CN109447791B - A method and device for fund transaction based on blockchain - Google Patents

Abstract

Embodiments of the present invention provide a blockchain-based fund transaction method and device. The method includes: the server in the blockchain receives the current transaction information sent by the client; the server obtains the last transaction information corresponding to the account identifier from historical transaction records; and verifies the current transaction sent by the client according to a preset verification algorithm Whether the random commitment, range proof and knowledge proof in the transaction information are valid; if the server verifies whether the random commitment, range proof and knowledge proof in this transaction information are all valid, the server will process this transaction according to the current transaction information . Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

Description

A method and device for fund transaction based on blockchain

technical field

The present invention relates to the technical field of Internet applications, in particular to a method and device for capital transaction based on block chain.

Background technique

In recent years, with the rapid development of loan business, the problem of loan risk management and control has become more and more severe. For example, malicious users may borrow a certain amount from each financial institution, and hide their past outstanding loan amounts when each financial institution (or bank) applies for a loan. In this case, the malicious user may make a large loan, and the loan amount may greatly exceed his ability to repay. If this behavior cannot be effectively controlled, this malicious over-lending will cause great harm to the financial system.

Currently, there is a simple way that financial institutions can prevent this kind of behavior: each financial institution shares each user's loan information with other financial institutions. However, this method has two important drawbacks: on the one hand, the bank exposes the user's loan information to others, which is a violation of the user's privacy; on the other hand, the financial institution exposes its own business information to other institutions , which is an invasion of the institution's own privacy.

Obviously, in the existing methods used by financial institutions to prevent malicious over-loan behavior of users, there is a lack of measures to protect the privacy of users and financial institutions, and it cannot guarantee that a user's total loan amount is less than a certain limit.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present invention is to provide a blockchain-based fund transaction method, so as to avoid the user's total transaction amount from exceeding the user's preset tradable amount range.

The specific technical solutions are as follows:

A first aspect provides a blockchain-based fund transaction method, the method is applied to a server in the blockchain, the server stores historical transaction records corresponding to each account identifier, and the historical transaction records in the historical transaction records are stored in the server. Including random commitment and scope proof, account identification and transaction type identification, the method includes:

Receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, and the current account identifier. The second random commitment and the second range proof corresponding to the remaining tradable amount of , the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

Obtain the last transaction record corresponding to the account identifier from the historical transaction record;

According to a preset verification algorithm, determine the first random commitment and the first range proof corresponding to the transaction amount, the second random commitment and the second range proof corresponding to the current remaining tradable amount of the account identifier, and the Whether the third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment are valid;

If the first random commitment, the first range proof, the second random commitment, the second range proof, the third random commitment and the knowledge proof corresponding to the third random commitment are valid, then according to The current transaction information is used to process the current transaction.

Further, before the step of receiving the current transaction information sent by the client, it may further include:

Receive account creation request information sent by the client; wherein, the account creation request information includes a user ID;

In the preset account information table, find out whether the account identification corresponding to the user identification is included;

If the account information table does not contain the account identifier corresponding to the user identifier, when receiving the knowledge certificate corresponding to the fourth random commitment sent by the client, verify the fourth random Whether the knowledge proof corresponding to the commitment is valid;

If the knowledge certificate corresponding to the fourth random commitment is valid, the account identifier corresponding to the user identifier and the total transaction amount are created.

In a second aspect, a blockchain-based fund transaction method is provided, the method is applied to a client, and the method includes:

Obtain the transaction application information input by the user, where the transaction application information includes an account identifier, a transaction type identifier and a transaction amount;

According to the transaction amount, determine the first random commitment and the first range proof corresponding to the transaction amount;

determining the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier;

According to the first random commitment corresponding to the transaction amount and the preset knowledge proof generation algorithm, determine the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

The transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, and the third random number of the account identifier. The knowledge proof corresponding to the commitment and the third random commitment constitutes the transaction information;

The current transaction information is sent to the server in the blockchain, so that the server verifies whether the current transaction information is correct according to a preset verification algorithm, and if correct, the current transaction processing is performed.

Further, before the step of acquiring the transaction application information input by the user, it may include:

Sending account creation request information to the server; wherein, the account creation request information includes a user ID;

Get the random number entered by the user;

determining a fourth random commitment according to the random number and a preset random commitment generation algorithm;

determining the knowledge proof corresponding to the fourth random commitment according to a preset knowledge proof generating algorithm;

Send the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to the server.

In a third aspect, a blockchain-based fund transaction device is provided, the device is applied to a server in the blockchain, and the server stores historical transaction records corresponding to each account identifier, and the historical transaction records in the historical transaction records Including random commitment and scope proof, account identification and transaction type identification, the device includes:

The receiving module is used to receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, the the second random commitment and the second range proof corresponding to the current remaining tradable amount of the account identifier, the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment;

an acquisition module, configured to acquire the last transaction record corresponding to the account identifier from the historical transaction record;

A determination module, configured to determine, according to a preset verification algorithm, a first random commitment and a first range proof corresponding to the transaction amount, and a second random commitment and a second range corresponding to the current remaining tradable amount of the account identifier proof, and whether the third random commitment identified by the account and the knowledge proof corresponding to the third random commitment are valid;

This transaction processing module is used for if the first random promise, the first range proof, the second random promise, the second range proof, the third random promise and the third random promise If the corresponding knowledge certificate is valid, the current transaction processing is performed according to the current transaction information.

Further, the device may also include:

an account creation request information receiving module, configured to receive account creation request information sent by the client; wherein, the account creation request information includes a user ID;

a search module, configured to search in the preset account information table whether the account identification corresponding to the user identification is included;

The verification module is configured to, if the account information table does not contain the account identifier corresponding to the user identifier, when receiving the knowledge certificate corresponding to the fourth random commitment sent by the client, verify the verification algorithm according to the preset knowledge certificate whether the knowledge proof corresponding to the fourth random commitment is valid;

A creating module is configured to create an account identifier corresponding to the user identifier and a total transaction amount if the knowledge certificate corresponding to the fourth random commitment is valid.

In a fourth aspect, a blockchain-based capital transaction device is provided, the device is applied to a client, and the device includes:

a transaction application information acquisition module, used for acquiring transaction application information input by a user, the transaction application information including an account identifier, a transaction type identifier and a transaction amount;

a first determining module, configured to determine, according to the transaction amount, a first random commitment and a first range proof corresponding to the transaction amount;

a second determining module, configured to determine the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier;

a third determination module, configured to determine the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment according to the first random commitment corresponding to the transaction amount and a preset knowledge proof generation algorithm;

This transaction information constitutes a module, which is used to combine the transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, and the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier. , The third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment constitute the transaction information;

The current transaction information verification module is used to send the current transaction information to the server in the blockchain, so that the server can verify whether the current transaction information is correct according to the preset verification algorithm. This transaction is processed.

Further, the device may also include:

an account creation request information sending module, configured to send account creation request information to the server; wherein the account creation request information includes a user ID;

The random number acquisition module is used to acquire the random number input by the user;

a fourth random commitment determination module, configured to determine a fourth random commitment according to the random number and a preset random commitment generation algorithm;

a knowledge proof determination module, configured to determine a knowledge proof corresponding to the fourth random commitment according to a preset knowledge proof generation algorithm;

A sending module, configured to send the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to the server.

