A database indexing method based on polynomial commitment mechanism

Abstract

A database indexing method and device based on a polynomial commitment mechanism, the method includes obtaining blocks and block data information to be indexed from a blockchain, forming a storage data value value corresponding to the block data information; establishing an index of the storage data value value location path for each block data information in a multi-layer vector commitment manner, and generating a polynomial commitment for the data value value storage location path, and forming an index list containing an index value key, a data value value, and a polynomial commitment formula; when querying the storage information corresponding to a certain search keyword, obtaining the index value key according to the index list of the polynomial commitment formula, and sequentially searching for all data values ​​value specified by the search keyword data in a multi-layer vector commitment manner; obtaining data information corresponding to the data value value according to all the indexed data values, and returning the search result information to the searcher. Therefore, the present invention can ensure the immutability of the index and the accuracy of the query data.

Description

Technical Field

[0001] The present invention relates to the field of big data processing and information technology, and more specifically, to a database indexing method based on a polynomial commitment mechanism. Background Art

[0002] With the development and application of blockchain technology (BT), the decentralized, tamper-proof and trustworthy features of blockchain are increasingly being used in various fields such as finance, trade settlement, asset management and digital evidence storage.

[0003] Blockchain (BC) is a distributed database system that divides data into different blocks. Each block is linked to the previous block through specific information, and the blocks are connected in sequence to present a complete set of tree-structured data. Among them, the block header of each block contains a previous block hash value, which is the value calculated by the hash function of the block header of the previous block; each block is linked to the previous block by such a hash value to form a chain.

[0004] That is to say, for each transaction in the block, it contains the address information of the trader and the transaction content. In order to ensure the immutability of blockchain data, all blocks contain transaction data within a certain period of time (the time when the block is generated) and generate specific data fingerprints to verify the validity of the block data. At the same time, it is also necessary to connect to the next block. Any modification of the data of any block in the blockchain will affect the data on the entire chain.

[0005] In the existing blockchain system, if you want to perform on-chain data query, you need to traverse the entire blockchain. This method is not only time-consuming, but also cannot support conditional query and range query functions. Therefore, most of the current on-chain data queries use synchronization technology to synchronize on-chain transaction data to traditional databases, and establish indexes based on various data items or keywords in the search formula to achieve fast query.

[0006] However, the above-mentioned query method for on-chain transaction data cannot guarantee the immutability of the index and the accuracy of the query data, which violates the immutability and decentralization characteristics of the blockchain. Summary of the invention

[0007] The purpose of the present invention is to provide a database indexing method and device based on a polynomial commitment mechanism, which can ensure the non-tamperability of the index, thereby ensuring the accuracy of the query data.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A database indexing method based on a polynomial commitment mechanism is used for data retrieval in a blockchain system; it includes a data storage step S1 and an indexing step S2:

[0010] The step S1 specifically includes:

[0011] Obtaining blocks and block data information to be indexed from the blockchain system, and forming a stored data value value corresponding to the block data information; wherein each of the data values ​​value is stored in layers according to the tree structure path node position in the blockchain system as a data storage location; the tree structure path node includes a leaf node and an intermediate node;

[0012] The step S2 specifically includes:

[0013] An index of a storage data value location path is established for each block data information in a multi-layer vector commitment manner, and a polynomial commitment is generated for the data value storage location path, and an index list including an index value key, a data value and a polynomial commitment formula is formed; wherein the leaf node includes an index value key and a corresponding data value value, the intermediate node has a fixed number of child nodes, and the fixed number of child nodes constitute the vector space of the vector commitment; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; the data value includes a search keyword or a search key formula;

[0014] The index value key is a set of intermediate index values ​​in each layer where the block data information is located in the multi-layer vector commitment, that is, a corresponding relationship between the block data information and its storage location is formed; a polynomial commitment method is used to prove the location path of the data value value and form a proof Proof, and the proof Proof promises that the data value value is indeed stored according to the nodes of the location path.

