the identity of transaction participants, and the transaction amount. Currently, there is a need for a digital asset processing solution on blockchain. Summary of the Invention This specification provides a method, computer system, and storage medium for digital asset processing on blockchain through one or more embodiments. According to a first aspect, a method for processing digital assets on a blockchain is provided, wherein the blockchain issues privacy-protected encrypted digital assets, and among the multiple parties involved in managing the encrypted digital assets is a target participant; the target participant holds a target device and manages the target digital assets; the method includes: the target device performing a preset operation to invalidate changes to the target digital assets after a target block; the target device obtaining a target key to be updated and requesting a node of the blockchain to perform a data reset operation based on the target key, so that the node of the blockchain receives at least one transaction invoking a target contract; the node of the blockchain executing the transaction and performing the data reset operation by running the target contract. According to a second aspect, a method for processing digital assets on a blockchain is provided, wherein the blockchain issues privacy-protected encrypted digital assets, and among the multiple parties involved in managing the encrypted digital assets is a target participant; the target participant holds a target device, the target participant manages the target digital assets, and the method is executed by the target device; the method includes: performing a preset operation to invalidate changes to the target digital assets after a target block; obtaining a target key to be updated, and requesting a node of the blockchain to perform a data reset operation based on the target key, so that the node of the blockchain receives at least one transaction invoking a target contract; and causing the node of the blockchain to perform the data reset operation by running the target contract. According to a third aspect, a computer system is provided, relating to a blockchain, wherein the blockchain issues privacy-protected encrypted digital assets.The multiple parties involved in managing the encrypted digital asset include a target participant; the target participant holds a target device and manages the target digital asset; the computer system includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, performs the following target operation at least once, achieving the following steps through the target operation: performing a preset operation to invalidate changes to the target digital asset after the target block; obtaining a target key to be updated, and requesting a data reset operation from a node of the blockchain based on the target key, causing the node of the blockchain to receive at least one transaction invoking the target contract; causing the node of the blockchain to perform the data reset operation by running the target contract. According to a fourth aspect, a computer-readable storage medium is provided, the storage medium storing a computer program, which, when executed by a processor, implements the method described in any one of the first aspects above. The technical solutions provided by the embodiments of this specification can include the following beneficial effects: The embodiments of this specification provide a digital asset processing solution on a blockchain. By executing a preset operation on a target device held by a target participant, changes to the target digital assets managed by the target participant after the target block are invalidated. The solution also obtains the target key to be updated and acquires the asset information of the target digital asset in the target block from historical data of the blockchain. Based on the target key and asset information, reset information is obtained. Based on the reset information, a request is made to the blockchain nodes to perform a data reset operation. The blockchain nodes receive a first transaction carrying the reset information and invoking the target contract. The blockchain nodes execute the first transaction and, by running the target contract, perform the data reset operation based on the reset information. Therefore, after the target participant forgets or discloses the privacy protection key, it provides users with a way to disable changes to the target digital assets and increases the way to reset the key, reducing the trouble and risks caused to users when their privacy protection key is forgotten or disclosed. It should be understood that the above general description and the following detailed description are merely exemplary and explanatory and do not limit this application. The accompanying drawings are provided to more clearly illustrate the technical solutions of the embodiments in this specification. The drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are merely some embodiments recorded in this specification. For those skilled in the art, the drawings can be easily understood without creative effort.Other accompanying drawings can also be obtained based on these drawings. Figure 1 is a schematic diagram of a digital asset processing system on a blockchain according to an exemplary embodiment of this specification. Figure 2 is a flowchart of a digital asset processing method on a blockchain according to an exemplary embodiment of this specification. Figure 3 is a flowchart of another digital asset processing method on a blockchain according to an exemplary embodiment of this specification. Figure 4 is a flowchart of another digital asset processing method on a blockchain according to an exemplary embodiment of this specification. HK 30135245 A Specification 3 Figure 5 is a flowchart of another digital asset processing method on a blockchain according to an exemplary embodiment of this specification. Figure 6 is a schematic diagram of a computer system according to an exemplary embodiment of this specification. Detailed Description In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification. Blockchain boasts advantages such as decentralization, traceability, and high security. In recent years, due to the rapid development of blockchain technology, various digital assets managed based on blockchain have emerged. Some institutions or organizations can issue digital assets with certain value and functions to users through blockchain. To improve data security, protect personal privacy, and prevent the leakage of personal financial information and the issuer's reserve funds, advanced cryptographic techniques can be used to enable the circulation of privacy-protecting encrypted digital assets (such as privacy tokens) on the blockchain. Encrypted digital assets can hide the account balance of their holders, the