Block chain transaction method supporting privacy protection and identity tracking

Abstract

The invention relates to a block chain transaction method supporting privacy protection and identity tracking, and belongs to the technical field of block chain application. The specific process of the method is as follows: a financial management institution FMA generates a public key / private key pair for member registration and anomaly analysis according to a security parameter lambda, and group sending is performed on public keys; deploying a recharging contract and a payment contract on the block chain; each consumer ui registers to the FMA through a mobile device to become a member user of the transaction system, and the consumer holds a group signature key gski returned by the FMA after successful registration; the payment service operator cj registers to the FMA to become a member before providing service, and after successful registration, the payment service operator holds the FMA to return an identifier pid of each product terminal managed by the payment service operator; and the consumer calls a payment contract to carry out order payment based on the signature key gski and the identifier pid of the product terminal, and finally, the method further comprises an anomaly analysis link.

Description

Technical Field

[0001] The present invention relates to a blockchain transaction method that supports privacy protection and identity tracking, and belongs to the technical field of blockchain applications. Background Art

[0002] Blockchain technology is widely used in the field of electronic payment due to its advantages such as decentralization and transparency to provide safe, reliable and anonymous transaction services. Blockchain is essentially a distributed ledger technology that uses distributed node consensus algorithms, cryptography technology, chain structures and smart contract automatic script codes to achieve secure data generation, storage, verification and access. In a blockchain-based payment system, users use blockchain addresses that are unrelated to their real identities to conduct transactions, and the transaction records generated will be stored on the blockchain in an unalterable form. Although blockchain technology protects the privacy of user payments to a certain extent, its open and transparent characteristics may also lead to the leakage of user transaction privacy. Attackers can identify user behavior patterns and identity information by analyzing transaction data. This risk not only involves the user's financial security, but may also expose the user's consumption habits, geographic location and social network, which in turn has a serious impact on their personal privacy and life. This potential threat has prompted people to seek new means of privacy protection, among which the coin mixing mechanism is a common privacy enhancement technology.

[0003] The coin mixing mechanism increases the difficulty of de-anonymization analysis through fund flow by blurring the direct mapping relationship between the addresses of both parties in the transaction. This mechanism pools funds from multiple transactions from different users into a cash pool, and redistributes the transaction outputs through the coin mixing protocol, making the fund flow untraceable. This method greatly enhances the privacy protection effect of users in the blockchain network and effectively prevents de-anonymization analysis attacks such as address correlation analysis. However, due to its powerful privacy enhancement effect, the coin mixing mechanism has also become a tool for some criminals to engage in criminal activities and escape regulatory investigation, such as money laundering, fraud, and terrorist financing. Criminals circumvent traditional financial supervision and tracking mechanisms by creating a large number of false transactions and using multiple addresses to confuse the flow of funds, making regulatory tracing difficult.

[0004] Therefore, how to ensure the traceability of abnormal transactions in the payment system while protecting user privacy and achieving transaction anonymity, and strike a balance between privacy protection and security supervision has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to address the problem of difficult balance between privacy protection and regulatory traceability in existing blockchain transactions, and propose a blockchain transaction method that supports privacy protection and identity tracking. It combines the dynamic group signature algorithm with the mixing coin mechanism based on smart contracts, which not only effectively protects the transaction privacy and identity privacy of the paying user, but also realizes identity tracking for abnormal transactions.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A blockchain transaction method that supports privacy protection and identity tracking. The specific process is as follows:

[0008] Step 1, initialization: The financial management agency FMA generates a public key / private key pair for member registration and anomaly analysis based on the security parameter λ, and sends the public key to a group; deploys the recharge contract and payment contract on the blockchain;

[0009] Step 2: Member registration: Each consumer Register with FMA through a mobile device to become a member user of the trading system. After successful registration, the consumer holds the group signature key gsk returned by FMA i ; Payment service operators Before providing services, the payment service operator registers with FMA to become a member. After successful registration, the payment service operator holds the identifier pid of each product terminal managed by FMA;

[0010] Step 3: Account recharge: The consumer calls the recharge contract and converts the funds into recharge notes of different denominations through the account recharge operation, which serves as the payment key for specific funds.