[0015] Furthermore, if the storage location path of a certain data value value has M layers, the index value key includes M bits; it is formed by the intermediate index values ​​contributed to the index value key by the intermediate nodes arranged in sequence from left to right starting from the first layer after the root node root; wherein the M value is determined by the storage path and location of the data value value.

[0016] Furthermore, the intermediate index values ​​are respectively composed of the positions in the vector space corresponding to the vector commitments of the intermediate nodes where the path passes; assuming that there is an intermediate node in the location path of the data value value with n child nodes, the vector commitment proof C is a list hashed at the storage location of the data value value at this layer:

[0017] h(z 1 , z 2 , z 3 ,...z n )->C

[0018] The vector commitment proof C is a commitment to the above set of numerical groups, where the value of the i-th position in the numerical group is z i , where i is any value from 1 to n.

[0019] Furthermore, the step S2 also includes: publishing some or all necessary proof parameters of the polynomial commitment formula for use by the verifier.

[0020] Furthermore, the database indexing method based on the polynomial commitment mechanism further includes a retrieval step S3, which specifically includes the following steps:

[0021] Step S31: when it is necessary to query the storage information corresponding to a certain search keyword or search key formula, the index value key is obtained according to the index list of the polynomial commitment formula, and all data values ​​value specified by the search keyword or search key formula data are sequentially searched in a multi-layer vector commitment manner;

[0022] Step S32: according to the index to all the data values, obtain the data information corresponding to the data value, and return the search result information to the searcher.

[0023] Furthermore, the database indexing method based on the polynomial commitment mechanism is characterized in that the step S3 can also include a verification step S33, which obtains the polynomial commitment formula of one or all of the retrieved data values ​​through the index list of the polynomial commitment formula, and verifies whether the data of the retrieval result information has been changed.

[0024] To achieve the above object, another technical solution of the present invention is as follows:

[0025] A database indexing device based on a polynomial commitment mechanism, comprising:

[0026] A data acquisition module acquires the blocks and block data information to be indexed from the blockchain system, and forms a storage data value value corresponding to the block data information; wherein each of the data values ​​value is stored according to its tree structure path node position in the blockchain system as a data storage location, and is stored according to the hierarchy of the tree structure; the tree structure path node includes a leaf node and an intermediate node;

[0027] An index establishment module is used to establish an index of a storage data value location path for each block data information in a multi-layer vector commitment manner, generate a polynomial commitment for the data value storage location path, and form an index list including index value key, data value and polynomial commitment formula; wherein, the leaf node includes an index value key and a corresponding data value value, and the intermediate node has a fixed number of child nodes; the fixed number of child nodes constitute the vector space of the vector commitment; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; an index of a storage data value location path is established for each block data information in a multi-layer vector commitment manner, and an index list of polynomial commitment formulas is formed, and a polynomial commitment is generated for the data value storage location path; the data value value includes a search keyword or a search key formula.

[0028] Furthermore, the database indexing device based on the polynomial commitment mechanism also includes a first verification module, which publishes all necessary proof parameters of the polynomial commitment formula to the outside for use by the verifier.

[0029] Furthermore, the database indexing device based on the polynomial commitment mechanism further includes:

[0030] The retrieval module, when it is necessary to query the storage information corresponding to a certain retrieval keyword or retrieval key formula, obtains the index value key according to the index list of the polynomial commitment formula, and sequentially searches for all data values ​​value specified by the retrieval keyword or retrieval key formula data in a multi-layer vector commitment manner; and obtains the data information corresponding to the data value value according to the index to all the data values ​​value, and returns the retrieval result information to the searcher.

[0031] Furthermore, the database indexing device based on the polynomial commitment mechanism also includes a second verification module, which obtains the polynomial commitment expression of one or all of the retrieved data values ​​through the index list of the polynomial commitment expression, and verifies whether the data of the retrieval result information has been changed.

