Attribute-based encryption method for decentralized key management

Abstract

The application discloses a kind of attribute-based encryption methods of decentralized key management, comprising the following steps: A: global initialization Setup, by trusted genesis node is executed, generates system parameter and the private key of attribute node;B: user key generation Keygen, by the attribute node in blockchain is executed;C: encrypt information Encrypt, by data owner is executed;D: decryption Decrypt, by cloud server on behalf of user is executed, it will obtain ciphertext.The application solves the single point failure and security dependency problem existing in the traditional key management system.By introducing attribute-based encryption technology, fine-grained access control of users is realized.Combined with the characteristics of decentralization, the key management is more secure, and an effective solution is provided for market monitoring agencies to solve the key management problem in open scenarios, which has been well applied and has promoted the progress and application of technology in the field of information security.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cryptography, in particular to an attribute-based searchable encryption method for decentralized key management and application in market monitoring. BACKGROUND

[0002] In today's digital world, information security has become one of the focuses of various fields of society. In particular, with the popularization of blockchain technology, the Internet of Things, and the rapid development of cloud computing, the demand for high-security, decentralized key management systems is increasingly urgent. Traditional key management methods often rely on centralized institutions or third-party service providers, which have single-point failures, security dependence on a small number of central nodes, and data leakage problems, which seriously hinder the further development of information security. In order to solve these problems, in recent years, more and more research has begun to focus on decentralized key management methods. Attribute-Based Encryption (ABE) technology, as a new encryption technology, has the characteristics of realizing fine-grained access control while ensuring data security, and has become an effective means to solve the problem of decentralized key management. Traditional public key encryption algorithms (such as RSA, ElGamal, etc.) can only implement identity-based encryption, i.e., only users with specific identities can decrypt. ABE technology, however, introduces the concept of attributes, allowing encrypted data to be decrypted based on the attributes possessed by users, rather than relying solely on the identity of the user. This makes it possible to achieve more flexible access control.

[0003] The patent document with publication number CN118199982A discloses a decentralized attribute-based encryption method and system that can be traced and resist key misuse. When the attribute is a new attribute, the institution end sends the first re-encryption key to the cloud service provider end to calculate the first attribute public key corresponding to the attribute. Otherwise, the fourth and fifth random parameters are selected to calculate the user's original attribute private key. The cloud service provider calculates the user's final attribute private key based on the ninth, second, sixth, and seventh random parameters. The user verifies the user's complete attribute private key to determine the integrity and usability of the user's complete attribute private key. This way, the misuse of keys by the institution, cloud service provider, and user is resisted. Upon receiving a revocation request, the institution and cloud service provider end jointly implement user attribute revocation, update the attribute public key, and call the second re-encryption algorithm to re-encrypt the re-encrypted ciphertext. The non-revoked user updates the user's final attribute private key, so that malicious users can be held accountable to protect access control security.

[0004] The patent document with publication number CN118264432A discloses a decentralized attribute-based encryption method supporting complete policy hiding, which adopts a decentralized multi-authority attribute-based encryption model to realize efficient privacy protection of data and user information. First, multiple authorities are set up to avoid single point failure and key escrow problems. Second, the completely hidden access policy is realized by anonymizing the attributes to protect the privacy of users. In this process, the method respectively utilizes reusable ciphertext pool and cloud proxy server to reduce the computational cost of user encryption and decryption phase. Finally, the user information is uniquely bound to the leaf node in the binary tree, and the leaf node is used to track malicious users, and the malicious users are revoked by performing partial ciphertext update.

[0005] In ABE, data owners can define access policies based on the attributes of data and encrypt data into an attribute. Only users who have the required attributes to meet the access policy requirements can decrypt the data. This attribute-based access control mechanism enables users to access data without prior registration or obtaining keys in advance, thereby realizing decentralized key management. However, current ABE schemes still have some challenges and limitations. First, traditional ABE schemes often require internal entities to obtain user information, which may lead to user information leakage, thereby failing to achieve decentralized goals. Second, existing ABE schemes have the problem of key leakage.

[0006] The market monitoring system database is established and the industry data is measured, and the height of the industrial development background, the industrial present situation investigation and research; to improve the scientific level of market monitoring, industry investigation, and to strengthen the research, application and promotion of market, industry, industry, enterprise statistical data monitoring technology and monitoring method; around the hot and difficult problems encountered in market economic construction Systematic investigation and research, provide macro and micro economic information and monitoring data to industry management organs and various industries, provide industry data analysis report and other work. As a market monitoring service agency or a market service monitoring management agency, some of the data involved in the unpublicized data and the processed data need to be effectively and securely encrypted; the existing market monitoring data is mostly saved by simple input password, and a relatively systematic data security protection has not been formed.

