CN114297721A - Information processing method, information processing apparatus, block chain platform, and storage medium - Google Patents

Abstract

The embodiment of the present application discloses an information processing method, the method includes: receiving transaction information between a target user and other users; wherein, the transaction information includes an account change value; obtaining first account book information of the target user from a blockchain; Wherein, the first ledger information includes a first ciphertext account value and a first public key of the target user, and the first ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key; Encrypt the account change value with the first public key to obtain the first ciphertext account change value; determine the second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and use The second ciphertext account value is recorded in the blockchain, so that the target user decrypts the second ciphertext account value with the first private key corresponding to the first public key to obtain the first plaintext account value; The key and the first private key are generated according to the homomorphic encryption parameters.

Description

Information processing method, information processing device, blockchain platform, and storage medium

technical field

This application relates to, but is not limited to, the field of computer technology, and in particular, relates to an information processing method, an information processing device, a blockchain platform, and a storage medium.

Background technique

Blockchain technology is generally divided into public chain and license chain, and license chain can be divided into alliance chain and private chain according to whether the data maintainer is a single individual. The data on the public chain is publicly shared, while in the permissioned chain, although the data is shared, the protected information is often open to some participants and kept secret to others according to business needs. In the field of privacy protection, with the requirements of the General Data Protection Regulation (GDPR) proposed by the European Union in 2018, data owners also have to provide data protection requirements. The data protection problem in the field of alliance chain has always been a key problem to be solved.

In the related art, the data protection method on the alliance chain is through the method of hashing on the chain. Since the transaction on the hashing chain occurs on the user side, it is only necessary to save the hash value of the result of the transaction, that is, the hash data. On the blockchain to achieve data invisibility. However, the hash data in this method can only be used as a deposit certificate, and the original plaintext data is still required when conducting transactions, and data protection is not really realized. It can be seen that there is an urgent need to provide an information processing method for privacy protection of data in a consortium chain.

SUMMARY OF THE INVENTION

The embodiments of the present application are expected to provide an information processing method, an information processing apparatus, a blockchain platform, and a storage medium.

The technical solution of the present application is realized as follows:

In a first aspect, an information processing method is applied to a first node of a blockchain, the method comprising:

Receive transaction information between the target user and other users; wherein the transaction information includes an account change value;

Obtain the first ledger information of the target user from the blockchain; wherein the first ledger information includes a first ciphertext account value and the first public key of the target user, the first ciphertext The account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key;

Encrypting the account change value with the first public key to obtain the first ciphertext account change value;

Determine a second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and record the second ciphertext account value in the blockchain , so that the target user decrypts the second ciphertext account value with the first private key corresponding to the first public key to obtain the first plaintext account value; wherein the first public key and the The first private key is generated according to the homomorphic encryption parameters, and the first evaluation function includes an operation function.

In a second aspect, an information processing apparatus, the apparatus includes:

a receiving module for receiving transaction information between the target user and other users; wherein the transaction information includes account change values;

an acquisition module, configured to acquire the first account book information of the target user from the blockchain; wherein, the first account book information includes a first ciphertext account value and the first public key of the target user, the first account book information A ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key;

A processing module, configured to encrypt the account change value with the first public key to obtain a first ciphertext account change value; based on the first ciphertext account value, the first ciphertext account change value and the first ciphertext account change value An evaluation function determines a second ciphertext account value, and records the second ciphertext account value in the blockchain, so that the target user can use the first private key corresponding to the first public key Decrypting the second ciphertext account value to obtain a first plaintext account value; wherein the first public key and the first private key are generated according to homomorphic encryption parameters, and the first evaluation function includes an operation function.

In a third aspect, a blockchain platform, the blockchain platform includes:

memory for storing executable instructions;

The processor is configured to execute the executable instructions stored in the memory to implement the above-mentioned information processing method.

In a fourth aspect, a storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the above-mentioned information processing method.

The information processing method, information processing device, blockchain platform and storage medium provided by the embodiments of this application receive transaction information between the target user and other users; wherein the transaction information includes account change values; Obtain the first account book information of the target user; wherein, the first account book information includes the first ciphertext account value and the first public key of the target user, and the first ciphertext account value is the first ciphertext account value of the target user to the target user with the first public key. Obtained after encrypting one transaction information; encrypting the account change value with the first public key to obtain the first ciphertext account change value; determined based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function The second ciphertext account value, and the second ciphertext account value is recorded in the blockchain, so that the target user decrypts the second ciphertext account value with the first private key corresponding to the first public key to obtain the first ciphertext account value. Plaintext account value; wherein, the first public key and the first private key are generated according to homomorphic encryption parameters, and the first evaluation function includes an operation function; in this way, it is realized that during the operation of the ciphertext data by the blockchain node, no The original information of the data is leaked, and the privacy operation between the data is realized.

Description of drawings

FIG. 1 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

FIG. 2 is an optional schematic diagram of sending a message to a first node according to an embodiment of the present application;

3 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

FIG. 4 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

5 is a schematic structural diagram of an optional ciphertext update provided by an embodiment of the present application;

FIG. 6 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

FIG. 7 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

FIG. 8 is an optional schematic flowchart of an information processing method provided by an embodiment of the present application;

FIG. 9 is an optional schematic diagram of a joint operation provided by an embodiment of the present application;

FIG. 10 is a schematic structural diagram of an information processing apparatus according to an embodiment of the present application;

FIG. 11 is a schematic structural diagram of a blockchain platform provided by an embodiment of this application. .

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below with reference to the accompanying drawings. All other embodiments obtained under the premise of creative work fall within the scope of protection of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" can be the same or a different subset of all possible embodiments, and Can be combined with each other without conflict.

In the following description, the term "first\second\third" is only used to distinguish similar objects, and does not represent a specific ordering of objects. It is understood that "first\second\third" Where permitted, the specific order or sequence may be interchanged to enable the embodiments of the application described herein to be practiced in sequences other than those illustrated or described herein.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

The embodiment of the present application provides an information processing method, which is applied to the first node of the blockchain. Referring to FIG. 1 , the method includes the following steps:

Step 101: Receive transaction information between the target user and other users.

The transaction information includes account change values. Here, the account change value may be the account change value of the target user, the account change value may also be the account change value of other users, and the account change value may also be the account change value of a user different from the target user and other users. This application does not make specific restrictions. It should be noted that, in this embodiment of the present application, the account change value is the account change value of the target user.

