CN111221569B - Document updating method and server - Google Patents

Abstract

The invention discloses a document updating method and a server, wherein the method comprises the following steps: generating homomorphic calculation functions and homomorphic parameters according to content information to be updated, wherein the content information to be updated is obtained by comparing an original document with the document to be updated; determining the identification of a sub-file to be updated according to the content information to be updated, wherein the sub-file to be updated is a file to be updated in the divided sub-file, and the divided sub-file is a file obtained by dividing an original document; generating an updated parameter according to a homomorphic calculation function, a parameter encryption result and an identifier and a number corresponding to a sub-file to be updated, wherein the parameter encryption result is obtained by homomorphic encryption of the homomorphic parameter by adopting a homomorphic encryption public key; and sending the update parameters to the blockchain network so that the storage node server updates the split subfiles stored by the storage node server according to the update parameters. The working efficiency is improved, and the waste of resources is avoided.

Description

Document update method and server

technical field

The invention relates to the technical field of computer applications, in particular to a document update method and server.

Background technique

Software documentation or source code documentation refers to the text associated with a software system and its software engineering process. Types of software documentation include software requirements documents, design documents, test documents, and user manuals, etc. Among them, requirements documents, design documents and test documents are generally written by developers during the software development process, while non-process documents such as user manuals are written by specialized non-technical writers. Software documentation can improve the efficiency of software development, ensure the quality of software, and can guide and help developers update the software during the use of the software. At the same time, in the process of software updating and testing, the corresponding software documentation also needs to be updated synchronously.

Usually, during the updating process of the software documentation, the content of the software documentation needs to be encrypted to ensure the security of the updated content; and when the content of the encrypted software documentation is updated again, the entire content of the software documentation must be re-uploaded to the server. For software documentation that only needs to update some chapters, this operation reduces work efficiency and also causes a waste of resources.

Contents of the invention

Therefore, the present invention provides a document update method and server to solve the problems of low work efficiency and waste of resources in the prior art due to the need to re-upload the entire content of the software document to the server when the content of the encrypted software document is updated again.

In order to achieve the above object, the first aspect of the present invention provides a document updating method, the method includes: generating a homomorphic calculation function and a homomorphic parameter based on the content information to be updated, the content information to be updated is the information obtained by comparing the original document and the document to be updated; determining the identification of the subfile to be updated according to the content information to be updated, the subfile to be updated is the file to be updated in the split subfile, and the split subfile is a file obtained by dividing the original document; the update parameter is generated according to the homomorphic calculation function, the parameter encryption result, and the identification and number corresponding to the subfile to be updated. The key is the result obtained by homomorphically encrypting the homomorphic parameters; sending the update parameters to the blockchain network, so that the storage node server can update the split sub-files stored by the storage node server according to the update parameters.

In some implementations, before the step of generating the homomorphic calculation function according to the content information to be updated, it also includes: dividing the original document, obtaining N divided sub-files, and assigning corresponding identifiers and numbers for the divided sub-files, N being an integer greater than or equal to 1; establishing a mapping relationship between the N divided sub-files and all leaf nodes of the hash tree structure except the root node; using a homomorphic encryption public key to perform homomorphic encryption on the N divided sub-files, and transferring the obtained N encrypted divided sub-files to the blockchain network, so that the storage node server stores the divided sub-files file, the homomorphic encryption public key is a secret key generated according to the homomorphic key generation algorithm.

In some implementations, after sending the update parameters to the blockchain network so that the storage node server updates the split sub-files stored by the storage node server according to the update parameters, it further includes: obtaining from the blockchain network the split sub-files stored by the storage node server, the numbers corresponding to the split sub-files, and the values of the leaf nodes of the hash tree corresponding to the split sub-files; adding the values of the leaf nodes in sequence according to the numbers to obtain the addition result, and the numbers are continuous numbers; The key is a secret key generated according to the homomorphic key generation algorithm.

In some implementations, the value of the root node of the hash tree is the value obtained by adding the values of all the leaf nodes included in the hash tree, the value of the leaf node is the value obtained by homomorphically encrypting the sub-files using the homomorphic encryption public key, and the value of the leaf node is the value obtained by sequentially adding the values of all the child leaf nodes under it in order of number.

In some embodiments, the step of generating a homomorphic calculation function according to the content information to be updated includes: generating a homomorphic calculation function and a homomorphic parameter according to the content information to be updated, the homomorphic calculation function and the homomorphic parameter satisfy the following rules: use the homomorphic calculation function to calculate the split sub-file and the corresponding homomorphic parameter, and obtain the sub-file to be updated corresponding to the split sub-file.

In order to achieve the above object, the second aspect of the present invention provides a method for updating a document. The method includes: obtaining the update parameters sent by the user node server from the blockchain network. The update parameters include a homomorphic calculation function, a parameter encryption result, and the identification and number corresponding to the subfile to be updated. The parameter encryption result is the result obtained by the user node server using a homomorphic encryption public key to perform homomorphic encryption on the homomorphic parameters corresponding to the subfile to be updated. The subfile to be updated is the file to be updated in the split subfile. Perform calculations to obtain subfiles to be updated; use the subfiles to be updated to update the split subfiles stored locally according to the identifier and number.

In some implementations, the step of calculating the update parameters according to the homomorphic encryption calculation function to obtain the subfile to be updated includes: calculating the update parameter according to the homomorphic encryption calculation function to obtain a calculation result; sampling the homomorphic encryption private key, and performing homomorphic decryption on the calculation result to obtain the subfile to be updated. The homomorphic encryption private key is a secret key generated according to a homomorphic key generation algorithm.

