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 target digital assets, which include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing information on multiple accounts holding the target digital assets. The target digital assets held by a target account include a first asset portion and a second asset portion, one of which is a non-privacy asset portion, and the other is a privacy asset portion. The method is executed by a target device corresponding to the target account and includes: determining to perform an asset conversion; converting the target amount of digital assets from the first asset portion to the second asset portion; sending a first transaction to a node in the blockchain to invoke the target contract; and enabling the blockchain node to execute the asset conversion operation by running the target contract based on the first transaction.

Description

PAR2612067HK Specification 1 Method, Computer System, and Storage Medium for Digital Asset Processing on Blockchain Technical Field This specification relates to the field of blockchain, specifically to a method, computer system, and storage medium for digital asset processing on a 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. 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 a blockchain through one or more embodiments. According to a first aspect, a method for processing digital assets on a blockchain is provided. The blockchain issues target digital assets, which include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing holding information of multiple accounts for the target digital assets. Among the multiple accounts is a target account, and the target digital assets held by the target account include a first asset portion and a second asset portion, where one of the first asset portion and the second asset portion is a non-privacy asset portion, and the other is a privacy asset portion. The method is executed by a target device corresponding to the target account, and the method includes: determining to perform an asset conversion; the asset conversion involves converting a target amount of digital assets from the first asset portion to the second asset portion; sending a first transaction to a node of the blockchain to invoke the target contract; the first transaction includes asset conversion instruction information indicating the asset conversion; and causing the node of the blockchain to execute the asset conversion operation by running the target contract based on the first transaction.According to a second aspect, a method for processing digital assets on a blockchain is provided. The blockchain issues target digital assets, which include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing holding information of multiple accounts for the target digital assets. One of the multiple accounts is a target account, and the target digital assets held by the target account include a first asset portion and a second asset portion, where one of the first asset portion and the second asset portion is a non-privacy asset portion, and the other is a privacy asset portion. The method is executed by nodes of the blockchain and includes: receiving a first transaction that invokes the target contract; the first transaction includes asset conversion instruction information indicating an asset conversion for the target account; the asset conversion involves converting a target amount of digital assets from the first asset portion to the second asset portion; and executing the asset conversion operation by running the target contract based on the first transaction. According to a third aspect, a method for processing digital assets on a blockchain is provided. The blockchain issues target digital assets, which include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing holding information of multiple accounts for the target digital assets. Among the multiple accounts is a target account, and the target digital assets held by the target account include a first asset portion and a second asset portion, where one of the first asset portion and the second asset portion is a non-privacy asset portion, and the other is a privacy asset portion. The method includes: a target device corresponding to the target account determining to perform an asset conversion; the asset conversion transferring a target amount of digital assets from the first asset portion to the second asset portion; the target device sending a first transaction to a node of the blockchain invoking the target contract; the first transaction including asset conversion instruction information indicating the asset conversion; and the blockchain node executing the asset conversion operation by running the target contract based on the first transaction.According to a fourth aspect, a computer system is provided, relating to a blockchain, wherein the blockchain issues target digital assets, the target digital assets including unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets; a target contract is deployed in the blockchain, the target contract storing holding information of multiple accounts for the target digital assets; the multiple accounts include a target account, the target digital assets held by the target account including a first asset portion and a second asset portion, one of the first asset portion and the second asset portion being a non-privacy asset portion and the other being a privacy asset portion; 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, through which the target operation achieves the following steps: determining to perform an asset conversion; the asset conversion converting a target amount of digital assets in the first asset portion into the second asset portion; sending a first transaction to a node of the blockchain invoking the target contract; the first transaction including asset conversion instruction information for instructing the asset conversion; causing the node of the blockchain to execute the asset conversion operation by running the target contract based on the first transaction. According to a fifth aspect, a computer system is provided, relating to a blockchain, wherein a target digital asset is issued on the blockchain, the target digital asset including unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets; a target