A chameleon hash function dynamic trapdoor management method, device and product

Abstract

The application discloses a chameleon hash function dynamic trapdoor management method, device and product, and relates to the technical field of network security. The method comprises the following steps: acquiring a public key and a corresponding private key of a chameleon hash function which are output by a key generation algorithm run by a trusted node in an editable blockchain, and taking the private key as a trapdoor; on a participating node, the trapdoor is split into a main secret and multiple sub-secrets by constructing an extension polynomial; wherein the main secret is a constant term of the extension polynomial; the sub-secrets are obtained by selecting different values for independent variables of each term except the constant term in the extension polynomial, and then taking modulo of the actual values of the terms on a large prime number satisfying a security parameter; and the main secret and the multiple sub-secrets are dynamically allocated on the participating node according to a pre-set weight of the participating node. The application improves the security of the blockchain network.

Description

Technical Field

[0001] This invention relates to the field of network security technology, and in particular to a method, apparatus and product for dynamic trapdoor management using a chameleon hash function. Background Technology

[0002] Editable blockchains, while ensuring security and trustworthiness, allow for controlled editing of on-chain data, including deletion, modification, and insertion. The security of editable blockchains primarily includes the security of editing permissions and the security of editing operations. The former largely depends on the key technology of the chameleon hash function. Editable blockchains use the chameleon hash function to construct Merkle trees and links between blocks. Only by controlling the trapdoor of the chameleon hash function can one gain editing permissions for the blockchain data. Currently, most editable solutions have only one trapdoor. Once stolen, not only can on-chain data be edited arbitrarily, but the security and trustworthiness of the on-chain data will also be compromised. Therefore, the storage and management of the trapdoor are crucial, and it is essential to prevent a single node from controlling it as much as possible.

[0003] To address the aforementioned issues, most existing research employs a multi-party secret sharing approach, dividing the trapdoor of the chameleon hash function into multiple shares and distributing them to multiple blockchain nodes. No single share holder can obtain or deduce the original trapdoor, but when a sufficient number of shares are combined, the original trapdoor can be reconstructed. While multi-party secret sharing provides a reliable and secure mechanism for trapdoor distribution and recovery, effectively reducing the security risks of malicious data tampering by a single or a few nodes using their acquired editing permissions, it also has certain limitations. First, the trapdoor is statically allocated; traditional schemes use fixed nodes holding trapdoor shares, which poses a security risk of targeted attacks and is difficult to adapt to dynamically changing network environments. Second, the update efficiency is low; when nodes change, the entire trapdoor needs to be regenerated, resulting in high communication overhead. Third, the security of trapdoor reconstruction is insufficient; an effective share verification mechanism has not yet been established, and there is a possibility that malicious nodes may submit false secret shares. Summary of the Invention

[0004] The purpose of this invention is to provide a method, device, and product for dynamic trapdoor management using chameleon hash functions, which can improve the security of blockchain networks.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A chameleon hash function dynamic trapdoor management method, the method comprising:

[0007] Obtain the public key and corresponding private key of the Chameleon Hash Function, which is output by a key generation algorithm run by a trusted node in the editable blockchain, and use the private key as a trapdoor;

[0008] At the participating nodes, the trapdoor is split into a master secret and multiple sub-secrets by constructing an extended polynomial. The master secret is the constant term of the extended polynomial. The sub-secrets are obtained by selecting different values ​​for the independent variables of the terms other than the constant term in the extended polynomial, obtaining the actual values ​​of each term, and taking the modulo of the actual values ​​of each term with a large prime number that satisfies the security parameters.

[0009] Based on the pre-set weights of the participating nodes, the master secret and the multiple sub-secrets are dynamically allocated among the participating nodes; wherein, the threshold value is greater than or equal to the weight of any participating node and less than or equal to the sum of the weights of all participating nodes.

[0010] Optionally, the above method further includes:

[0011] When on-chain data is edited, the aforementioned trapdoor is reconstructed.