In some embodiments, before obtaining the update parameter step sent by the user node server from the blockchain network, it also includes: obtaining from the blockchain network N encrypted split sub-files sent by the user node server, the encrypted split sub-files are files obtained by the user node server using a homomorphic encryption public key to homomorphically encrypt the split sub-files, and there is a mapping relationship between the N split sub-files and all leaf nodes of the hash tree except the root node, and N is an integer greater than or equal to 1; perform homomorphic decryption on the N encrypted split sub-files respectively , to obtain N split sub-files; according to the capacity of the storage space, select M split sub-files from the N split sub-files and store them locally. The capacity of the storage space is greater than the file storage capacity.

In order to achieve the above object, the third aspect of the present invention provides a user node server, including: a function generation module, which is used to generate a homomorphic calculation function and a homomorphic parameter according to the content information to be updated. The content information to be updated is information obtained by comparing the original document and the document to be updated; a determination module, which is used to determine the identification of the subfile to be updated according to the content information to be updated. , to generate update parameters, and the parameter encryption result is the result obtained by homomorphically encrypting the homomorphic parameters with the homomorphic encryption public key;

The sending module is configured to send the update parameter to the block chain network, so that the storage node server updates the split sub-file stored by the storage node server according to the update parameter.

In order to achieve the above object, the fourth aspect of the present invention provides a storage node server, including: an acquisition module, which is used to obtain the update parameters sent by the user node server from the blockchain network. The update parameters include a homomorphic calculation function, a parameter encryption result, and an identification and number corresponding to the subfile to be updated. The parameter encryption result is the result obtained by the user node server using a homomorphic encryption public key to perform homomorphic encryption on the homomorphic parameters corresponding to the subfile to be updated. The subfile to be updated is the file to be updated in the split subfile. The encryption calculation function calculates the update parameters to obtain the sub-file to be updated; the update module is used to update the locally stored split sub-file with the sub-file to be updated according to the identifier and number.

The present invention has the following advantages: by comparing the original document and the document to be updated, the content information to be updated is obtained, so that the homomorphic calculation function and the homomorphic parameter can be generated according to the content information to be updated, and then the identification of the sub-file to be updated is determined according to the content information to be updated, and the homomorphic calculation function, the parameter encryption result obtained by homomorphic encryption of the homomorphic parameter using the homomorphic encryption public key, the identification of the sub-file to be updated and the corresponding number are sent to the blockchain network as update parameters, so that the storage node server can receive the update parameter, and update the corresponding split sub-file according to the update parameter, avoiding The original document can only be updated by uploading all the content of the document to be updated to the server, and the update of the original document can be completed only by updating the sub-file to be updated stored on the storage node server, which improves work efficiency and avoids waste of resources.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention.

Fig. 1 is a flowchart of a document updating method provided in the first embodiment of the present invention.

Fig. 2 is a flowchart of a document updating method provided in the second embodiment of the present invention.

Fig. 3 is a flowchart of a document updating method provided in the third embodiment of the present invention.

Fig. 4 is a flow chart of a document updating method based on blockchain technology provided in the fourth embodiment of the present invention.

FIG. 5 is a flowchart of a document update method using a Markle hash tree provided in the fifth embodiment of the present invention.

FIG. 6 is a branch structure diagram of the Markle hash tree provided in the fifth embodiment of the present invention.

Fig. 7 is a block diagram of a user node server provided in the sixth embodiment of the present invention.

FIG. 8 is a block diagram of a storage node server provided in a seventh embodiment of the present invention.

In the attached picture:

4010: user node server 4020: storage node server

4021: storage node server A 4022: storage node server B

701: generate module 702: determine module

703: send module 801: get module

802: Calculation module 803: Update module

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

The first embodiment of the present invention relates to a document updating method. It is used to improve the efficiency of document updating and avoid waste of resources.

The implementation details of the document update method in this embodiment will be described in detail below. The following content is only for the convenience of understanding the implementation details of the solution, and is not necessary for implementing the solution.

FIG. 1 is a flow chart of a document updating method in this embodiment, which can be used in a user node server. The method may include the following steps.

In step 101, a homomorphic calculation function and homomorphic parameters are generated according to the content information to be updated.

Wherein, the content information to be updated is information obtained by comparing the original document and the document to be updated.

For example, when it is necessary to update the original document c to the document c+ to be updated, compare the original document c and the document c+ to be updated, and know that the content information to be updated includes the contents of the first chapter and the fourth chapter of the original document c, then generate the homomorphic calculation function f and the homomorphic parameter ca according to the contents of the first chapter and the fourth chapter. During specific implementation, the homomorphic calculation function f and the homomorphic parameter ca satisfy the following relationship: f(c, ca)=c+. That is, using the homomorphic calculation function f to calculate the original document c and the corresponding homomorphic parameter ca, the document c+ to be updated corresponding to the original document c can be obtained.

In step 102, the identification of the sub-file to be updated is determined according to the content information to be updated.

Wherein, the sub-file to be updated is a file to be updated in the split sub-file, and the split sub-file is a file obtained by splitting the original document. For example, if the original document A is divided into 5 parts, 5 divided sub-files can be obtained: A1, A2, A3, A4 and A5. If it is determined according to the content information to be updated that the split sub-file A2 and the split sub-file A3 need to be updated, then the sub-file to be updated is the split sub-file A2 and the split sub-file A3, and the identifiers of the corresponding sub-files to be updated are A2 and A3.

In step 103, an update parameter is generated according to the homomorphic calculation function, the parameter encryption result, and the identification and number corresponding to the subfile to be updated.

It should be noted that the result of parameter encryption is the result of homomorphic encryption of homomorphic parameters using a homomorphic encryption public key, where the homomorphic encryption public key is a secret key generated according to a homomorphic key generation algorithm.

In step 104, update parameters are sent to the blockchain network.

When the storage node server in the blockchain network obtains the update parameter sent by the user node server through the blockchain network, it will update the split sub-file stored by the storage node server according to the update parameter. The split sub-file stored on the storage node server is the latest sub-file, which is convenient for subsequent user nodes to obtain the latest sub-file.