In the embodiment of the present application, the target user is a user who increases the account value, that is, a user who transfers a certain account value; the target user can also be a user who reduces the account value, that is, a user who transfers a certain account value.

In the embodiment of the present application, the first node of the blockchain determines the changed account value of the target user based on the original account value and the account change value of the target account.

Here, the transaction information can be generated by the blockchain platform, and the transaction information can also be generated by the target user, other users or the user X specified by the upper layer of the blockchain and sent to the first node of the blockchain, which does not do anything by itself. specific restrictions.

In the embodiment of this application, the transaction information may also include the first identifier of the target user and the second identifiers of other users, that is, the transaction information may be represented as Tran(ID _A , ID _B , value), where ID _A represents the target user's The first identifier, ID _B represents the second identifier of other users, and value represents the account change value. Here, the transaction information between the target user and other users can also be submitted to the first node of the blockchain in the form of a contract.

In practical applications, blockchain includes public chain, private chain and alliance chain; among them, the public chain is open to all users, so the data information on the public chain, that is, the ledger information, can be shared publicly; Users are open, so the data information on the private chain, that is, the ledger information, can be accessed by users who have been granted write permission without data verification, which has a high degree of trust; the alliance chain grants certain permissions to users participating in management, and needs to be authorized by the alliance chain. The data information among the members of the PBX is the privacy protection of the ledger information, so as to enhance the trust between the members. The information processing method provided by the embodiment of the present application is applied to the consortium chain, so as to realize the privacy protection of the data in the transaction process of the data information among the members of the consortium chain.

In this embodiment of the present application, the first node is any node among multiple nodes included in the blockchain.

Step 102: Obtain the first ledger information of the target user from the blockchain.

The first ledger information includes a first ciphertext account value and a first public key of the target user, and the first ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key.

In the embodiment of the present application, the first public key is the key required for encryption generated by the target user through the key generation algorithm based on the given homomorphic encryption parameters. Here, the target user passes the key based on the given homomorphic encryption parameters The generation algorithm generates a homomorphic key required for encryption, including a first public key and a first private key, and the first private key corresponds to the first public key. Exemplarily, based on a given homomorphic encryption parameter λ, the target user generates the first public key PK _A and the first private key sk _A by the key generation algorithm KeyGen(1 ^λ ). It should be noted that, according to different encryption and decryption algorithms selected, the required homomorphic encryption parameters are also different, and this application does not specifically limit the encryption and decryption algorithms.

In the embodiment of this application, after receiving the transaction information between the target user and other users, the first node of the blockchain obtains the first ledger of the target user including the first ciphertext account value and the first public key from the blockchain information.

In other embodiments of the present application, the first ledger information may further include the first identifier of the target user. After receiving the transaction information between the target user and other users, the first node of the blockchain obtains the first ledger information corresponding to the first identification from the blockchain based on the first identification of the target user included in the transaction information.

Step 103: Encrypt the account change value with the first public key to obtain the first ciphertext account change value.

In the embodiment of the present application, when the first node of the blockchain obtains the first account book information of the target user from the blockchain, it obtains the first public key in the first account book information. Further, the first public key is used to encrypt the account change value in the transaction information through the encryption algorithm to obtain the first ciphertext account change value, so that the first node uses the evaluation algorithm under homomorphism to encrypt the same key and obtain at least two ciphertext values of .

Step 104: Determine the second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and record the second ciphertext account value in the blockchain, so that the target user Decrypt the second ciphertext account value with the first private key corresponding to the first public key to obtain the first plaintext account value.

The first public key and the first private key are generated according to homomorphic encryption parameters; the first evaluation function includes an operation function.

In the embodiments of the present application, the operation functions include, but are not limited to, an addition operation function, a subtraction operation function, a multiplication operation function, a division operation function, and an average operation function.

In the embodiment of the present application, the evaluation function can be understood as combining at least two ciphertext values obtained by encrypting with the same public key, and forming a new ciphertext value through a specific function included in the evaluation function, such as an operation function, to pass The private key corresponding to the public key decrypts the new ciphertext value to obtain a new plaintext value after the operation. Exemplarily, the evaluation algorithm is Eval(F, ct1, ct2, ..., ctn). The evaluation algorithm combines n ciphertexts ct1, ct2, ..., ctn, and uses an operation function F to form a new ciphertext ct' And ct'=F(ct1, ct2, . . . , ctn). Due to the nature of homomorphic encryption, it is guaranteed that Dec(sk, ct')=F(m1, m2, ..., mn), that is, through the decryption function Dec function, the new ciphertext ct' is homomorphically decrypted using the private key sk, The plaintext m1 corresponding to the ciphertext ct1, the plaintext m2 corresponding to the ciphertext ct2, and the plaintext mn corresponding to the ciphertext ctn are obtained, and the plaintext m1, m2 and mn are calculated by the operation function F to obtain a new plaintext.

In the embodiment of the present application, when the first node of the blockchain encrypts the account change value with the first public key to obtain the first ciphertext account change value, the first node uses the operation function in the first evaluation function to Calculate the first ciphertext account value and the change value of the first ciphertext account to obtain the second ciphertext account value, and record the second ciphertext account value in the blockchain, so that the target user can use the first public key with the first public key. The corresponding first private key decrypts the second ciphertext account value to obtain the first plaintext account value.

In an achievable application scenario, the target user is a user whose account value is reduced. First, the target user executes the key generation algorithm according to the given homomorphic encryption parameters, that is, the KeyGen algorithm generates the first public key PK _A and the first private key sk _A ; secondly, the target user uses the first public key PK through the encryption algorithm Enc algorithm _A encrypts the previous transaction information m _A of the target user to obtain the first ciphertext account value ct _A , which can be expressed as executing Enc(m _A , PK _A ) to obtain ct _A . Further, referring to FIG. 2 , A in FIG. 2 shows a schematic diagram of sending the first account book information to the first node, the target user creates the first account book information Create(ID _A , ct _A , PK _A ), and Send the first ledger information to the first node of the blockchain, and provide the information of the first node with endorsement and synchronization, and synchronize it to other nodes of the blockchain to achieve consistency eventually; The key-value pair structure is stored on the blockchain, and the first ledger information is ID _A : [ct _A ,PK _A ]. Then, referring to FIG. 2 , B in FIG. 2 shows a schematic diagram of sending transaction information to the first node, and the first node receives the transaction information Tran(ID _A , ID _B , value between the target user and other users) ), obtain the first ledger information from the blockchain based on the first identification ID _A , and encrypt the account change value value in the transaction information with the first public key PK _A to obtain the first ciphertext account change value ct _v1 . Further, the first node obtains the second ciphertext account value ct _A' based on executing the first evaluation algorithm Eval(Sub, ct _A , ct _v1 ), and regards the second ciphertext account value ct _A' as the final ledger value , recorded in the blockchain, where the final first ledger information of the target user is ID _A :[ct _A′ ,PK _A ]. Finally, the target user decrypts the second ciphertext account value ct _A' with the first private key sk _A through the decryption algorithm DEC algorithm to obtain the first plaintext account value, so as to verify the accuracy of the transaction.