[0011] Step 4: Order payment: The consumer pays based on the group signature key gsk i and the product terminal identifier pid, calling the payment contract to transfer the corresponding funds to the blockchain address of the payment service operator according to the product service sharing ratio through its own withdrawal function;

[0012] Module Five: Abnormal Analysis: Financial management institutions conduct abnormal analysis based on authorization requests, track the true identity of the payer for suspected abnormal transactions and issue verifiable proof materials to assist law enforcement agencies in security supervision and ensure financial security and compliance.

[0013] Furthermore, the specific process of step one of the present invention is:

[0014] First, FMA calls DGS.GKeyGen algorithm to generate public / private key pairs (IPK, isk) and (OPK, osk) for member registration and anomaly analysis according to the input security parameter λ; FMA publishes the group public key GPK = {IPK, OPK} and keeps the master key msk = {isk, osk} secret;

[0015] Second, FMA initializes two lists and Empty, used to store the registration information of consumers and payment service operators respectively. The data in the list can only be accessed by FMA;

[0016] Finally, FMA deploys the recharge contract S on the blockchain recharge and payment contract S payment .

[0017] Furthermore, the recharge contract S of the present invention recharge To: Allow consumers to complete fixed denomination d using their blockchain address addr a Recharge your account and receive the specified amount through your own deposit function a The contract then returns the recharge note to the consumer. If the consumer’s blockchain address balance is sufficient to pay for the recharge fee, the contract successfully returns a valid note. Otherwise, the contract returns an invalid note.

[0018] Furthermore, the payment contract S of the present invention payment is: Allow consumers to redeem denomination d a The recharge note note is sent to the PSP blockchain address addr specified in the transaction order m. PSP Pay the product service fee; if the consumer's signature verification is passed, the contract transfers the corresponding funds to the PSP blockchain address according to the product service sharing ratio r through its own withdrawal function, and returns the success mark true; otherwise, the contract returns the failure mark false.

[0019] Furthermore, the specific process of consumer registration in step 2 of the present invention is as follows:

[0020] First, consumers i Based on the input security parameter λ, call the DGS.UKeyGen algorithm to generate your own public key / private key pair (UPK i ,usk i );

[0021] Secondly, consumers i According to the public key UPK i And generate the blockchain address addr by calling the blockchain address generation function AddrGen i ;

[0022] Again, consumers i Send the entry {u i ,addr i ,UPK i}Send to FMA;

[0023] Then, consumer u i and FMA use algorithms DGS.Join and DGS.Issue respectively to interactively execute the DGS.GJoin protocol;

[0024] Finally, after verifying the received information, FMA generates (gsk i ,ureg i ), send the group signature key gsk i to u i , authorize u i Become a system member user and change u i Registration Informationureg i Add to List middle.

[0025] Furthermore, the specific process of payment service operator registration in step 2 of the present invention is as follows:

[0026] First, payment service operators c j Based on the input security parameter λ, DGS.UkeyGen is called to generate a public / private key pair (UPK j ,usk j );

[0027] Secondly, c j According to the public key UPK j And generate the blockchain address addr by calling the blockchain address generation function AddrGen j ;

[0028] Again, c j Safely put the entry {c j ,addr j ,UPK j ,n p} sent to FMA, where n p Indicates the number of product terminals managed by the payment service operator;

[0029] Then, FMA and c j Execute the algorithms DGS.Issue and DGS.Join to interact and complete the DGS.GJoin protocol registration;

[0030] Finally, when the protocol is completed, FMA is c j Each managed product terminal is assigned an identifier pid k , and will contain a collection of identifiers Registration information of creg j Add to List middle.

[0031] Furthermore, the specific process of step three of the present invention is:

[0032] First, the consumer queries its calculator list Get information about denomination d a Current consumption and generate a serial number

[0033] Secondly, the consumer uses the blockchain address addr to call the recharge contract S recharge Complete the recharge and obtain the recharge certificate note returned by the contract;

[0034] Once the received note is verified to be valid, a new update key A is set using the randomly generated reversible matrix A′, and the hash table is recalculated using this key. The key-value information (key, value) stored in

[0035] Then, get the new ticket key information (key′, value′) and add it to the hash table middle;

[0036] Finally, the denomination d a The current generated sequence number is increased by one, and the counter list is updated The denomination d stored in a Serial number information.