In some implementations, a homomorphic calculation function and a homomorphic parameter are generated according to the content information to be updated, and the homomorphic calculation function and the homomorphic parameter meet the following rules: use the homomorphic calculation function to calculate the split sub-file and the corresponding homomorphic parameter, and obtain the sub-file to be updated corresponding to the split sub-file.

For example, the homomorphic parameter corresponding to the split sub-file A1 is ca1, and the corresponding homomorphic parameter of the split sub-file A2 is ca2, then the homomorphic parameter corresponding to the split sub-file A1 is ca1 using the homomorphic calculation function f, and the sub-file A1+ to be updated is obtained, which satisfies the following relationship: f(A1, ca1)=A1+; similarly, using the homomorphic calculation function f to split the corresponding homomorphic parameter of the sub-file A2 is ca2, and obtaining the sub-file A2+ to be updated also needs to satisfy the following relationship: f(A2 , ca2)=A2+.

In this embodiment, the content information to be updated is obtained by comparing the original document with the document to be updated, so that the homomorphic calculation function and homomorphic parameters can be generated according to the content information to be updated, and then the identity of the sub-file to be updated is determined according to the content information to be updated, and the homomorphic calculation function, the parameter encryption result obtained by homomorphic encryption of the homomorphic parameter using the homomorphic encryption public key, the identification of the sub-file to be updated and the corresponding number are sent to the blockchain network as update parameters, so that the storage node server can receive the update parameter, and update the corresponding split sub-file according to the update parameter, avoiding The original document can only be updated by uploading all the content of the document to be updated to the server, and the update of the original document can be completed only by updating the sub-file to be updated stored on the storage node server, which improves work efficiency and avoids waste of resources.

The second embodiment of the present invention relates to a document updating method. The second embodiment is roughly the same as the first embodiment, the main difference is that: a Markle hash tree is established to map each segmented sub-document, so as to improve the update efficiency of the updated document.

Fig. 2 is a flow chart of the document update method in this embodiment, which can be used in the user node server. The method may include the following steps.

In step 201, the original document is segmented to obtain N segmented sub-files, and corresponding identifiers and numbers are assigned to the segmented sub-files.

Wherein, N is an integer greater than or equal to 1. For example, the original document C is divided into n divided sub-files, and the identifier and division number of each divided sub-file are correspondingly obtained: C1, C2, C3, ..., Cn, and C=C1+C2+C3+...+Cn.

In step 202, a mapping relationship between N split sub-files and all leaf nodes except the root node of the hash tree structure is established.

It should be noted that the mapping relationship includes: the value of the root node of the hash tree is the value obtained by adding the values of all the leaf nodes included in the hash tree, the value of the leaf node is the value obtained by homomorphically encrypting the sub-files using the homomorphic encryption public key, and the value of the leaf node is the value obtained by adding the values of all child leaf nodes under it in sequence according to the numbering order.

For example, the original document C is divided into n split sub-files, correspondingly obtain the identifier and split number of each split sub-file: C1, C2, C3, ..., Cn, and C=C1+C2+C3+...+Cn. In the Markle hash tree, the value of each leaf node of the Markle hash tree is the value obtained by homomorphically encrypting the corresponding split sub-files using the homomorphic encryption public key. For example, each leaf node corresponds to record Enc (C1), Enc (C2), Enc (C3) ... Enc (Cn), wherein, Enc (C1) represents the value that the user node server 4010 performs homomorphic encryption on the split sub-file C1 using the homomorphic encryption public key, and Enc (C2) represents the value of the user node server 4 010 uses the homomorphic encryption public key to carry out the value of homomorphic encryption to the split sub-file C2, Enc (C3) represents the value that the user node server 4010 uses the homomorphic encryption public key to carry out homomorphic encryption to the split sub-file C3, ..., Enc (Cn) represents the value that the user node server 4010 uses the homomorphic encryption public key to carry out homomorphic encryption to the split sub-file Cn. And, the value of the root node of the Markle hash tree is the value obtained by adding the values of all leaf nodes included in the Markle hash tree (i.e. Enc(C1), Enc(C2), Enc(C3)...Enc(Cn)), and the value of any leaf node is the value obtained by adding the values of all sub-leaf nodes under it in sequence according to the division number order.

In step 203, the homomorphic encryption is performed on the N split sub-files respectively by using the homomorphic encryption public key, and the obtained N encrypted split sub-files are transmitted to the blockchain network.

When the storage node server connected to the blockchain network obtains N encrypted split sub-files sent by the user node server from the blockchain network, it will select one or more split sub-files according to the size of its own local storage space for storage.

For example, when N is equal to 7, the user node server divides the original document C into seven different sub-files, namely B1, B2, B3, B4, B5, B6, and B7: the first storage node server may select the sub-files B1, B2, and B3 for storage; the second storage node server may select the sub-files B4, B5, B6, and B7 for storage.

In step 204, a homomorphic calculation function and homomorphic parameters are generated according to the content information to be updated.

In step 205, the identification of the sub-file to be updated is determined according to the content information to be updated.

In step 206, an update parameter is generated according to the homomorphic calculation function, the parameter encryption result, and the identification and number corresponding to the subfile to be updated.

In step 207, update parameters are sent to the blockchain network.

It should be noted that steps 204 to 207 in this embodiment are the same as steps 101 to 104 in the first embodiment, and will not be repeated here.

In a specific implementation, after step 207, it may further include: obtaining from the blockchain network the split sub-file stored by the storage node server, the number corresponding to the split sub-file, and the value of the leaf node of the hash tree corresponding to the split sub-file; adding the values of the leaf nodes in sequence according to the number to obtain the sum result, and the number is a continuous number; using the homomorphic encryption private key to perform homomorphic decryption on the sum result to obtain an updated document. The homomorphic encryption private key is a secret key generated according to a homomorphic key generation algorithm.

