Spot transaction management method based on block chain privacy protection calculation

Abstract

The invention provides a spot transaction management method based on blockchain privacy protection calculation, and belongs to the technical field of spot transaction. Building a block chain node at each transaction participant, and constructing a transaction block chain; distributing and storing the service information on each bookkeeping node of each transaction participant of the block chain; encrypting a key data plaintext in the service information to generate a key data ciphertext; after zero-knowledge proof is carried out on the key data ciphertext, transaction operation is carried out in a ciphertext state; performing zero-knowledge proof on the ciphertext obtained by the transaction operation; after the key data ciphertext, the ciphertext obtained through operation and the zero-knowledge proof serve as parameters after the key data ciphertext, the ciphertext obtained through operation and the zero-knowledge proof are passed, and the parameters are transmitted to the block chain in a mode of calling a block chain intelligent contract interface; and block data and a transaction data list in the block chain are obtained through a block chain bottom layer interface, and a transaction process is traced. According to the invention, the transaction information is stored in the block chain, decentralization of the transaction is realized, the efficiency is improved, and transparency and credibility of transaction management are realized.

Description

Technical Field

[0001] The present invention relates to the field of spot trading technology, and in particular to a spot trading management method based on blockchain privacy protection computing. Background Art

[0002] As an efficient market mechanism, spot trading of commodities allows enterprises to complete the purchase and sale of commodities in a short period of time, thereby quickly responding to market changes. This trading method covers various types such as basis trading, fixed price trading and futures-for-cash, providing enterprises with a series of flexible risk management and cost control measures, helping to reduce operating costs, improve capital efficiency, and increase delivery flexibility. However, due to the imbalance of supply and demand between the two parties to the transaction, the large price fluctuations in the commodity market, the funds and credit of the trading parties, there are risks of default such as arrears of payment, delayed or refused delivery, and issuing false warehouse receipts in the transaction, causing losses to the transaction participants. Therefore, the performance bond system is implemented. If one party violates the contract agreement, the other party has the right to compensate for the corresponding losses with the performance bond, but at the same time, it has the disadvantages of capital occupation, increased costs, market volatility risks, market liquidity impact and dependence on financial markets.

[0003] In the existing methods, spot trading is often conducted through centralized trading platforms, but there are problems such as low efficiency, insufficient security, and inconvenient supervision. Centralized trading platforms have a set of fixed trading rules and processes, which are applicable to a limited range of goods or services. In a rapidly changing market environment, it is difficult for centralized platforms to quickly adapt to new business needs or market trends. Any changes to rules or processes require strict and complex approval processes and documentation, which is not only time-consuming, but also increases transaction costs and time delays, resulting in limited ability to respond to market changes. And with the increase in the number of users and transaction volume, centralized platforms face scalability issues, leading to system overload, affecting transaction processing speed and user experience. And there are certain security risks in centralized systems when processing sensitive data, especially when it comes to key information such as inventory information, production data, and transaction data. Key data is stored in centralized systems. If the system is attacked, a large amount of data will be leaked, causing huge losses to enterprises and users. In order to protect data, centralized systems will use encryption technology, but the custody of secret keys leads to a small number of people or systems having access to all keys, that is, having full control over sensitive data. Concentrated authority can lead to abuse of power or misconduct. In transaction management, the audit process of the centralized system is not transparent, and data is stored in a centralized database, which is at risk of being tampered with or deleted. Data integrity relies on the integrity and security measures of the centralized entity. If the centralized entity fails or acts maliciously, data integrity may be threatened, resulting in losses to customers and businesses.

[0004] Therefore, a transaction management method is needed to improve transaction efficiency and protect transaction security. Summary of the invention

[0005] In view of this, the present invention provides a spot transaction management method based on blockchain privacy protection computing to solve the problem that efficiency and transaction security cannot be achieved at the same time in existing transaction methods.