A fifth aspect provides a server that stores historical transaction records corresponding to each account identifier, and the historical transaction records include random commitments and scope proofs, account identifiers and transaction type identifiers, including processors, communication interfaces, A memory and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

memory for storing computer programs;

When the processor is used to execute the program stored in the memory, the following method steps are implemented:

Receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, and the current account identifier. The second random commitment and the second range proof corresponding to the remaining tradable amount of , the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

Obtain the last transaction record corresponding to the account identifier from the historical transaction record;

According to a preset verification algorithm, determine the first random commitment and the first range proof corresponding to the transaction amount, the second random commitment and the second range proof corresponding to the current remaining tradable amount of the account identifier, and the Whether the third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment are valid;

If the first random commitment, the first range proof, the second random commitment, the second range proof, the third random commitment and the knowledge proof corresponding to the third random commitment are valid, then according to The current transaction information is used to process the current transaction.

In a sixth aspect, a client is provided, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

memory for storing computer programs;

When the processor is used to execute the program stored in the memory, the following method steps are implemented:

Obtain the transaction application information input by the user, where the transaction application information includes an account identifier, a transaction type identifier and a transaction amount;

According to the transaction amount, determine the first random commitment and the first range proof corresponding to the transaction amount;

determining the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier;

According to the first random commitment corresponding to the transaction amount and the preset knowledge proof generation algorithm, determine the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

The transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, and the third random number of the account identifier. The knowledge proof corresponding to the commitment and the third random commitment constitutes the transaction information;

The current transaction information is sent to the server in the blockchain, so that the server verifies whether the current transaction information is correct according to a preset verification algorithm, and if correct, the current transaction processing is performed.

The embodiments of the present invention provide a blockchain-based loan method and device, wherein the server in the blockchain receives the current transaction information sent by the client, and obtains the last transaction information corresponding to the account identifier from the historical transaction records; According to the preset verification algorithm, determine the first random commitment corresponding to the transaction amount in the current transaction information sent by the client, the first scope proof, the second random commitment corresponding to the current remaining tradable amount of the account identifier, the second Whether the range proof, the third random commitment of the account identifier, and the knowledge proof corresponding to the third random commitment are valid; if the first random commitment and the first range proof corresponding to the first random commitment and the second random commitment, the The second range certificate corresponding to the second random commitment, the third random commitment of the account identifier, and the knowledge certificate corresponding to the third random commitment are valid, and the current transaction is processed according to the current transaction information. Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

Of course, it is not necessary for any product or method to implement the present invention to simultaneously achieve all of the advantages described above.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a schematic flowchart of a blockchain-based fund transaction method provided by an embodiment of the present invention;

2 is a schematic flowchart of another blockchain-based capital transaction method provided by an embodiment of the present invention;

3 is a schematic structural diagram of a blockchain-based capital transaction device provided by an embodiment of the present invention;

4 is a schematic structural diagram of another blockchain-based capital transaction device provided by an embodiment of the present invention;

5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a blockchain-based fund transaction method, which is applied to a server in the blockchain, and the server may be a server set by each financial institution in the blockchain. The types of capital transactions in the capital transaction method provided in the embodiment of the present invention may include loan transactions and repayment transactions. The server stores historical transaction records corresponding to each account identifier.

Among them, historical transaction records may include random commitment and scope proof, account identification and transaction type identification. The transaction type identifier is used to distinguish the type of each transaction record, that is, whether the transaction is a loan transaction or a repayment transaction; if the transaction is a loan transaction, the transaction type identifier can be loan (Chinese: loan); The transaction is a repayment transaction, and the transaction type identifier can be repay (Chinese: repayment).

Since the random commitment and range proof are data calculated based on the transaction amount, and only the random commitment and the range proof are stored in the server without the transaction amount, the transaction amount corresponding to the random commitment cannot be determined by looking at the random commitment. That is, when each server in the blockchain only stores the random commitment and range proof of each account ID, each server realizes the hidden guarantee of the confidentiality of the user's transaction amount.

Based on the above theoretical basis, in the embodiment of the present invention, a plurality of financial institutions form an alliance, and the financial institutions in the alliance store the user's transaction data (such as loan amount or repayment amount, etc.) on the blockchain. Because random commitments can hide transaction data, random commitments stored on the blockchain not only realize resource sharing, but also hide the transaction data corresponding to random commitments. For example, when a user applies for a loan at a financial institution in the alliance, the institution can use all the loan data of the user on the blockchain (all loan data generated in the alliance) to determine "If the money is lent to this user, does the user's total loan amount exceed the total amount that he can loan". If the user fails this judgment, the financial institution will not lend to the user because "after the user has loaned this money, the total amount of all his loans will exceed the total amount he can lend", thus avoiding The user's total loan amount exceeds the user's maximum loan amount.

The following first introduces a blockchain-based fund transaction method provided by an embodiment of the present invention. Referring to FIG. 1 , the method includes the following steps:

S101: Receive the current transaction information sent by the client.

During implementation, a server in the blockchain creates a unique account identifier for a user of the client, and stores the account identifier in a preset account information table. When the client performs a capital transaction with a server in the blockchain, the client generates the transaction information and sends the transaction information to the server that conducts this transaction with the client. The server has verified this transaction After the random commitment and scope proof in the transaction information, the transaction is processed and part of the information in the transaction information is extracted, a transaction record is generated and stored; and the server sends the transaction record to all servers in the blockchain; Therefore, each server in the blockchain stores the same transaction record, and the transaction record is all transaction records made by each user with each server in the alliance.

The account identifier is used to distinguish different users, and corresponds to the user identifier one by one. The account identifier may be any identification information used to identify different users, for example, account ID (Identification, identification), account name, etc., which are not specifically limited in the present invention.

The current transaction information may include transaction amount, account identification, transaction type identification, first random commitment and first range certificate corresponding to the transaction amount, and second random commitment corresponding to the current remaining tradable amount of the account identification The knowledge proof corresponding to the second range proof, the third random commitment identified by the account, and the third random commitment.

Optionally, before the server receives the current transaction information sent by the client in step S101, the server may first receive the account creation request information sent by the client; Account identification; if the account information table does not contain the account identification corresponding to the user identification, the server, when receiving the knowledge proof corresponding to the fourth random commitment sent by the client, verifies the corresponding fourth random commitment according to the preset knowledge proof verification algorithm. Whether the knowledge proof is valid; if the knowledge proof corresponding to the fourth random commitment is valid, the account ID corresponding to the user ID and the total transaction amount are created.

The account creation request information may include a user ID, and the user ID is identification information used to distinguish different users, and may be a user ID, a user name, etc., which is not limited here.

During implementation, when the server receives the current transaction information sent by the client, the server searches in the preset account information table whether the account identifier in the current transaction information is stored. If the account identifier in the above-mentioned current transaction information is stored in the preset account information table in the server, it means that the user identifier corresponding to the account identifier is not the first time to conduct a fund transaction with a financial institution, then step S102 is executed; The set account information table does not store the account identifier in the above-mentioned current transaction information, indicating that the user identifier is the first time to conduct a fund transaction with a financial institution, and the server needs to create an account identifier for the user identifier.

Further, the server can receive the fourth random commitment sent by the client and the knowledge proof corresponding to the fourth random commitment; and verify whether the knowledge proof corresponding to the fourth random commitment is valid according to a preset knowledge proof verification algorithm. If the knowledge certificate corresponding to the fourth random commitment is valid, the server creates an account corresponding to the user ID for the user ID, and sets the account ID and the total transaction amount of the account.

In this embodiment of the present invention, the client can calculate R=kH according to the random number k input by the user; wherein, the coordinates of the point R are (x ₂ , y ₂ ); let r=x ₂ , if r=0, then Reselect the random number k; calculate the hash value of the value m according to the preset hash function: z=Hash(m); then calculate s=k ^-1 (z+r×sk), if s=0, then Reselect random number k. Finally, take the remainder of the calculation result s to obtain s', and determine {r, s'} as the knowledge proof corresponding to the fourth random commitment.