It should be noted that the above endorsement can be understood as the first node as the submission node, which submits all the information included in itself to the endorsement node first. Here, the endorsement node can be a node designated by the blockchain platform, and the endorsement node performs calculations and updates first. After the information is received, the updated information is returned to the submitting node, and the submitting node verifies that it is correct before sending the updated information to other nodes in the blockchain.

In another achievable application scenario, if the transaction information is Tran(ID _A , ID _B , value), it means that the user corresponding to ID _A is the transaction sender, and the user corresponding to ID _B is the transaction receiver, that is, the target The user is the user who reduces the account value, and the other users are the users who increase the account value. First, the target user executes the key generation algorithm according to the given homomorphic encryption parameters, that is, the KeyGen algorithm generates the first public key PK _A and the first private key sk _A ; other users execute the key generation algorithm according to the given homomorphic encryption parameters That is, the KeyGen algorithm generates the fourth public key PK _B and the fourth private key sk _B . Secondly, the target user encrypts the previous transaction information mA of the target user with the first public key PK _A through the encryption algorithm Enc algorithm to obtain the first ciphertext account value ct _A , which can be expressed as executing Enc(m _A , PK _{A .} ) to obtain ct _A ; other users obtain the fourth ciphertext account value ct _B after encrypting the previous transaction information m _B of other users with the fourth public key PK _B through the encryption algorithm Enc algorithm, which can be expressed as executing Enc (m _B , PK _B ) to get ct _B . Further, as shown in FIG. 2 , the target user creates the first account book information Create(ID _A , ct _A , PK _A ), sends the first account book information to the first node of the blockchain, and sends the first account book information to the first node of the blockchain. The information provides a way of endorsement and synchronization, which is synchronized to other nodes in the blockchain. The first ledger information is stored on the blockchain in a key-value structure, and the first ledger information is ID _A : [ct _A ,PK _A ]. Other users create the third ledger information Create(ID _B , ct _B , PK _B ), and send the third ledger information to the first node of the blockchain, and provide the first node's information with endorsement and synchronization methods to synchronize to other nodes of the blockchain. Among them, the third ledger information is stored on the blockchain in a key-value structure, and the third ledger information is ID _B : [ct _B ,PK _B ]. Then, the first node receives the transaction information Tran(ID _A , ID _B , value) between the target user and other users, obtains the first ledger information from the blockchain based on the first identification ID _A , and obtains the first ledger information based on the second identification ID _B obtains the third ledger information from the blockchain. After that, the first node encrypts the account change value value in the transaction information with the first public key PK _A to obtain the first ciphertext account change value ct _v1 , and uses the fourth public key PK _B to encrypt the account change value in the transaction information value is encrypted to obtain the third ciphertext account change value ct _v2 . Further, the first node obtains the second ciphertext account value ct _A' based on executing the first evaluation algorithm Eval(Sub, ct _A , ct _v1 ), and regards the second ciphertext account value ct _A' as the final ledger value , recorded in the blockchain, where the final first ledger information of the target user is ID _A :[ct _A′ ,PK _A ]. The first node obtains the eighth ciphertext account value ct _B′ based on the execution of the first evaluation algorithm Eval (Add, ct _B , ct _v2 ), and regards the eighth ciphertext account value ct _B′ as the final ledger value, which is recorded in the In the blockchain, the final third ledger information of other users is ID _B :[ct _B′ ,PK _B ]. Finally, the target user decrypts the second ciphertext account value ct _A' with the first private key sk _A through the decryption algorithm DEC algorithm to obtain the first plaintext account value; other users use the fourth private key sk _B to decrypt the The eighth ciphertext account value ct _B' is decrypted to obtain the second plaintext account value to verify the accuracy of the transaction.

The information processing method provided by the embodiment of the present application receives transaction information between the target user and other users; wherein, the transaction information includes account change values; the first ledger information of the target user is obtained from the blockchain; A ledger information includes a first ciphertext account value and the target user's first public key, and the first ciphertext account value is obtained by the target user encrypting the target user's previous transaction information with the first public key; The public key encrypts the account change value to obtain the first ciphertext account change value; the second ciphertext account value is determined based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and the second ciphertext account value is determined. The text account value is recorded in the blockchain, so that the target user decrypts the second cipher text account value with the first private key corresponding to the first public key to obtain the first plain text account value; A private key is generated according to the homomorphic encryption parameters, and the first evaluation function includes an operation function; in this way, it is realized that the original information of the data will not be leaked during the operation of the ciphertext data by the blockchain nodes, and the data communication between the data is realized. Privacy Computing.

The embodiment of the present application provides an information processing method, which is applied to the first node of the blockchain. Referring to FIG. 3 , the method includes the following steps:

Step 201: Receive transaction information between the target user and other users.

The transaction information includes account change values.

Step 202: Obtain the first ledger information of the target user from the blockchain.

The first ledger information includes a first ciphertext account value and a first public key of the target user, and the first ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key.

Step 203: Obtain the key update information of the target user from the blockchain.

The key update information includes a first ciphertext private key and a second public key, and the first ciphertext private key is obtained after the target user encrypts the first private key with the second public key.

In this embodiment of the present application, the second public key is another key required for the target user to generate encryption through a key generation algorithm based on given homomorphic encryption parameters.

In the embodiment of the present application, after receiving the transaction information between the target user and other users, the first node of the blockchain obtains the first ledger information of the target user from the blockchain, and obtains the information of the target user from the blockchain. There are key update information of the first ciphertext private key and the second public key.

In this embodiment of the present application, the key update may be performed before the first account book information is obtained and the first ciphertext book value in the first account book information is updated. The first ciphertext ledger value in the first ledger information is updated, and the updated first ciphertext ledger value is obtained and executed. This application does not specifically limit the timing of key update. Here, the steps performed below are to update the key and the ciphertext ledger value in the first ledger information before the first ledger information is obtained and the first ciphertext ledger value in the first ledger information is updated .