[0006] To this end, the present invention provides the following technical solutions:

[0007] A spot transaction management method based on blockchain privacy protection computing, comprising:

[0008] Build blockchain nodes at each transaction participant to construct a transaction blockchain;

[0009] Distribute and store business information on each accounting node of each transaction participant in the blockchain;

[0010] Encrypt the key data plaintext in the business information to generate key data ciphertext;

[0011] After the key data ciphertext passes the zero-knowledge proof, the transaction operation is performed in the ciphertext state;

[0012] Perform zero-knowledge proof on the ciphertext obtained from the transaction operation;

[0013] After passing, the key data ciphertext, the ciphertext obtained by calculation and the zero-knowledge proof are passed to the blockchain as parameters by calling the blockchain smart contract interface;

[0014] Obtain the block data and transaction data list in the blockchain through the underlying blockchain interface to trace the transaction process.

[0015] Furthermore, the transaction participants include: cargo owners, warehouses, exchanges, traders and banks.

[0016] Furthermore, the encrypting of the key data plaintext in the business information to generate the key data ciphertext includes:

[0017] The blockchain client uses the elliptic curve algorithm to generate a key pair including a public key and a private key;

[0018] The key data is homomorphically encrypted based on the public key in the key pair to generate the key data ciphertext:

[0019] The plaintext m is converted into a triple (C, D, H) through the public key H, the generator G of the elliptic curve group and the random number y, where C = G y , D=G m ·H y .

[0020] Furthermore, the zero-knowledge proof includes:

[0021] Decompose the key data plaintext into a binary number of 31 bits;

[0022] Split the given ciphertext triple (C, D, H) and call the member set to prove that the plaintext of each split (C, D, H) is 0 or 2 i ;

[0023] For plaintext (C, D, H) outside the range, it cannot be written as a 31-bit binary number and no legal proof is generated;

[0024] For the two homomorphic numbers that generate the legal proof, they are (C1, D1, H) and (C2, D2, H). After the homomorphic subtraction operation, the plaintext corresponding to the new homomorphic number is equal to 0, that is:

[0025] (C, D, H) = (C1 / C2, D1 / D2, H).

[0026] Furthermore, obtaining the block data and transaction data list in the blockchain through the underlying blockchain interface and tracing the transaction process includes:

[0027] Obtain the block data and transaction data list in the blockchain through the underlying blockchain interface, and use the corresponding interface to retrieve detailed transaction information through the transaction hash, including block number, block hash, transaction time, transaction sender, receiver, and transaction input information;

[0028] Using the private key and the ABI definition of the smart contract, the transaction input information is parsed through recursive length prefix deserialization and off-chain homomorphic ciphertext decryption to obtain the specific parameters and data structure of the smart contract call.

[0029] Furthermore, the key data includes the number of warehouse receipts and the amount of margin for spot transactions.

[0030] Advantages and positive effects of the present invention:

[0031] The present invention introduces blockchain technology into the spot trading system, and with the advantages of blockchain's distributed ledger, traceability, and non-tamperability, records key business processes and data on the blockchain, realizes data traceability of spot trading management, ensures accurate and clear transfer of spot goods rights, and improves transaction transparency and efficiency.

[0032] The present invention uses homomorphic encryption to store the spot inventory quantity in ciphertext on the blockchain, and calculates sensitive data in the ciphertext state on the chain. This achieves efficient calculation using blockchain, improves transaction efficiency, protects the information security of both parties to the transaction, and avoids property losses of both parties to the transaction. In the process of encrypted transmission, zero-knowledge proof is introduced to verify the authenticity of the encrypted transaction information, avoiding false transactions and causing economic losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 Schematic diagram of blockchain network deployment design in an embodiment of the present invention;

[0035] Figure 2 Basis trading management business flow chart in the embodiment of the present invention;

[0036] Figure 3 Design diagram of basis trading architecture based on blockchain privacy protection in an embodiment of the present invention;

[0037] Figure 4 Schematic diagram of the on-chain and off-chain interaction process in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] The homomorphic encryption used in the present invention can store the spot inventory quantity in ciphertext on the blockchain, and can perform the addition and subtraction calculations of the inventory quantity in the ciphertext state. Homomorphic encryption allows mathematical operations to be performed on encrypted data, realizing that calculation first and then decryption is equivalent to decryption first and then calculation.