contract is deployed in the blockchain, the target contract storing holding information of multiple accounts for the target digital asset; the multiple accounts include a target account, the target digital asset held by the target account including a first asset portion and a second asset portion, HK 30135837 A PAR2612067HK Specification 3, one of the first asset portion and the second asset portion is a non-privacy asset portion, and the other is a privacy asset portion; the computer system includes a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it performs the following target operation at least once, through the target operation realizing the following steps: receiving a first transaction that invokes the target contract; the first transaction includes asset conversion instruction information for instructing an asset conversion for the target account; the asset conversion converts a target amount of digital assets in the first asset portion into the second asset portion; based on the first transaction, the asset conversion operation is performed by running the target contract. According to a sixth aspect, a computer-readable storage medium is provided, the storage medium storing a computer program that, when executed by a processor, implements the method described in any one of the first or second aspects above.The technical solutions provided by the embodiments of this specification can include the following beneficial effects: The blockchain-based digital asset processing solution provided by the embodiments of this specification issues target digital assets on the blockchain, including unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing information on multiple accounts holding the target digital assets. Each account holds a portion of the target digital assets, including a non-privacy asset portion and a privacy asset portion. Any account, when needing to convert between the non-privacy asset portion and the privacy asset portion, can send a first transaction to a node in the blockchain via its held device to invoke the target contract. The first transaction includes asset conversion instruction information indicating the asset conversion, enabling the blockchain node to execute the asset conversion operation by running the target contract based on the first transaction. This achieves flexible conversion between non-privacy digital assets and privacy digital assets, meeting users' different needs for digital assets. Since non-privacy digital assets and privacy digital assets are managed uniformly through the same contract, the difficulty of regulating digital assets is reduced, and the efficiency of digital asset use is improved. 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. Brief Description of the Drawings To more clearly illustrate the technical solutions of the embodiments of this specification, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 is a schematic diagram of a blockchain-based digital asset management system according to an exemplary embodiment of this specification. Figure 2 is a schematic diagram of a blockchain-based digital asset processing scenario according to an exemplary embodiment of this specification. Figure 3 is an interactive flowchart of a blockchain-based digital asset processing method according to an exemplary embodiment of this specification. HK 30135837 A PAR2612067HK Specification 4 Figure 4 is a schematic diagram of a computer system according to an exemplary embodiment of this specification. Detailed Description 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 in conjunction with 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 has advantages such as decentralization, traceability, and high security. In recent years, due to the rapid development of blockchain technology, various digital assets based on blockchain management have gradually 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 holder's account balance, the identity of transaction participants, and the transaction amount. However, in some scenarios, only plaintext digital assets can be used, and encrypted digital assets are not supported. Therefore, if a user's plaintext digital asset balance is insufficient, for example, they need to exchange their encrypted digital assets for other plaintext digital assets before they can use them. This not only reduces the efficiency of digital asset use but also increases the difficulty of regulating digital asset use. This specification provides a blockchain-based digital asset processing solution, issuing target digital assets on the blockchain that include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing information on multiple accounts holding the target digital assets. Each account's target digital assets include a non-privacy asset portion and a privacy asset portion. Any account, when needing to convert between non-privacy assets and privacy assets, can send a first transaction to a blockchain node via its device to invoke the target contract. This first transaction includes asset conversion instruction information, enabling the blockchain node to execute the asset conversion operation by running the target contract based on the first transaction. This achieves flexible conversion between non-privacy and privacy digital assets, meeting users' diverse needs for digital assets. Because non-privacy and privacy digital assets are managed uniformly through the same contract, the difficulty of regulating digital assets is reduced, and the efficiency of digital asset use is improved. Figure 1 is a schematic diagram of a blockchain-based digital asset management system according to an exemplary embodiment. 