[0012] Optionally, when on-chain data editing is performed, the trapdoor described above is reconstructed, including:

[0013] In response to the initiator's request to edit on-chain data, a broadcast refactoring request is initiated;

[0014] Based on the above broadcast reconstruction request, the master secret and multiple sub-secrets whose sum of weights is greater than a threshold value are obtained from the above participating nodes, thus obtaining multiple secrets to be verified;

[0015] The aforementioned secrets to be verified are verified individually;

[0016] If the verification result of the above-mentioned secret to be verified is that the secret is correct, then the above-mentioned secret to be verified is accepted.

[0017] If the verification result of the above-mentioned secret to be verified is that the secret is wrong, the secret to be verified with the verification result of the secret being wrong is excluded, and the secret to be verified is re-obtained from the participating node with the verification result of the secret being wrong, and the verification is performed until the verification result of the secret to be verified is that the secret is correct.

[0018] Based on the multiple secrets to be verified, the aforementioned trapdoor is reconstructed by constructing an extended polynomial.

[0019] Optionally, the above method further includes:

[0020] Based on the aforementioned public key, the Chameleon Hash Function is applied to calculate the Chameleon Hash Value of the data to be stored, and the Chameleon Hash Value is written into a block, which is then added to the editable blockchain.

[0021] Optionally, the above method further includes:

[0022] In response to a user's edit request, configure edit permissions for the target participating nodes;

[0023] Edit the stored data and corresponding random number corresponding to the chameleon hash value on the target block of the aforementioned target participating node to obtain the edited stored data and random number; wherein, the edited chameleon hash value obtained by applying the chameleon hash function to calculate the above-mentioned edited stored data and random number is consistent with the chameleon hash value on the aforementioned target block.

[0024] Optionally, the above method further includes:

[0025] After obtaining the edited storage data and the random number, the chameleon hash value on the target block and the edited chameleon hash value are verified.

[0026] When the verification results of the chameleon hash value on the target block and the edited chameleon hash value are consistent, the storage data corresponding to the chameleon hash value on the target block will be updated to the edited storage data.

[0027] Optionally, a one-way function of a lattice problem can be applied to verify the multiple secrets to be verified separately.

[0028] A computer device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described chameleon hash function dynamic trapdoor management methods.

[0029] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described chameleon hash function dynamic trapdoor management methods.

[0030] A computer program product includes a computer program that, when executed by a processor, implements any of the above-described chameleon hash function dynamic trapdoor management methods.

[0031] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0032] This invention provides a dynamic trapdoor management method for chameleon hash functions. It employs a secret sharing mechanism and secure multi-party computation to achieve layered splitting, dynamic allocation, and verification and recovery of trapdoors. This improves the security, reliability, flexibility, and efficiency of chameleon hash function trapdoor management. It also enables multiple nodes to share and collaborate to manage the editing permissions of on-chain data, thus providing effective protection for the practical application of editable blockchains. Furthermore, dynamic trapdoor management enhances the security of the blockchain network. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the dynamic trapdoor management method using the chameleon hash function provided in Embodiment 1 of the present invention;

[0035] Figure 2 A schematic diagram of a dynamic trapdoor management process based on multi-party secret sharing;

[0036] Figure 3 This is a diagram illustrating the data storage and editing process.

[0037] Figure 4 This is a diagram of the internal structure of a computer device. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] As a crucial underlying technology supporting the digital economy, blockchain has rapidly become a hot topic in academia, industry, and society at large due to its decentralized, secure, reliable, traceable, and transparent characteristics. Immutability is blockchain's most revolutionary technological feature, considered its "source of trust." While immutability guarantees the trustworthiness and integrity of on-chain data, it is a double-edged sword in blockchain application development. In data management, errors, sensitive, or malicious data may exist during collection, transmission, verification, and on-chain processing. Due to its immutability, this could lead to the permanent storage of inappropriate content, limiting blockchain's application in digital industry clusters and leaving it in a state of regulatory "out of control." Regarding data inflation, blockchain is a data storage technology that can only append data, not delete it, which violates domestic and international policies regarding the right to delete personal data. With the continuous growth of digital industry clusters, deleting expired historical data on the chain has become an inevitable choice for improving computing performance and scalability.