[0041] Homomorphic encryption is a cryptographic technology based on the computational complexity theory of mathematical problems. Its main feature is that it allows specific operations to be performed on encrypted data, and the plaintext obtained after decrypting the calculation results is the same as the result obtained by directly performing the same operation on the original plaintext data.

[0042] The present invention provides a spot transaction management method based on blockchain privacy protection computing, which performs efficient and secure transaction management through blockchain, homomorphic encryption, and zero-knowledge proof technology.

[0043] S1. Combination Figure 1 , further illustrating the blockchain network deployment architecture of this embodiment:

[0044] When building a blockchain network, the deployment and maintenance costs, the security and reliability of blockchain nodes, and the characteristics of the basis trading management business requirements are comprehensively considered. In this embodiment, blockchain nodes are built in warehouses, industrial traders, exchanges and other participants, and smart contracts are deployed to execute on-chain logic and record transaction data. Smart contracts are automated contract codes running on blockchains that can execute pre-coded logic and trigger corresponding operations when specific conditions are met. Once a smart contract is deployed on a blockchain, its code will be recorded on the blockchain in an unalterable manner. Therefore, the execution logic of smart contracts is credible, and anyone can verify the behavior of the contract.

[0045] S2. Combination Figure 2 , further illustrating the business process in this embodiment:

[0046] In this embodiment, the scenario of the seller defining the contract and the seller listing in the basis transaction is used for explanation.

[0047] The participants in basis trading include cargo owners (sellers), traders (buyers), warehouses, exchanges, etc. In basis trading, both buyers and sellers can define basis trading contracts independently, and both buyers and sellers can publish trading intentions through listing operations.

[0048] As the owner of the spot warehouse receipt, the consignor is responsible for customizing the basis contract, applying for spot warehouse receipt registration, seller listing, delivery application, etc. When the seller lists, he / she will inquire about the spot inventory quantity and list it. When listing, the platform will send a spot inventory freezing instruction. After receiving the successful freezing result, the seller's listing will take effect. After entering the delivery period, the seller will initiate a delivery application through the platform and fill in the delivery amount.

[0049] The dealer's business includes: buyer delisting, payment of margin, confirmation of delivery application, and collection of buyer margin when the buyer delists successfully.

[0050] As a third-party custodian, the warehouse is responsible for verifying the authenticity of the warehouse receipts, executing warehouse receipt registration confirmation, warehouse receipt quantity update (in and out of warehouse), spot freezing, spot transfer, etc.

[0051] As the system management agency, the exchange is responsible for managing basis trading and circulation, publishing transaction information, etc., and when cargo owners, traders and warehouses apply to join the alliance chain, they open accounts at the exchange and file relevant information.

[0052] Combination Figure 3 , further illustrating the data structure of this embodiment:

[0053] The core business data of basis trading management includes: warehouse receipt registration information, basis trading contract information, transaction market information and other information. Its data structure is designed as follows:

[0054] Warehouse receipt registration information: warehouse receipt number, customer number, variety, warehouse number, warehouse name, original quantity on the warehouse receipt, remaining quantity on the warehouse receipt, place of origin, production date, quality inspection report number, registration application hash, warehouse review hash, warehouse receipt status (pending warehouse review, passed review, failed review), etc.

[0055] Basis trading contract information: product, transaction quantity, benchmark futures contract, basis, grade, place of delivery, last price quotation date, last delivery date, quotation party, guarantee calling party, transaction margin rate, etc.

[0056] Trading information: product type, grade, delivery location (warehouse), benchmark contract, basis price, instant price, buying and selling direction, transaction quantity (tons), grade description, last price quote date, last delivery date, etc. Because trading information is publicly released, the relevant data does not need to consider privacy protection needs.

[0057] During basis trading, the privacy protection of spot warehouse receipt quantity information (including the original quantity of warehouse receipts and the remaining quantity of warehouse receipts) in warehouse receipt registration information is crucial, as this data may affect market prices, competitive strategies and business secrets.

[0058] Therefore, combined with Figure 4 In this embodiment, as a preferred embodiment, the privacy protection calculation based on blockchain is further explained by the number of spot warehouse receipts:

[0059] In this embodiment, privacy-preserving computing includes two parts: on-chain and off-chain.