[0037] Furthermore, in step 3 of the present invention, when the consumer makes a first-time recharge, the account needs to be initialized. The specific initialization process is as follows:

[0038] Initialize a counter list, the counter list Used to record the current consumption of bills of different denominations ctr d,s And generate the serial number ctr d,e ;

[0039] Creating a Hash Table Used to store and manage the information of recharge tickets (key, value), where key and value represent the index and obfuscated information of the recharge ticket respectively;

[0040] Select a secure random function F of length l, generate a secure key K based on the security parameter λ, and create an updated key A whose initial value is the l-order identity matrix I.

[0041] Furthermore, the specific process of step 4 of the present invention is:

[0042] First, the consumer uses the algorithm DGS.GSign and the group signature key gsk i, signed with the payment service operator’s blockchain address addr Mer , product service identifier pid and specific transaction information info (such as timestamp and service amount) of order m, generate the corresponding signature σ;

[0043] Second, the consumer queries the counter list About denomination d a The current consumption and generated sequence number; using the security key K, the secure random function F, the update key A and the transposition function ConvertV, calculate the current consumption sequence number The corresponding key key; from the hash table Get the stored key-value information (key, value) and recalculate and restore to get the recharge voucher note;

[0044] Finally, based on the signature σ and the recharge voucher note, the consumer calls the payment contract S payment Make order payment. When the payment is successful and true is received, it will be stored in the hash table. Delete the used key-value information (key, value), denomination d a Current consumption sequence number Add one and update the counter list The denomination d stored in a Serial number information.

[0045] Furthermore, the specific process of step five of the present invention is as follows:

[0046] When a transaction order m is abnormal, FMA receives personal identity u through a secure channel i and order information m, and in After successfully verifying the member identity information, trace the generator of the signature σ, and the resulting proof Π indicates that the signature σ for m is generated by user u i Generate; Consumer i And / or law enforcement agencies verify the validity of Π through the algorithm DGS.Judge.

[0047] Beneficial Effects

[0048] First, while ensuring the privacy and security of user transactions, the present invention supports regulatory agencies in tracking the identities of abnormal transactions, effectively solving the problem of the difficulty in balancing privacy protection and regulatory traceability in existing blockchain transaction systems. The present invention combines the dynamic group signature algorithm with the currency mixing mechanism based on smart contracts, and enhances user transaction privacy by blurring the association of transaction addresses, preventing malicious attackers from using the public nature of the ledger to identify user behavior patterns. At the same time, it supports the identity tracking of abnormal transactions and addresses under authorized conditions, preventing lawbreakers from abusing the privacy protection strategy of this method to conduct illegal activities such as money laundering and tax evasion.

[0049] Second, the present invention has strong scalability, high decoupling between modules, adopts a unified interface design, supports general group signature algorithms and hybrid mechanisms, and can flexibly configure the group signature algorithms, hybrid mechanisms, and blockchain networks used according to the actual needs of actual application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 It is the entity composition and execution flow chart of the method of the present invention;

[0052] Figure 2 It is a simplified interactive flow chart of the consumer and the recharge contract of the present invention.

[0053] Figure 3 It is a simplified flow chart of interaction between consumers and payment contracts of the present invention. DETAILED DESCRIPTION

[0054] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0055] It should be noted that the following embodiments and features in the embodiments may be combined with each other in the absence of conflict; and, based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work are within the scope of protection of the present disclosure.

[0056] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0057] Definition: Entities participating in a blockchain transaction method that supports privacy and identity tracking.

[0058] The proposed method consists of four participating entities: financial management institutions, payment service operators, consumers (users), and blockchain networks.

[0059] 1) Financial Management Agency (FMA): FMA is a fully trusted authority, usually controlled by the government, responsible for the specific execution of the three modules of system initialization, member registration and exception tracking. It distributes key pairs and public parameters to registered members through secure communication channels and secretly stores the master key and member registration information.

[0060] 2) Payment Service Providers (PSPs): PSPs are a group of honest but curious entities that provide professional product services to consumers by deploying payment terminals throughout the city. They explicitly execute the algorithms of each module of the proposed method while trying to infer consumers' private information such as transaction addresses and real identities.