When the user node server completes one or more document updates and wants to obtain the latest document, it will download the latest split subfile number corresponding to the split subfile and the leaf node value of the hash tree corresponding to the split subfile stored by each storage node server from each storage node server in the blockchain network according to the mapping relationship between the split subfile and the hash tree; then add all the consecutive numbers once to obtain the value of the root node of the hash tree. , for example, use the homomorphic encrypted private key to homomorphically decrypt the value of the root node to obtain the latest document.

When obtaining the updated document specifically, it is also possible to obtain only the most updated chapters of the original document, or the corresponding chapters required by the user. For example, if it is necessary to update Chapter 1 and Chapter 8 of the original document, the corresponding split sub-files of Chapter 1 are C3, C4, and C5, and the corresponding split sub-files of Chapter 8 are C26 and C27, then the user node server 4010 needs to process the contents of these two chapters separately, and each chapter forms an independent small Markle hash tree. The values of the root nodes of these two Markle hash trees are respectively Enc(C3+)+Enc(C4+)+Enc(C5+) and Enc(C5+) 26+)+Enc(C27+), and then the user node server 4010 uses its own homomorphic encryption private key to calculate and obtain Dec(Enc(C3+)+Enc(C4+)+Enc(C5+)), and the latest document of Chapter 1 can be obtained. Similarly, the user node server 4010 uses its own homomorphic encryption private key to calculate and obtain Dec(Enc(C26+)+Enc(C27+)), and then the latest document of Chapter 8 can be obtained.

In this embodiment, according to the structure of the hash tree, a mapping relationship is established between the split sub-file and all leaf nodes in the hash tree except the root node, so that the user node server can find the sub-file to be updated more quickly according to the hash tree, speed up the document update speed, improve work efficiency, and avoid waste of resources. This enables users to obtain the latest documents more quickly and conveniently, improving user experience.

The third embodiment of the present invention relates to a document updating method. FIG. 3 is a flow chart of the document update method in this embodiment, which can be used for storage node servers. The method may include the following steps.

In step 301, the update parameters sent by the user node server are obtained from the blockchain network.

Among them, the update parameters include the homomorphic calculation function, the parameter encryption result, the identification and number corresponding to the subfile to be updated, the parameter encryption result is the result obtained by the user node server using the homomorphic encryption public key to perform homomorphic encryption on the homomorphic parameters corresponding to the subfile to be updated, the subfile to be updated is the file to be updated in the split subfile, and the split subfile is the file obtained by splitting the original document.

In step 302, the update parameters are calculated according to the homomorphic encryption calculation function to obtain the sub-file to be updated.

In some embodiments, the update parameters are calculated according to the homomorphic encryption calculation function to obtain the calculation result; the homomorphic encryption private key is sampled, and the calculation result is subjected to homomorphic decryption to obtain the sub-file to be updated. The homomorphic encryption private key is a secret key generated according to the homomorphic key generation algorithm.

It should be noted that the homomorphic encryption private key used by the storage node server corresponds to the homomorphic encryption public key used by the user node server. Only the corresponding storage node server can obtain the update parameters sent by the user node server, and then obtain the sub-file to be updated, which improves the security of file information during transmission.

In step 303, according to the identifier and number, the subfile to be updated is used to update the locally stored split subfile.

It should be noted that each storage node server only obtains subfiles to be updated that are consistent with the identification and number of the split subfiles stored locally, so that the subfiles to be updated can be updated on the storage node server, which is convenient for the user node server to quickly obtain the latest split subfiles. For example, according to the identification and division number of the division sub-file C3, the storage node server will search for the division sub-file stored locally, obtain the division sub-file consistent with the identification and division number, and then update the division sub-file C3 locally stored in the storage node server to the sub-file C3+ to be updated.

In this embodiment, the storage node server obtains the update parameters sent by the user node server from the blockchain network, uses the homomorphic encryption calculation function to calculate the update parameters, and obtains the subfile to be updated, and then according to the identification and number corresponding to the subfile to be updated, finds the locally stored split subfile, uses the subfile to be updated to update the locally stored split subfile, and ensures that the stored split subfiles are all up-to-date, so that the user node server can quickly obtain the latest document when updating the document.

In some embodiments, before step 301, the following steps may also be included:

In step 3011, N encrypted sub-files sent by the user node server are obtained from the block chain network.

Wherein, the encrypted split sub-file is a file obtained by performing homomorphic encryption on the split sub-file by the user node server using a homomorphic encryption public key, and there is a mapping relationship between N split sub-files and all leaf nodes of the hash tree except the root node, and N is an integer greater than or equal to 1;

In step 3012, perform homomorphic decryption on the N encrypted sub-files respectively, and obtain N corresponding sub-files.

In step 3013, according to the capacity of the storage space, select M split sub-files from the N split sub-files and store them locally,

Wherein, the capacity of the storage space is larger than the file storage capacity, and the file storage capacity is the capacity obtained by adding the file sizes of M divided sub-files, M is an integer greater than or equal to 1, and M is less than or equal to N. For example, the storage capacity of a certain storage node server is 30M. When the storage node server obtains multiple sub-files from the blockchain network, it may obtain sub-files of the following sizes: 5M sub-file C1, 15M sub-file C2, 10M sub-file C3, 20M sub-file C4, etc., but the storage node server can only store files with a maximum size of 30M. Therefore, the storage node server chooses sub-file C1, sub-file C2 and sub-file C 3 is stored, and other split sub-files such as the split sub-file C4 are discarded.

In this embodiment, by performing homomorphic decryption on N encrypted sub-files, N corresponding sub-files are obtained, and then according to the capacity of the storage node server's own storage space, an appropriate sub-file is selected for storage to ensure the integrity of the sub-files.