[0060] The off-chain part, i.e. the blockchain client, completes the generation of asymmetric key pairs based on the elliptic curve algorithm, including public and private keys. The key data is homomorphically encrypted based on the public key in the key pair. The characteristic of homomorphic encryption is that it allows direct calculation of ciphertext, and the result is also in encrypted form. Because the warehouse receipt quantity information on the chain is ciphertext, in order to ensure the credibility and privacy of the off-chain data, it is necessary to generate a zero-knowledge proof. The zero-knowledge proof can prove the authenticity of a certain assertion without leaking the original data. Through the zero-knowledge proof algorithm, the encrypted data is generated into a zero-knowledge proof based on the private key in the above key pair, and then the homomorphic ciphertext and zero-knowledge proof are passed to the blockchain as parameters by calling the blockchain smart contract interface.

[0061] The on-chain privacy computing process includes smart contracts and blockchain precompiled contracts. Smart contracts are responsible for calling precompiled contracts for complex calculations and verifications. Smart contracts perform zero-knowledge proof verification on the ciphertext data uploaded off-chain. After the verification logic passes, the inventory information is ciphertext calculated in the smart contract with the help of the homomorphic encryption algorithm, and the calculation results are saved on the blockchain. The digital signature of the underlying blockchain network realizes the signing of transactions. Transactions that pass the signature verification will be packaged into new blocks, and the consensus will be completed by the blockchain consensus mechanism.

[0062] S41. Blockchain network related encryption process

[0063] The digital signature and identity authentication system of the underlying blockchain network is based on the ECDSA algorithm, in which the elliptic curve group operation protocol uses the secp256k1 curve, whose curve equation is y 2 =x 3 +7, the prime number p in the finite field = 2 256 -2 32-977, which provides an efficient and secure method for digital signatures and key generation. In the ECDSA implementation, the Keccak-256 algorithm is used for hash calculation of relevant transaction data after RLP encoding. Keccak-256 can accept input data of any length, but the output hash value length is fixed to 256 bits. It has anti-collision properties and is widely used in the field of cryptography, including digital signatures, cryptocurrencies (such as smart contracts and transactions in Ethereum), and data integrity verification.

[0064] S42. Business data privacy protection calculation process

[0065] In the basis trading management business of this embodiment, it is necessary to perform ciphertext addition and subtraction operations on numerical content such as warehouse receipt quantity. Although fully homomorphic encryption supports any form of calculation on ciphertext, due to the large computing resource overhead, the computing efficiency problem still affects its use in actual application scenarios; therefore, this embodiment adopts an encryption algorithm with semi-homomorphic properties. Different encryption algorithms are used to perform data encryption and decryption, elliptic curve calculation, homomorphic calculation, zero-knowledge proof and other processes, including:

[0066] Homomorphic encryption system: This embodiment adopts the ElGamal public key cryptosystem with multiplicative homomorphism based on the discrete logarithm problem on the cyclic group to achieve key generation, data encryption, decryption and homomorphic addition calculation of warehouse receipt sensitive data.

[0067] The key generation process is a pure key exchange process: first, a 256-bit private key x is generated using the cryptographically secure pseudo-random number generator HMAC_DRBG, and then it is used as a random number to generate a public key H=G through the altbn128 elliptic curve calculation. x modp.

[0068] The data encryption process is a calculation process that mixes key exchange calculation with message calculation. The plaintext m is calculated through the public key H, the generator G of the elliptic curve group and the random number y:

[0069] C=G y , D=G m ·H y

[0070] A triple (C, D, H) is obtained, which represents the generated homomorphically encrypted ciphertext data.

[0071] The decryption process of homomorphic ciphertext data is based on the ciphertext data (C, D, H) and the private key x, combined with the Baby-step Giant-step algorithm, to restore the plaintext m = D·C -x .

[0072] Based on the above definition, the process of homomorphic ciphertext addition operation is the process of calculating C1, C2 and D1, D2 of this triple:

[0073]

[0074] That is, the addition calculation result of homomorphic ciphertext (C1, D1, H) and (C2, D2, H) can be expressed as (C1·C2, D1·D2, H).