Step 204: Update the first ledger information based on the first ciphertext private key and the second public key to obtain the updated first ledger information, so that the first node can update the block based on the updated first ledger information. The ciphertext account value of the target user of the chain is re-recorded.

In this embodiment of the present application, referring to FIG. 4 , step 204 updates the first ledger information based on the first ciphertext private key and the second public key, and obtains the updated first ledger information, which can be implemented by the following steps:

Step A1: Re-encrypt the first ciphertext account value with the second public key to obtain the first ciphertext account value in the first cipher state.

Step A2: Determine the third ciphertext account value based on the first ciphertext private key, the first ciphertext account value in the first cipher state, and the second evaluation function.

The updated first ledger information includes the third ciphertext account value and the second public key.

In the embodiment of the present application, after the first node of the blockchain obtains the key update information of the target user including the first ciphertext private key and the second public key from the blockchain, the second public key is used by the encryption algorithm. Re-encrypt the first ciphertext account value to obtain the first ciphertext account value in the first cipher state, and based on the first ciphertext private key, the first ciphertext account value in the first ciphertext state and the second evaluation function , and determine the third ciphertext account value.

In the embodiment of the present application, step A2 determines the third ciphertext account value based on the first ciphertext private key, the first ciphertext account value in the first cipher state, and the second evaluation function, which can be implemented in the following manner:

Through the homomorphic decryption function in the second evaluation function, the first ciphertext account value in the first ciphertext state is decrypted with the first ciphertext private key to obtain the third ciphertext account value.

Wherein, the second evaluation function includes a homomorphic decryption function.

It can be seen from the above that, in the embodiment of the present application, in the process of realizing the key update through the above method, the target user does not need to decrypt the ciphertext ledger to obtain the plaintext ledger, and then use the new public key to update the plaintext ledger. When the target user updates the key, the plaintext ledger data is changed at the same time, and the privacy and security of the data are protected.

It should be noted that the key update method in the related art downloads the remote ciphertext locally, uses the corresponding private key locally to decrypt the plaintext account, and then uses the new key to encrypt the plaintext account to obtain a new key. For ciphertext accounts, this method at least has the problem of changing the plaintext ledger.

Step 205: Encrypt the account change value with the second public key to obtain the second ciphertext account change value.

Step 206: Determine the updated second ciphertext account value based on the ciphertext account value, the second ciphertext account change value and the first evaluation function in the updated first ledger information, and use the updated second ciphertext The account value is recorded in the blockchain, so that the target user decrypts the updated second ciphertext account value with the second private key corresponding to the second public key to obtain the first plaintext account value.

Wherein, the second public key and the second private key are generated according to homomorphic encryption parameters; the first evaluation function includes an operation function.

In the embodiment of the present application, when the first node of the blockchain encrypts the account change value with the second public key to obtain the second ciphertext account change value, the first node uses the operation function in the first evaluation function to The third ciphertext account value and the second ciphertext account change value are calculated to obtain the updated second ciphertext account value, and the updated second ciphertext account value is recorded in the blockchain, so that the target user Decrypt the updated second ciphertext account value with the second private key corresponding to the second public key to obtain the first plaintext account value.

可以表示为执行Enc(sk_A,PK′_A)得到

然后，参照图2所示，图2中的C示出的是发送密钥更新信息至第一节点的示意图，目标用户生成密钥更新信息

并将密钥更新信息发送给第一节点。进一步地，第一节点基于第一标识ID_A从区块链中获取密钥更新信息，并通过加密算法Enc算法用第二公钥PK′_A对第一密文账户值ct_A进行加密后得到第一密态下的第一密文账户值

可以表示为执行Enc(ct_A,PK′_A)得到

最后，通过第二评估函数中的同态解密函数如Dec函数，用第一密文私钥

对第一密态下的第一密文账户值

进行解密，得到第三密文账户值ct′_A，可以表示为执行

得到ct′_A，且密钥更新后的目标用户的第一账本信息为ID_A:[ct′_A,PK′_A]。最后，目标用户为确保更新后账本信息的正确性，目标用户可以通过第一标识ID_A查询区块链，得到第三密文账户值ct′_A并执行Dec(sk′_A,ct′_A)得到m′_A，验证m_A是否等于m′_A，如果相等，则密文更新成功。如此，无需将密文账本进行解密得到明文账本后，再用新的公钥对明文账本进行更新，避免了目标用户在更新密钥时，同时改变了明文账本数据，实现了保护数据的隐私和安全。In an achievable application scenario, as shown in FIG. 5 , first, after the target user obtains the first account information including the first ciphertext account value and the first public key from the blockchain, the target user according to The given homomorphic encryption parameters execute the key generation algorithm, namely the KeyGen algorithm, to generate a new key, namely the second public key PK' _A and the second private key sk' _A , and use the second public key PK through the encryption algorithm Enc algorithm ' _A encrypts the first private key sk _A to obtain the first ciphertext private key

It can be expressed as executing Enc(sk _A ,PK′ _A ) to get

Then, referring to FIG. 2 , C in FIG. 2 shows a schematic diagram of sending the key update information to the first node, and the target user generates the key update information

and send the key update information to the first node. Further, the first node obtains the key update information from the blockchain based on the first identification ID _A , and encrypts the first ciphertext account value ct _A with the second public key PK' _A through the encryption algorithm Enc algorithm to obtain The first ciphertext account value in the first cipher state

It can be expressed as executing Enc(ct _A ,PK′ _A ) to get

Finally, through the homomorphic decryption function in the second evaluation function, such as the Dec function, use the first ciphertext private key

For the first ciphertext account value in the first cipher state

Decrypt to obtain the third ciphertext account value ct' _A , which can be expressed as execution

Obtain ct' _A , and the first ledger information of the target user after the key update is ID _A : [ct' _A , PK' _A ]. Finally, in order to ensure the correctness of the updated ledger information, the target user can query the blockchain through the first identifier ID _A , obtain the third ciphertext account value ct' _A and execute Dec(sk' _A , ct' _A ) Obtain m' _A , verify whether m _A is equal to m' _A , if it is equal, the ciphertext update is successful. In this way, there is no need to decrypt the ciphertext ledger to obtain the plaintext ledger, and then use the new public key to update the plaintext ledger, which prevents the target user from changing the plaintext ledger data when updating the key, and realizes the protection of data privacy and security. Safety.