A fourth embodiment of the present invention relates to a document updating method. Fig. 4 is a flow chart of a document update method based on blockchain technology in this embodiment. When the size of the document does not exceed the preset threshold, the document is not divided, that is, the number of divided sub-files is 1. Specifically, the document update system is composed of the user node server 4010 and the storage node server 4020, and the document update system communicates through the block chain network. Document update steps are as follows.

In step 401, the user node server 4010 generates a homomorphic encryption public key and a homomorphic encryption private key according to a homomorphic key generation algorithm. For example, suppose the document is c. After the user node server 4010 prepares the document c, it performs homomorphic encryption on the document c to obtain the homomorphic encryption result Enc(c) of the document c.

In step 402, the user node server 4010 signs Enc(c) with its own blockchain private key, and broadcasts the signed Enc(c) to the blockchain network.

In step 403, when the user node server 4010 needs to update the document c to document c+, compare the document c and document c+ to obtain the content information to be updated, and then generate a homomorphic calculation function f and a homomorphic parameter ca according to the content information to be updated. The generated homomorphic calculation function f and the homomorphic parameter ca satisfy the following relationship: f(c, ca)=c+. That is, use the homomorphic calculation function f to calculate the original document c and the corresponding homomorphic parameter ca to obtain the updated document c+.

In step 404, the user node server 4010 generates update parameters according to the identification of the document c, the homomorphic computation function f and the homomorphic encryption result Enc(ca). Then use the block chain private key of the user node server 4010 to sign the update parameters, and send the signed update parameters to the block chain network.

Wherein, the homomorphic encryption result Enc(ca) is the result obtained by the user node server 4010 performing homomorphic encryption on the homomorphic parameter ca.

In step 405, after receiving the signed update parameters sent in step 404, the storage node server 4020 storing document c verifies the private key of the signature. After the verification is passed, the storage node server 4020 uses a homomorphic encryption calculation function to process the update parameters, obtains and stores the calculation results locally, that is, stores document c++ locally.

Wherein, the homomorphic encryption computing function can be expressed as c++=Evaluate(f, Enc(c), Enc(ca); wherein, f represents the homomorphic computing function, Enc(c) represents the result obtained by performing homomorphic encryption on the document c, Enc(ca) represents the result obtained by performing homomorphic encryption on the homomorphic parameter ca, ca represents the homomorphic parameter, and c++ represents the updated document stored on the storage node server 4020.

In step 406, when the user node server 4010 wants to obtain an updated document from the blockchain network, it can download the document c++ from the storage node server 4020 to the local user node server 4010, and then use the homomorphic decryption algorithm function to calculate the document c++ to obtain Dec(c++). Due to the characteristics of homomorphic encryption, c++ should be equal to Enc(c+), and Dec(c++) should be equal to c+; the updated document c+ can be obtained.

In this embodiment, the content information to be updated is obtained by comparing the original document with the document to be updated, so that the homomorphic calculation function and homomorphic parameters can be generated according to the content information to be updated, and then the identity of the sub-file to be updated is determined according to the content information to be updated, and the homomorphic calculation function, the parameter encryption result obtained by homomorphic encryption of the homomorphic parameter using the homomorphic encryption public key, the identification of the sub-file to be updated and the corresponding number are sent to the blockchain network as update parameters, so that the storage node server can receive the update parameter, and update the corresponding split sub-file according to the update parameter, avoiding The original document can only be updated by uploading all the content of the document to be updated to the server, and the update of the original document can be completed only by updating the sub-file to be updated stored on the storage node server, which improves work efficiency and avoids waste of resources.

A fifth embodiment of the present invention relates to a document updating method. Fig. 5 is a flowchart of a document updating method using a Markle hash tree. When the size of the document exceeds the preset threshold, the document is divided to obtain N divided sub-files, and the mapping relationship between the Markle hash tree and the N divided sub-files is established to improve the efficiency of document updating. Specifically, multiple storage node servers such as user node server 4010, storage node server A4021, and storage node server B4022 form a document update system, and the document update system communicates through a blockchain network. Document update steps are as follows.

In step 501, the user node server 4010 generates a homomorphic encryption public key and a homomorphic encryption private key according to a homomorphic key generation algorithm. For example, assuming that the document is C, the user node server 4010 fragments the document C through a Markle hash tree to obtain N split sub-files.

For example, Fig. 6 is a branch structure diagram of a Markle hash tree, wherein the document C is divided into n split sub-files, correspondingly obtaining the identification and split number of each split sub-file: C1, C2, C3, ..., Cn, and C=C1+C2+C3+...+Cn. In the Markle hash tree, the value of each leaf node of the Markle hash tree is the value obtained by homomorphically encrypting the corresponding split sub-files using the homomorphic encryption public key. For example, each leaf node corresponds to record Enc (C1), Enc (C2), Enc (C3) ... Enc (Cn), wherein, Enc (C1) represents the value that the user node server 4010 performs homomorphic encryption on the split sub-file C1 using the homomorphic encryption public key, and Enc (C2) represents the value of the user node server 4 010 uses the homomorphic encryption public key to carry out the value of homomorphic encryption to the split sub-file C2, Enc (C3) represents the value that the user node server 4010 uses the homomorphic encryption public key to carry out homomorphic encryption to the split sub-file C3, ..., Enc (Cn) represents the value that the user node server 4010 uses the homomorphic encryption public key to carry out homomorphic encryption to the split sub-file Cn. And, the value of the root node of the Markle hash tree is the value obtained by adding the values of all leaf nodes included in the Markle hash tree (i.e. Enc(C1), Enc(C2), Enc(C3)...Enc(Cn)), and the value of any leaf node is the value obtained by adding the values of all sub-leaf nodes under it in sequence according to the division number order.