[0040] Blockchain technology faces real-world editing needs in areas such as information oversight, privacy protection, data updates, and scalability, making these key issues that urgently require resolution. Chameleon hashing is a special collision-resistant hash function with a built-in trapdoor. A trapdoor holder can easily calculate hash collisions with any input data, thus altering the hash function's input without changing its output. For unknown trapdoor holders, chameleon hashing functions exhibit strong collision resistance, similar to traditional hash functions. Therefore, using chameleon hashing functions to implement editable blockchains is currently the most promising editable blockchain technology solution.

[0041] Most existing studies employ a multi-party secret sharing approach to divide the trapdoor of the chameleon hash function into multiple shares and distribute them to multiple blockchain nodes. While this effectively reduces the security risk of a single or a few nodes maliciously tampering with data using the obtained editing permissions, it also has certain application limitations.

[0042] The purpose of this invention is to provide a method, device, and product for dynamic trapdoor management using chameleon hash functions, which aims to provide security for the trustworthiness, controllability, and practical application of blockchain data editing.

[0043] This invention proposes a dynamic trapdoor management method using chameleon hash functions for editable blockchains. It employs a secret-sharing mechanism and secure multi-party computation to achieve layered splitting, dynamic allocation, and verification recovery of trapdoors. The trapdoor is split into a master secret and several sub-secrets, which are then qualitatively and randomly distributed to improve the security of trapdoor sharing. The share of sub-secrets is dynamically updated and allocated based on node changes and actual needs, increasing the flexibility of trapdoor management. Trapdoor reconstruction is performed after verifying the legality of the collected secret shares, improving the reliability of trapdoor recovery. This method dynamically adapts to changes in the network environment and meets the diverse and growing application requirements, significantly improving the security, reliability, flexibility, and efficiency of chameleon hash function trapdoor management. It also enables multiple nodes to trustfully share and collaborate to manage editing permissions for on-chain data, thus providing security guarantees for the trustworthiness and controllability of blockchain data editing and its practical application.

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Example 1

[0046] like Figure 1 As shown, the chameleon hash function dynamic trapdoor management method in this embodiment includes:

[0047] Step S1: Obtain the public key and corresponding private key of the Chameleon Hash Function output by the key generation algorithm run by trusted nodes in the editable blockchain, and use the private key as a trapdoor.

[0048] In practical applications, a safety parameter λ is selected, a large prime number q satisfying the safety parameter λ is constructed, a common parameter p is output, and p is assumed to be the implicit input for other algorithms. The set of nodes participating in trapdoor management, P = {P1, P2, ..., P...}, is determined. n}, threshold parameter (k,n) and satisfy k≤n.

[0049] The key generation algorithm is run by trusted nodes in the editable blockchain. It takes a public parameter p as input and outputs a public-private key pair (pk, sk) of the chameleon hash function, where the private key sk is the trapdoor of the chameleon hash function.

[0050] Step S2: On the participating nodes, the trapdoor is split into a master secret and multiple sub-secrets by constructing an extended polynomial; where the master secret is the constant term of the extended polynomial; the sub-secrets are obtained by selecting different values ​​for the independent variables of the other terms in the extended polynomial, obtaining the actual values ​​of each term, and taking the modulo of the actual values ​​of each term with a large prime number that satisfies the security parameters.

[0051] In practical applications, the set of participating nodes is P = {P1, P2, ..., P...} n} Run the secret distribution algorithm Share(sk) = (s i ,s i1 ,…s ij The trapdoor sk is split into a master secret and several sub-secrets in a hierarchical manner:

[0052]

[0053] In equation (1), s i The Lord's secret, s ij It's a secret for you.