It should be noted that, for the description of the same steps and the same content in this embodiment as in other embodiments, reference may be made to the descriptions in other embodiments, and details are not repeated here.

The embodiment of the present application provides an information processing method, which is applied to the first node of the blockchain. Referring to FIG. 6 , the method includes the following steps:

Step 301: Receive transaction information between the target user and other users.

The transaction information includes the account change value. Here, the account change value may be the account change value of the target user, the account change value may also be the account change value of other users, and the account change value may also be different from the target user and other users. Account change value, which is not specifically limited in this application. It should be noted that, in this embodiment of the present application, the account change value is an account change value that is different from the account change value of the target user and other users. Here, the transaction information further includes the first identification of the target user, the second identification of other users, and the operation function. The transaction information is used to calculate the target user's account value and other user account values, so the transaction information is also called joint operation information.

Step 302: Obtain the first ledger information of the target user from the blockchain.

The first ledger information includes a first ciphertext account value and a first public key of the target user, and the first ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key.

In the embodiment of the present application, after receiving the transaction letter between the target user and other users, the first node of the blockchain obtains the first ledger information of the target user corresponding to the first identifier from the blockchain.

Step 303: Obtain the second ledger information of the proxy user from the blockchain.

Wherein, the second ledger information includes a null value and a third public key, and the proxy user is different from the target user and other users.

In the embodiment of the present application, the second public key is the key required for encryption generated by the proxy user through the key generation algorithm based on the given homomorphic encryption parameters.

Step 304: Obtain the second ciphertext private key of the target user from the blockchain.

The second ciphertext private key is obtained after the target user encrypts the first private key with the third public key.

Step 305: Obtain the third ciphertext private key and third ledger information of other users from the blockchain.

The second ledger information includes the fourth ciphertext account value and the fourth public key of other users, and the third ciphertext private key is that other users encrypt the fourth private key corresponding to the fourth public key with the third public key The fourth ciphertext account value is obtained after other users encrypt the previous transaction information of other users with the fourth public key.

In the embodiment of this application, after the first node of the blockchain obtains the first ledger information of the target user from the blockchain, it continues to obtain from the blockchain the second node of the proxy user that contains the null value and the third public key. Ledger information, obtain the second ciphertext private key of the target user, and obtain the third ciphertext private key of other users corresponding to the second identifier, and the third ledger information including the fourth ciphertext account value and the fourth public key.

Step 306: Determine the fifth ciphertext account value of the proxy user based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value, the fourth ciphertext account value and the third public key, and assign The fifth ciphertext account value is recorded in the blockchain, so that the proxy user decrypts the fifth ciphertext account value with the third private key corresponding to the third public key to obtain the second plaintext account value.

In the embodiment of the present application, referring to FIG. 7 , step 306 determines the proxy based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value, the fourth ciphertext account value and the third public key The user's fifth ciphertext account value, including:

Step B1: Encrypt the first ciphertext account value with the third public key to obtain the first ciphertext account value in the second cipher state.

Step B2, encrypting the fourth ciphertext account value with the third public key to obtain the fourth ciphertext account value in the first cipher state.

Step B3: Determine the fifth ciphertext account based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second ciphertext state and the fourth ciphertext account value in the first ciphertext state value.

In the embodiment of the present application, the first node of the blockchain encrypts the first ciphertext account value with the third public key through the encryption algorithm to obtain the first ciphertext account value in the second encryption state, and uses the third The public key encrypts the fourth ciphertext account value to obtain the fourth ciphertext account value in the first cipher state, and finally, based on the second ciphertext private key, the third ciphertext private key, and the first ciphertext in the second cipher state The ciphertext account value and the fourth ciphertext account value in the first cipher state determine the fifth ciphertext account value.

In the embodiment of this application, referring to FIG. 8 , step B3 is based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second cipher state, and the fourth ciphertext in the first cipher state. The value of the ciphertext account and determining the value of the fifth ciphertext account can be achieved by the following steps:

Step C1: Decrypt the first ciphertext account value in the second ciphertext state with the second ciphertext private key through the homomorphic decryption function in the second evaluation function to obtain the sixth ciphertext account value.

Step C2: Decrypt the fourth ciphertext account value in the first ciphertext state with the third ciphertext private key through the homomorphic decryption function to obtain the seventh ciphertext account value.

Step C3: Calculate the sixth ciphertext account value and the seventh ciphertext account value through the operation function in the first evaluation function to determine the fifth ciphertext account value.

In the embodiment of the present application, the first node of the blockchain uses the second ciphertext private key to decrypt the first ciphertext account value in the second cipher state through the homomorphic decryption function in the second evaluation function, and obtains the first ciphertext account value in the second ciphertext state. Six ciphertext account values; through the homomorphic decryption function, use the third ciphertext private key to decrypt the fourth ciphertext account value in the first cipher state to obtain the seventh ciphertext account value; The operation function calculates the sixth ciphertext account value and the seventh ciphertext account value, and determines the fifth ciphertext account value obtained after the operation.

It can be seen from the above that the embodiment of the present application implements privacy operations between account book data between different users by introducing proxy users. It should be noted that when performing joint operations in the related art, since the ciphertext ledger values of the target user and other users are encrypted by using their respective keys, if you want to perform joint operations on them, for example, find Sum (m _A ,m _B )=m _A +m _B , which cannot be realized under the existing model, because the evaluation of the Eval function under homomorphism requires that each ciphertext be generated under the same key.

之后，目标用户和其他用户分别查询代理用户的第三公钥PK_D，且目标用户通过加密算法Enc算法用第三公钥PK_D对第一私钥sk_A进行加密后得到第二密文私钥

可以表示为执行Enc(sk_A,PK_D)得到

其他用户通过加密算法Enc算法用第三公钥PK_D对第四私钥sk_B进行加密后得到第三密文私钥

可以表示为执行Enc(sk_B,PK_D)得到

目标用户将第二密文私钥

发送给第一节点，以及其他用户将第三密文私钥

发送给第一节点。In an achievable application scenario, as shown in FIG. 9 , first, the target user executes a key generation algorithm, that is, the KeyGen algorithm, according to the given homomorphic encryption parameters to generate the first public key PK _A and the first private key sk _A ; Other users execute the key generation algorithm according to the given homomorphic encryption parameters, that is, the KeyGen algorithm generates the fourth public key PK _B and the fourth private key sk _B ; the proxy user executes the key generation algorithm according to the given homomorphic encryption parameters, namely The KeyGen algorithm generates the third public key PK _D and the third private key sk _D . Then, the proxy user submits the third public key PK _D to the first node, and the first node creates empty second ledger information for the proxy user

After that, the target user and other users query the proxy user's third public key PK _D respectively, and the target user encrypts the first private key sk _A with the third public key PK _D through the encryption algorithm Enc algorithm to obtain the second ciphertext private key. key

It can be expressed as executing Enc(sk _A ,PK _D ) to get

Other users encrypt the fourth private key sk _B with the third public key PK _D through the encryption algorithm Enc algorithm to obtain the third ciphertext private key

It can be expressed as executing Enc(sk _B ,PK _D ) to get

The target user sends the second ciphertext private key

Send the third ciphertext private key to the first node and other users

sent to the first node.