In the embodiment of the present invention, the following knowledge proof verification algorithm can be used to verify the knowledge proof {r, s'} corresponding to the fourth random commitment, and the specific calculation formula is as follows:

z=Hash(m)

w=s' ^-1

(x ₁ , y ₁ )=z×w×H+r×w×pk

Among them, m is the hash value sent by the client, and the hash value can be the hash value corresponding to the user ID, the hash value corresponding to the business serial number, or the hash value corresponding to the business serial number calculated by the client according to the preset hash function, or a financial institution. One or more of the hash values corresponding to information such as ID, r and s' are the signatures in the knowledge proof corresponding to the fourth random commitment, pk is the public key, and the coordinates of H are (x ₀ , y ₀ ).

If (x ₁ , y ₁ )=0, it is proved that the knowledge proof {r, s′} corresponding to the fourth random commitment is invalid; if (x ₁ , y ₁ )≠0, and x ₁ =r, then it is proved that The knowledge proof {r, s'} corresponding to the above fourth random commitment is valid.

In this embodiment of the present application, after the server verifies that the knowledge certificate corresponding to the fourth random commitment is valid, and creates a corresponding account ID and a total transaction amount for the user ID, the server can also create a corresponding total transaction amount S for the user ID according to the created user ID. , and determine the random commitment corresponding to the account identifier and the total amount S of capital transactions conducted by all financial institutions in the alliance.

Among them, the calculation formula of the random commitment preset in the server is:

CM=n×G+k×H

CM is a random commitment, n is the transaction amount input by the user, k is a random number input by the user, the coordinates of H are (x ₀ , y ₀ )), and G is the coordinate point (x ₀₁ , y ₀₁ ).

和服务器为该账户标识创建的交易总金额S可知，账户标识的交易总金额对应的随机承诺为：A fourth random promise based on the account ID sent by the client

From the total transaction amount S created by the server for the account ID, the random commitment corresponding to the total transaction amount of the account ID is:

为第四随机承诺。Among them, CM ₀ is the random commitment corresponding to the total tradable amount of the account identifier, S is the total amount of capital transactions between the account identifier and all financial institutions in the alliance, and the coordinates of G are (x ₀₁ , y ₀₁ ),

for the fourth random commitment.

After that, the server stores the account identifier, the total tradable amount of the account identifier, the random commitment corresponding to the total tradable amount of the account identifier, the knowledge proof corresponding to the random commitment of the total tradable amount, and the transaction type identifier in the blockchain. middle. When the server sends the above account identifier, the total tradable amount of the account identifier, the random commitment corresponding to the total tradable amount of the account identifier, the fourth random commitment, and the knowledge proof and transaction type identifier corresponding to the fourth random commitment to the blockchain When storing in other servers in the above information, other servers can verify the knowledge proof corresponding to the random commitment of the total tradable amount in the above information. The specific verification method is as described in the verification description process of the above knowledge proof. If the verification is passed, other servers in the blockchain store the above account ID, the total tradable amount of the account ID, the random commitment corresponding to the total tradable amount of the account ID, the fourth random commitment and the knowledge certificate corresponding to the fourth random commitment and transaction type identifier; otherwise, other servers in the blockchain discard the account identifier, the total tradable amount of the account identifier, the random commitment corresponding to the total tradable amount of the account identifier, the fourth random commitment, and the fourth random commitment. Proof of knowledge and transaction type identification.

In the embodiment of the present invention, the verification process of the knowledge proof corresponding to all random commitments may use the same verification algorithm as described above. Similarly, the embodiments of the present invention only provide an optional verification algorithm for knowledge proof, and any other verification algorithms that can be used for knowledge proof corresponding to random commitments can be applied to the embodiments of the present invention, which are not specifically limited here.

S102: Obtain the last transaction record corresponding to the account identifier from the historical transaction record.

In implementation, the server stores the transaction information of each transaction in the blockchain on the blockchain, and calls all transaction information before the current transaction information as historical transaction records; the historical transaction records may include Random commitment and range proofs, account IDs, and transaction type IDs.

The server obtains the last transaction information corresponding to the above account identification in the blockchain storing the historical transaction records, and reads the current remaining tradables corresponding to the account identification recorded in the last transaction information corresponding to the account identification The second random commitment corresponding to the amount, the server checks the current remaining tradable amount corresponding to the account identifier in the second random commitment according to the preset random commitment transaction amount checking method, and compares the current remaining tradable amount corresponding to the account identifier with the current remaining tradable amount corresponding to the account identifier. Compare the transaction amount of the account ID in the current transaction application sent by the client with the transaction amount of the current application, if the transaction amount of the account ID in the current transaction application sent by the client is greater than and/or equal to the current remaining balance corresponding to the account ID tradable amount, the server sends this transaction application failure information to the client; if the transaction amount of the account ID in the current transaction application sent by the client is less than the current remaining tradable amount corresponding to the account ID, the server will Step S104 is performed.

Optionally, if the current transaction information sent by the client is the first transaction application for a certain user ID, then the commitment corresponding to the remaining tradable amount in the last transaction information corresponding to the account ID queried by the server is exactly the same. It is also the commitment of the user's total tradable quota (obtained when the account is established). However, if the subsequent client sends a transaction application again, when the server queries the latest transaction information of the account ID, the server will find the random commitment of the current remaining tradable amount.

For example, the total transaction amount created by the server for the user whose account ID is P is S. In the transaction application information sent by the client for the first time, the loan amount applied for by the user is n1. Then, when the client second time When sending the transaction application information, in the commitment corresponding to the last remaining tradable amount corresponding to the account ID obtained by the server, the recorded current remaining loanable amount corresponding to the account ID is S-n1; The loan amount of the second application is n2, then when the client sends the third transaction application information, in the commitment corresponding to the last remaining tradable amount corresponding to the account ID obtained by the server, the current account ID corresponding to the recorded current The remaining loanable amount is S-n1-n2, and so on. It is understandable that, if the transaction application information sent by the client indicates that the transaction type is repay, that is, a repayment transaction, after the server has executed this transaction, in the commitment corresponding to the user's remaining tradable amount, the record is recorded. The current remaining tradable amount corresponding to the account identifier is S-n1+n2, where n2 is the repayment amount in the current transaction information sent by the client.

S103: According to the preset verification algorithm, determine the first random commitment and the first range certificate corresponding to the transaction amount in the current transaction information, and the second random commitment and the second range certificate corresponding to the current remaining tradable amount of the account identifier , and the third random commitment identified by the account and whether the knowledge corresponding to the third random commitment is valid.

In the implementation, the range proof is constituted by the algorithm of ring signature containing two public keys, which is provided by the client to the server in order to prove that the transaction amount in the random commitment sent by the client is within a certain range. data evidence.

The verification of the range proof corresponding to the random commitment is essentially the verification of the ring signature that constitutes the range proof. Specifically, the calculation formula for verifying the ring signature that constitutes the range proof is as follows:

T ₀ =c ₀ ×pk ₀ +z ₀ ×H

T ₁ =c ₁ ×pk ₁ +z ₁ ×H

h=Hash(pk ₀ ,pk ₁ ,T ₀ ,T ₁ )

Among them, pk ₀ is the user's public key, pk ₁ and pk ₂ are the preset public keys of other users, the coordinates of H are (x ₀ , y ₀ ), z ₁ and c ₁ are random numbers input by the user, T ₀ , T ₁ , c ₀ and z ₀ are parameters in the ring signature.