identities of transaction participants, and transaction amounts. Generally, users participating in the management of encrypted digital assets hold their own privacy protection keys, which can include a public key and a private key. The public key can be made public, while the private key is held only by the user. Taking User A as an example, when other users transfer funds to User A, the transfer information can be encrypted based on User A's public key, and User A's encrypted digital assets can be updated on the blockchain through the transaction. User A can view the transfer information and balance information of the encrypted digital assets based on the private key, thereby protecting User A's asset privacy information. However, if the private key portion of a user's privacy protection key is forgotten or leaked, it can cause significant trouble and risk for the user. This specification provides a digital asset processing solution on a blockchain, which, through a preset operation performed on a target device held by a target participant, renders subsequent changes to the target digital assets managed by the target participant invalid after the target block is blocked.The system obtains the target key to be updated and the asset information of the target digital asset in the target block from the historical data of the blockchain. Based on the target key and asset information, reset information is obtained. Based on the reset information, a request is made to the blockchain node to perform a data reset operation. The blockchain node receives the first transaction carrying the reset information and calling the target contract. The blockchain node executes the first transaction and performs the data reset operation based on the reset information by running the target contract. Thus, after the target participant forgets or discloses the privacy protection key, it provides users with a way to disable the change operation for the target digital asset and increases the way to reset the key, reducing the trouble and risk to users when the user's privacy protection key is forgotten or disclosed. Figure 1 is a schematic diagram of a blockchain-based digital asset management system according to an exemplary embodiment. HK 30135245 A Specification 4 As shown in Figure 1, the blockchain-based digital asset management system may include a blockchain 101, at least one issuer 102, at least one regulator 103, and at least one user 104. Among them, issuer 102, regulator 103, and user 104 can all establish a communication connection with blockchain 101 through their respective devices. Blockchain 101 may contain, for example, eight nodes, from node 1 to node 8. Each node can be implemented as any device, server, or equipment cluster with computing and processing capabilities. It is understood that although Figure 1 shows eight nodes in blockchain 101, this embodiment is not limited to this and may include other numbers of nodes. Each node in the blockchain can generate the same state in the blockchain by executing the same transaction, and each node stores the same state database. At least one smart contract for managing encrypted digital assets can be deployed in blockchain 101 (each smart contract corresponds to one encrypted digital asset, and one encrypted digital asset is issued by one issuer). The smart contract can record information such as the total issuance of encrypted digital assets and the balance of each account. Issuer 102 is an institution / organization capable of creating and issuing encrypted digital assets on the blockchain. Issuer 102 can issue encrypted digital assets to user 104 through blockchain 101, and can also liquidate and destroy some or all of the encrypted digital assets held by user 104 in blockchain 101. It can also query information such as the amount of related transactions recorded on the blockchain for that encrypted digital asset and the balance of each user. Regulator 103 is a participant in overseeing the issuance and balance of encrypted digital assets. Regulator 103 can query information such as transaction amounts, individual user balances, and the issuance volume of encrypted digital assets from Blockchain 101. Furthermore, when issuing or transferring encrypted digital assets...The issuer or transferor typically sends the issuance or transfer amount to regulator 103 simultaneously in homomorphic ciphertext to monitor the issuance and transfer process. However, regulator 103 does not have the authority to operate on the encrypted digital assets (such as issuance, transfer, liquidation, etc.). User 104 is an individual or organization holding encrypted digital assets. They can obtain a predetermined amount of encrypted digital assets from issuer 102, or from other users' accounts, and can also transfer a predetermined amount of encrypted digital assets to other users' accounts (e.g., user 104a transfers to user 104b, or user 104b transfers to user 104a). User 104 can query the balance information of their held encrypted digital assets on blockchain 101 and has the authority to decrypt their own encrypted digital assets. Specifically, taking the scenario of issuer 102 issuing encrypted digital asset Z to user 104a as an example, issuer 102 first obtains the issuance quota n of encrypted digital asset Z, and uses the public key portion KG2 of the privacy protection key held by issuer 102, the public key portion KG4a of the privacy protection key held by user 104a, and the public key portion KG3 of the privacy protection key held by regulator 103 to homomorphically encrypt the issuance quota n, obtaining homomorphic ciphertext Enc(Zn). Next, based on the private key portion KS2 of the privacy protection key held by issuer 102, proof data Q is generated. This proof data Q can be used to prove that the issuance quotas decrypted by user 104a and regulator 103 are consistent (both are n), and that the issuance quota issued by issuer 102 has not exceeded the predetermined quota (i.e., there is no over-issuance). In addition, issuer 102 will also generate data D1, etc., to provide decryption information to user 104a and regulator 103. Then, issuer 102 can submit transaction TX1, which calls contract C, to blockchain 101. Transaction TX1 includes homomorphic ciphertext Enc(Zn), proof data Q, and data D1. Generally, issuer 102 will sign transaction TX1 using its blockchain private key to obtain signature data. After receiving transaction TX1, each node of blockchain 101 executes contract C, first verifying the signature data using the blockchain public key held by issuer 102. After successful verification, the proof data Q is verified. After successful verification, the ciphertext Enc(Zm) of user 104a's account balance can be read from the state data of contract C. The ciphertext Enc(Zn) is added to the ciphertext Enc(Zm) to obtain a new balance ciphertext Enc(Zn+Zm). The user 104a's