[0054] The more shares a trapdoor is split into, the higher the security of secret sharing and trapdoor management, but the lower the reliability. For on-chain data editing, k ∈ [n / 2, n] is usually chosen, meaning that more than half of the participating nodes jointly manage the trapdoor of the chameleon hash function.

[0055] Construct the Lagrange interpolation polynomial:

[0056] f i (x)=a i0 +a i1 x + … + a ij x j (2)

[0057] In equation (2), when x = 0, f i (0) = a i0 =s iThat is, the secret of the Lord is f i The constant term of (x). Generating sub-secrets by choosing different x. ij =f ij (x)modq.

[0058] By using a zero-knowledge proof protocol, the reputation of each node participating in secret sharing is accumulated, and the master secret s is stored in the master secret. i The secret share is distributed to the node with the highest reputation among the participating nodes, ensuring that a few low-reputation or even malicious participating nodes cannot use their share of the secret to recover the complete trapdoor; k-1 random numbers are generated using a chaotic sequence, and the sub-secret s is then used to... ij The secrets are randomly distributed to participating nodes with different roles, such as those proposing and verifying, and the unpredictability of the sub-secret holders effectively prevents targeted security attacks. Each secret is appended with a timestamp τ and a version number v, and a verification commitment value is generated and made public through the blockchain's distributed ledger, enabling audit traceability.

[0059] Step S3: Based on the pre-set weights of the participating nodes, dynamically distribute the master secret and multiple sub-secrets among the participating nodes; wherein, the threshold value is greater than or equal to the weight of any participating node and less than or equal to the sum of the weights of all participating nodes.

[0060] In practical applications, to adapt to network changes and make the allocation of secrets dynamically adaptable, an initial share is set to prevent a single node from controlling the trapdoor and to ensure security; an elastic share is designed to be dynamically adjusted according to the network status to reflect flexibility.

[0061] Let the set of participating nodes be P = {P1, P2, ..., P...} n The set of weighted nodes corresponding to} is w = {w1, w2, ..., w n},in:

[0062] w i =weight(P i ), i = 1, 2, ..., n (3)

[0063] k represents the threshold value in the trapdoor reconstruction phase, satisfying:

[0064]

[0065] When the role or permissions of a participating node change, the elasticity share is calculated according to the following formula:

[0066]

[0067] In equation (5), w i (t) represents the dynamic weight value, w max This is the preset maximum weight value.

[0068] It supports dynamic updating of trapdoor share allocation when participating nodes are added or removed, without regenerating the entire trapdoor information. When adding a participating node, the polynomial degree is expanded and the coefficients are regenerated; when removing a participating node, a new polynomial is reconstructed using the remaining valid shares.

[0069] The chameleon hash function's dynamic trapdoor management method also includes: reconstructing the trapdoor when on-chain data is edited, specifically including:

[0070] Step S101: In response to the initiator's request to edit on-chain data, initiate a broadcast reconstruction request.

[0071] Step S102: Based on the broadcast reconstruction request, obtain the master secret and multiple sub-secrets whose sum of weights is greater than the threshold value from the participating nodes, and obtain multiple secrets to be verified.

[0072] Step S103: Verify each of the multiple secrets to be verified separately.

[0073] Specifically, one-way functions of lattice problems are applied to verify the multiple secrets to be verified separately.

[0074] In practical applications, when a complete trapdoor is required for on-chain data editing, the initiator broadcasts a reconstruction request, collecting at least the master secret and a sufficient number of valid shares of the sub-secret from the participating node set. The number of sub-secret shares required to reconstruct the trapdoor can be dynamically adjusted as needed, but the sum of the participants' weights must be greater than or equal to a threshold value k, i.e.:

[0075]

[0076] This ensures that even if some nodes are attacked, attackers cannot deduce the trapdoor through insufficient shares; it also reduces the dependence on the number of participating nodes and improves the robustness of trapdoor management.

[0077] After a participating node sends its share of the secret and security parameters representing its identity to the trusted reconstruction node, it first verifies the legitimacy of the received secret and calculates:

[0078]

[0079] In equation (7), The trapdoor holder calculates the verification value, and A is an Ajtai one-way function based on the lattice problem.