If the calculation result h and the parameter c ₁ in the range proof sent by the client perform a bit-by-bit modulo 2 operation (h⊕c ₁ ), and the obtained value is equal to the parameter c ₀ in the ring signature sent by the client, it proves that the above The ring signature is valid. Since the range proof is composed of a series of ring signatures, if the ring signature is valid, the range proof formed by the ring signature is also valid. Among them, the calculation process of the range proof will be introduced in the subsequent description.

Optionally, in the above step, the server determines, according to a preset verification algorithm, the first random commitment corresponding to the transaction amount in the current transaction information, the first range certificate and the second random amount corresponding to the current remaining tradable amount of the account identifier. After the commitment and the second range proof, as well as the knowledge corresponding to the third random commitment of the account ID and the third random commitment are valid, you can also judge whether the following formula holds:

CM _1,1 = CM ₀ -CM _1,0

为账户标识的第三随机承诺。Among them, CM _1,1 is the second random commitment corresponding to the current remaining tradable amount of the account identifier, CM ₀ is the random commitment corresponding to the total transaction amount corresponding to the account identifier, and CM _1,0 is the transaction amount corresponding to the current transaction information. The first random commitment, n ₁ is the transaction amount applied by the user in this transaction information, and the coordinates of G are (x ₀₁ , y ₀₁ ),

A third random commitment identified for the account.

和CM_1,1＝CM₀-CM_1,0等式成立，则服务器执行步骤S104；如果上述等式

和CM_1,1＝CM₀-CM_1,0等式不成立，则服务器向客户端发送本次交易申请失败信息。If the above

and CM _1,1 =CM ₀ -CM _1,0 equation is established, then the server executes step S104; if the above equation

If the equation of and CM _1,1 =CM ₀ -CM _1,0 does not hold, the server sends the client a message that the transaction application fails.

S104: If the knowledge certificates corresponding to the first random promise, the first range proof, the second random promise and the second range proof, the third random promise and the third random promise are valid, the current transaction is processed according to the current transaction information.

During implementation, the server proves that the knowledge certificates corresponding to the first random commitment, the first range proof, the second random commitment, the second range proof, the third random commitment and the third random commitment are valid according to the preset verification algorithm After that, the server processes the current transaction according to the transaction type identifier recorded in the current transaction information.

If the transaction type identifier recorded in the current transaction information is a loan identifier (ie loan), the server sends the amount of the loan applied for by the user in the current transaction information to the client. If the transaction type identifier recorded in the current transaction information is a repayment identifier (ie repay), the server receives the repayment amount recorded in the current transaction information sent by the client.

Further, after the server has processed the above transaction, the server may also send the first random commitment and the first range certificate corresponding to the transaction amount in the current transaction information sent by the client, and the account identifier corresponding to the current remaining tradable amount. The second random commitment and the second range proof, account identifier and transaction type identifier corresponding to the second random commitment are stored in the blockchain as historical transaction records.

The embodiment of the present invention provides a loan method. The server in the blockchain receives the current transaction information sent by the client, and then obtains the previous transaction information corresponding to the account identifier from the historical transaction records; according to a preset verification algorithm , determine the first random commitment corresponding to the transaction amount in the current transaction information, the first range certificate, the second random commitment corresponding to the current remaining tradable amount of the account identifier, the second range certificate, the account identifier The third random commitment and Whether the knowledge proof corresponding to the third random commitment is valid; if the first random commitment and the first range proof corresponding to the first random commitment and the second random commitment, the second range proof corresponding to the second random commitment, The knowledge corresponding to the three random commitments and the third random commitment is valid, and the transaction is processed according to the current transaction information. Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

Referring to FIG. 2, FIG. 2 is a schematic flowchart of another blockchain-based fund transaction method according to an embodiment of the present invention. The method is applied to a client and includes the following steps:

S201: Obtain transaction application information input by a user.

In implementation, every time the client performs a fund transaction with any server in the blockchain, it needs to apply for information to the input transaction first. The transaction application information may include an account identifier, a transaction type identifier, and a transaction amount. Similarly, the transaction type identifier is used to distinguish whether the transaction is a loan transaction or a repayment transaction; if the transaction is a loan transaction, the transaction type identifier can be loan; if the transaction is a repayment transaction, the transaction type identifier can be for repay.

When the client terminal receives the transaction application information input by the user, it needs to determine whether the user who sent the transaction application information is the first time to send the transaction application information; if not, step S202 is directly executed;

When the client receives the transaction application information input by the user, it needs to determine whether the user who sent the transaction application information is the first time to send the transaction application information; if not, step S202 is directly executed; If the user of the transaction application information is sending the transaction application information for the first time, the client terminal sends the account creation request information to the server; wherein, the account creation request information includes the user ID; and the client terminal obtains the random number input by the user; according to the user input determine the fourth random commitment; according to the preset knowledge proof generation algorithm, determine the knowledge proof corresponding to the fourth random commitment; combine the fourth random commitment and the knowledge corresponding to the fourth random commitment The proof is sent to the above server.

During implementation, the calculation formula of the preset random commitment generation algorithm may be as follows:

CM=n×G+k×H

Among them, CM is a random commitment, k is a random number input by the user, and the coordinates of H are (x ₀ , y ₀ ).

其中，

Since this step is the fourth random commitment calculation process performed when the user enters the transaction application information for the first time in order to create an account ID for the user ID in the server device, the value of the transaction amount n is zero, Then the fourth random commitment obtained by the client is

in,

Optionally, the random promise generation algorithm provided in the embodiment of the present invention is only one of many random promise generation algorithms, and any other generation algorithm for generating random promises can be applied to the embodiment of the present invention, which is not described here. Specific restrictions.

During implementation, the client can calculate R=kH according to the random number k input by the user; wherein, the coordinates of the point R are (x ₂ , y ₂ ); let r=x ₂ , if r=0, re-select the random number Number k; according to the preset hash function, calculate the hash value of the value m: z=Hash(m); then calculate s=k ^-1 (z+r×sk), if s=0, then re-select random number k. Finally, take the remainder of the calculation result s to obtain s', and determine {r, s'} as the knowledge proof corresponding to the fourth random commitment.

S202: Determine a first random commitment corresponding to the transaction amount and a first range proof corresponding to the first random commitment according to the transaction amount.

In the implementation, since the range proof is formed by the algorithm of the ring signature containing two public keys, the calculation of the range proof corresponding to the random commitment is the calculation of the ring signature.

The specific steps to generate a ring signature are as follows:

The user has his own public key pk ₀ and private key sk ₀ , and a public key pk ₁ of other people. The client can obtain T ₁ =k ₁ ×pk ₁ + according to three different random numbers k ₁ , k ₂ and k ₃ input by the user, and the preset public key pk ₀ , pk ₁ and private key sk ₀ k ₂ ×H and T ₀ =k ₃ ×H; and then according to the preset hash function, we can get:

Hash(pk ₀ , pk ₁ , T ₀ , T ₁ )

And through Hash(pk ₀ , pk ₁ , T ₀ , T ₁ ) and k ₁ for bit-by-bit modulo 2 addition, we get:

和z₀＝k₃-c₀sk₀

and z ₀ =k ₃ -c ₀ sk ₀

And {pk ₀ , pk ₁ , c ₀ , k ₁ , z ₀ , k ₂ } is called a ring signature with {pk ₀ , pk ₁ } as the public key. The validity of the ring signature can prove that the signer must hold the private key corresponding to a public key in pk ₀ and pk ₁ , otherwise the signer cannot generate a valid ring signature. However, the verifier cannot determine whether the signer holds the private key sk ₀ of pk ₀ or the private key sk _{1 of pk 1 .} The signer can adjust the order of the public keys in {pk ₀ , pk ₁ }, that is, the user can also generate a ring signature with {pk ₁ , pk ₀ } as the public key. But it should be emphasized that if the public key order is {pk ₁ , pk ₀ }, then when calculating the hash value, the order of the input should be Hash(pk ₁ , pk ₀ , T ₁ , T ₀ ), and the final The ring signature should also be {pk ₁ , pk ₀ , k, c ₀ , k ₂ , z ₀ }.