account balance in the state data of contract C is then updated to the new balance ciphertext Enc(Zn+Zm). Additionally, Blockchain 101 can notify users 104a and regulators 103.User 104a and regulator 103 obtain the content of transaction TX1 from the blockchain transaction data, and also obtain the homomorphic ciphertext Enc(Zn) and data D1. User 104a can decrypt the homomorphic ciphertext Enc(Zn) based on the private key portion KS4a of its privacy-protected key and data D1 to obtain the plaintext issuance amount n, and use the issuance amount n to update the balance of its locally recorded encrypted digital asset Z. Regulator 103 can also decrypt the homomorphic ciphertext Enc(Zn) based on the private key portion KS3 of its privacy-protected key and data D1 to obtain the plaintext issuance amount n, and perform regulatory review, etc., based on the issuance amount n. Taking the scenario of user 104b transferring encrypted digital asset Z to user 104a as an example, user 104b first obtains the transfer amount w of encrypted digital asset Z. Using the public key portion KG4b of the privacy-protected key held by user 104b, the public key portion KG4a of the privacy-protected key held by user 104a, and the public key portion KG3 of the privacy-protected key held by regulator 103, user 104b homomorphically encrypts the transfer amount w, obtaining the homomorphic ciphertext Enc(Zw). Next, based on the private key portion K4b of the privacy-protected key held by user 104b, proof data Q is generated. This proof data Q can be used to prove that the transfer amounts decrypted by user 104a and regulator 103 are consistent (both are n), and that user 104b's transfer amount does not exceed its total balance. In addition, user 104b also generates data D2, etc., to provide decryption information to user 104a and regulator 103. Then, user 104b can submit transaction TX2, which calls contract C, to blockchain 101. Transaction TX2 includes homomorphic ciphertext Enc(Zw), proof data Q, and data D2. Generally, user 104b will sign transaction TX2 using its blockchain private key to obtain signature data. After receiving transaction TX2, each node of blockchain 101 executes contract C, first verifying the signature data using the blockchain public key held by user 104b. After successful verification, the proof data Q is verified. After successful verification, the ciphertext Enc(Zm) of user 104a's account balance can be read from the state data of contract C. The ciphertext Enc(Zw) is added to the ciphertext Enc(Zm) to obtain a new balance ciphertext Enc(Zw+Zm). The account balance of user 104a in the state data of contract C is then updated to the new balance ciphertext Enc(Zw+Zm). Similarly, read the ciphertext Enc(Zv) of the user's 104b account balance, subtract it from the ciphertext Enc(Zw) to obtain the new balance ciphertext Enc(Zv-Zw). Then, use the user's 104b account balance from the state data of contract C.The transaction is updated to the new balance ciphertext Enc(Zv-Zw). Additionally, blockchain 101 can notify user 104b of the successful transaction, allowing user 104b to directly update the balance of its locally recorded encrypted digital asset Z using the transfer limit HK 30135245 A (Instruction Manual 6 w). Blockchain 101 can also notify user 104a and regulator 103, enabling them to retrieve the content of transaction TX2 from the blockchain's transaction data, and obtain the homomorphic ciphertext Enc(Zw) and data D2. User 104a can decrypt the homomorphic ciphertext Enc(Zw) based on the private key portion KS4a in its privacy-protected key and data D2, obtaining the plaintext issuance limit w, and using the issuance limit w to update the balance of its locally recorded encrypted digital asset Z. Regulator 103 can also decrypt the homomorphic ciphertext Enc(Zw) based on the private key portion KS3 and data D2 in its privacy protection key to obtain the plaintext issuance amount w, and conduct regulatory review based on the issuance amount w. When any participant forgets, leaks, or needs to reset the privacy protection key for management reasons, a preset operation can be executed first to invalidate any subsequent changes to their held encrypted digital assets after the target block. Then, the new privacy protection key can be uploaded to the blockchain for privacy protection key reset, and the asset information of their held encrypted digital assets can be reset using the new privacy protection key. Taking user 104a as an example, user 104a can first notify issuer 102 that asset information needs to be reset. Issuer 102 submits transaction TX3, which calls contract C, to blockchain 101. After receiving transaction TX3, each node on blockchain 101 executes contract C to close user 104a's account in encrypted digital asset Z, thus prohibiting any transfer operations involving user 104a. Transaction TX3 belongs to block M; therefore, after block M, any changes to encrypted digital asset Z held by user 104a are invalid. Next, user 104a can obtain a new privacy protection key, use the public key portion KG4n included in the new privacy protection key as the reset key information, and send a data reset request including the reset key information to issuer 102. Issuer 102 can submit transaction TX4, which invokes contract C, to blockchain 101. Upon receiving transaction TX4, each node on blockchain 101 executes contract C, resetting the key information of user 104a in the state data of contract C using the reset key information. Additionally, issuer 102 can obtain encrypted information corresponding to user 104a's account in encrypted digital asset Z from blockchain 101, such as encrypted balance information, and decrypt the encrypted information to obtain plaintext data. Then...Based on the public key portion KG4n corresponding to user 104a, the plaintext data is re-encrypted to obtain new ciphertext data. Then, transaction TX5, which calls contract C, is submitted to blockchain 101. Upon receiving transaction TX5, each node on blockchain 101 executes contract C, using the new ciphertext data to update the old encrypted digital asset information of user 104a in the state data of contract C. Taking issuer 102 as another example, if issuer 102 has only disclosed the private key portion included in the privacy protection key, but has not forgotten this private key portion, then issuer 102 can directly submit transaction TX6, which calls contract C, to blockchain 101. Upon receiving transaction TX6, each node on blockchain 101 executes contract C to close various changes to the encrypted digital asset Z (e.g., issuance, destruction, transfer, etc.). If issuer 102 forgets the private key portion included in the privacy protection key, and cannot send transaction TX6 to the blockchain, issuer 102 can send a notification message to each user, including block information for block M. This notification message