[0007] Therefore, how to realize effective and secure protection of data and effectively combine data protection application with market monitoring activities is a problem worth studying. SUMMARY

[0008] To address the technical problems existing in the prior art, this invention proposes an attribute-based encryption method with decentralized key management. This method not only enables fine-grained access control while ensuring data security, but also overcomes the centralization problem in traditional ABE schemes, improving key management security. In particular, it can effectively protect data in market monitoring activities, providing more reliable protection for information security in the digital age and promoting the healthy development of the digital economy.

[0009] The objective of this invention is achieved as follows:

[0010] The attribute-based encryption method with decentralized key management includes the following steps:

[0011] A: Global initialization Setup, executed by the trusted genesis node, generates system parameters and the private keys for attribute nodes. The genesis node uses Shamir's Secret Sharing Scheme (SSS) to divide the master key into key fragments as attribute nodes P. i private key PSK i After executing this algorithm, the genesis node will permanently exit the program and will no longer participate in any operations;

[0012] B: User key generation (Keygen) is performed by attribute nodes within the blockchain. It uses the system parameter Param and the user's global GID. u User attribute set S' and the private key PSK of the attribute node i As input, the output is the SK of the user's private key. u ;

[0013] C: Encrypt message, executed by the data owner. It uses system parameters Param, access tree Γ, plaintext M, and access structure. As input, the output is the ciphertext Cw associated with the plaintext M;

[0014] D: Decrypt, executed by the cloud server on behalf of the user. It will retrieve the ciphertext. Returns 1 if the attribute matches successfully. Returns ⊥ if the attribute does not match or the user is not authorized to perform the search;

[0015] Step A includes the following specific steps;

[0016] A1: A private blockchain generates a trusted genesis node to produce master keys and system parameters for data owners and users. Assume the total number of attributes is m, and the indices of all attributes are S = {attr1, attr2, ..., attr...} m Once the system is initialized, the genesis node will no longer participate in blockchain operations. The specific generation process is as follows:

[0017] First, the trusted genesis node in the private blockchain randomly selects three anti-collusion hash functions: H:{0,1}→G. as well as The above function can map any attribute described as a binary string to random group elements.

[0018] Secondly, the trusted genesis node in a private blockchain is randomly selected. This serves as the master key for the system. Let the n attribute nodes be represented as P = {P1, P2, ..., P...} n}

[0019] Finally, the system parameter generation process Param is as follows: The trusted genesis node in the private blockchain calculates e(g,g). α and h=g β The system parameter Param is as follows:

[0020] Param = {G, G} T ,H,H1,H1,e,g,e(g,g) α h=g β}

[0021] After the system parameter Param is generated, it will be broadcast to all users in the private blockchain.

[0022] A2: The trusted genesis node of a private blockchain generates public parameters for the private keys of attribute nodes, assuming the total number of attribute nodes is m. The specific generation process is as follows:

[0023] First, the trusted genesis node of the private blockchain uses Shamir(m,n)-threshold secret sharing technology to distribute a fragment α of the master key to participant P. i .

[0024] Secondly, the trusted genesis node of the private blockchain randomly selects a polynomial f(x) = s + a1x + a2x of degree m-1. 2 +…+a m-1 x m-1 (mod p) such that α = s and a1, a2, ..., a m-1 It is a random element in a finite field.

[0025] Finally, the trusted genesis node of the private blockchain calculates and distributes α. i Give attribute node P i Then, for each attribute j, the algorithm randomly selects... Generate a random number set R = {r1, r2, ..., r} for the attribute. n}

[0026] A3: The trusted genesis node of a private blockchain generates its own private key PSK for each attribute node. i Assume the total number of attribute nodes is m. The specific generation process is as follows:

[0027] The trusted genesis node of a private blockchain uses the key fragment of the attribute node for attribute node P. i Construct the private key and calculate Construct attribute node P i The formula for the private key is as follows:

[0028]

[0029] Step B includes the following specific steps:

[0030] B1: The user sends their GID information to all attribute nodes. The specific generation process is as follows:

[0031] User calculates H2(GID) u )=φ u as well as Then, the user randomly selects a polynomial h(x) = u + u1x + u2x with a degree of q-1. 2 +…+u q-1 x q-1 (mod p) makes φ u =u and u1,u2,…,u q-1 It is a random element in a finite field. The user calculates φ1=h(1),φ2=h(2),…,φ n =h(n). Then, the user distributes φ using Shamir(m,n)-threshold secret sharing technology. i and Give attribute node P i .