[0061] 3) Consumers: Consumers need to register as members of the payment system to obtain professional product services. Only a few consumers are malicious and try to forge payment transactions by impersonating other legitimate registered consumers to obtain illegal benefits or evade regulatory tracking.

[0062] 4) Blockchain network: Both permissioned and permissionless blockchain networks are applicable. Most of the full nodes in the blockchain network are honest, and they correctly package batch payment transactions into blocks and store them synchronously on the blockchain.

[0063] The following is combined with Figure 1 To Attachment Figure 3 The embodiments of the present invention are further described.

[0064] like Figure 1 As shown, a blockchain transaction method that supports privacy protection and identity tracking includes five steps: system initialization, member registration, account recharge, order payment, and anomaly analysis, involving four participating entities.

[0065] Step 1, initialization: The financial management agency FMA generates a public key / private key pair for member registration and anomaly analysis based on the security parameter λ, and sends the public key to a group; deploys the recharge contract and payment contract on the blockchain;

[0066] Step 2: Member registration: Each consumer Register with FMA through a mobile device to become a member user of the trading system. After successful registration, the consumer holds the group signature key gsk returned by FMA i ; Payment service operators Before providing services, the payment service operator registers with FMA to become a member. After successful registration, the payment service operator holds the identifier pid of each product terminal managed by FMA;

[0067] Step 3: Account recharge: The consumer calls the recharge contract and converts the funds into recharge notes of different denominations through the account recharge operation, which serves as the payment key for specific funds.

[0068] Step 4: Order payment: The consumer pays based on the group signature key gsk i and the product terminal identifier pid, calling the payment contract to transfer the corresponding funds to the blockchain address of the payment service operator according to the product service sharing ratio through its own withdrawal function;

[0069] Module Five: Abnormal Analysis: Financial management institutions conduct abnormal analysis based on authorization requests, track the true identity of the payer for suspected abnormal transactions and issue verifiable proof materials to assist law enforcement agencies in security supervision and ensure financial security and compliance.

[0070] First, the general dynamic group signature algorithm and the smart contract-based currency mixing mechanism adopted by the proposed method are defined:

[0071] Definition 1: General dynamic group signature algorithm DGS = {GKeyGen, UKeyGen, GJoin, GSign, GVerify, Open, Judge}

[0072] 1) GKeyGen(λ)→(GPK,msk): With the security parameter λ as input, the trusted party calls the algorithm to generate the master key msk={isk,osk} and the group public key GPK={IPK,OPK}, where (IPK,isk) and (OPK,osk) represent the public / private key pairs of the issuing administrator and tracking administrator, respectively.

[0073] 2)UKeyGen(λ)→(UPK i ,usk i ): Taking the security parameter λ as input, user u i Execute the algorithm to generate a public / private key pair (UPK i ,usk i ), where UPK i Certified by an authoritative organization.

[0074] 3) User i The release manager interacts with the issue manager using the Join and Issue algorithms to execute the GJoin protocol. i , group public key GPK and private key usk i As input, the user finally obtains the group signature key gsk i . Use one of the master keys isk and the user public key UPK i and identity iAs input, the publishing administrator will register the user's registration information after interaction. i Add to registration list The registration list is only accessible to publishing administrators and tracking administrators.

[0075] 4) GSign(gsk i ,m)→σ: message m and group signature key gsk i As input, user u i Call this algorithm to generate a signature σ for m.

[0076] 5) GVerify(σ,m,GPK)→true / false: With signature σ, message m and group public key GPK as input, anyone can run the algorithm to verify the validity of signature σ. If σ is valid, the algorithm outputs true; otherwise, it outputs false.

[0077] 6) With signature σ, message m, one of the master keys osk and registration list As input, the tracking administrator executes the algorithm to track the signer of σ. The signer exists in the algorithm, and the algorithm outputs the identity u i And prove Π, prove u i Generates the preceding σ for m; otherwise, outputs ⊥.

[0078] 7)Judge(σ,m,Π,GPK,UPK i )→true / false: with signature σ, message m, proof Π, group public key GPK and user public key UPK i As input, anyone can run the algorithm to verify the validity of proof Π. If Π is valid, the algorithm outputs true; otherwise, it outputs false.