is used to notify each user that all changes to the encrypted digital asset Z after block M are invalid. Next, issuer 102 can obtain a new privacy protection key, using the public key portion KG2n included in the new privacy protection key as the reset key information. Then, it retrieves the encrypted information corresponding to the encrypted digital asset Z from blockchain 101, such as the encrypted balances of each user, and decrypts the encrypted information to obtain plaintext data. Based on the public key portion KG2n corresponding to issuer 102, it re-encrypts the plaintext data to obtain new ciphertext data. Using the reset key information and the new ciphertext data as reset information, it sends transaction TX7, which calls contract C, to blockchain 101. Transaction TX7 includes the reset information. After receiving transaction TX7, each node of blockchain 101 executes contract C, using reset information to reset the key information of issuer 102 and the data of encrypted digital asset Z in the state data of contract C. The solution provided in this specification will be described in detail below with reference to specific embodiments. As shown in Figure 2, Figure 2 is a flowchart illustrating a digital asset processing method on a blockchain according to an exemplary embodiment. This blockchain issues privacy-protected encrypted digital assets, and multiple participants in managing the encrypted digital assets each hold their own corresponding privacy-protecting keys. Each participant's privacy-protecting key includes a public key and a private key. Among the multiple participants is a target participant, which holds a target device. This method involves not only the target device but also nodes of the blockchain. Both the target device and the blockchain nodes can be implemented as any device, server, or device cluster with computing and processing capabilities. The method may include the following steps: In step 201, the target device performs a preset operation.This renders subsequent changes to the target digital asset invalid. In this embodiment, the target participant can be a user managing the encrypted digital asset or an issuer, and the target device can be a terminal device held by the target participant. The target digital asset can be an encrypted digital asset managed by the target participant. If the target participant is a user, the target digital asset is an encrypted digital asset held by the user; if the target participant is an issuer, the target digital asset is an encrypted digital asset issued and managed by the issuer. The target participant holds the original privacy protection key, which includes an original public key and an original private key. When the target participant forgets the original private key, discovers a high probability of leaking the original private key, or needs to reset the privacy protection key due to managing the encrypted digital asset, a preset operation can be performed through the target device to render subsequent changes to the target digital asset invalid. The target block can be the block corresponding to the execution of the preset operation or a designated block after the execution of the preset operation; this embodiment is not limited in this respect. Changes to the target digital asset can include, but are not limited to, transferring out the target digital asset, issuing the target digital asset, or destroying the target digital asset. Specifically, in one implementation, the target device can request a blockchain node to close an asset change, causing the blockchain node to receive a first transaction that invokes the target contract. The blockchain node executes the first transaction, closing the changes to the target digital asset by running the target contract. For example, as shown in Figure 3, if the target participant is a user, and the user forgets part of the original private key, discovers a high probability of leaking part of the original private key, or needs to reset the privacy protection key due to managing encrypted digital assets, the target device can send a first request to the issuing device held by the issuing party to request the closure of changes to the target digital asset. The issuing device can then send a first transaction invoking the target contract to the blockchain node based on the first request. The blockchain node executes the first transaction, freezing the target digital asset held by the user by running the target contract, making any changes to the target digital asset invalid during the freeze period. Therefore, in this implementation, the target block can be the block to which the first transaction belongs. It should be noted that if the target participant finds or determines that the original private key portion has not been leaked, they can also request the blockchain nodes to unfreeze the frozen target digital asset, so that the changes to the target digital asset are restored after unfreezing. For example, as shown in Figure 4, if the target participant is the issuer, and the issuer discovers a high probability of leaking the original private key portion, or needs to reset the privacy protection key due to managing encrypted digital assets,The target device can directly send a first transaction to the blockchain nodes to invoke the target contract. The blockchain nodes execute the first transaction, and by running the target contract, they can terminate the target digital asset managed by the issuer, making any changes to the target digital asset after termination invalid. In this implementation, the target block can also be the block to which the first transaction belongs. It should be noted that even if the target participant confirms that it has not disclosed the original private key, it cannot request the blockchain nodes to unterminate the terminated target digital asset; only the issuer can reset the privacy protection key. In another implementation, for example, as shown in Figure 5, if the target participant is the issuer, and the issuer forgets the original private key, it cannot use the original private key to terminate the target digital asset managed by the issuer. Therefore, the target device sends a notification message including the target block information to the user's device to notify the user that any changes to the target digital asset after the target block are invalid. In this implementation, the target block can be a specified block. For example, the target block can be the Nth block after the block corresponding to the moment the target device sends the notification message, where N is an integer greater than 0 determined based on experience. It is understood that this embodiment does not limit the specific value of N. It should be noted that since the original private key has been forgotten, the issuer can only reset the privacy protection key and migrate