[0032] It can be seen from the above technical scheme that the database indexing and retrieval method based on the polynomial commitment mechanism proposed by the present invention uses a multi-layer vector commitment method to establish the storage and indexing of blockchain data, which can ensure the authenticity and verifiability of the establishment of the data index. When it is necessary to index data, the data can be directly searched in sequence according to the data storage location in the vector according to the index value key, without comparing one by one, and the data can be verified through the polynomial commitment formula in the index list, which improves the retrieval efficiency while ensuring the data is not tamperable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 FIG. 1 is a flow chart of a database indexing method based on a polynomial commitment mechanism in an embodiment of the present invention.

[0034] Figure 2 FIG. 1 is a schematic diagram of a vector commitment method in an embodiment of the present invention.

[0035] Figure 3 FIG. 1 is a schematic diagram of a polynomial commitment method in an embodiment of the present invention.

[0036] Figure 4 The figure is a schematic diagram of the process of creating an index in an embodiment of the present invention.

[0037] Figure 5 The figure is a schematic diagram of the retrieval method in the embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-5 , the specific implementation modes of the present invention are further described in detail.

[0039] See also Figure 1 , Figure 1 FIG. 2 is a flow chart of a database indexing method based on a polynomial commitment mechanism in an embodiment of the present invention. Figure 1 As shown, the method for database indexing based on the polynomial commitment mechanism and data retrieval of the blockchain system may include the following steps:

[0040] Step S1: Obtain the block and block data information that need to be indexed from the blockchain system, and form a storage data value corresponding to the block data information.

[0041] Different from the prior art, in an embodiment of the present invention, the block data information obtained from the blockchain system is not directly synchronized to the database, but the block data information is stored and indexed in the blockchain data in a multi-layer vector commitment manner.

[0042] That is to say, each data value is stored in the tree structure node position in the blockchain system as the data storage location, and is stored in the tree structure layer by layer. Usually, the tree structure path node includes leaf nodes and intermediate nodes; a node on the tree structure is either an empty node, a leaf node, or an intermediate node.

[0043] Among them, the data value value stored in step S1 is located in a leaf node, and the leaf node contains an index value key and a corresponding data value value. The intermediate node has a fixed number of child nodes, and the fixed number of child nodes constitute the vector space committed by the vector; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; the data value value includes a search keyword or a search key formula.

[0044] In an embodiment of the present invention, the index list of the polynomial commitment formula includes an index key value, a stored data value value and a polynomial commitment formula; the index value key is a set of intermediate index values ​​in each layer where the block data information in the multi-layer vector commitment is located; that is, a corresponding relationship between the block data information and its storage location is formed; the polynomial commitment formula is a commitment proof generated for the location path of the data value value, promising that the data value value is indeed stored according to the nodes of the location path, and generating a polynomial commitment formula.

[0045] If the storage location path of a certain data value value has M layers, the index value key includes M bits; it is formed by the intermediate index values ​​contributed to the index value key by the intermediate nodes arranged in sequence from left to right starting from the first layer after the root node root; wherein the M value is determined by the storage path and location of the data value value.

[0046] Specifically, the intermediate index values ​​are respectively composed of the positions in the vector space corresponding to the vector commitments where the path passes through the intermediate nodes; assuming that there is an intermediate node in the location path of the data value value with n child nodes, the vector commitment proof C is a list hashed at the storage location of the data value value at this layer:

[0047] h(z 1 , z 2 , z 3 ,...z n )->C

[0048] The vector commitment proof C is a commitment to the above set of numerical groups, where the value of the i-th position in the numerical group is z i, where i is any value from 1 to n.

[0049] See also Figure 2 , Figure 2 FIG. 2 is a schematic diagram of a vector commitment method in an embodiment of the present invention. Figure 2 As shown, a short proof is required for each vector commitment of the path. For example, in the first layer, to commit to the 4th number in a list, a hash commitment proof is required. 1 , the value for the 4th position is z 4 .