[0079] Definition 2: General smart contract-based currency mixing mechanism MS = {Deposit, Withdraw}.

[0080] 1) Deposit(addr, d) → note: This function takes blockchain address addr and denomination d as input, transfers funds with value d from addr to the contract, and generates a note to the owner of addr. The contract automatically inserts the hash and amount information of note as a new entry into the public list. Note can be regarded as the private key of mixed funds, and only the user holding note can withdraw the corresponding funds from the contract.

[0081] 2) Withdraw(addr,note,d)→true / false: This function takes blockchain address addr, note note and denomination d as inputs and transfers funds with value d to addr. If the transfer operation is successful, it returns true; otherwise, it returns false.

[0082] The embodiment of the present application provides a blockchain transaction method that supports privacy protection and identity tracking, which includes five steps: system initialization, member registration, account recharge, order payment and abnormality analysis.

[0083] 1. Initialization of financial management institutions

[0084] FMA takes the security parameter λ as input and first calls the algorithm DGS.GKeyGen to generate the public / private key pair (IPK, isk) and (OPK, osk) for member registration and anomaly analysis. FMA publishes the group public key GPK = {IPK, OPK} and keeps the master key msk = {isk, osk} secret. Two lists and The two lists are initialized to be empty and are used to store the registration information of consumers and payment service operators respectively. The data in these two lists can only be accessed by FMA. Subsequently, FMA deploys smart contract S on the blockchain. recharge and S payment ,The specific contents of the contract are shown below, and the execution of the system initialization is described in Algorithm 1.

[0085] Smart ContractS recharge It is a recharge contract that allows consumers to complete a fixed denomination d using their blockchain address addr a The contract receives the specified amount d through its own deposit function. a The contract will then return the recharge note to the consumer. If the consumer's blockchain address balance is sufficient to pay for the recharge fee, the contract will successfully return a valid note; otherwise, the contract will return an invalid note.

[0086] Smart ContractS payment is a payment contract that allows consumers to redeem a denomination of d a The recharge note note is sent to the PSP blockchain address addr specified in the transaction order m. PSP Pay product service fees. If the consumer's signature verification is passed, the contract transfers the corresponding funds to the PSP blockchain address according to the product service sharing ratio r through its own withdrawal function, and returns a success mark of true; otherwise, the contract returns a failure mark of false.

[0087]

[0088]

[0089] 2. Member Registration

[0090] Consumer registration: Each consumer Register with FMA via mobile device to become a member user of the trading system. i Using the security parameter λ as input, call UKeyGen to get your own public / private key pair (UPK i ,usk i )←DGS.UKeyGen(λ), based on the public key UPK i Generate the blockchain address addr through the blockchain address generation function AddrGen i ,addr j =AddrGen(UPK i ). It then sends the entry {u i ,addr i ,UPK i}Sent to FMA. Consumer u i and FMA use algorithms DGS.Join and DGS.Issue to interactively execute the DGS.GJoin protocol. After the DGS.GJoin protocol is executed, FMA generates (gsk i ,ureg i ), send the group signature key gsk i to u i , authorize u i Become a system member user and register your information i Add to List In. Consumer i Secretly holds the group signature key gsk i The execution of consumer registration is as described in Algorithm 2.

[0091]

[0092] Payment Service Operator Registration: A new payment service operator Before providing professional product services, you need to register with the FMA. Specifically, first, the operator c j Using the security parameter λ as input, call DGS.UkeyGen to generate a public / private key pair (UPK j ,usk j ), based on the public key UPK j Generate the blockchain address addr through the blockchain address generation function AddrGen j ; Second, it safely converts the entry {c j ,addrj ,UPK j ,n p} sent to FMA, where n p Indicates the number of product terminals managed by the payment service operator; then FMA and c j Execute the algorithms DGS.Issue and DGS.Join to complete the DGS.GJoin protocol registration. When the protocol is completed, FMA generates (gsk j ,creg j ), send the group signature key gsk j to c j , authorized j Become a system operator, and FMA is c j Each managed product terminal is assigned an identifier pid k , and will contain a collection of identifiers Registration information of creg j Add to List middle.

[0093] The registration of payment service operator is performed as described in Algorithm 3.