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. Issuer 102, regulator 103, and user 104 can all establish a communication connection with blockchain 101 through their respective devices. HK 30135837 A PAR2612067HK Specification 5 Blockchain 101, for example, includes 8 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 blockchain 101 including 8 nodes, the embodiments in this specification are not limited to this, and may include other numbers of nodes.Each node in the blockchain can generate the same state by executing the same transaction, and each node stores the same state database. At least one smart contract for managing digital assets can be deployed in blockchain 101 (each smart contract corresponds to a digital asset, and each digital asset is issued by an issuer). The smart contract can record information such as the total issuance of digital assets and the balance of each account. Issuer 102 is an institution / organization capable of creating and issuing digital assets on the blockchain. Issuer 102 can issue digital assets to user 104 through blockchain 101, and can also liquidate and destroy some or all of the 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 digital asset and the balance of each user. Regulator 103 is a participant that supervises the issuance and balance of digital assets. Regulator 103 can query information such as the amount of transactions related to digital assets, the balance of each user, and the issuance of digital assets from blockchain 101. Furthermore, when issuing or transferring digital assets, the issuer or transferor typically sends the issuance or transfer amount to regulator 103 simultaneously to monitor the issuance and transfer process. However, regulator 103 does not have the authority to operate on digital assets (such as issuance, transfer, liquidation, etc.). User 104 is an individual or organization holding digital assets. They can obtain a predetermined amount of digital assets from issuer 102, obtain a predetermined amount of digital assets from other users' accounts, and transfer a predetermined amount of 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 digital assets on blockchain 101. Figure 2 is a schematic diagram of a digital asset processing scenario on a blockchain according to an exemplary embodiment. As shown in Figure 2, in blockchain 200, a contract C for managing digital asset Z is deployed. Digital asset Z is issued by issuer A. Digital asset Z consists of two parts: an unencrypted, non-privacy digital asset Z1 and a homomorphically encrypted privacy digital asset Z2. Furthermore, non-privacy digital asset Z1 and privacy digital asset Z2 are convertible between each other. Digital asset Z is held by multiple users, each user corresponding to an account for digital asset Z. Contract C records the balance of digital asset Z for each account. The digital asset Z in any user's account can include a plaintext portion belonging to non-privacy digital asset Z1 and a ciphertext portion belonging to privacy digital asset Z2. The balance of digital asset Z in that account is the sum of the plaintext balance and the decrypted balance of the ciphertext portion.It should be noted that the non-privacy digital asset Z1 and the privacy digital asset Z2 correspond to the same unit. The amount of non-privacy digital asset Z1 can be homomorphically encrypted and directly added to the amount of privacy digital asset Z2. Alternatively, the amount of privacy digital asset Z2 can be homomorphically decrypted and added to the amount of non-privacy digital asset Z1. For example, as shown in Figure 2, the plaintext balance of the account with the username 0X12 is 1, and the decrypted ciphertext balance is 10. Therefore, the total balance of its digital asset Z is 11 (the sum of 10 and 1). Specifically, issuer A can issue / destroy a certain amount of non-privacy digital asset Z1 to any user, or issue / destroy a certain amount of privacy digital asset Z2 to any user, or simultaneously issue / destroy the same or different amounts of non-privacy digital asset Z1 and privacy digital asset Z2 to any user. A user can transfer a certain amount of non-privacy digital assets Z1 to another user individually, or transfer a certain amount of privacy digital assets Z2 to another user individually, or transfer the same or different amounts of non-privacy digital assets Z1 and privacy digital assets Z2 to another user simultaneously. Furthermore, any user can convert a certain amount of their held non-privacy digital assets Z1 into their held privacy digital assets Z2, or convert a certain amount of their held privacy digital assets Z2 into their held non-privacy digital assets Z1. The solution provided in this specification will be described in detail below with reference to specific embodiments. As shown in Figure 3, Figure 3 is an interactive flowchart illustrating a digital asset processing method on a blockchain according to an exemplary embodiment. The blockchain issues target digital assets, which may include unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing information on multiple accounts holding the target digital assets. Among the multiple accounts is the target account. The target digital assets held by the target account include a first asset portion and a second asset portion, where one of the first asset portion and the second asset portion is a non-privacy asset portion, and the other is a privacy asset portion. The target account corresponds to the target device. This method involves not only the target device but also blockchain nodes. Both the target device and the blockchain nodes can be implemented as any device, server, or cluster of devices with computing and processing capabilities. The method includes the following steps: In step 301, the target device determines to perform an asset conversion. In this embodiment, the asset conversion may be to convert a target amount of digital assets from a first asset portion to a second asset portion.For example, asset conversion can be either transferring a target amount of digital assets from the non-privacy asset portion to the privacy asset portion, or transferring a target amount of digital assets from the privacy asset portion to the non-privacy asset portion. The target device can first determine to perform the asset conversion. In some implementations, the user can directly instruct the target device to perform the asset conversion through preset operations. In other implementations, when the user needs to use digital assets in the second asset portion, the target device can first determine the amount of assets to be used in the second asset portion and compare the amount to be used with the balance of the second asset portion. If the comparison result indicates that the amount of assets to be used is greater than the balance of the second asset portion, then the asset conversion is determined. Specifically, for example, in some