Since the range proof is constituted by the algorithm of ring signature including two public keys, it is the data evidence provided by the client to the server in order to prove that the transaction amount in the random commitment sent by the client is within a certain range. As long as the client can generate the above ring signature, and the ring signature is valid, the client proves that n in the random commitment CM=n×G+k×H belongs to (0, 2 ^d+1 ).

The procedure for generating a range proof for n is as follows:

The client converts n in the above into binary form, as follows:

n=n _d 2 ^d +n _d-1 2 ^d-1 +...+n ₁ 2+n ₀

Wherein, n _m =0 or 1, and the value of m is 0, 1, 2, . . . , d.

The client uses {n _m 2 ^m ×G+k _m ×H, nm 2 _m ×G+ _k ^m ×H-2 _m ×G} as the public key of the ring signature, and ^km as the private key of the ring signature, Compute a ring signature σ _m . If the ring signature σ _m is valid, it can prove that n _m must be 0 or 1.

In this way, the client can generate all σ _d , σ _d-1 , . . . , σ ₁ , σ ₀ . If σ _d , σ _d-1 , ..., σ ₁ , σ ₀ are all valid, it is proved that n belongs to (0, 2 ^d+1 ). {σ _d , σ _d-1 , ..., σ ₁ , σ ₀ } is the range proof of n.

The value of m is 1, 2, ..., d, and the specific process of generating σ _m is as follows:

When n _m = 0:

At this time { _{n m} 2 ^m G+ _km H, nm 2 _m G+ ^km H-2 _m G}= ^{ _km H, _km H-2 ^m G}, The random number input by the client and ^{km H is the discrete logarithm with respect to H; therefore, the above {n m 2 m G+km H, nm 2 m G+km H-2 m} _{G } generated by} ^the _client ^is A valid ring signature of the public key.

When n _m = 1:

At this time {n _m 2 ^m G+km H, nm 2 _m G+ ^{km H-2 m} _G }= _{{ n m} 2 ^m G+ _km H, ^km H}, since _km is determined by the user The random numbers entered at the client and ^km H are discrete logarithms with respect to H; therefore, the client-generated above { _{n m} 2 _m G+ _km H, nm 2 ^m G+ _km H-2 ^m G } is a valid ring signature for the public key.

When n _m ≠ 1 and n _m ≠ 0:

At this time, the public key is {n _m 2 ^m G+ ^{km H, nm 2 m G+km H-2 m} _G ^} _, because _{k m is} a random number entered by the user at the client and _km H is about The discrete logarithm of H; therefore, the user does not enter the private key corresponding to any of the public keys in the above {n _m 2 ^m G+ _km H, nm 2 _m G+ ^km H-2 _m G} in the ^client key, so the client cannot generate a ring signature with { ⁿ _m 2 ^m G+ _km H, nm 2 _m G+ ^km H-2 _m G} as the public key.

Therefore, as long as the client has {n _m 2 ^m G+ _km H, nm 2 _m G+ ^km H-2 _m G} as the public key to generate a ring signature, and the ring signature is valid, then _n ^m The value of is 0 or 1, so the range proof proves that a certain data in the random commitment corresponding to the range proof does not exceed the preset range.

For the specific implementation of the first random commitment corresponding to the transaction amount in this step and related explanation contents, reference may be made to the calculation process of the random commitment in the foregoing step S101 , which will not be repeated here.

S203: Determine the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier.

During implementation, for the specific implementation of the second random commitment and the second range proof corresponding to the remaining tradable amount in this step and related explanations, please refer to the calculation process of the random commitment in the above step S101 and the calculation process of the range proof in step S202. , which will not be repeated here.

S204: According to the first random commitment corresponding to the transaction amount and the preset knowledge proof generation algorithm, determine the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment.

During implementation, when the first random commitment CM=n×G+k×H corresponding to the transaction amount is obtained in step S201, the client calls kH in the first random commitment as the third random commitment of the account identifier; In the calculation process of the knowledge proof corresponding to the random commitment in step S101, the knowledge proof corresponding to the third random commitment can be obtained. The knowledge proof corresponding to the third random commitment identified by the account can prove that the third random commitment is indeed the random commitment corresponding to the transaction amount n input by the user.

S205: Compare the transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, the third random commitment of the account identifier and the The knowledge proof corresponding to the third random commitment constitutes the transaction information.

S206: Send the current transaction information to the server in the blockchain, so that the server verifies whether the current transaction information is correct according to the preset verification algorithm, and if correct, the current transaction processing is performed.

In this embodiment of the present invention, the same verification algorithm is used in the verification process of the range proofs corresponding to all random commitments, and the relevant explanation content can refer to the method embodiment shown in FIG. 1 above, which will not be repeated here.

The embodiment of the present invention provides a loan method based on blockchain, the server in the blockchain receives the current transaction information sent by the client, and then obtains the last transaction information corresponding to the account identifier from the historical transaction records; The preset verification algorithm determines the first random commitment corresponding to the transaction amount in this transaction information, the first range certificate, the second random commitment corresponding to the current remaining tradable amount of the account ID, the second range certificate, and the account ID. Whether the third random commitment and the knowledge proof corresponding to the third random commitment are valid; if the first random commitment and the first range proof corresponding to the first random commitment and the second random commitment and the second random commitment correspond , the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment are valid, and the current transaction is processed according to the current transaction information. Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

In order to make the description clearer, a block chain-based fund transaction method provided by an embodiment of the present invention will be described in detail below through a specific embodiment.

Assume that the user with the user ID 12 applies for a loan to the financial institution B in the blockchain for the first time; first, the financial institution B creates an account P for the user 12, which includes the following steps:

Step 1: The client sends the account creation request information to the server B, wherein the account creation request information includes the user identifier 12 .

Step 2: The user 12 selects a random number k, and determines a fourth random commitment according to the random commitment generation algorithm preset by the client.

Step 3: The client determines the knowledge proof corresponding to the fourth random commitment according to the preset knowledge proof generation algorithm.

Step 4: The client sends the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to server B;

When financial institution B (server B) receives the fourth random commitment sent by the client and the knowledge proof corresponding to the fourth random commitment, it verifies whether the knowledge proof corresponding to the fourth random commitment is valid according to the preset knowledge proof verification algorithm, If it is valid, the financial institution B creates an account identifier P for the user with the user identifier 12, and sets the total loanable amount S of all the financial institutions in the alliance for the user, and calculates all the financial institutions in the alliance for the user. the random commitment corresponding to the total loanable amount S of the The knowledge proof corresponding to the random commitment is stored in the blockchain whose transaction type is identified as loan.

Then, the user 12 inputs the first transaction application information, wherein the first transaction application information includes the account identifier P, the transaction type identifier loan and the transaction amount n; the client terminal, according to the transaction amount n in the transaction application information input by the user 12, Determine the first random commitment and the first range proof corresponding to the transaction amount n; the client sends the current remaining tradable amount acquisition information of the account identifier P to the financial institution B, and receives the current remaining balance of the account identifier P sent by the financial institution B. The tradable amount, and the second random commitment and the second range proof are determined according to the current remaining tradable amount of the account identifier P; according to the first random commitment corresponding to the first transaction amount n1 and the preset knowledge proof generation algorithm, Determine the third random commitment of the account identifier P and the knowledge certificate corresponding to the third random commitment; then, the client corresponds to the transaction application information, the first random commitment corresponding to the transaction amount, the first range certificate, and the remaining tradable amount of the account identifier. The second random commitment and the second scope proof of , the third random commitment of the account identification and the knowledge proof corresponding to the third random commitment constitute the transaction information; and the transaction information will be sent to financial institution B.