可以表示为执行Enc(ct_A,PK_D)，得到

用第三公钥PK_D对第四密文账户值ct_B进行加密得到第一密态下的第四密文账户值

可以表示为执行Enc(ct_B,PK_D)，得到

Then, the first node receives the joint operation information compute(F, ID _A , ID _B ) between the target user and other users, obtains the first ledger information from the blockchain based on the first identification ID _A , and obtains the first ledger information based on the second identification ID _B obtains the third ledger information from the blockchain. After that, the first node encrypts the first ciphertext account value ct _A with the third public key PK _D to obtain the first ciphertext account value in the second encrypted state

It can be expressed as executing Enc(ct _A ,PK _D ), we get

Encrypt the fourth ciphertext account value ct _B with the third public key PK _D to obtain the fourth ciphertext account value in the first cipher state

It can be expressed as executing Enc(ct _B ,PK _D ), we get

第二密态下的第一密文账户值

进行解密，得到第六密文账户值

可以表示为执行

得到

通过第二评估函数即Eval函数中的同态解密函数Dec函数，用第三密文私钥对

第二密态下的第一密文账户值

进行解密，得到第七密文账户值

可以表示为执行

得到

再然后，第一节点获取联合运算信息中的运算函数F，并确定为第一评估函数中的运算函数F，通过第一评估函数中的运算函数F，对第六密文账户值

和第七密文账户值

进行计算，确定第五密文账户值

将第五密文账户值记录在区块链上，以确定代理用户最终的第三账本信息为Dealer:

最后，代理用户通过代理标识Dealer查询区块链，得到第五密文账户值

此时，代理用户使用第三私钥sk_D对第五密文账户值

进行解密，得到

F(m_A,m_B)即为对A和B的账本数据执行函数F的计算结果，从而将计算结果保存到区块链上。如此，通过引入代理用户，实现不同用户之间的账本数据之间的隐私运算。Further, the first node uses the second ciphertext private key to pair with the second evaluation function, namely the homomorphic decryption function Dec function in the Eval function.

The first ciphertext account value in the second cipher state

Decrypt to get the sixth ciphertext account value

can be expressed as executing

get

Through the second evaluation function, that is, the homomorphic decryption function Dec function in the Eval function, use the third ciphertext private key to pair

The first ciphertext account value in the second cipher state

Decrypt to get the seventh ciphertext account value

can be expressed as executing

get

Then, the first node obtains the operation function F in the joint operation information, and determines it as the operation function F in the first evaluation function. Through the operation function F in the first evaluation function, the sixth ciphertext account value is determined.

and the seventh ciphertext account value

Perform calculations to determine the value of the fifth ciphertext account

Record the fifth ciphertext account value on the blockchain to determine the final third ledger information of the proxy user as Dealer:

Finally, the proxy user queries the blockchain through the proxy identifier Dealer to obtain the fifth ciphertext account value

At this time, the proxy user uses the third private key sk _D to pair the fifth ciphertext account value

decrypt to get

F(m _A , m _B ) is the calculation result of executing function F on the ledger data of A and B, thereby saving the calculation result to the blockchain. In this way, by introducing proxy users, privacy operations between account book data between different users are realized.

It should be noted that, for the description of the same steps and the same content in this embodiment as in other embodiments, reference may be made to the descriptions in other embodiments, and details are not repeated here.

An embodiment of the present application provides an information processing apparatus, and the information processing apparatus can be applied to an information processing method provided by the embodiments corresponding to FIG. 1 , FIGS. 3 to 4 , and FIGS. 6 to 8 . As shown, the information processing device 10 includes:

The receiving module 1001 is used for receiving transaction information between the target user and other users; wherein, the transaction information includes account change value;

The obtaining module 1002 is used to obtain the first account book information of the target user from the blockchain; wherein, the first account book information includes the first ciphertext account value and the first public key of the target user, and the first ciphertext account value is the target Obtained after the user encrypts the previous transaction information of the target user with the first public key;

The processing module 1003 is configured to encrypt the account change value with the first public key to obtain the first ciphertext account change value; determine the second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function; and record the second ciphertext account value in the blockchain, so that the target user decrypts the second ciphertext account value with the first private key corresponding to the first public key to obtain the first plaintext account value ; wherein, the first public key and the first private key are generated according to homomorphic encryption parameters, and the first evaluation function includes an operation function.

In other embodiments of the present application, the obtaining module 1002 is further configured to obtain the key update information of the target user from the blockchain, wherein the key update information includes the first ciphertext private key and the second public key, and the first ciphertext private key and the second public key are A ciphertext private key is obtained after the target user encrypts the first private key with the second public key; the processing module 1003 is further configured to perform the first ledger information based on the first ciphertext private key and the second public key. After updating, the updated first ledger information is obtained, so that the first node re-records the ciphertext account value of the target user of the blockchain according to the updated first ledger information.

In other embodiments of the present application, the processing module 1003 is further configured to re-encrypt the first ciphertext account value with the second public key to obtain the first ciphertext account value in the first cipher state; based on the first ciphertext The private key, the first ciphertext account value in the first cipher state, and the second evaluation function determine the third ciphertext account value; wherein, the updated first ledger information includes the third ciphertext account value and the second public key.

In other embodiments of the present application, the processing module 1003 is further configured for the second evaluation function to include a homomorphic decryption function, and through the homomorphic decryption function in the second evaluation function, the first encrypted state is encrypted with the first ciphertext private key. The first ciphertext account value below is decrypted to obtain the third ciphertext account value.