scenarios, if the user needs to use digital assets of amount m in the non-privacy asset portion, the amount m can be used as the amount of assets to be used in the non-privacy asset portion, and the balance n of the non-privacy asset portion can be determined. By comparing the amount m and the balance n, if the amount m is less than or equal to the balance n, the digital assets of amount m in the non-privacy asset portion can be used directly; if the amount m is greater than the balance n, then the asset conversion is determined. HK 30135837 A PAR2612067HK Specification 7 In step 302, the target device sends a first transaction invoking the target contract to the blockchain node. In this embodiment, after determining to perform an asset conversion, the target device can first obtain asset conversion instruction information, which may include the target plaintext and target ciphertext corresponding to the target amount. The target ciphertext may be homomorphically encrypted data obtained by homomorphically encrypting the target plaintext corresponding to the target amount. Then, the target device can further generate proof information, which may include at least a first zero-knowledge proof. The first zero-knowledge proof can be used to prove that the amounts corresponding to the target plaintext and the target ciphertext are consistent. For example, if the target plaintext is 'a' and the target ciphertext is 'b', the first zero-knowledge proof can be used to prove that after homomorphically decrypting the target ciphertext 'b', the resulting plaintext data is consistent with 'a' (or after homomorphically encrypting the target plaintext 'a', the resulting ciphertext data is consistent with 'b'). If the target amount of digital assets in the privacy asset portion is converted to the non-privacy asset portion (i.e., the first asset portion is the privacy asset portion, and the second asset portion is the non-privacy asset portion), the proof information can further include a second zero-knowledge proof to prove that the current balance of the privacy asset portion is greater than or equal to the target amount. This means that after subtracting the target ciphertext corresponding to the target amount from the total encrypted balance of the privacy asset portion, the remaining encrypted balance is still a non-negative value. Finally, the target device can send the first transaction invoking the target contract to the blockchain node based on the asset conversion instruction information and the proof information.The first transaction may include asset conversion instruction information to instruct the asset conversion. This instruction information includes not only the target plaintext and target ciphertext corresponding to the target amount, but also the account address corresponding to the target account, and information about the first and second asset portions (e.g., whether the conversion is from a non-privacy asset portion to a privacy asset portion, or vice versa). The first transaction may further include proof information. In step 303, the blockchain node executes the asset conversion operation by running the target contract based on the first transaction. In this embodiment, after receiving the first transaction, the blockchain node can execute it and call the target contract to perform the asset conversion operation. Specifically, the blockchain node can first perform a legality verification based on the proof information included in the first transaction. For example, it can verify whether the amounts corresponding to the target plaintext and target ciphertext included in the asset conversion instruction information are consistent based on a first zero-knowledge proof. Furthermore, if the target amount of digital assets in the privacy asset portion is converted to the non-privacy asset portion, it can also verify whether the current balance of the privacy asset portion is greater than or equal to the target amount based on a second zero-knowledge proof. If the amounts corresponding to the target plaintext and the target ciphertext are consistent, and the current balance of the privacy-verifying asset portion is greater than or equal to the target amount, then the legitimacy verification is successful. In this embodiment, after the legitimacy verification is successful, the blockchain node can reduce the target amount of digital assets in the first asset portion and increase the target amount of digital assets in the second asset portion based on the asset conversion instruction information. Specifically, in one implementation, if the first asset portion is a privacy-verifying asset portion and the second asset portion is a non-privacy-verifying asset portion, the target amount of digital assets can be subtracted from the ciphertext balance of the first asset portion based on the target ciphertext, and the target amount of digital assets can be increased from the plaintext balance of the second asset portion based on the target plaintext. HK 30135837 A PAR2612067HK Specification 8 In another implementation, if the first asset portion is a non-privacy-verifying asset portion and the second asset portion is a privacy-verifying asset portion, the target amount of digital assets can be subtracted from the plaintext balance of the first asset portion based on the target plaintext, and the target amount of digital assets can be increased from the ciphertext balance of the second asset portion based on the target ciphertext. The blockchain-based digital asset processing method provided in this specification involves issuing a target digital asset on the blockchain, comprising unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets. A target contract is deployed in the blockchain, storing holding information of multiple accounts for the target digital asset. Each account holds a non-privacy asset portion and a privacy asset portion of the target digital asset.Any account, when needing to convert between non-privacy assets and privacy assets, can send a first transaction via its device to a blockchain node to invoke the target contract. This first transaction includes asset conversion instruction information, allowing the blockchain node to execute the asset conversion operation by running the target contract based on the first transaction. This enables flexible conversion between non-privacy and privacy digital assets, meeting users' diverse needs for digital assets. Because both non-privacy and privacy digital assets are managed uniformly through the same contract, the difficulty of regulating digital assets is reduced, and the efficiency of digital asset use is improved. 