[0075] From the above algorithm process, it can be seen that the premise for the addition operation of two homomorphic data is to have the same elliptic curve group generator G and public key H.

[0076] Homomorphic encryption elliptic curve algorithm: The elliptic curve group operation of ElGamal homomorphic operation uses the altbn128 curve, whose equation is y 2 =x 3 +3, prime number:

[0077] p=21888242871839275222246405745257275088696311157297823662689037894645226208583.

[0078] By calling the ecadd (address 0x06) and ecmul (address 0x06) methods of the altbn128 precompiled contract (elliptic curve underlying file altbn_128.sol), the efficiency of homomorphic operations in the execution of smart contracts in EVM is improved.

[0079] On the other hand, according to the description of EIP-1108, the Gas cost of the optimized altbn128 precompiled contract has been reduced a lot, among which the Gas consumption of eccadd has been reduced from 500 to 150, and the Gas consumption of ecmul has been reduced from 40,000 to 6,000.

[0080] In the scenario applied by this embodiment, the number of warehouse receipts is encrypted in the smart contracts of business logic such as warehouse receipt registration, seller listing, and confirmation of delivery application. Although each transaction is subject to the Gas Limit, the computational Gas consumption of each project is greatly reduced compared to before. It can ensure the normal execution of the homomorphic operations contained in the smart contract of each basis transaction without setting an excessively high Gas Limit. Therefore, the amount of information of the ciphertext data on the chain in the relevant smart contracts is reasonably expanded.

[0081] S43. Zero-knowledge proof generation and verification process

[0082] Zero-knowledge proofs are divided into interactive and non-interactive. Interactive ones require the Prover or Verifier to exchange multiple rounds of data to achieve the purpose of proof. Non-interactive protocols only require the prover to directly give a proof to achieve the purpose of proof, and anyone can participate in the verification.

[0083] In this embodiment, a non-interactive zero-knowledge proof system is used to sign the ciphertext message based on the ring signature algorithm implemented by Schnorr to prove the integrity of the message and authenticate the identity of the sender. The elliptic curve algorithm corresponding to the signature algorithm uses the altbn128 elliptic curve that is the same as the zk-SNARK framework.

[0084] However, what is different from the zk-SNARK zero-knowledge proof framework is that the implementation process in this embodiment does not rely on a third-party trusted setting to generate public numbers, reducing the threat of system vulnerabilities and attacks caused in the trusted setting. In the zero-knowledge calculation process, the prover generates a signature related to the above, which will become part of the proof to prove the authenticity of certain statements without revealing any content related to private information. The verifier verifies the validity of the signature provided by the prover by using the signature verification algorithm associated with the public key. In this embodiment, the following two types of zero-knowledge proof generation and signature verification processes are completed. The range proof is mainly used to prove that the plaintext corresponding to a ciphertext belongs to a certain range without revealing the private key; the equality proof is used to prove that the plaintext corresponding to two ciphertexts is the same.

[0085] Among them, range proof requires proving that the plaintext corresponding to a given ciphertext is greater than 0 without revealing the private key. The numerical range of the plaintext in the basis trading management business scenario is between 0 and 2. 31 -1. The specific method of generating the proof is: the plaintext needs to be decomposed into a 31-bit binary number, and then the given ciphertext triple (C, D, H) is split, and then the member set is called to prove that the plaintext of each split (C, D, H) is either 0 or 2. i As for the plaintext (C, D, H) outside the range, it cannot be written as a 31-bit binary number, so a legal proof cannot be generated.

[0086] Among them, for equality proof, the prover needs to prove that the plaintexts corresponding to the two homomorphic numbers are the same without revealing the private key. Implementation method: For two homomorphic numbers (C1, D1, H) and (C2, D2, H), after homomorphic subtraction, the plaintext corresponding to the new homomorphic number is equal to 0, that is:

[0087] (C,D,H)=(C1 / C2,D1 / D2,H)

[0088] Combined with the above range proof, it can be proved that the plaintext of (C,D,H) is 0.