[0050] See also Figure 3 , Figure 3 FIG. 4 is a schematic diagram of a polynomial commitment method in an embodiment of the present invention. Figure 3 As shown, a polynomial commitment scheme involves hashing a polynomial and proving the value of the entire hashed polynomial at any point.

[0051] In the polynomial commitment scheme of the present invention, the prover calculates a commitment of a polynomial and can verify at any point of the polynomial that the value of the polynomial at a specific position is consistent with the specified value, that is, it can be committed that there is a polynomial P, and for any i∈[1..n], P(c i )=y i That is to say, by using the polynomial commitment scheme of the present invention, a single proof can be used to prove multiple parent-child relationships, that is, a polynomial commitment-style proof Proof can be used to prove the authenticity and non-tamperability of the index of the data storage location path data.

[0052] Please see again Figure 1 The database indexing method based on the polynomial commitment mechanism of the present invention further includes a retrieval step S3, which specifically includes the following steps:

[0053] Step S31: when it is necessary to query the storage information corresponding to a certain search keyword or search key formula, the index value key is obtained according to the index list of the polynomial commitment formula, and all data values ​​value specified by the search keyword or search key formula data are sequentially searched in a multi-layer vector commitment manner;

[0054] Step S32: according to the index to all the data values ​​value, obtain the data information corresponding to the data value value, and return the search result information to the searcher.

[0055] In addition, the step S3 may also include a verification step S33, which obtains the polynomial commitment formula of one or all of the retrieved data values ​​value through the index list of the polynomial commitment formula, and verifies whether the data of the retrieval result information is changed.

[0056] The following describes in detail the database index establishment method and retrieval method based on the polynomial commitment mechanism of the present invention through two specific embodiments.

[0057] Example 1

[0058] See also Figure 4 , Figure 4 FIG. 2 is a schematic diagram of a process for creating an index in an embodiment of the present invention. Figure 4 As shown, according to the data index establishment step based on the polynomial commitment mechanism, the block data information that needs to be stored and indexed is obtained, and the storage data value value corresponding to the block data information is formed. The index of the stored data value value horse is created according to the polynomial vector commitment method, where the key is 4cb. The block data information can be blockchain transaction information, block height, and other information.

[0059] Please refer to Figure 3 ,like Figure 3 As shown, the data value value(horse) is stored at position b in the third-layer vector (vector), which is linked to position c in the second layer. Therefore, the prefix index of position C in the second-layer vector (vector) is 4c. This position on the second-layer vector (vector) is linked to the fourth position in the first-layer vector, and then connected to the root node root, so the index of the data value value(horse) is 4cb.

[0060] The index list format is shown in the following table:

[0061] key value Polynomial Commitment 4cb horse <![CDATA[P(c i )=y i and the y value of the corresponding point]]>

[0062] Example 2

[0063] See also Figure 5 , Figure 5 FIG. 2 is a schematic diagram of a search method in an embodiment of the present invention. Figure 5 As shown, the retrieval process is as follows:

[0064] First, according to the index list of the polynomial commitment formula, the index value key of the data value to be queried is obtained.

[0065] Second, according to the index value key value, through the multi-layer vector commitment method, the data of the entire database is searched to obtain all the data values ​​corresponding to the index value key.

[0066] Specifically, when you need to retrieve the specific data value information stored in the index value key 4cb, perform the following steps:

[0067] ① Split and match the index value key layer by layer. It can be seen that the first digit in the index value key is 4, so the fourth position in the array is searched in the first layer. An inner node in the first layer in the figure stores the vector of the second layer.