[0080] Step S104: If the verification result of the secret to be verified is that the secret is correct, then receive the secret to be verified.

[0081] Step S105: When the verification result of the secret to be verified is that the secret is wrong, exclude the secret to be verified that the verification result is that the secret is wrong, and re-obtain the secret to be verified from the participating node whose verification result is that the secret is wrong, and perform verification until the verification result of the secret to be verified is that the secret is correct.

[0082] In practical applications, if the verified secret is correct, the secret share is successfully received and the process enters the trapdoor recovery phase; if the verified secret is incorrect, the secret share submitted by the trapdoor holder is excluded, and the trapdoor holder is required to resend it. By verifying the secret share, the system aims to resist deception by external adversaries, semi-honest participating nodes, and malicious participating nodes.

[0083] Step S106: Based on the multiple secrets to be verified, reconstruct the trapdoor by constructing an extended polynomial.

[0084] In practical applications, trapdoors are recovered by using a multi-party secret sharing mechanism, and the polynomial is reconstructed:

[0085]

[0086] When x = 0, the master secret s can be recovered. i By performing parallelized Lagrange interpolation, the sub-secret s can be recovered. ij This leads to the recovery of the completed trapdoor Rec(s) i ,s ij ) = sk.

[0087] The chameleon hash function dynamic trapdoor management method also includes: calculating the chameleon hash value of the data to be stored using the chameleon hash function based on the public key, writing the chameleon hash value into a block, and adding the block to the editable blockchain.

[0088] In practical applications, given the public key pk, for any data m and a random number r, participating nodes perform the Chameleon Hash function operation:

[0089] CH(pk,m,r)=H (9)

[0090] In equation (9), the value space of data m and random number r depends on the mathematical problem upon which the chameleon hash function relies.

[0091] The hash value H output by the chameleon hash operation is written into the block. When the participating node obtains the right to record transactions, it adds the block and data to the blockchain chain.

[0092] The security requirements satisfied by Chameleon Hash are as follows:

[0093] Collision resistance: Given the public key pk, and given data m and its corresponding random number r, for any data m' and m≠m', there is no efficient algorithm that can find r' in polynomial time such that CH(pk,m,r)=CH(pk,m',r').

[0094] Trapdoor collision: Given a trapdoor sk, for any data m and its corresponding random number r, given data m', there exists an efficient algorithm that can compute its random number r' in polynomial time, and satisfy CH(pk,m,r)=CH(pk,m',r').

[0095] Semantic security: For any different data m and m', it is impossible to distinguish the probability distributions of CH(pk,m,r) and CH(pk,m',r'); when r is randomly selected, it is impossible to obtain any information about m from the chameleon hash value CH(pk,m,r).

[0096] The chameleon hash function dynamic trapdoor management method also includes:

[0097] Step S201: In response to the user's edit request, configure edit permissions for the target participating node.

[0098] Step S202: Edit the stored data and corresponding random number corresponding to the chameleon hash value on the target block of the target participating node to obtain the edited stored data and random number; wherein, the edited chameleon hash value obtained by applying the chameleon hash function to calculate the edited stored data and random number is consistent with the chameleon hash value on the target block.

[0099] In practical applications, given a trapdoor sk and a chameleon hash value H, a node with edit privileges runs the chameleon hash collision algorithm, which can find a collision in polynomial time. Taking the new data m' to be replaced or added, the original data m and its corresponding random number r, the trapdoor sk, and the hash value H as input, a hash collision CH(sk,m,r,H,m')=r' is constructed while keeping the hash value H unchanged, and a new random number r' for the new data m' is calculated.

[0100] The chameleon hash function dynamic trapdoor management method also includes:

[0101] Step S301: After obtaining the edited storage data and the random number, verify the chameleon hash value on the target block and the edited chameleon hash value.