In step 502, the user node server 4010 uses its own blockchain private key to sign Enc(C1), Enc(C2), Enc(C3)...Enc(Cn) respectively, obtain and send signed Enc(C1), signed Enc(C2), signed Enc(C3),...signed Enc(Cn) to the blockchain network.

In step 503, the storage node server A4021 and the storage node server B4022 respectively receive the homomorphically encrypted split sub-files C1, C2, C3, ..., Cn after each signature in step 502, and then verify the private key signatures of the signed Enc (c1), signed Enc (c2), signed Enc (c3), ... signed Enc (cn), and if the verification is passed, then according to the size of their local storage space , select one or more split sub-files for storage.

For example, when n is 7, the storage node server A4021 selects the split subfiles C1, C2, and C3 for storage; the storage node server B4022 selects the split subfiles C4, C5, C6, and C7 for storage.

In step 504, when the user node server 4010 needs to update document C to document C+, it compares document C+ with each divided sub-file C1, C2, C3, ..., Cn in step 501, and learns that the updated part only involves the divided sub-files C3 and C6, and only needs to update the divided sub-file C3 to the sub-file C3+ to be updated, and update the divided sub-file C6 to the sub-file C6+ to be updated. The user node server 4010 generates a homomorphic calculation function f and a homomorphic parameter ca according to the difference between the split subfile C3 and the subfile C3+ to be updated, and the difference between the split subfile C6 and the subfile C6+ to be updated. The homomorphic calculation function f and the homomorphic parameter ca satisfy the following relationship: f(C3, ca3)=C3+; f(C6, ca6)=C6+.

In step 505, the user node server 4010 performs homomorphic encryption on the homomorphic parameter ca3 and the homomorphic parameter ca6 respectively to obtain the homomorphic encryption results Enc (ca3) and Enc (ca6). Afterwards, the first update parameter is generated according to the homomorphic calculation function f, Enc (ca3), the identification of the document segmentation sub-file C3 and the segmentation number, and then the user node server 4010 uses its own block chain private key to sign the first update parameter, and sends the signed first update parameter to the blockchain network; State calculation function f, Enc (ca6), the identification of the split sub-file C6 and the split number of the split sub-file generate the second update parameter, then use the block chain private key of the user node server 4010 to sign the second update parameter, and send the signed second update parameter to the block chain network. The storage node server storing the split sub-file C3 and the split sub-file C6 can obtain the first update parameter and the second update parameter respectively.

In step 506, the storage node server A4021 obtains the first update parameter signed by the private key of the user node server 4010 from the blockchain network, and first verifies the private key signature of the first update parameter. When the verification is passed, obtain the first update parameter, i.e. homomorphic calculation function f, Enc (ca3), the identification and the segmentation number of the sub-file C3; then, the homomorphic encryption calculation function C3++=Evaluate (f, Enc (C3), Enc (ca3) can be run to calculate, obtain the sub-file C3 ++ to be updated, then, use the homomorphic decryption algorithm function to calculate the sub-file C3 ++ to be updated, and obtain Dec (C3 ++), due to the characteristics of homomorphic encryption, C3 ++ should be equal to Enc ( C3+), Dec(C3++) should be equal to C3+; the updated sub-file C3+ to be updated can be obtained; according to the identification and the segmentation number of the split sub-file C3, the locally stored split sub-file C3 is updated to the sub-file C3+ to be updated.

At the same time, the storage node server B 4022 obtains the second updated parameter signed by the private key of the user node server 4010 from the blockchain network, and first verifies the private key signature of the second updated parameter. When the verification is passed, obtain the second update parameter, i.e. homomorphic calculation function f, Enc (ca6), the identification and the segmentation number of the sub-file C6; then, the homomorphic encryption calculation function C6++=Evaluate (f, Enc (C6), Enc (ca6) can be run to calculate, obtain the sub-file C6 ++ to be updated, then use the homomorphic decryption algorithm function to calculate the sub-file C6 ++ to be updated, and obtain Dec (C6 ++), due to the characteristics of homomorphic encryption, C6 ++ should be equal to Enc ( C6+), Dec(C6++) should be equal to C6+; the updated sub-file C6+ to be updated can be obtained; according to the identification and the segmentation number of the split sub-file C6, the locally stored split sub-file C6 is updated to the sub-file C6+ to be updated.

In step 507, when the user node server 4010 wants to obtain updated documents from the blockchain network, the user node server 4010 can obtain the homomorphically encrypted storage values of all split sub-files from different storage node servers. Then, arrange these stored values according to the rules of the leaf nodes of the Markle hash tree, and add them up sequentially to obtain the value of the root node of the entire Markle hash tree; the user node server 4010 uses its own homomorphic encryption private key to perform homomorphic decryption on the value of the root node to obtain the latest document.

Similarly, if the user node server 4010 only needs to update a few chapters of the original document (for example, the first 100 pages of the original document, or update chapters 3 and 6, etc.), it only needs to download the document parts to be updated from each storage node server in the block chain network according to the identification and division number of the divided sub-files, and then combine these sub-files to be updated according to the combination of Markle trees to obtain the document chapters to be updated.

For example, the third chapter of the updated document is stored on the storage node server A4021, that is, the split sub-file C3+; the sixth chapter of the updated document is stored on the storage node server B4022, that is, the split sub-file C6+; then the user node server 4010 only needs to download the split sub-file C3+ from the storage node server A4021; download and obtain the split sub-file C6+ from the storage node server B4022. Then according to the identification and the division number of the division sub-file, the chapters of the original document can be updated correspondingly.