Since this is the first time that the user applies for a loan to financial institution B, the current remaining tradable amount of the account identifier P is the total amount S that the user can borrow in all financial institutions in the alliance. The second time is when the user sends a loan application to financial institution B for the second time. In the commitment corresponding to the last remaining tradable amount corresponding to the account identifier sent by financial institution B to the client, the current remaining loanable amount corresponding to the account identifier is recorded. is S-n1; among them, n1 is the loan amount applied by the user to the financial institution B.

After that, after receiving the current transaction information sent by the client, the financial institution B obtains the last transaction information corresponding to the account identifier P from the loan blockchain, and verifies the above-mentioned first random commitment according to the preset verification algorithm , whether the first range proof, the second random commitment, the second range proof, the third random commitment and the knowledge proof corresponding to the third random commitment are valid; if the first random commitment, the first range proof, the second random commitment, the second random commitment If the range proof, the third random promise and the knowledge proof corresponding to the third random promise are all valid, then the financial institution B sends the loan amount applied by the user 12 to the client; the server B sends the first random promise and the first range proof, the account The identifier P and the transaction type identifier Loan form historical transaction records and store the historical transaction records in the loan blockchain in the server.

Optionally, after the user 12 applies for the first loan at the financial institution B, the user needs to repay the loan within the time specified by the financial institution B; it is assumed that the user 12 makes the first repayment after the first loan , then the steps for the user 12 to repay the financial institution B are as follows:

Step 1: the user 12 inputs the first transaction application information in the client terminal, wherein the first transaction application information includes the account identifier P, the transaction type identifier repay and the repayment amount n1; the client terminal is based on the transaction application information input by the user 12 In the repayment amount n1, determine the first random commitment and the first range proof corresponding to the repayment amount n1; the client sends the current remaining tradable amount of the account ID P to the financial institution B to obtain the information, and receives the information sent by the financial institution B The current remaining tradable amount of the account identifier P, and according to the current remaining tradable amount of the account identifier P, the second random commitment and the second range proof are determined; according to the first random commitment corresponding to the first repayment amount n1 and the preset knowledge proof generation algorithm to determine the third random commitment of the account ID P and the knowledge proof corresponding to the third random commitment; then, the client sends the transaction application information, the first random commitment corresponding to the transaction amount and the first range proof , the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier, the third random commitment corresponding to the account identifier and the knowledge certificate corresponding to the third random commitment, form this transaction information; Sent to Financial Institution B.

Each repayment of the user can make up for the current remaining tradable amount of the account identifier P. For example, suppose the current remaining tradable amount of the account identifier P is S-n1; where n1 is the loan applied by the user to the financial institution B amount; when financial institution B receives the current transaction information sent by the client, it obtains the last transaction information corresponding to the account identifier P from the loan blockchain, and verifies the above-mentioned first random transaction according to the preset verification algorithm. Whether the knowledge proof corresponding to the commitment, the first range proof, the second random commitment, the second range proof, the third random commitment, and the third random commitment is valid; if the first random commitment, the first range proof, the second random commitment, the third random commitment The knowledge proof corresponding to the second range proof, the third random commitment and the third random commitment are all valid, and the financial institution B receives the repayment amount n1 sent by the client; at this time, after the user performs the first repayment transaction, the user is in the The remaining tradable amount of the money institution B becomes S-n1+n1; after that, the server B combines the first random commitment and the first range proof, the account identifier P and the transaction type identifier repay to form a historical transaction record, and records the historical transaction records. Transaction records are stored in the repayment blockchain in the server.

The embodiment of the present invention provides a loan method. The server in the blockchain receives the current transaction information sent by the client, and then obtains the previous transaction information corresponding to the account identifier from the historical transaction records; according to a preset verification algorithm , determine the first random commitment corresponding to the transaction amount in the current transaction information, the first range certificate, the second random commitment corresponding to the current remaining tradable amount of the account identifier, the second range certificate, the account identifier The third random commitment and Whether the knowledge proof corresponding to the third random commitment is valid; if the first random commitment and the first range proof corresponding to the first random commitment and the second random commitment, the second range proof corresponding to the second random commitment, If the third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment are valid, the current transaction is processed according to the current transaction information. Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

Based on the same technical concept, corresponding to the method embodiment shown in FIG. 1 , an embodiment of the present invention further provides a blockchain-based fund transaction device. As shown in FIG. 3 , the device is applied to a server in a blockchain. , the server stores historical transaction records corresponding to each account identifier, and the historical transaction records include random commitment and scope proof, account identifier and transaction type identifier, and the device includes:

The receiving module 301 is used to receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, and the current account identifier. The second random commitment and the second range proof corresponding to the remaining tradable amount of , the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

The obtaining module 302 is used for obtaining the last transaction record corresponding to the account identifier from the historical transaction record;

A determination module 303, configured to determine, according to a preset verification algorithm, a first random commitment and a first range certificate corresponding to the transaction amount, a second random commitment and a second range certificate corresponding to the current remaining tradable amount of the account identifier, and Whether the third random commitment identified by the account and the knowledge proof corresponding to the third random commitment are valid;

The current transaction processing module 304 is configured to, if the knowledge certificates corresponding to the first random commitment, the first range proof, the second random commitment, the second range proof, the third random commitment and the third random commitment are valid, then according to the current transaction information to process this transaction.

In this embodiment of the present invention, the above device may further include:

The account creation request information receiving module is used to receive the account creation request information sent by the client; wherein, the account creation request information includes the user ID;

A search module, configured to search whether the account identification corresponding to the user identification is included in the preset account information table;

The verification module is used to verify the fourth random commitment according to the preset knowledge proof verification algorithm when receiving the knowledge certificate corresponding to the fourth random commitment sent by the client if the account information table does not contain the account identifier corresponding to the user identifier Whether the corresponding knowledge proof is valid;

The creation module is configured to create an account ID corresponding to the user ID and the total transaction amount if the knowledge certificate corresponding to the fourth random commitment is valid.

Based on the same technical concept, corresponding to the method embodiment shown in FIG. 2 , an embodiment of the present invention further provides a fund transaction device. As shown in FIG. 4 , the device is applied to a client, and the device includes:

The transaction application information acquisition module 401 is used to acquire transaction application information input by the user, the transaction application information includes an account identifier, a transaction type identifier and a transaction amount;

The first determination module 402 is configured to determine the first random commitment and the first range proof corresponding to the transaction amount according to the transaction amount;

The second determination module 403 is configured to determine the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier;

The third determination module 404 is configured to determine the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment according to the first random commitment corresponding to the transaction amount and the preset knowledge certificate generation algorithm;

This transaction information constitutes a module 405, which is used to combine the transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, and the account identifier The third random commitment and the knowledge proof corresponding to the third random commitment constitute the transaction information;

The current transaction information verification module 406 is used to send the current transaction information to the server in the blockchain, so that the server can verify whether the current transaction information is correct according to the preset verification algorithm, and if it is correct, the current transaction is performed deal with.

In this embodiment of the present invention, the above device may further include:

The account creation request information sending module is used to send the account creation request information to the server; wherein, the account creation request information includes the user ID;

The random number acquisition module is used to acquire the random number input by the user;

The fourth random commitment determination module is used to determine the fourth random commitment according to the random number and the preset random commitment generation algorithm;

The knowledge proof determination module is used to determine the knowledge proof corresponding to the fourth random commitment according to the preset knowledge proof generation algorithm;

A sending module, configured to send the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to the server.