the target digital assets it manages to the address corresponding to the new privacy protection key. In step 202, the target device obtains the target key to be updated and requests the blockchain nodes to perform a data reset operation based on the target key, so that the blockchain nodes receive at least one transaction calling the target contract. In step 203, the blockchain nodes execute the above transaction and perform the data reset operation by running the target contract. In this embodiment, the target key can include a target public key and a target private key. The target device can obtain the target key to be updated and request the blockchain nodes to perform a data reset operation based on the target key, so that the blockchain nodes receive at least one transaction calling the target contract. The blockchain nodes perform the data reset operation by executing the above transaction and running the target contract. The data reset operation can include resetting key information and resetting asset information of the target digital asset. Specifically, in one implementation, as shown in Figure 3, if the target participant is a user, the target participant can obtain the target public key portion included in the target key as reset key information through the target device (HK 30135245 A Specification 9), and send a second request for data reset to the issuer's device. This second request can include the reset key information. The issuer's device can obtain the asset information corresponding to the target digital asset held by the target participant in the target block from the historical data of the blockchain.The asset information may include, for example, balance information. Next, the issuing device can encrypt the asset information corresponding to the target digital asset based on the target public key portion of the reset key information to obtain the reset asset information. Finally, the issuing device can send a second transaction carrying the reset key information and invoking the target contract to the blockchain nodes, enabling the blockchain nodes to perform key reset based on the second transaction. It then sends a third transaction carrying the reset asset information and invoking the target contract to the blockchain nodes, enabling the blockchain nodes to reset the asset information based on the third transaction. In another implementation, as shown in Figure 4 or Figure 5, if the target participant is the issuing party, the issuing party's target device can obtain the target public key portion included in the target key as the reset key information, and obtain the asset information of the target digital asset in the target block. Based on this asset information and the target public key portion, the reset asset information is obtained, and the reset key information and reset asset information are determined as the reset information. A fourth transaction carrying this reset information and invoking the target contract is then sent to the blockchain nodes, enabling the blockchain nodes to perform data reset operations based on the fourth transaction. Finally, the blockchain nodes execute the aforementioned transactions, performing data reset operations by running the target contract. For example, key reset can be performed using reset key information, and asset reset can be performed using reset asset information. The blockchain digital asset processing method provided in this specification's embodiments executes a preset operation on the target device held by the target participant, rendering changes to the target digital asset invalid after the target block. The target device obtains the target key to be updated and requests the blockchain nodes to perform data reset operations based on the target key. This causes the blockchain nodes to receive at least one transaction invoking the target contract, which the blockchain nodes execute, performing the data reset operation by running the target contract. This provides users with a way to disable target digital asset change operations and a way to reset data in cases where there is a risk of key leakage, reducing the trouble and risks caused to users if their private key portion is forgotten or leaked. It should be noted that although the operations of the methods in the embodiments of this specification are described in a specific order in the above embodiments, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Rather, the steps depicted in the flowcharts can be executed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and / or one step may be broken down into multiple steps for execution. This specification also provides a computer-readable non-transitory storage medium storing a computer program that, when executed by a processor, can be used to perform one or more steps of one or more methods described or illustrated herein, or to provide the functionality described or illustrated herein. Here,One or more computer-readable non-transitory storage media may include one or more semiconductor-based or other integrated circuits (ICs) (e.g., field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs)), hard disk drives (HDDs), hybrid hard disk drives (HHDs), optical disks, optical disk drives (ODDs), magneto-optical disks, magneto-optical disk drives, floppy disks, floppy disk drives (FDDs), magnetic tape, solid-state drives (SSDs), RAM drives, secure digital cards or drives, any other suitable computer-readable non-transitory storage media, or any suitable combination of two or more of these, where appropriate. The computer-readable non-transitory storage media may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. This specification also provides a computer system. Figure 6 illustrates an exemplary computer system 1000. In a particular embodiment, one or more computer systems 1000 perform one or more steps of one or more methods described or illustrated herein. In a particular embodiment, one or more computer systems 1000 provide the functionality described or illustrated herein. In a particular embodiment, software running on one or more computer systems 1000 performs one or more steps of one or more methods described or illustrated herein, or provides the functionality described or illustrated herein. The particular embodiment includes one or more portions of one or more computer systems 1000. Herein, references to computer systems may include computing devices, and vice versa, where appropriate. Furthermore, references to computer systems may include one or more computer systems, where appropriate. This disclosure contemplates any suitable number of computer systems 1000. This disclosure envisions computer systems 1000 taking any suitable physical form. By way of example and not limitation, computer system 1000 may be an embedded computer system, a system-on-a-chip (SOC), a single-board computer system (SBC) (e.g., a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a computer system network, a mobile phone, a personal digital assistant (PDA), a server, a tablet computer system, or a combination of two or more of these. Where appropriate, computer system 1000 may include one or more computer systems 1000; single or distributed; spanning multiple locations; spanning multiple machines; spanning multiple data centers; or residing in the cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems 1000 may perform one or more steps of one or more methods described or illustrated herein.There are no substantial spatial or temporal limitations. By way of example and not limitation, one or more computer systems 1000 may execute one or more steps of the methods described or illustrated herein in real time or in batch mode. Where appropriate, one or more computer systems 1000 may execute one or more steps of the methods described or illustrated herein at different times or in different locations. In a particular embodiment, computer system 1000 includes processor 1002, memory 1004, storage 1006, input / output (I / O) interface 1008, communication interface 1010, and bus 1012. Although this disclosure describes and illustrates a particular computer system having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable computer system having any suitable number of any suitable components in any suitable arrangement. In a particular embodiment, processor 1002 includes hardware for executing instructions, such as instructions constituting a computer program. By way of example and not limitation, in order to execute instructions, processor 1002 may retrieve (or fetch) instructions from internal registers, internal caches, memory 1004, or memory 1006; decode and execute them; and then write one or more results to internal registers, internal caches, memory 1004, or memory 1006. In a particular embodiment, processor 1002 may include one or more internal caches for data, instructions, or addresses, as described in HK 30135245 A specification 11. This disclosure contemplates that processor 1002 may include any appropriate number of appropriate internal caches where appropriate. By way of example and not limitation, processor 1002 may include one or more instruction caches, one or more data caches, and one or more translation back-of-care buffers (TLBs). Instructions in the instruction cache may be copies of instructions in memory 1004 or memory 1006, and the instruction cache may accelerate the retrieval of those instructions by processor 1002. The data in the data cache may be a copy of data in memory 1004 or memory 1006 for instruction operations executed at processor 1002; the result of a previous instruction executed at processor 1002 for subsequent instructions executed at processor 1002 to access or write to memory 1004 or memory 1006; or other suitable data. The data cache can accelerate read or write operations of processor 1002. The TLB can accelerate virtual address translation of processor 1002. In a particular embodiment,Processor 1002 may include one or more internal registers for data, instructions, or addresses. This disclosure contemplates that processor 1002 may include any suitable number of suitable internal registers where appropriate. Where appropriate, processor 1002 may include one or more arithmetic logic units (ALUs), may be a multi-core processor, or may include one or more processors 1002. Although this disclosure describes and illustrates specific processors, this disclosure contemplates any suitable processor. In a particular embodiment, memory 1004 includes main memory for storing instructions to be executed by processor 1002 or data to be operated on by processor 1002. By way of example and not limitation, computer system 1000 may load instructions from memory 1006 or another source (e.g., another computer system 1000) into memory 1004. Processor 1002 may then load instructions from memory 1004 into internal registers or internal caches. To execute instructions, processor 1002 may retrieve instructions from internal registers or internal caches and decode them. During or after instruction execution, processor 1002 may write one or more results (which may be intermediate or final results) to internal registers or internal caches. Processor 1002 may then write one or more of these results to memory 1004. In a particular embodiment, processor 1002 executes only the instructions in one or more internal registers or internal caches or memory 1004 (as opposed to memory 1006 or elsewhere) and operates only on the data in one or more internal registers or internal caches or memory 1004 (as opposed to memory 1006 or elsewhere). One or more memory buses (each memory bus may include an address bus and a data bus) may couple processor 1002 to memory 1004. As described below, bus 1012 may include one or more memory buses. In a particular embodiment, one or more memory management units (MMUs) reside between processor 1002 and memory 1004 and facilitate access to memory 1004 requested by processor 1002. In a particular embodiment, memory 1004 includes random access memory (RAM). Where appropriate, the RAM may be volatile memory. Where appropriate, the RAM may be dynamic RAM (DRAM) or static RAM (SRAM). Furthermore, where appropriate, the RAM may be single-port or multi-port RAM. This disclosure considers any suitable RAM. Where appropriate, memory 1004 may include one or more memories 1004. Although this disclosure describes and illustrates specific memories,However, this disclosure contemplates any suitable memory. HK 30135245 A Specification 12 In a particular embodiment, storage 1006 includes a mass storage device for data or instructions. By way of example and not limitation, storage 1006 may include a hard disk drive (HDD), floppy disk drive, flash memory, optical disk drive, magneto-optical disk drive, magnetic tape drive, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, storage 1006 may include removable or non-removable (or fixed) media. Where appropriate, storage 1006 may be internal or external to computer system 1000. In a particular embodiment, storage 1006 is a non-volatile solid-state memory. In a particular embodiment, storage 1006 includes read-only memory (ROM). Where appropriate, the ROM may be a mask-programmable ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically changeable ROM (EAROM), or flash memory, or a combination of two or more of these. This disclosure contemplates mass storage 1006 in any suitable physical form. Where appropriate, storage 1006 may include one or more storage control units that facilitate communication between processor 1002 and storage 1006. Where appropriate, storage 1006 may include one or more storage units 1006. Although specific storage is described and illustrated in this disclosure, any suitable storage is contemplated in this disclosure. In