In other embodiments of this application, the obtaining module 1002 is further configured to obtain the second ledger information of the proxy user from the blockchain; wherein the second ledger information includes a null value and a third public key, the proxy user and the target user Different from other users; obtain the second ciphertext private key of the target user from the blockchain; wherein, the second ciphertext private key is obtained by the target user after encrypting the first private key with the third public key; Obtain the third ciphertext private key and third ledger information of other users in the block chain; wherein, the second ledger information includes the fourth ciphertext account value and the fourth public key of other users, and the third ciphertext private key is the other user's Obtained after encrypting the fourth private key corresponding to the fourth public key with the third public key, and the fourth ciphertext account value is obtained after other users encrypt the previous transaction information of other users with the fourth public key The processing module 1003 is also used to determine the fifth ciphertext of the proxy user based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value, the fourth ciphertext account value and the third public key account value, and record the fifth ciphertext account value in the blockchain, so that the proxy user decrypts the fifth ciphertext account value with the third private key corresponding to the third public key to obtain the second plaintext account value.

In other embodiments of the present application, the processing module 1003 is further configured to encrypt the first ciphertext account value with the third public key to obtain the first ciphertext account value in the second cipher state; The fourth ciphertext account value is encrypted to obtain the fourth ciphertext account value in the first ciphertext state; based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second ciphertext state and The fourth ciphertext account value in the first cipher state determines the fifth ciphertext account value.

In other embodiments of the present application, the processing module 1003 is further configured to decrypt the first ciphertext account value in the second cipher state with the second ciphertext private key through the homomorphic decryption function in the second evaluation function , obtain the sixth ciphertext account value; use the third ciphertext private key to decrypt the fourth ciphertext account value in the first cipher state through the homomorphic decryption function to obtain the seventh ciphertext account value; pass the first evaluation The operation function in the function calculates the sixth ciphertext account value and the seventh ciphertext account value, and determines the fifth ciphertext account value.

The embodiments of the present application provide a blockchain platform, which can be applied to an information processing method provided by the embodiments corresponding to FIG. 1 , FIG. 3 to FIG. 4 , and FIGS. 6 to 8 . As shown in 11, the blockchain platform 11 (the blockchain platform 11 in FIG. 11 corresponds to the information processing device 10 in FIG. 10 ) includes: a memory 1101 and a processor 1102, wherein:

a memory 1101 for storing executable instructions;

The processor 1102 is configured to execute the executable instructions stored in the memory 1101 to realize the following steps:

Receive transaction information between the target user and other users; wherein the transaction information includes account change values;

Obtain the first account book information of the target user from the blockchain; wherein, the first account book information includes the first ciphertext account value and the first public key of the target user, and the first ciphertext account value is the target user's first public key Obtained by encrypting the previous transaction information of the target user;

Encrypting the account change value with the first public key to obtain the first ciphertext account change value;

The second ciphertext account value is determined based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and the second ciphertext account value is recorded in the blockchain, so that the target user can use the same value as the first ciphertext account. A first private key corresponding to a public key decrypts the second ciphertext account value to obtain a first plaintext account value; wherein, the first public key and the first private key are generated according to homomorphic encryption parameters; the first evaluation function includes an operation function .

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

Obtain the key update information of the target user from the blockchain, wherein the key update information includes a first ciphertext private key and a second public key, and the first ciphertext private key is the target user's use of the second public key to pair the first Obtained after the private key is encrypted; based on the first ciphertext private key and the second public key, the first ledger information is updated to obtain the updated first ledger information, so that the first node can obtain the updated first ledger according to the updated first ledger. information, re-record the ciphertext account value of the target user of the blockchain.

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

Re-encrypt the first ciphertext account value with the second public key to obtain the first ciphertext account value in the first cipher state; based on the first ciphertext private key, the first ciphertext account value in the first cipher state and The second evaluation function determines the third ciphertext account value; wherein, the updated first ledger information includes the third ciphertext account value and the second public key.

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

The second evaluation function includes a homomorphic decryption function. Through the homomorphic decryption function in the second evaluation function, the first ciphertext account value in the first cipher state is decrypted with the first ciphertext private key to obtain the third ciphertext account value.

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

Obtain the second ledger information of the proxy user from the blockchain; wherein the second ledger information includes a null value and a third public key, and the proxy user is different from the target user and other users; obtain the second ledger of the target user from the blockchain Ciphertext private key; wherein, the second ciphertext private key is obtained after the target user encrypts the first private key with the third public key; obtain the third ciphertext private key and the third ciphertext private key of other users from the blockchain Ledger information; wherein, the second account book information includes the fourth ciphertext account value and the fourth public key of other users, and the third ciphertext private key is the fourth private key corresponding to the fourth public key paired with the third public key by other users. The value of the fourth ciphertext account is obtained after other users encrypt the previous transaction information of other users with the fourth public key; based on the second ciphertext private key, the third ciphertext private key, The first ciphertext account value, the fourth ciphertext account value and the third public key determine the proxy user's fifth ciphertext account value, and record the fifth ciphertext account value in the blockchain, so that the proxy user can use The third private key corresponding to the third public key decrypts the fifth ciphertext account value to obtain the second plaintext account value.

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

Encrypt the first ciphertext account value with the third public key to obtain the first ciphertext account value in the second cipher state; encrypt the fourth ciphertext account value with the third public key to obtain the first ciphertext account value in the first cipher state. Four ciphertext account values; the fifth ciphertext account value is determined based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second ciphertext state, and the fourth ciphertext account value in the first ciphertext state Ciphertext account value.

In other embodiments of the present application, the processor 1102 is further configured to execute executable instructions stored in the memory 1101 to implement the following steps:

Through the homomorphic decryption function in the second evaluation function, use the second ciphertext private key to decrypt the first ciphertext account value in the second ciphertext state to obtain the sixth ciphertext account value; through the homomorphic decryption function, use The third ciphertext private key decrypts the fourth ciphertext account value in the first cipher state to obtain the seventh ciphertext account value; through the operation function in the first evaluation function, the sixth ciphertext account value and the seventh ciphertext account value are decrypted. The ciphertext account value is calculated to determine the fifth ciphertext account value.

Embodiments of the present application provide a storage medium, where one or more programs are stored in the storage medium, and the one or more programs can be executed by one or more processors to implement FIG. 1 , FIG. 3 to FIG. 4 , and FIG. An information processing method provided by the embodiments corresponding to FIG. 6 to FIG. 8 .