[0102] Step S302: When the verification results of the chameleon hash value on the target block and the edited chameleon hash value are consistent, update the storage data corresponding to the chameleon hash value on the target block to the edited storage data.

[0103] In practical applications, the initiator of the edit can only trigger the edit request; the actual execution requires collaborative verification by verification nodes using the Chameleon Hash Verify algorithm. Given the public key pk, hash value H, original data m, and its corresponding random value r as input, if:

[0104] CHV(pk,m,r,H)=CHV(pk,m',r',H)=1 (10)

[0105] If the operation is verified as a legitimate edit, the node that controls the trapdoor can perform a hash collision to successfully update the original data m to the new data m'.

[0106] Editable blockchains combine data storage and editing capabilities; only those who master the trapdoor of the chameleon hash function can gain editing privileges, making trapdoor management crucial. The technical approach is as follows... Figure 1 As shown, a multi-party secret sharing mechanism is used to manage the trapdoor of the chameleon hash function. The trapdoor undergoes layered splitting, dynamic allocation, and verification recovery, enabling multiple participating nodes to collaborate and dynamically manage the editing permissions of on-chain data. This method effectively prevents a single or small number of malicious nodes from arbitrarily tampering with data after obtaining the trapdoor, thus ensuring the security and trustworthiness of blockchain data storage. Simultaneously, it allows for dynamic allocation and updating of secrets to adapt to changes in on-chain nodes, thereby improving the efficiency and flexibility of blockchain data editing.

[0107] This invention proposes a dynamic trapdoor management method using chameleon hash functions suitable for editable blockchains, the specific advantages of which are summarized as follows:

[0108] 1. Employing a secret sharing mechanism and secure multi-party computation provides a reliable and secure solution for the distribution and recovery of chameleon hash function trapdoors, which will effectively reduce the risk of a single or a few verification nodes maliciously tampering with or editing data by using the editing permissions they have obtained.

[0109] 2. The trapdoor is split into layers, with the master secret being distributed to the participating node with the highest reputation, and the child secrets being randomly distributed to other participating nodes. Even if the child secrets of some participating nodes are leaked, attackers cannot reconstruct the complete trapdoor information, which further enhances the security of secret distribution and reduces the risk of trapdoor information leakage.

[0110] 3. The trapdoor dynamic allocation supports the dynamic expansion or contraction of the participating node set. Under the premise that the trapdoor remains unchanged and the old share becomes invalid, the share allocation of the sub-secret can be flexibly adjusted according to actual needs, which reduces unnecessary computation and resource overhead and increases the flexibility of secret sharing and trapdoor management.

[0111] 4. The trapdoor is restored only after verifying the legality of the secret share submitted by the trapdoor holder, thus avoiding deception by external adversaries, semi-honest and malicious participating nodes and improving the reliability of trapdoor management; combined with Chameleon Hash collaborative verification, the legality of data editing is ensured, effectively preventing malicious data editing.

[0112] Example 2

[0113] A computer device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the Chameleon Hash Function Dynamic Trapdoor Management Method of Embodiment 1.

[0114] Example 3

[0115] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the Chameleon Hash Function Dynamic Trapdoor Management Method of Embodiment 1.

[0116] Example 4

[0117] A computer program product includes a computer program that, when executed by a processor, implements the Chameleon Hash Function Dynamic Trapdoor Management Method of Embodiment 1.

[0118] Example 5

[0119] A computer device, which may be a database, may have an internal structure diagram as shown below. Figure 3 As shown, the computer device includes a processor, memory, input / output interfaces (I / O), and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores pending transactions. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements the chameleon hash function dynamic trapdoor management method in Embodiment 1.