[0032] B2: After receiving information from the user, the attribute node uses its private key PSK. i This component calculates and sends the key to the user. The specific generation process is as follows:

[0033] First, each attribute node P i Using the private key PSK i Calculate fragment information of the user's private key. A partial fragment of the user's key is as follows:

[0034] D u,i =(k f(i) )·(k h(i) )∈G

[0035] Finally, regarding attributes The attribute subkey components calculated for all attribute nodes are as follows:

[0036]

[0037] B3: User-interventional computation, where the parameters of the Lagrange interpolation method are defined as follows when users reconstruct their keys: and of Users rebuild their keys as follows:

[0038]

[0039] Finally, the user utilizes and D u Reconstruct your own key as follows:

[0040]

[0041] Step C includes the following specific steps:

[0042] C1: The data owner generates the necessary encrypted data and access tree structure. The specific generation process is as follows:

[0043] The data owner uses system parameters Param, the access tree Γ, and plaintext M as input. The data owner encrypts the plaintext M using SM3. This step encrypts M based on the access tree structure Γ and selects a polynomial q for each node x (including leaves) in the access tree Γ. x Choose polynomials from the root node R in a top-down manner. For each node x in the tree, let polynomial q... x $'s order d x It is the threshold k x Subtract node x, i.e., d x =K x -1.

[0044] C2: The data owner uses system parameters, encrypted data, and the access tree structure to encrypt plaintext data and embed it within the tree. The specific generation process is as follows:

[0045] First, plaintext M starts from the root node R, and the data owner is randomly selected. And set q R (0) = s. Then, randomly select the polynomial q. R b x Define the polynomial using other points. For any other node x, let q x (0)=q parent(x) (0) index(x) And randomly select polynomial q x b x Other points are used to define the polynomial.

[0046] Next, let Y be the set of leaf nodes of tree Γ. Then, the ciphertext of the plaintext is constructed by accessing the tree structure Γ. The plaintext and ciphertext are as follows:

[0047]

[0048] C = g βs ∈G

[0049] So,

[0050]

[0051] Finally, the ciphertext Cw of the plaintext is as follows:

[0052]

[0053] Step D includes the following specific steps:

[0054] D1: The user performs a decryption operation using a cloud server. It will take the encrypted plaintext Cw as input. If S' satisfies the access structure... If the attributes match, the plaintext can be correctly searched and retrieved. For accessing a tree structure, the decryption process is recursive. The specific generation process is as follows:

[0055] First, let x be a leaf node in the tree structure Γ, i.e., x∈Γ. We define a recursive algorithm DecryptNode(Cw,Tw,x) for the leaf case. The input of this algorithm is the plaintext Cw and the leaf node x in tree Γ. Let i = att(x) and assume i∈S, then the following definition applies:

[0056]

[0057] Then, if Then we define DecryptNode(Cw,x) = ⊥.

[0058] Now consider the recursive case, where x is a non-leaf node. The algorithm DecryptNode(Cw,x) is calculated as follows: For all child nodes z of node x, call the function DecryptNode(Cw,z), and store the result as F. z Let S be the value of S. x It is of size k x Let F be any set z of its sub-items, such that F z ≠⊥ satisfies this condition. If such a set does not exist, the function will return ⊥.

[0059] If F is satisfied z ≠⊥, we define i = index(z), S' x ={index(z):z∈Sx And calculate as follows:

[0060]

[0061] Secondly, by defining the function DecryptNode, we can define the decryption algorithm. This algorithm begins execution by simply calling the function at the root node R of the access tree Γ. If the set of attributes S' satisfies the access tree Γ, then let... The final decryption algorithm is as follows:

[0062]

[0063] Finally, if the access tree Γ is successfully satisfied, the above equation holds. The decryption result of the algorithm is plaintext M, proving that the attribute set S' satisfies the access tree Γ and the attribute match is successful. The cloud server will return the corresponding data to the user. Otherwise, the attribute match fails, and ⊥ is returned; both are indispensable.

[0064] The decentralized key management attribute-based encryption method described above is applied to the protection of data in market monitoring activities.