[0089] S5. Smart contract interaction design for basis trading management business

[0090] In the process of writing smart contracts, it is necessary to define the structure of the smart contract on the chain and the corresponding mapping table according to the design of warehouse receipt registration information and basis trade contract information. The contents of the mapping table are assigned in functions such as spot warehouse receipt registration, seller listing, buyer delisting, delivery application, and delivery confirmation. The ABI (Application Binary Interface) interface file corresponding to the smart contract provides a standardized method for contract interaction and communication using different languages.

[0091] Through the underlying interface of the blockchain, the block data and transaction data list in the blockchain can be obtained, and the corresponding transaction information can be obtained through the transaction hash. According to the hash value of the transaction, the corresponding interface can be used to retrieve the detailed information of the transaction, including block number, block hash, transaction time, transaction sender, receiver, transaction input information (including contract call parameter information), etc. In the case of holding the private key corresponding to the homomorphic calculation, the ABI definition of the contract can be used to parse the transaction input information through RLP (recursive length prefix) deserialization and off-chain homomorphic ciphertext decryption, obtain the specific parameters and data structure of the contract call, and trace the transaction process of the basis trading management business. This not only enhances the transparency and credibility of the transaction, but also provides a powerful tool for supervision and auditing to ensure that basis trading is carried out in a safe and compliant environment.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spot transaction management method based on blockchain privacy protection computing, characterized in that: include: Build blockchain nodes at each transaction participant to construct a transaction blockchain; Distribute and store business information on each accounting node of each transaction participant in the blockchain; Encrypt the key data plaintext in the business information to generate key data ciphertext; After the key data ciphertext passes the zero-knowledge proof, the transaction operation is performed in the ciphertext state; Perform zero-knowledge proof on the ciphertext obtained from the transaction operation; After passing, the key data ciphertext, the ciphertext obtained by calculation and the zero-knowledge proof are passed to the blockchain as parameters by calling the blockchain smart contract interface; Obtain the block data and transaction data list in the blockchain through the underlying blockchain interface to trace the transaction process.

2. According to claim 1, a spot transaction management method based on blockchain privacy protection computing is characterized in that: The transaction participants include: cargo owners, warehouses, exchanges, traders and banks.

3. According to claim 1, a spot transaction management method based on blockchain privacy protection computing is characterized in that: The step of encrypting the key data plaintext in the business information to generate the key data ciphertext includes: The blockchain client uses the elliptic curve algorithm to generate a key pair including a public key and a private key; The key data is homomorphically encrypted based on the public key in the key pair to generate the key data ciphertext: The plaintext m is converted into a triple (C, D, H) through the public key H, the generator G of the elliptic curve group and the random number y, where C = G y , D=G m ·H y .

4. According to claim 1, a spot transaction management method based on blockchain privacy protection computing is characterized in that: The zero-knowledge proof includes: Decompose the key data plaintext into a binary number of 31 bits; Split the given ciphertext triple (C, D, H) and call the member set to prove that the plaintext of each split (C, D, H) is 0 or 2 i ; For plaintext (C, D, H) outside the range, it cannot be written as a 31-bit binary number and no legal proof is generated; For the two homomorphic numbers that generate the legal proof, they are (C1, D1, H) and (C2, D2, H). After the homomorphic subtraction operation, the plaintext corresponding to the new homomorphic number is equal to 0, that is: (C, D, H) = (C1 / C2, D1 / D2, H).

5. According to claim 1, a spot transaction management method based on blockchain privacy protection computing is characterized in that: The method of obtaining the block data and transaction data list in the blockchain through the underlying blockchain interface and tracing the transaction process includes: Obtain the block data and transaction data list in the blockchain through the underlying blockchain interface, and use the corresponding interface to retrieve detailed transaction information through the transaction hash, including block number, block hash, transaction time, transaction sender, receiver, and transaction input information; Using the private key and the ABI definition of the smart contract, the transaction input information is parsed through recursive length prefix deserialization and off-chain homomorphic ciphertext decryption to obtain the specific parameters and data structure of the smart contract call.

6. According to claim 1, a spot transaction management method based on blockchain privacy protection computing is characterized in that: The key data include the number of warehouse receipts and margin amount for spot transactions.

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