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 flowchart can be executed in a different order. Additionally or alternatively, certain steps can be omitted, multiple steps can be combined into one step, and / or one step can be broken down into multiple steps. 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 medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. This specification also provides a computer system. Figure 4 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 certain embodiments, one or more computer systems 1000 provide the functionality described or illustrated herein. In certain embodiments, 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.Specific embodiments include one or more portions of one or more computer systems 1000. Here, references to computer systems may include computing devices, as appropriate, as described in HK 30135837 A PAR2612067HK Specification 9. Furthermore, references to computer systems may include one or more computer systems, as 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 without material spatial or temporal limitations. By way of example and not limitation, one or more computer systems 1000 may perform one or more steps of one or more methods described or illustrated herein in real time or in batch mode. Where appropriate, one or more computer systems 1000 may perform one or more steps of one or more methods described or illustrated herein at different times or at 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. While 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 storage 1006; decode and execute them; and then write one or more results to internal registers, internal caches, memory 1004, or storage 1006.In certain embodiments, processor 1002 may include one or more internal caches for data, instructions, or addresses. This disclosure contemplates that processor 1002 may include any suitable number of suitable 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 lookup buffers (TLBs). Instructions in the instruction cache may be copies of instructions in memory 1004 or memory 1006, and the instruction cache may accelerate retrieval of those instructions by processor 1002. Data in the data cache may be copies of data in memory 1004 or memory 1006 for instruction operations executed at processor 1002; results of previous instructions 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 may accelerate read or write operations of processor 1002. The TLB may 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 for execution by processor 1002 or data for operation 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 can retrieve instructions from internal registers or internal caches and decode them. During or after instruction execution, processor 1002 can write one or more results (which may be intermediate or final results) to internal registers or internal caches. Processor 1002 can then write one or more of these results to memory 1004.In a particular embodiment, processor 1002 executes only instructions in one or more internal registers or internal caches or memory 1004 (as opposed to memory 1006 or elsewhere), and operates only on 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) 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 contemplates any suitable RAM. Where appropriate, memory 1004 may include one or more memories 1004. Although this disclosure describes and illustrates specific memories, it contemplates any suitable memories. In a particular embodiment, memory 1006 includes mass storage for data or instructions. By way of example and not limitation, memory 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, memory 1006 may include removable or non-removable (or fixed) media. Where appropriate, memory 1006 may be internal or external to computer system 1000. In a particular embodiment, memory 1006 is a non-volatile solid-state memory. In a particular embodiment, memory 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 a large-capacity storage 1006 in any suitable physical form. Where appropriate, storage 1006 may include one or more storage control units facilitating communication between processor 1002 and storage 1006. Where appropriate, storage 1006 may include one or more storage units 1006.Although this disclosure describes and illustrates specific storage, any suitable storage is contemplated. 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 contemplates any suitable I / O devices and any suitable I / O interface 1008 for them. Where appropriate, I / O interface 1008 may include one or more devices or software drivers enabling 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 this disclosure describes and illustrates specific I / O interfaces, this disclosure contemplates any suitable I / O interface. 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 one or more 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 a combination 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 couples components of computer system 1000 to each other. 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 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 a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The various embodiments in this specification are described in a progressive manner, and similar or identical parts between embodiments can be referred to mutually. 