The embodiment of the present invention provides a loan device based on blockchain, the server in the blockchain receives the current transaction information sent by the client, and obtains the last transaction information corresponding to the account identifier from the historical transaction records; Set the verification algorithm to determine the first random commitment corresponding to the transaction amount in the current transaction information sent by the client, the first range certificate, and the second random commitment and the second range certificate corresponding to the current remaining tradable amount of the account ID. , whether the third random commitment identified by the account and the knowledge proof corresponding to the third random commitment are valid; The second range proof, the third random commitment of the account identifier, and the knowledge certificate corresponding to the third random commitment are valid, and this transaction is processed according to the current transaction information. Because the random commitment and range proof are combined with the blockchain in the embodiment of the present invention, while ensuring the confidentiality of the user's transaction amount, it can effectively prevent malicious users from malicious excess transactions in multiple financial institutions.

The embodiment of the present invention also provides a server, in which historical transaction records corresponding to each account identifier are stored, and the historical transaction records include random commitment and scope proof, account identifier and transaction type identifier, as shown in FIG. The processor 501, the communication interface 502, the memory 503 and the communication bus 504, wherein the processor 501, the communication interface 502, and the memory 503 complete the communication with each other through the communication bus 504,

a memory 503 for storing computer programs;

The processor 501 is configured to implement a fund transaction method provided by the embodiment of the present invention when executing the program stored in the memory 503 . The method includes:

Receive the current transaction information sent by the client. The current transaction information includes the transaction amount, the account ID and the transaction type ID, the first random commitment and the first range certificate corresponding to the transaction amount, and the current remaining tradable amount corresponding to the account ID. The second random commitment and the second range proof of , the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

Obtain the last transaction record corresponding to the account ID from the historical transaction record;

According to the preset verification algorithm, determine the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the current remaining tradable amount of the account identifier, and the third random number of the account identifier. Whether the knowledge proof corresponding to the commitment and the third random commitment is valid;

If the knowledge certificates corresponding to the first random promise, the first range proof, the second random promise, the second range proof, the third random promise and the third random promise are valid, the transaction will be processed according to the current transaction information.

For the specific implementation of each step of the method and related explanation contents, reference may be made to the method embodiment shown in FIG. 1 above, which will not be repeated here.

In addition, other implementation manners of a fund transaction method implemented by the processor 501 executing the program stored in the memory 503 are the same as the implementation manners mentioned in the foregoing method embodiment section, and will not be repeated here.

An embodiment of the present invention further provides a client, as shown in FIG. 6 , including a processor 601 , a communication interface 602 , a memory 603 and a communication bus 604 , wherein the processor 601 , the communication interface 602 , and the memory 603 pass through the communication bus 604 complete communication with each other,

a memory 603 for storing computer programs;

The processor 601 is configured to implement a fund transaction method provided by the embodiment of the present invention when executing the program stored in the memory 303 .

Specifically, the above-mentioned method for fund transaction based on blockchain, the method is applied to the client, and the method includes:

Obtain the transaction application information input by the user, the transaction application information includes account ID, transaction type ID and transaction amount;

According to the transaction amount, determine the first random commitment and the first range proof corresponding to the transaction amount;

determining the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier;

According to the first random commitment corresponding to the transaction amount and the preset knowledge proof generation algorithm, determine the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment;

The transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, and the third random commitment and the third random commitment of the account identifier. The corresponding knowledge proof constitutes the transaction information;

Send the transaction information to the server in the blockchain, so that the server can verify whether the transaction information is correct according to the preset verification algorithm. If it is correct, the transaction processing will be performed.

For the specific implementation of each step of the method and related explanation contents, reference may be made to the method embodiment shown in FIG. 2 above, which will not be repeated here.

In addition, other implementation manners of a fund transaction method implemented by the processor 601 executing the program stored in the memory 603 are the same as the implementation manners mentioned in the foregoing method embodiment section, and will not be repeated here.

The communication bus mentioned in the above electronic device may be a peripheral component interconnect standard (Peripheral Component Interconnect, PCI) bus or an Extended Industry Standard Architecture (Extended Industry Standard Architecture, EISA) bus or the like. The communication bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of presentation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

The communication interface is used for communication between the above electronic device and other devices.

The memory may include random access memory (Random Access Memory, RAM), and may also include non-volatile memory (Non-Volatile Memory, NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

The above-mentioned processor may be a general-purpose processor, including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; may also be a digital signal processor (Digital Signal Processing, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), Field-Programmable Gate Array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

In yet another embodiment provided by the present invention, a computer-readable storage medium is also provided, where instructions are stored in the computer-readable storage medium, when the computer-readable storage medium is run on a computer, the computer is made to execute any one of the above-mentioned embodiments. The described blockchain-based capital transaction method.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), among others.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Each embodiment in this specification is described in a related manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the apparatus, electronic device, and computer-readable storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and reference may be made to some descriptions of the method embodiments for related parts.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (10)