[0120] It should be noted that the object information (including but not limited to object device information, object personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this invention are all information and data authorized by the object or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0121] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided by this invention may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided by this invention may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A dynamic trapdoor management method using a chameleon hash function, characterized in that, The method includes: Obtain the public key and corresponding private key of the Chameleon Hash Function, which is output by a key generation algorithm run by a trusted node in an editable blockchain, and use the private key as a trapdoor; At the participating nodes, the trapdoor is split into a master secret and multiple sub-secrets by constructing an extended polynomial; wherein, the master secret is the constant term of the extended polynomial; the sub-secrets are obtained by selecting different values ​​for the independent variables of each term other than the constant term in the extended polynomial, obtaining the actual values ​​of each term, and taking the modulo of each actual value with a large prime number that satisfies the security parameter; specifically, the set of participating nodes Run the secret distribution algorithm Share(sk) = The trapdoor sk is split into a master secret and several sub-secrets in a hierarchical manner: Among them, S i For the Lord's secret, S ij To keep the sub-secret secret; construct the Lagrange interpolation polynomial: When x=0, The Lord's secret is The constant term; by choosing different x generator secrets ; Based on the pre-set weights of the participating nodes, the master secret and the plurality of sub-secrets are dynamically allocated among the participating nodes; wherein, a threshold value is greater than or equal to the weight of any participating node and less than or equal to the sum of the weights of all participating nodes; specifically, in the set of participating nodes... The corresponding set of weighted nodes is ,in, ;k represents the threshold value in the trapdoor reconstruction phase, When the roles or permissions of participating nodes change, the elastic share is adjusted according to... calculate, For dynamic weight values, The preset maximum weight value; When on-chain data editing is performed, the trapdoor is reconstructed.

2. The chameleon hash function dynamic trapdoor management method according to claim 1, characterized in that, When on-chain data editing is performed, the trapdoor is reconstructed, including: In response to the initiator's request to edit on-chain data, a broadcast refactoring request is initiated; Based on the broadcast reconstruction request, the master secret and multiple sub-secrets whose sum of weights is greater than a threshold value are obtained from the participating nodes, thus obtaining multiple secrets to be verified; The multiple secrets to be verified are verified separately; If the verification result of the secret to be verified is that the secret is correct, then the secret to be verified is received; If the verification result of the secret to be verified is that the secret is incorrect, the secret to be verified with the verification result of the secret being incorrect is excluded, and the secret to be verified is re-obtained from the participating node with the verification result of the secret being incorrect, and the verification is performed until the verification result of the secret to be verified is that the secret is correct. The trapdoor is reconstructed by constructing an extended polynomial based on the multiple secrets to be verified.

3. The chameleon hash function dynamic trapdoor management method according to claim 1, characterized in that, The method further includes: Based on the public key, the Chameleon Hash Function is applied to calculate the Chameleon Hash Value of the data to be stored, and the Chameleon Hash Value is written into a block, which is then added to the editable blockchain.

4. The chameleon hash function dynamic trapdoor management method according to claim 1, characterized in that, The method further includes: In response to a user's edit request, configure edit permissions for the target participating nodes; The stored data and corresponding random number corresponding to the chameleon hash value on the target block of the target participating node are edited to obtain the edited stored data and random number; wherein, the edited chameleon hash value obtained by applying the chameleon hash function to calculate the edited stored data and random number is consistent with the chameleon hash value on the target block.

5. The chameleon hash function dynamic trapdoor management method according to claim 4, characterized in that, The method further includes: After obtaining the edited storage data and the random number, the chameleon hash value on the target block and the edited chameleon hash value are verified. When the verification results of the chameleon hash value on the target block and the edited chameleon hash value are consistent, the storage data corresponding to the chameleon hash value on the target block is updated to the edited storage data.

6. The chameleon hash function dynamic trapdoor management method according to claim 2, characterized in that, The one-way function of the lattice problem is applied to verify the multiple secrets to be verified.

7. A computer device, comprising: The memory and processor contain a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the Chameleon Hash Function Dynamic Trapdoor Management Method according to any one of claims 1-6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the Chameleon Hash Function Dynamic Trapdoor Management Method as described in any one of claims 1-6.

9. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the Chameleon Hash Function Dynamic Trapdoor Management Method as described in any one of claims 1-6.

Images