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 description 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 30135837 A PAR2612067HK Claims 1 1. A method for processing digital assets on a blockchain, wherein the blockchain issues target digital assets, the target digital assets including unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets; a target contract is deployed in the blockchain, the target contract storing holding information of multiple accounts for the target digital assets; the multiple accounts include a target account, the target digital assets held by the target account including a first asset portion and a second asset portion, one of the first asset portion and the second asset portion being a non-privacy asset portion and the other being a privacy asset portion; the method is executed by a target device corresponding to the target account, the method comprising: determining to perform an asset conversion; the asset conversion being the conversion of a target amount of digital assets from the first asset portion to the second asset portion; sending a first transaction to a node of the blockchain invoking the target contract; the first transaction including asset conversion instruction information for instructing the asset conversion; causing the node of the blockchain to execute the asset conversion operation by running the target contract based on the first transaction. 1. The method of claim 1, wherein determining to perform an asset conversion includes: determining the amount of assets to be used for the second asset portion; comparing the amount of assets to be used with the balance of the second asset portion; and determining to perform the asset conversion if the comparison indicates that the amount of assets to be used is greater than the balance of the second asset portion. 2. The method of claim 1, wherein the asset conversion indication information includes target plaintext and target ciphertext corresponding to the target amount; the first transaction further includes proof information, the proof information including a first zero-knowledge proof proving that the amounts corresponding to the target plaintext and the target ciphertext are consistent. 3. The method of claim 3, wherein before sending the first transaction to a node of the blockchain, the method further includes generating proof information including the first zero-knowledge proof. 4. The method of claim 3, wherein the first asset portion is a privacy-preserving asset portion, and the second asset portion is a non-privacy-preserving asset portion; the proof information further includes a second zero-knowledge proof proving that the current balance of the first asset portion is greater than or equal to the target amount.6. A method for processing digital assets on a blockchain, wherein the blockchain issues target digital assets, the target digital assets including unencrypted non-privacy digital assets and homomorphically encrypted privacy digital assets; a target contract is deployed in the blockchain, the target contract storing holding information of multiple accounts for the target digital assets; the multiple accounts include a target account, the target digital assets held by the target account including a first asset portion and a second asset portion, one of the first asset portion and the second asset portion being a non-privacy asset portion and the other being a privacy asset portion; the method is executed by nodes of the blockchain, the method comprising: receiving a first transaction invoking the target contract; the first transaction including asset conversion instruction information for instructing an asset conversion for the target account HK 30135837 A PAR2612067HK claim 2; the asset conversion being the conversion of a target amount of digital assets in the first asset portion to the second asset portion; and executing the asset conversion operation by running the target contract based on the first transaction. 7. 8. The method of claim 6, wherein the asset conversion instruction information includes target plaintext and target ciphertext corresponding to the target amount; the first transaction further includes proof information, the proof information including a first zero-knowledge proof for proving that the amounts corresponding to the target plaintext and the target ciphertext are consistent. 9. The method of claim 7, wherein performing the asset conversion operation includes: performing a legality verification based on the proof information; after the legality verification is passed, reducing the target amount of digital assets in the first asset portion and increasing the target amount of digital assets in the second asset portion based on the asset conversion instruction information. 10. The method of claim 8, wherein the first asset portion is a privacy asset portion and the second asset portion is a non-privacy asset portion; wherein reducing the target amount of digital assets in the first asset portion and increasing the target amount of digital assets in the second asset portion based on the asset conversion instruction information includes: subtracting the target amount of digital assets from the ciphertext balance of the first asset portion based on the target ciphertext; increasing the target amount of digital assets in the plaintext balance of the second asset portion based on the target plaintext.10. The method of claim 8, wherein the first asset portion is a non-privacy asset portion and the second asset portion is a privacy asset portion; wherein, the step of reducing the target amount of digital assets in the first asset portion and increasing the target amount of digital assets in the second asset portion based on the asset conversion instruction information comprises: subtracting the target amount of digital assets from the plaintext balance of the first asset portion based on the target plaintext; and increasing the target amount of digital assets in the ciphertext balance of the second asset portion based on the target ciphertext. HK 30135837 A PAR2612067HK Manual Appendix 1 103 101 102 104 104a 104b Figure 1 HK 30135837 A PAR2612067HK Manual Appendix 2 0x12:io1h(10) 0x0e:091j(6) 0xb3:kwej(200) 0x88:c712(1) 0x12:1 0x0e:1882 0xb3:88 0x88:10 200 Blockchain Contract C Issuer A Non-privacy Digital Asset Z1 Privacy Digital Asset Z2 Digital Asset Z User User Figure 2 HK 30135837 A PAR2612067HK Manual Appendix 3 Target Device 301 Blockchain Node 302 The first transaction that determines the asset conversion is sent to the target contract. Based on the first transaction, the asset conversion operation is performed by running the target contract. Figure 3 shows the computer system 1000, processor 1002, input / output (I / O) interface 1008, memory 1004, storage 1006, communication interface 1010. Figure 4 shows HK 30135837 A.

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