1. A method for capital transaction based on blockchain, characterized in that the method is applied to a server in the blockchain, and the server stores the corresponding historical transaction records of each account identifier, and the historical transaction records in the historical transaction records are stored in the server. Including random commitment and scope proof, account identification and transaction type identification, the method includes: Receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, and the current account identifier. The second random commitment and the second range proof corresponding to the remaining tradable amount of , the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment; Obtain the last transaction record corresponding to the account identifier from the historical transaction record; According to a preset verification algorithm, determine the first random commitment and the first range proof corresponding to the transaction amount, the second random commitment and the second range proof corresponding to the current remaining tradable amount of the account identifier, and the Whether the third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment are valid; determining, according to a preset verification algorithm, a first random commitment and a first range proof corresponding to the transaction amount, a second random commitment and a second range proof corresponding to the current remaining tradable amount of the account identifier, and After the third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment are valid, the method further includes: judging whether the following formula holds: CM _1,0 =n ₁ ×G+CM ₁ ^* ; CM ₁ , ₁ =CM ₀ -CM _1,0 ; Wherein, CM ₁ , 1 is the second random commitment corresponding to the current remaining tradable amount of the account identifier, CM ₀ is the random commitment corresponding to the total transaction amount corresponding to the account identifier, and CM 1, ₀ is the corresponding random commitment of the transaction amount The first random commitment of , n ₁ is the transaction amount applied by the user in the transaction information, the coordinates of G are (x ₀₁ , y ₀₁ ), and CM ₁ * is the third random commitment identified by the account; If the equation of CM _1,0 =n ₁ ×G+CM ₁ ^* and CM _1,1 =CM ₀ -CM _1,0 is established, the server will process this transaction according to the current transaction information; if CM _{1, 0} =n ₁ ×G+CM ₁ ^* and CM ₁ , ₁ =CM ₀ -CM _1,0 if the equation does not hold, the server sends the client a failure message of this transaction application. 2. The method according to claim 1, wherein before receiving the current transaction information sent by the client, the method further comprises: Receive account creation request information sent by the client; wherein, the account creation request information includes a user ID; In the preset account information table, find out whether the account identification corresponding to the user identification is included; If the account information table does not contain the account identifier corresponding to the user identifier, when receiving the knowledge certificate corresponding to the fourth random commitment sent by the client, verify the fourth random Whether the knowledge proof corresponding to the commitment is valid; If the knowledge certificate corresponding to the fourth random commitment is valid, the account identifier corresponding to the user identifier and the total transaction amount are created. 3. A blockchain-based fund transaction method, wherein the method is applied to a client, and the method comprises: Obtain the transaction application information input by the user, where the transaction application information includes an account identifier, a transaction type identifier and a transaction amount; According to the transaction amount, determine the first random commitment and the first range proof corresponding to the transaction amount; determining the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier; According to the first random commitment corresponding to the transaction amount and the preset knowledge proof generation algorithm, determine the third random commitment of the account identifier and the knowledge proof corresponding to the third random commitment; The transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier, and the third random number of the account identifier. The knowledge proof corresponding to the commitment and the third random commitment constitutes the transaction information; Send the current transaction information to the server in the blockchain, so that the server verifies whether the current transaction information is correct according to the preset verification algorithm. If it is correct, determine whether the following formula holds: CM _1,0 =n ₁ ×G+CM ₁ ^* ; CM ₁ , ₁ =CM ₀ -CM _1,0 ; Wherein, CM ₁ , 1 is the second random commitment corresponding to the current remaining tradable amount of the account identifier, CM ₀ is the random commitment corresponding to the total transaction amount corresponding to the account identifier, and CM 1, ₀ is the corresponding random commitment of the transaction amount The first random commitment of , n ₁ is the transaction amount applied by the user in the transaction information, the coordinates of G are (x ₀₁ , y ₀₁ ), and CM ₁ * is the third random commitment identified by the account; If the equation of CM _1,0 =n ₁ ×G+CM ₁ ^* and CM _1,1 =CM ₀ -CM _1,0 is established, the server will process this transaction according to the current transaction information; if CM _{1, 0} =n ₁ ×G+CM ₁ ^* and CM ₁ , ₁ =CM ₀ -CM _1,0 if the equation does not hold, the server sends the client a failure message of this transaction application. 4. The method according to claim 3, wherein before acquiring the transaction application information input by the user, the method comprises: Sending account creation request information to the server; wherein, the account creation request information includes a user ID; Get the random number entered by the user; determining a fourth random commitment according to the random number and a preset random commitment generation algorithm; determining the knowledge proof corresponding to the fourth random commitment according to a preset knowledge proof generating algorithm; Send the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to the server. 5. A blockchain-based capital transaction device, characterized in that the device is applied to a server in the blockchain, and the server stores historical transaction records corresponding to each account identifier, and in the historical transaction records Including random commitment and scope proof, account identification and transaction type identification, the device includes: The receiving module is used to receive the current transaction information sent by the client, the current transaction information includes the transaction amount, the account identifier and the transaction type identifier, the first random commitment and the first range certificate corresponding to the transaction amount, the the second random commitment and the second range proof corresponding to the current remaining tradable amount of the account identifier, the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment; an acquisition module, configured to acquire the last transaction record corresponding to the account identifier from the historical transaction record; A determination module, configured to determine, according to a preset verification algorithm, a first random commitment and a first range proof corresponding to the transaction amount, and a second random commitment and a second range corresponding to the current remaining tradable amount of the account identifier proof, and whether the third random commitment identified by the account and the knowledge proof corresponding to the third random commitment are valid; This transaction processing module is used for if the first random promise, the first range proof, the second random promise, the second range proof, the third random promise and the third random promise If the corresponding knowledge proof is valid, then judge whether the following formula holds: CM _1,0 =n ₁ ×G+CM ₁ ^* ; CM ₁ , ₁ =CM ₀ -CM _1,0 ; Wherein, CM ₁ , 1 is the second random commitment corresponding to the current remaining tradable amount of the account identifier, CM ₀ is the random commitment corresponding to the total transaction amount corresponding to the account identifier, and CM 1, ₀ is the corresponding random commitment of the transaction amount The first random commitment of , n ₁ is the transaction amount applied by the user in the transaction information, the coordinates of G are (x ₀₁ , y ₀₁ ), and CM ₁ * is the third random commitment identified by the account; If the equation of CM _1,0 =n ₁ ×G+CM ₁ ^* and CM _1,1 =CM ₀ -CM _1,0 is established, the server will process this transaction according to the current transaction information; if CM _{1, 0} =n ₁ ×G+CM ₁ ^* and CM ₁ , ₁ =CM ₀ -CM _1,0 if the equation does not hold, the server sends the client a failure message of this transaction application. 6. The apparatus according to claim 5, wherein the apparatus further comprises: an account creation request information receiving module, configured to receive account creation request information sent by the client; wherein, the account creation request information includes a user ID; a search module, configured to search in the preset account information table whether the account identification corresponding to the user identification is included; The verification module is configured to, if the account information table does not contain the account identifier corresponding to the user identifier, when receiving the knowledge certificate corresponding to the fourth random commitment sent by the client, verify the verification algorithm according to the preset knowledge certificate whether the knowledge proof corresponding to the fourth random commitment is valid; A creating module is configured to create an account identifier corresponding to the user identifier and a total transaction amount if the knowledge certificate corresponding to the fourth random commitment is valid. 7. A fund transaction device based on blockchain, wherein the device is applied to a client, and the device comprises: a transaction application information acquisition module, used for acquiring transaction application information input by a user, the transaction application information including an account identifier, a transaction type identifier and a transaction amount; a first determining module, configured to determine, according to the transaction amount, a first random commitment and a first range proof corresponding to the transaction amount; a second determining module, configured to determine the current remaining tradable amount of the account identifier, and the second random commitment and the second range proof corresponding to the remaining tradable amount of the account identifier; a third determination module, configured to determine the third random commitment of the account identifier and the knowledge certificate corresponding to the third random commitment according to the first random commitment corresponding to the transaction amount and a preset knowledge proof generation algorithm; This transaction information constitutes a module, which is used to combine the transaction application information, the first random commitment and the first range certificate corresponding to the transaction amount, and the second random commitment and the second range certificate corresponding to the remaining tradable amount of the account identifier. , The third random commitment identified by the account and the knowledge certificate corresponding to the third random commitment constitute the transaction information; The current transaction information verification module is used to send the current transaction information to the server in the blockchain, so that the server can verify whether the current transaction information is correct according to the preset verification algorithm. Then judge whether the following formula holds: CM _1,0 =n ₁ ×G+CM ₁ ^* ; CM ₁ , ₁ =CM ₀ -CM _1,0 ; Wherein, CM ₁ , 1 is the second random commitment corresponding to the current remaining tradable amount of the account identifier, CM ₀ is the random commitment corresponding to the total transaction amount corresponding to the account identifier, and CM 1, ₀ is the corresponding random commitment of the transaction amount The first random commitment of , n ₁ is the transaction amount applied by the user in the transaction information, the coordinates of G are (x ₀₁ , y ₀₁ ), and CM ₁ * is the third random commitment identified by the account; If the equation of CM _1,0 =n ₁ ×G+CM ₁ ^* and CM _1,1 =CM ₀ -CM _1,0 is established, the server will process this transaction according to the current transaction information; if CM _{1, 0} =n ₁ ×G+CM ₁ ^* and CM ₁ , ₁ =CM ₀ -CM _1,0 if the equation does not hold, the server sends the client a failure message of this transaction application. 8. The apparatus according to claim 7, wherein the apparatus further comprises: an account creation request information sending module, used for sending account creation request information to the server; wherein, the account creation request information includes a user ID; The random number acquisition module is used to acquire the random number input by the user; a fourth random commitment determination module, configured to determine a fourth random commitment according to the random number and a preset random commitment generation algorithm; a knowledge proof determination module, configured to determine a knowledge proof corresponding to the fourth random commitment according to a preset knowledge proof generation algorithm; A sending module, configured to send the fourth random commitment and the knowledge proof corresponding to the fourth random commitment to the server. 9. A server, characterized in that it comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; memory for storing computer programs; The processor is configured to implement the method described in any one of claims 1-2 when executing the program stored in the memory. 10. A client, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; memory for storing computer programs; The processor is configured to implement the method described in any one of claims 3-4 when executing the program stored in the memory.

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