[0094]

[0095]

[0096] 3. Account Recharge

[0097] Consumers exchange funds for recharge notes of different denominations through account recharge operations. As the payment key for specific funds, the recharge note is essentially a string of length l that only the user knows. Figure 2 shown.

[0098] Account initialization is a pre-operation for the first account recharge, which initializes a counter list To record the current consumption and generation sequence number of bills of different denominations (i.e. ctr d,s and ctr d,e ). Set the initial value of the counter list to 1 (Algorithm 4, lines 3-7). In addition, the user creates a hash table It is used to store and manage the information of recharge tickets. It consists of (key, value), where key and value represent the index and obfuscated information of the recharge ticket respectively. The index is a secure random function selected by the user. and key Each time you recharge, you need to update the key with the new one you choose. Select a secure random function F of length l, generate a secure key K based on the security parameter λ, and create an update key A with an initial value of the l-order identity matrix I. Account initialization is performed as described in Algorithm 4.

[0099]

[0100]

[0101] After the account is initialized, the consumer can perform account recharge operations. The consumer first queries the counter list Get information about denomination d a The current consumption and generation sequence number (i.e. and ); then use the blockchain address addr to call the contract S recharge To complete the recharge, the contract uses the deposit function of the mixing service contract to transfer the specified amount d a The assets are transferred to the cash pool, and then the recharge note is returned to the user. If the balance is sufficient, the deposit function is called to return a valid note, that is, the recharge voucher note returned by the contract is obtained; when the received note is verified to be valid, a new update key A is set using the randomly generated reversible matrix A′, and the hash table is recalculated using the key The key-value information (key, value) stored in the , and the derived new bill key-value information (key′, value′) is added to the hash table T (Algorithm 5, lines 7-17); finally, the denomination d a The current generated sequence number is increased by one, and the counter list is updated The denomination d stored in a If the returned ticket is an empty string, it means that the account recharge failed and the program terminates abnormally.

[0102] This recharge method avoids the risk of privacy leakage caused by direct transactions between consumers and payment service operators by introducing a cash pool.

[0103]

[0104]

[0105] 4. Order Payment

[0106] Consumer calls payment contract S payment Realize the purchase and payment of product services. Specifically, first, the consumer uses the algorithm DGS.GSign and the group signature key gsk i, sign the order m marked with the payment service operator blockchain address addrMer, product service identifier pid and specific transaction information info, and generate the corresponding signature σ. Then, the consumer queries the counter list The current consumption and generation sequence number of denomination d (i.e. and ) ; Use the security key K, the secure random function F, the update key A and the transposition function ConvertV to calculate the current consumption sequence number The corresponding key key; from the hash table Get the stored key value information (key, value) and recalculate and restore the recharge voucher note. Then, the consumer calls the contract S payment Make order payment. When the payment is successful and true is received, it will be stored in the hash table. Delete the used key-value information (key, value), denomination d a Current consumption sequence number Add one and update the counter list The denomination d stored in a After the payment service operator confirms that the order payment is successful, it will provide the user with the corresponding product services.

[0107] The execution of order payment is as described in Algorithm 6.

[0108]

[0109] 5. Abnormal Analysis

[0110] When a transaction order m is abnormal, for example, consumer u i Successful payment but no receipt from payment service operator j When a law enforcement agency needs FMA’s cooperation in investigating suspected transactions, FMA can provide proof of analysis. i , order information m and signature σ, and in Verify i FMA uses the DGS.Open algorithm and the master key osk to perform anomaly analysis and obtains the generator u and proof Π of the signature σ, where proof Π indicates that the signature σ for the order information m is generated by user u. i is the same person, then FMA returns the proof Π to the anomaly analysis requester (i.e. u i or law enforcement agencies). Consumer i Or law enforcement agencies can verify the validity of Π through algorithm DGS.Judge. The execution of anomaly analysis is described in Algorithm 7.

[0111]

[0112] In the initialization phase of the system in the embodiment of the present application, the financial management agency (FMA) first needs to initialize the blockchain network, including deploying blockchain nodes, configuring infrastructure, and issuing recharge and payment contracts. This stage needs to ensure that the smart contract and blockchain network operate normally and accurately to provide support for the subsequent functional operations of each module.