It should be noted that if the split numbers are not consecutive numbers, the homomorphic encryption results of each split sub-file cannot be added directly, and need to be processed separately. For example, if Chapter 1 and Chapter 12 of the original document need to be updated, the sub-files corresponding to Chapter 1 are C3, C4, and C5, and the sub-files corresponding to Chapter 12 are C26 and C27, then the user node server 4010 needs to process the content of these two chapters separately, and each chapter forms an independent small Markle hash tree. (C26+)+Enc(C27+), and then the user node server 4010 uses its own homomorphic encryption private key to calculate and obtain DeC(Enc(C3+)+Enc(C4+)+Enc(C5+)), and then the latest document of Chapter 1 can be obtained. Similarly, the user node server 4010 uses its own homomorphic encryption private key to perform calculations to obtain Dec(Enc(C26+)+Enc(C27+)), and then the latest document of Chapter 12 can be obtained.

In this embodiment, according to the structure of the hash tree, a mapping relationship is established between the split sub-file and all leaf nodes in the hash tree except the root node, so that the user node server can find the sub-file to be updated more quickly according to the hash tree, speed up the document update speed, improve work efficiency, and avoid waste of resources. This enables users to obtain the latest documents more quickly and conveniently, improving user experience.

The division of the steps of the above methods is only for the sake of clarity. When implementing, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs, but not changing the core design of the algorithm and process are all within the scope of protection of this patent.

The sixth embodiment of the present invention relates to a user node server. For the specific implementation of the server, reference may be made to the relevant description of the first embodiment, and repeated descriptions will not be repeated. It is worth noting that, for the specific implementation of the server in this embodiment, refer to the relevant descriptions of the second embodiment, and also refer to the relevant descriptions of the fourth embodiment, but it is not limited to the above three embodiments, and other undescribed embodiments are also within the scope of protection of this server.

As shown in Figure 7, the user node server mainly includes: a function generation module 701 is used to generate homomorphic calculation functions and homomorphic parameters according to the content information to be updated. The content information to be updated is information obtained by comparing the original document and the document to be updated; the determination module 702 is used to determine the identification of the subfile to be updated according to the content information to be updated. , to generate update parameters, and the result of parameter encryption is the result obtained by homomorphically encrypting the homomorphic parameters using the homomorphic encryption public key; the sending module 704 is used to send the update parameters to the blockchain network, so that the storage node server updates the split sub-files stored by the storage node server according to the update parameters.

The seventh embodiment of the present invention relates to a storage node server. For the specific implementation of the server, reference may be made to the relevant description of the third embodiment, and repeated descriptions will not be repeated. It is worth noting that, for the specific implementation of the server in this embodiment, refer to the relevant description in the fourth embodiment, but it is not limited to the above two embodiments, and other undescribed embodiments are also within the protection scope of this server.

As shown in Figure 8, the storage node server mainly includes: an acquisition module 801 used to obtain the update parameters sent by the user node server from the blockchain network. The update parameters include homomorphic calculation functions, parameter encryption results, and identification and numbers corresponding to the subfiles to be updated. The parameter encryption results are the results obtained by the user node server using the homomorphic encryption public key to perform homomorphic encryption on the subfiles to be updated. Perform calculations to obtain subfiles to be updated; the update module 803 is configured to use the subfiles to be updated to update locally stored split subfiles according to the identification and number.

It is worth mentioning that all the modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, or a part of a physical unit, or can be realized by a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, units that are not closely related to solving the technical problems proposed by the present invention are not introduced in this embodiment, but this does not mean that there are no other units in this embodiment.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (9)

1. A method of document updating, the method comprising:

generating homomorphic calculation functions and homomorphic parameters according to content information to be updated, wherein the content information to be updated is obtained by comparing an original document with the document to be updated;

determining the identification of a sub-file to be updated according to the content information to be updated, wherein the sub-file to be updated is a file to be updated in a divided sub-file, and the divided sub-file is a file obtained by dividing an original document;

generating an update parameter according to the homomorphic calculation function, a parameter encryption result and the identifier and the number corresponding to the sub-file to be updated, wherein the parameter encryption result is obtained by homomorphic encryption of the homomorphic parameter by adopting a homomorphic encryption public key;

transmitting the update parameters to a blockchain network so that a storage node server updates the split subfiles stored by the storage node server according to the update parameters;

Before the step of generating the homomorphic calculation function according to the content information to be updated, the method further comprises the following steps:

dividing the original document to obtain N divided subfiles, and distributing corresponding identifiers and numbers for the divided subfiles, wherein N is an integer greater than or equal to 1;

establishing mapping relations between the N divided subfiles and all leaf nodes except a root node of the hash tree structure;

and carrying out homomorphic encryption on the N split sub-files respectively by adopting homomorphic encryption public keys, and transmitting the obtained N encrypted split sub-files to a blockchain network so as to enable a storage node server to store the split sub-files, wherein the homomorphic encryption public keys are secret keys generated according to a homomorphic key generation algorithm.

2. The method of claim 1, further comprising, after the step of sending update parameters to a blockchain network to cause a storage node server to update split subfiles stored by the storage node server according to the update parameters:

obtaining the split sub-file, the number corresponding to the split sub-file and the value of the leaf node of the hash tree corresponding to the split sub-file stored by a storage node server from a blockchain network;

Sequentially adding the values of the leaf nodes according to the numbers, and obtaining an addition result, wherein the numbers are continuous numbers;

and homomorphic decryption is carried out on the addition result by using a homomorphic encryption private key, so that an updated document is obtained, wherein the homomorphic encryption private key is a secret key generated according to a homomorphic key generation algorithm.

3. The method according to claim 2, wherein the value of the root node of the hash tree is a value obtained by adding values of all leaf nodes included in the hash tree, the value of the leaf node is a value obtained by homomorphic encrypting the split subfile using a homomorphic encryption public key, and the value of the leaf node is a value obtained by sequentially adding values of all cotyledon child nodes subordinate thereto in the order of numbers.