a particular embodiment, I / O interface 1008 includes hardware, software, or both, providing one or more interfaces for communication between computer system 1000 and one or more I / O devices. Where appropriate, computer system 1000 may include one or more of these I / O devices. One or more of these I / O devices can enable communication between a person and computer system 1000. By way of example and not limitation, I / O devices may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, graphics tablet, touchscreen, trackball, camera, other suitable I / O devices, or combinations of two or more of these devices. I / O devices may include one or more sensors. This disclosure considers any suitable I / O devices and any suitable I / O interface 1008 for them. Where appropriate, the I / O interface 1008 may include one or more devices or software drivers that enable the processor 1002 to drive one or more of these I / O devices. Where appropriate,I / O interface 1008 may include one or more I / O interfaces 1008. Although specific I / O interfaces are described and illustrated in this disclosure, any suitable I / O interface is contemplated in this disclosure. In a particular embodiment, communication interface 1010 includes hardware, software, or both, providing one or more interfaces for communication (e.g., packet-based communication) between computer system 1000 and one or more other computer systems 1000 or one or more networks. By way of example and not limitation, communication interface 1010 may include a network interface controller (NIC) or network adapter for communicating with Ethernet or other wired networks, or a wireless NIC (WNIC) or wireless adapter for communicating with wireless networks such as Wi-Fi networks. This disclosure contemplates any suitable network and any suitable communication interface 1010 for that network. By way of example and not limitation, computer system 1000 may communicate with one or more portions of an ad hoc network, personal area network (PAN), local area network (LAN), wide area network (WAN), metropolitan area network (MAN), or the Internet, or a combination of two or more of these. One or more portions of these networks may be wired or wireless. As an example, computer system 1000 may communicate with a wireless PAN (WPAN) (e.g., Bluetooth WPAN), a Wi-Fi network, a Wi-Fi Max network, a cellular telephone network (e.g., a Global System for Mobile Communications (GSM) network), or other suitable wireless networks, or combinations of two or more of these networks. Where appropriate, computer system 1000 may include any suitable communication interface 1010 for any of these networks. Where appropriate, communication interface 1010 may include one or more communication interfaces 1010. Although specific communication interfaces are described and illustrated in this disclosure, any suitable communication interface is contemplated in this disclosure. In a particular embodiment, bus 1012 includes hardware, software, or both that couple components of computer system 1000 to each other. This is by way of example and not limitation.Bus 1012 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), an HyperTransport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBAND interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCIe) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or another suitable bus, or a combination of two or more of these buses. Where appropriate, bus 1012 may include one or more buses 1012. Although this disclosure describes and illustrates specific buses, this disclosure contemplates any suitable bus or interconnect. It should also be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes said element. The various embodiments in this specification are described in a progressive manner, with reference to each other for similar or identical parts. Each embodiment focuses on describing the differences from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions of the method embodiments. The above descriptions are merely embodiments of this specification and are not intended to limit this specification. Various modifications and variations can be made to this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of the claims of this application. HK 30135245 A Claims 1 1. A method for processing digital assets on a blockchain, wherein the blockchain issues privacy-protected encrypted digital assets, and among multiple participants managing the encrypted digital assets is a target participant; the target participant holds a target device and manages the target digital assets; the method includes: the target device performing a preset operation to invalidate changes to the target digital assets after a target block; the target device obtaining a target key to be updated and requesting a data reset operation from a node of the blockchain based on the target key, causing the node of the blockchain to receive at least one transaction invoking a target contract; and the node of the blockchain executing the transaction by running the target contract.1. Perform a data reset operation. 2. The method according to claim 1, wherein the target device performs a preset operation, including: the target device requests a node in the blockchain to perform an asset change closure operation, causing the node in the blockchain to receive a first transaction; the first transaction invokes the target contract; the node in the blockchain executes the first transaction, closing the change for the target digital asset by running the target contract. 3. The method according to claim 2, wherein the plurality of participants include the user and issuer of the encrypted digital asset; if the target participant is a user, the target device's request for the blockchain node to perform an asset change closure operation includes: the target device sending a first request to the issuer's device for requesting closure of the change for the target digital asset; the issuer's device sending the first transaction to the blockchain node based on the first request. 4. The method according to claim 2, wherein the plurality of participants include the user and issuer of the encrypted digital asset; if the target participant is an issuer, the target device's request for the blockchain node to perform an asset change closure operation includes: the target device sending the first transaction to the blockchain node. 5. According to the method of claim 1, the plurality of participants include the user and issuer of the encrypted digital asset; if the target participant is the issuer, the target device requests the nodes of the blockchain to perform an asset change closure operation, including: the target device sending a notification message including the target block information to the user device held by the user, to notify the user that changes to the target digital asset are invalid after the target block. 