[0113] In the member registration phase of the embodiment of this application, consumers and payment service providers (PSP) need to register with FMA in advance to become members of the payment system. After completing identity verification, consumers obtain an independent blockchain address, and payment service providers are authorized to allow registered terminals to provide product services. This step ensures the legitimacy of the transaction and provides a basis for subsequent identity tracking and abnormal transaction analysis.

[0114] In the account recharge phase of the present application embodiment, the consumer interacts with the recharge contract to obtain a deposit ticket by pre-depositing funds. In this stage, the coin mixing mechanism is used to confuse the source of funds to avoid the leakage of transaction amounts and account information in the subsequent PSP product service payment process, such as Figure 2 shown.

[0115] In the order payment process of the embodiment of the present application, consumers interact with the payment contract to pay the pre-generated PSP terminal product service order. The PSP confirms the transaction records and terminal product service order information on the blockchain. After confirmation, its terminal provides the corresponding product service. Based on smart contracts, the order payment process is transparent, preventing the source of transaction funds from being traced, and ensuring payment privacy and security. Figure 3 shown.

[0116] The financial management agency for abnormal analysis in the embodiment of the present application can conduct abnormal analysis based on the authorization request, track the true identity of the payee for suspected abnormal transactions and issue verifiable certification materials, so as to assist law enforcement agencies in security supervision and ensure financial security and compliance.

[0117] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A blockchain transaction method supporting privacy protection and identity tracking, characterized in that: The specific process is: Step 1, initialization: The financial management agency FMA generates a public key / private key pair for member registration and anomaly analysis based on the security parameter λ, and sends the public key to a group; deploys the recharge contract and payment contract on the blockchain; Step 2: Member registration: Each consumer u i Register with FMA through a mobile device to become a member user of the trading system. After successful registration, the consumer holds the group signature key gsk returned by FMA i ; Payment service operatorc j Before providing services, the payment service operator registers with FMA to become a member. After successful registration, the payment service operator holds the identifier pid of each product terminal managed by FMA; Step 3: Account recharge: The consumer calls the recharge contract and converts the funds into recharge notes of different denominations through the account recharge operation, which serves as the payment key for specific funds. Step 4: Order payment: The consumer pays based on the group signature key gsk i and the product terminal identifier pid, calling the payment contract to transfer the corresponding funds to the blockchain address of the payment service operator according to the product service sharing ratio through its own withdrawal function; Module Five: Abnormal Analysis: Financial management institutions conduct abnormal analysis based on authorization requests, track the true identity of the payer and issue verifiable certification materials for suspected abnormal transactions.

2. The blockchain transaction method supporting privacy protection and identity tracking according to claim 1, characterized in that: The specific process of step one is: First, FMA calls DGS.GKeyGen algorithm to generate public / private key pairs (IPK, isk) and (OPK, osk) for member registration and anomaly analysis according to the input security parameter λ; FMA publishes the group public key GPK={IPK, OPK} and keeps the master key msk={isk, osk} secret; Second, FMA initializes two lists and Empty, used to store the registration information of consumers and payment service operators respectively. The data in the list can only be accessed by FMA; Finally, FMA deploys the recharge contract S on the blockchain recharge and payment contract S payment .

3. The blockchain transaction method supporting privacy protection and identity tracking according to claim 2, characterized in that: The recharge contract S recharge To: Allow consumers to complete fixed denomination d using their blockchain address addr a Recharge your account and receive the specified amount through your own deposit function a The contract then returns the recharge note to the consumer. If the consumer’s blockchain address balance is sufficient to pay for the recharge fee, the contract successfully returns a valid note. Otherwise, the contract returns an invalid note.

4. The blockchain transaction method supporting privacy protection and identity tracking according to claim 2, characterized in that: The payment contract S payment is: Allow consumers to redeem denomination d a The recharge note note is sent to the PSP blockchain address addr specified in the transaction order m. PSP Pay the product service fee; if the consumer's signature verification is passed, the contract transfers the corresponding funds to the PSP blockchain address according to the product service sharing ratio r through its own withdrawal function, and returns the success mark true; otherwise, the contract returns the failure mark false.