[0068] ②. Parse the second value in the index value key to get the position of the data in the second layer, that is, c, so it points to the 12th position in the second layer array. At this time, the node is still an inner node, linking the vector of the third layer;

[0069] ③. Parse the third value in the index value key to get the position of the data in the third layer, that is, b, so it points to the 11th position in the third layer array. At this time, it no longer points to other data, so the data at this time is the data corresponding to the index value key; each of the above layers can be verified according to the corresponding polynomial commitment formula in the index table to ensure the correctness of the index.

[0070] In an embodiment of the present invention, the above-mentioned database indexing method based on the polynomial commitment mechanism can be implemented using a database indexing device based on the polynomial commitment mechanism, which includes a data acquisition module, an index establishment module, a first verification module, a retrieval module and a second verification module.

[0071] The data acquisition module acquires the blocks and block data information that need to be indexed from the blockchain system, and forms a storage data value value corresponding to the block data information; wherein each of the data values ​​value is stored according to its tree structure path node position in the blockchain system as a data storage location, and is stored according to the hierarchy of the tree structure; the tree structure path nodes include leaf nodes and intermediate nodes.

[0072] The index establishment module establishes an index of the storage data value location path for each of the block data information in a multi-layer vector commitment manner, generates a polynomial commitment for the data value storage location path, and forms an index list including index value key, data value and polynomial commitment formula; wherein, the leaf node includes an index value key and a corresponding data value value, and the intermediate node has a fixed number of child nodes; the fixed number of child nodes constitute the vector space of the vector commitment; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; an index of the storage data value location path is established for each of the block data information in a multi-layer vector commitment manner, and forms an index list of polynomial commitment formulas, and generates a polynomial commitment for the data value storage location path; the data value value includes a search keyword or a search key formula.

[0073] The first verification module publishes all necessary proof parameters of the polynomial commitment formula for use by the verifier.

[0074] The retrieval module is used to obtain the index value key according to the index list of the polynomial commitment formula when it is necessary to query the storage information corresponding to a certain retrieval keyword or retrieval key formula, and sequentially search for all data values ​​value specified by the retrieval keyword or retrieval key formula data in a multi-layer vector commitment manner; and obtain the data information corresponding to the data value value according to the index to all the data values ​​value, and return the retrieval result information to the searcher.

[0075] The second verification module obtains the polynomial commitment expression of one or all of the retrieved data values ​​through the index list of the polynomial commitment expression, and verifies whether the data of the retrieval result information has been changed.

[0076] It should be noted that the above device can be implemented by hardware, software or a combination of hardware and software, which will not be described in detail here.

[0077] The above-described embodiments are only preferred embodiments of the present invention, and the embodiments are not intended to limit the patent protection scope of the present invention. Therefore, any equivalent structural changes made using the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A database indexing method based on polynomial commitment mechanism for data retrieval in blockchain system; It is characterized in that It includes the step of establishing data storage S1 and the step of establishing index S2: The step S1 specifically includes: Obtaining blocks and block data information to be indexed from the blockchain system, and forming a stored data value value corresponding to the block data information; wherein each of the data values ​​value is stored in layers according to the tree structure path node position in the blockchain system as a data storage location; the tree structure path node includes a leaf node and an intermediate node; The step S2 specifically includes: An index of a storage data value location path is established for each block data information in a multi-layer vector commitment manner, and a polynomial commitment expression is generated for the data value storage location path, and an index list including an index value key, a data value and a polynomial commitment expression is formed; wherein the leaf node includes an index value key and a corresponding data value value, the intermediate node has a fixed number of child nodes, and the fixed number of child nodes constitute the vector space of the vector commitment; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; the data value value includes a search keyword or a search key expression; The index value key is a set of intermediate index values ​​in each layer where the block data information is located in the multi-layer vector commitment, that is, a corresponding relationship between the block data information and its storage location is formed; the location path of the data value value is proved by a polynomial commitment method and a proof Proof is formed, and the proof Proof promises that the data value value is indeed stored according to the node of the location path; The search step S3 is also included, which specifically includes the following steps: Step S31: when it is necessary to query the storage information corresponding to a certain search keyword or search key formula, the index value key is obtained according to the index list of the polynomial commitment formula, and all data values ​​value specified by the search keyword or search key formula data are sequentially searched in a multi-layer vector commitment manner; Step S32: according to the index to all the data values, obtain the data information corresponding to the data value, and return the search result information to the searcher; The step S3 also includes a verification step S33, which obtains the polynomial commitment expression of one or all of the retrieved data values ​​through the index list of the polynomial commitment expression, and verifies whether the data of the retrieval result information has been changed.