4. The method of claim 1, wherein the step of generating a homomorphic calculation function from the content information to be updated comprises:

generating homomorphic calculation functions and homomorphic parameters according to the content information to be updated, wherein the homomorphic calculation functions and the homomorphic parameters meet the following rules:

and calculating the split subfiles and the corresponding homomorphic parameters by using the homomorphic calculation function to obtain subfiles to be updated corresponding to the split subfiles.

5. A method of document updating, the method comprising:

the method comprises the steps that updating parameters sent by a user node server are obtained from a blockchain network, the updating parameters comprise homomorphic calculation functions and parameter encryption results, identifiers and numbers corresponding to subfiles to be updated, the parameter encryption results are obtained by homomorphic encryption of homomorphic parameters corresponding to subfiles to be updated by the user node server through homomorphic encryption public keys, the subfiles to be updated are files to be updated in segmentation subfiles, and the segmentation subfiles are files obtained by segmenting original documents;

calculating the update parameters according to homomorphic encryption calculation functions to obtain the subfiles to be updated;

updating the locally stored divided subfiles by using the subfiles to be updated according to the identification and the number;

wherein, before the step of generating the homomorphic calculation function, the method further comprises:

dividing the original document to obtain N divided subfiles, and distributing corresponding identifiers and numbers for the divided subfiles, wherein N is an integer greater than or equal to 1;

establishing mapping relations between the N divided subfiles and all leaf nodes except a root node of the hash tree structure;

And carrying out homomorphic encryption on the N split sub-files respectively by adopting homomorphic encryption public keys, and transmitting the obtained N encrypted split sub-files to a blockchain network so as to enable a storage node server to store the split sub-files, wherein the homomorphic encryption public keys are secret keys generated according to a homomorphic key generation algorithm.

6. The method according to claim 5, wherein the step of calculating the update parameter according to a homomorphic encryption calculation function to obtain the subfile to be updated comprises:

calculating the update parameters according to the homomorphic encryption calculation function to obtain a calculation result;

and sampling a homomorphic encryption private key, and homomorphic decrypting the calculation result to obtain the subfiles to be updated, wherein the homomorphic encryption private key is a secret key generated according to a homomorphic key generation algorithm.

7. The method according to claim 5 or 6, further comprising, prior to the step of obtaining the update parameters sent by the user node server from the blockchain network:

obtaining N encrypted split subfiles sent by the user node server from a blockchain network, wherein the encrypted split subfiles are files obtained by homomorphic encryption of the split subfiles by the user node server through homomorphic encryption public keys, and mapping relations exist between the N split subfiles and all leaf nodes of a hash tree except a root node, and N is an integer greater than or equal to 1;

Homomorphic decryption is carried out on the N encrypted divided sub-files respectively, and N divided sub-files are correspondingly obtained;

and selecting M divided subfiles from the N divided subfiles according to the capacity of a storage space, wherein the capacity of the storage space is larger than the file storage capacity, the file storage capacity is obtained by adding the file sizes of the M divided subfiles, M is an integer greater than or equal to 1, and M is smaller than or equal to N.

8. A user node server, comprising:

the function generation module is used for generating homomorphic calculation functions and homomorphic parameters according to content information to be updated, wherein the content information to be updated is obtained by comparing an original document with the document to be updated;

the determining module is used for determining the identification of the subfiles to be updated according to the content information to be updated, wherein the subfiles to be updated are files to be updated in the segmentation subfiles, and the segmentation subfiles are files obtained by segmenting the original document;

the updating parameter generating module is used for generating updating parameters according to the homomorphic calculation function, the parameter encryption result and the identifier and the number corresponding to the sub-file to be updated, wherein the parameter encryption result is obtained by homomorphic encrypting the homomorphic parameters by adopting a homomorphic encryption public key

The sending module is used for sending the update parameters to the blockchain network so that the storage node server updates the split subfiles stored by the storage node server according to the update parameters;

before the step of generating the homomorphic calculation function according to the content information to be updated, the method further comprises the following steps:

dividing the original document to obtain N divided subfiles, and distributing corresponding identifiers and numbers for the divided subfiles, wherein N is an integer greater than or equal to 1;

establishing mapping relations between the N divided subfiles and all leaf nodes except a root node of the hash tree structure;

and carrying out homomorphic encryption on the N split sub-files respectively by adopting homomorphic encryption public keys, and transmitting the obtained N encrypted split sub-files to a blockchain network so as to enable a storage node server to store the split sub-files, wherein the homomorphic encryption public keys are secret keys generated according to a homomorphic key generation algorithm.

9. A storage node server, comprising:

the system comprises an acquisition module, a processing module and a processing module, wherein the acquisition module is used for acquiring update parameters sent by a user node server from a blockchain network, the update parameters comprise homomorphic calculation functions, parameter encryption results, identifiers and numbers corresponding to subfiles to be updated, the parameter encryption results are obtained by homomorphic encryption of homomorphic parameters corresponding to the subfiles to be updated by the user node server through homomorphic encryption public keys, the subfiles to be updated are files to be updated in segmentation subfiles, and the segmentation subfiles are files obtained by segmenting original documents;

The computing module is used for computing the updating parameters according to the homomorphic encryption computing function to obtain the subfiles to be updated;

the updating module is used for updating the locally stored divided subfiles by using the subfiles to be updated according to the identification and the number;

wherein, before the step of generating the homomorphic calculation function, the method further comprises:

dividing the original document to obtain N divided subfiles, and distributing corresponding identifiers and numbers for the divided subfiles, wherein N is an integer greater than or equal to 1;

establishing mapping relations between the N divided subfiles and all leaf nodes except a root node of the hash tree structure;

and carrying out homomorphic encryption on the N split sub-files respectively by adopting homomorphic encryption public keys, and transmitting the obtained N encrypted split sub-files to a blockchain network so as to enable a storage node server to store the split sub-files, wherein the homomorphic encryption public keys are secret keys generated according to a homomorphic key generation algorithm.