5. The blockchain transaction method supporting privacy protection and identity tracking according to claim 2, characterized in that: The specific process of consumer registration in step 2 is as follows: First, consumers i Based on the input security parameter λ, call the DGS.UKeyGen algorithm to generate your own public key / private key pair (UPK i ,usk i ); Secondly, consumers i According to the public key UPK i And generate the blockchain address addr by calling the blockchain address generation function AddrGen i ; Again, consumers i Send the entry {u i ,addr i , UPK i }Send to FMA; Then, consumer u i and FMA use algorithms DGS.Join and DGS.lssue to interactively execute the DGS.GJoin protocol; Finally, after verifying the received information, FMA generates (gsk i ,ureg i ), send the group signature key gsk i to u i , authorize u i Become a system member user and change u i Registration Informationureg i Add to List middle.

6. The blockchain transaction method supporting privacy protection and identity tracking according to claim 2, characterized in that: The specific process of payment service operator registration in step 2 is as follows: First, payment service operators c j Based on the input security parameter λ, DGS.UkeyGen is called to generate a public / private key pair (UPK j ,usk j ); Secondly, c j According to the public key UPK j And generate the blockchain address addr by calling the blockchain address generation function AddrGen j ; Again, c j Safely put the entry {c j ,addr j , UPK j , n p } sent to FMA, where n p Indicates the number of product terminals managed by the payment service operator; Then, FMA and c j Execute the algorithms DGS.Issue and DGS.Join to interact and complete the DGS.GJoin protocol registration; Finally, when the protocol is completed, FMA is c j Each managed product terminal is assigned an identifier pid k , and will contain a collection of identifiers Registration information of creg j Add to List middle.

7. The blockchain transaction method supporting privacy protection and identity tracking according to claim 3, characterized in that: The specific process of step three is: First, the consumer queries its calculator list Get information about denomination d a Current consumption and generate a serial number Secondly, the consumer uses the blockchain address addr to call the recharge contract S recharge Complete the recharge and obtain the recharge certificate note returned by the contract; Once the received note is verified to be valid, a new update key A is set using the randomly generated reversible matrix A′, and the hash table is recalculated using this key. The key-value information (key, value) stored in Then, obtain the new ticket key information (key′, value′) and add it to the hash table middle; Finally, the denomination d a The current generated sequence number is increased by one, and the counter list is updated The denomination d stored in a Serial number information.

8. The blockchain transaction method supporting privacy protection and identity tracking according to claim 7, characterized in that: In step 3, when the consumer recharges for the first time, the account needs to be initialized. The specific initialization process is as follows: Initialize a counter list, the counter list Used to record the current consumption of bills of different denominations ctr d,s And generate the serial number ctr d,e ; Creating a Hash Table Used to store and manage the information of recharge tickets (key, value), where key and value represent the index and obfuscated information of the recharge ticket respectively; Select a secure random function F of length l, generate a secure key K based on the security parameter λ, and create an updated key A whose initial value is the l-order identity matrix I.

9. The blockchain transaction method supporting privacy protection and identity tracking according to claim 4, characterized in that: The specific process of step 4 is as follows: First, the consumer uses the algorithm DGS.GSign and the group signature key gsk i , signed with the payment service operator’s blockchain address addr Mer , product service identifier pid and specific transaction information info of order m, generate the corresponding signature σ; Second, the consumer queries the counter list About denomination d a The current consumption and generated sequence number; using the security key K, the secure random function F, the update key A and the transposition function ConvertV, calculate the current consumption sequence number The corresponding key key; from the hash table Get the stored key-value information (key, value) and recalculate and restore to get the recharge voucher note; Finally, based on the signature σ and the recharge voucher note, the consumer calls the payment contract S payment Make order payment. When the payment is successful and true is received, it will be stored in the hash table. Delete the used key value information (key, value), the current consumption sequence number of the denomination da Add one and update the counter list The denomination d stored in a Serial number information.

10. The blockchain transaction method supporting privacy protection and identity tracking according to claim 9, characterized in that: The specific process of step five is as follows: When a transaction order m is abnormal, FMA receives personal identity u through a secure channel i and order information m, and in After successfully verifying the member identity information, trace the generator of the signature σ, and the resulting proof Π indicates that the signature σ for m is generated by user u i Generate; Consumer i And / or law enforcement agencies verify the validity of Π through the algorithm DGS.Judge.

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