2. The database indexing method based on the polynomial commitment mechanism according to claim 1, It is characterized in that If the storage location path of a certain data value value has M layers, the index value key includes M bits; it is formed by the intermediate index values ​​contributed to the index value key by the intermediate nodes arranged in sequence from left to right starting from the first layer after the root node root; wherein the M value is determined by the storage path and location of the data value value.

3. The database indexing method based on the polynomial commitment mechanism according to claim 2, It is characterized in that The intermediate index values ​​are respectively composed of the positions in the vector space corresponding to the vector commitments of the intermediate nodes where the path passes; assuming that an intermediate node in the location path of the data value value has n child nodes, the vector commitment proof C is a list hashed at the storage location of the data value value: Wherein, the vector commitment proof C is a commitment to a set of numerical groups, the value of the i-th position in the numerical group is z i , where i is any value from 1 to n.

4. The database indexing method based on the polynomial commitment mechanism according to claim 1, It is characterized in that The step S2 also includes: publishing some or all necessary proof parameters of the polynomial commitment formula for use by the verifier.

5. A database indexing device based on a polynomial commitment mechanism using the database indexing method based on a polynomial commitment mechanism according to claim 1, It is characterized in that include: A data acquisition module acquires the blocks and block data information to be indexed from the blockchain system, and forms a storage data value value corresponding to the block data information; wherein each of the data values ​​value is stored according to its tree structure path node position in the blockchain system as a data storage location, and is stored according to the hierarchy of the tree structure; the tree structure path node includes a leaf node and an intermediate node; An index establishment module is used to establish an index of a storage data value location path for each block data information in a multi-layer vector commitment manner, generate a polynomial commitment expression for the data value storage location path, and form an index list including index value key, data value and polynomial commitment expression; wherein, the leaf node includes an index value key and a corresponding data value value, and the intermediate node has a fixed number of child nodes; the fixed number of child nodes constitute the vector space of the vector commitment; the intermediate index value contributed by the intermediate node to the index value key is determined by the position of the path passing through the intermediate node in the vector space; an index of a storage data value location path is established for each block data information in a multi-layer vector commitment manner, and an index list of polynomial commitment expressions is formed, and a polynomial commitment expression is generated for the data value storage location path; the data value value includes a search keyword or a search key expression.

6. The database indexing device based on the polynomial commitment mechanism according to claim 5, It is characterized in that It also includes a first verification module, which publishes all necessary proof parameters of the polynomial commitment formula for use by the verifier.

7. The database indexing device based on the polynomial commitment mechanism according to claim 5 or 6, It is characterized in that Also includes: The retrieval module, when it is necessary to query the storage information corresponding to a certain retrieval keyword or retrieval key formula, obtains the index value key according to the index list of the polynomial commitment formula, and sequentially searches for all data values ​​value specified by the retrieval keyword or retrieval key formula data in a multi-layer vector commitment manner; and obtains the data information corresponding to the data value value according to the index to all the data values ​​value, and returns the retrieval result information to the searcher.

8. The database indexing device based on the polynomial commitment mechanism according to claim 7, It is characterized in that It also includes a second verification module, which obtains the polynomial commitment expression of one or all of the retrieved data values ​​through the index list of the polynomial commitment expression, and verifies whether the data of the retrieval result information has been changed.

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