6. According to the method of claim 1, wherein the plurality of participants include the user and issuer of the encrypted digital asset; if the target participant is the user, the step of requesting the blockchain node to perform a data reset operation based on the target key includes: the target device obtaining the target public key portion of the target key as reset key information, and sending a second request for requesting data reset to the issuer device held by the issuer (HK 30135245 A, claim 2), the second request including the reset key information; the issuer device determining reset asset information based on the reset key information; the issuer device sending a second transaction carrying the reset key information and invoking the target contract to the blockchain node; causing the blockchain node to perform a key reset based on the second transaction; and sending a third transaction carrying the reset asset information and invoking the target contract to the blockchain node; causing the blockchain node to perform a key reset based on the third transaction.7. The method according to claim 1, wherein the plurality of participating parties include the user and issuer of the encrypted digital asset; if the target participating party is the issuer, the step of requesting the blockchain node to perform a data reset operation based on the target key includes: the target device obtaining the target public key portion included in the target key as reset key information; and the target device obtaining the asset information of the target digital asset in the target block; obtaining reset asset information based on the asset information and the target key; determining the reset key information and the reset asset information as reset information; sending a fourth transaction carrying the reset information and invoking the target contract to the blockchain node; causing the blockchain node to perform a data reset operation based on the fourth transaction. 8. The method according to claim 1, wherein the change to the target digital asset includes transferring out the target digital asset, or issuing the target digital asset, or destroying the target digital asset. 9. A method for processing digital assets on a blockchain, wherein the blockchain issues privacy-protected encrypted digital assets, and a target participant is among multiple participants managing the encrypted digital assets; the target participant holds a target device and manages the target digital assets, and the method is executed by the target device; the method includes: performing a preset operation to invalidate changes to the target digital assets after the target block; obtaining a target key to be updated, and requesting a node of the blockchain to perform a data reset operation based on the target key, causing the node of the blockchain to receive at least one transaction invoking a target contract; and causing the node of the blockchain to perform the data reset operation by running the target contract. HK 30135245 A Specification Appendix 1 103 101 102 104 104a 104b Figure 1 The target device obtains the target key to be updated and requests the blockchain node to perform a data reset operation based on the target key, so that the blockchain node receives at least one transaction calling the target contract 201 The target device executes a preset operation to invalidate changes to the target digital asset after the target block 202 The blockchain node executes the above transaction and performs a data reset operation by running the target contract 203 Figure 2 HK 30135245 A Specification Appendix 2 The issuing device sends a first transaction calling the target contract to the blockchain node based on the first request. The target device sends a first request to the issuing device held by the issuer to request the closure of changes to the target digital asset. The first transaction is executed.By running the target contract, the target digital asset is frozen, rendering any changes to the target digital asset during the freeze period invalid. Off-chain, the target device obtains the target public key portion included in the target key as reset key information and sends a second request to the issuing device to request data reset. This second request includes the reset key information. The issuing device obtains the asset information corresponding to the target digital asset in the target block and encrypts the asset information based on the target public key portion to obtain reset asset information. Based on the second transaction, a key reset is performed; based on the third transaction, asset information reset is performed. The issuing device sends a second transaction carrying the reset key information and invoking the target contract to the blockchain nodes, and a third transaction carrying the reset asset information and invoking the target contract to the blockchain nodes. (Figure 3, HK 30135245 A, Appendix 3 of the specification) The target device sends a first transaction to the blockchain node, invoking the target contract. This first transaction terminates the target digital asset, invalidating any changes to the target digital asset after termination. Off-chain and on-chain, the target device obtains the target public key portion from the target key as reset key information. It then obtains the asset information of the target digital asset in the target block. Based on this asset information and the target public key portion, the target device obtains reset asset information. Using the reset key information and reset asset information as reset information, a fourth transaction is performed to reset the data. The target device then sends a fourth transaction carrying this reset information and invoking the target contract to the blockchain node. Figure 4 shows the target device sending a notification message including target block information to the user device, informing the user that changes to the target digital asset are invalid after the target block. Off-chain and on-chain, the target device obtains the target public key portion from the target key as reset key information. It then obtains the asset information of the target digital asset in the target block. Based on this asset information and the target public key portion, the target device obtains reset asset information. Using the reset key information and reset asset information as reset information, a fourth transaction is performed.The data reset operation sends a fourth transaction carrying the reset information to the blockchain node and invokes the target contract. Figure 5 shows the attached figure from the HK 30135245 A manual. The computer system consists of 1000 processors, 1002 input / output (I / O) interfaces, 1008 memory, 1004 storage, and 1006 communication interfaces. Figure 6 shows the HK 30135245 A.