The storage medium provided by the embodiment of the present application receives transaction information between the target user and other users; wherein, the transaction information includes an account change value; the first ledger information of the target user is obtained from the blockchain; The ledger information includes the first ciphertext account value and the first public key of the target user. The first ciphertext account value is obtained after the target user encrypts the previous transaction information of the target user with the first public key; The key-pair account change value is encrypted to obtain the first ciphertext account change value; the second ciphertext account value is determined based on the first ciphertext account value, the first ciphertext account change value and the first evaluation function, and the second ciphertext account value is determined. The account value is recorded in the blockchain, so that the target user decrypts the second ciphertext account value with the first private key corresponding to the first public key to obtain the first plaintext account value; wherein the first public key and the first The private key is generated according to the homomorphic encryption parameters, and the first evaluation function includes the operation function; in this way, the original information of the data will not be leaked during the operation of the ciphertext data by the blockchain nodes, and the privacy between the data is realized. operation.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the application may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media having computer-usable program code embodied therein, including but not limited to disk storage, optical storage, and the like.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the protection scope of the present application.

Claims (10)

1. An information processing method applied to a first node of a block chain, the method comprising:

receiving transaction information between a target user and other users; wherein the transaction information includes an account change value;

acquiring first account book information of the target user from the block chain; the first account book information comprises a first ciphertext account value and a first public key of the target user, wherein the first ciphertext account value is obtained after the target user encrypts previous transaction information of the target user by using the first public key;

encrypting the account variation value by using the first public key to obtain a first ciphertext account variation value;

determining a second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and a first evaluation function, and recording the second ciphertext account value in the block chain, so that the target user decrypts the second ciphertext account value with a first private key corresponding to the first public key to obtain a first plaintext account value; the first public key and the first private key are generated according to homomorphic encryption parameters; the first evaluation function comprises an arithmetic function.

2. The method of claim 1, after the obtaining the first ledger information of the target user from the blockchain, the method comprising:

acquiring key updating information of the target user from the block chain, wherein the key updating information comprises a first ciphertext private key and a second public key, and the first ciphertext private key is obtained after the target user encrypts the first private key by using the second public key;

updating the first account book information based on the first ciphertext private key and the second public key to obtain updated first account book information, so that the first node records the ciphertext account value of the target user of the block chain again according to the updated first account book information.

3. The method of claim 2, wherein the updating the first ledger information based on the first ciphertext private key and the second public key to obtain updated first ledger information comprises:

encrypting the first ciphertext account value again by using the second public key to obtain a first ciphertext account value in a first secret state;

determining a third ciphertext account value based on the first ciphertext private key, the first ciphertext account value in the first ciphertext state, and a second evaluation function; wherein the updated first ledger information comprises the third ciphertext account value and the second public key.

4. The method of claim 3, the second evaluation function comprising a homomorphic decryption function, the determining a third ciphertext account value based on the first ciphertext private key, the first ciphertext account value in the first ciphertext state, and the second evaluation function comprising:

and decrypting the first ciphertext account value in the first secret state by using the first ciphertext private key through a homomorphic decryption function in the second evaluation function to obtain the third ciphertext account value.

5. The method of any of claims 1 to 4, after the obtaining of the first ledger information of the target user from the blockchain, the method comprising:

acquiring second account book information of the agent user from the blockchain; wherein the second ledger information comprises a null value and a third public key, and the agent user is different from the target user and the other users;

acquiring a second ciphertext private key of the target user from the block chain; the second ciphertext private key is obtained by encrypting the first private key by the target user by using the third public key;

acquiring a third ciphertext private key and third account book information of the other users from the block chain; the second account book information comprises a fourth ciphertext account value and a fourth public key of the other user, the third ciphertext private key is obtained by the other user by encrypting a fourth private key corresponding to the fourth public key by using the third public key, and the fourth ciphertext account value is obtained by the other user by encrypting previous transaction information of the other user by using the fourth public key;

determining a fifth ciphertext account value of the agent user based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value, the fourth ciphertext account value, and the third public key, and recording the fifth ciphertext account value in the block chain, so that the agent user decrypts the fifth ciphertext account value with the third private key corresponding to the third public key to obtain a second plaintext account value.

6. The method of claim 5, the determining a fifth ciphertext account value of the proxy user based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value, the fourth ciphertext account value, and the third public key, comprising:

encrypting the first ciphertext account value by using the third public key to obtain a first ciphertext account value in a second secret state;

encrypting the fourth ciphertext account value by using the third public key to obtain a fourth ciphertext account value in a first secret state;

determining the fifth ciphertext account value based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second ciphertext state, and the fourth ciphertext account value in the first ciphertext state.

7. The method of claim 6, the determining the fifth ciphertext account value based on the second ciphertext private key, the third ciphertext private key, the first ciphertext account value in the second secret state, and the fourth ciphertext account value in the first secret state, comprising:

decrypting the first ciphertext account value in the second cipher state by using the second ciphertext private key through a homomorphic decryption function in a second evaluation function to obtain a sixth ciphertext account value;

decrypting a fourth ciphertext account value in the first ciphertext state by using the third ciphertext private key through the homomorphic decryption function to obtain a seventh ciphertext account value;

and calculating the sixth ciphertext account value and the seventh ciphertext account value through the operation function in the first evaluation function, and determining the fifth ciphertext account value.

8. An information processing apparatus, the apparatus comprising:

the receiving module is used for receiving transaction information between the target user and other users; wherein the transaction information includes an account change value;

the acquisition module is used for acquiring first account book information of the target user from a block chain; the first account book information comprises a first ciphertext account value and a first public key of the target user, wherein the first ciphertext account value is obtained after the target user encrypts previous transaction information of the target user by using the first public key;

the processing module is used for encrypting the account change value by using the first public key to obtain a first ciphertext account change value; determining a second ciphertext account value based on the first ciphertext account value, the first ciphertext account change value and a first evaluation function, and recording the second ciphertext account value in the block chain, so that the target user decrypts the second ciphertext account value with a first private key corresponding to the first public key to obtain a first plaintext account value; the first public key and the first private key are generated according to homomorphic encryption parameters, and the first evaluation function comprises an operation function.

9. A blockchain platform, the blockchain platform comprising:

a memory for storing executable instructions;

a processor for executing the executable instructions stored in the memory to implement the information processing method of any one of claims 1 to 7.

10. A storage medium storing one or more programs, the one or more programs being executable by one or more processors to implement the information processing method according to any one of claims 1 to 7.

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