[0065] Positive and Beneficial Effects: This invention proposes an attribute-based encryption method for decentralized key management, employing attribute-based encryption and Shamir(m,n)-threshold secret sharing technology. This method aims to address the single point of failure and security dependency issues present in traditional key management systems. By introducing attribute-based encryption, fine-grained access control for users is achieved. Furthermore, this method utilizes Shamir(m,n)-threshold secret sharing technology and blockchain technology, combined with decentralized characteristics, to enhance key management security. It provides an effective solution for market monitoring agencies to address key management challenges in open scenarios, and has been successfully applied, thus promoting technological advancement and application in the field of information security. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0067] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0068] like Figure 1 As shown, the attribute-based encryption method with decentralized key management according to the present invention includes the following steps:

[0069] A: Global Initialization Setup

[0070] The trusted genesis node executes, generating system parameters and the private keys for attribute nodes. The genesis node uses Shamir's Secret Sharing Scheme (SSS) to divide the master key into key fragments as attribute nodes P. i private key PSK i After executing this algorithm, the genesis node will permanently exit the program and will no longer participate in any operations;

[0071] Step A includes the following specific steps;

[0072] A1: A private blockchain generates a trusted genesis node to produce master keys and system parameters for data owners and users. Assume the total number of attributes is m, and the indices of all attributes are S = {attr1, attr2, ..., attr...} m Once the system is initialized, the genesis node will no longer participate in blockchain operations. The specific generation process is as follows:

[0073] First, the trusted genesis node in the private blockchain randomly selects three anti-collusion hash functions: H:{0,1}→G. as well as The above function can map any attribute described as a binary string to random group elements.

[0074] Secondly, the trusted genesis node in a private blockchain is randomly selected. This serves as the master key for the system. Let the n attribute nodes be represented as P = {P1, P2, ..., P...} n}

[0075] Finally, the system parameter generation process Param is as follows: The trusted genesis node in the private blockchain calculates e(g,g). α and h=g β The system parameter Param is as follows:

[0076] Param = {G, G} T ,H,H1,H1,e,g,e(g,g) α h=g β}

[0077] After the system parameter Param is generated, it will be broadcast to all users in the private blockchain.

[0078] A2: The trusted genesis node of a private blockchain generates public parameters for the private keys of attribute nodes, assuming the total number of attribute nodes is m. The specific generation process is as follows:

[0079] First, the trusted genesis node of the private blockchain uses Shamir(m,n)-threshold secret sharing technology to distribute a fragment α of the master key to participant P. i .

[0080] Secondly, the trusted genesis node of the private blockchain randomly selects a polynomial f(x) = s + a1x + a2x of degree m-1. 2 +…+a m-1 x m-1 (mod p) such that α = s and a1, a2, ..., a m-1 It is a random element in a finite field.

[0081] Finally, the trusted genesis node of the private blockchain calculates and distributes α. i Give attribute node P i Then, for each attribute j, the algorithm randomly selects... Generate a random number set R = {r1, r2, ..., r} for the attribute. n}

[0082] A3: The trusted genesis node of a private blockchain generates its own private key PSK for each attribute node. i Assume the total number of attribute nodes is m. The specific generation process is as follows:

[0083] The trusted genesis node of a private blockchain uses the key fragment of the attribute node for attribute node P. i Construct the private key and calculate Construct attribute node P i The formula for the private key is as follows:

[0084]

[0085] B: User key generation (Keygen);

[0086] User key generation (Keygen) is performed by attribute nodes within the blockchain. It uses the system parameter Param and the user's global GID. u User attribute set S' and the private key PSK of the attribute node i As input, the output is the SK of the user's private key. u ;

[0087] Step B includes the following specific steps:

[0088] B1: The user sends their GID information to all attribute nodes. The specific generation process is as follows:

[0089] User calculates H2(GID) u )=φ u as well as Then, the user randomly selects a polynomial h(x) = u + u1x + u2x with a degree of q-1. 2 +…+u q-1 x q-1(mod p) makes φ u =u and u1,u2,…,u q-1 It is a random element in a finite field. The user calculates φ1=h(1),φ2=h(2),…,φ n =h(n). Then, the user distributes φ using Shamir(m,n)-threshold secret sharing technology. i and Give attribute node P i .

[0090] B2: After receiving information from the user, the attribute node uses its private key PSK. i This component calculates and sends the key to the user. The specific generation process is as follows:

[0091] First, each attribute node P i Using the private key PSK i Calculate fragment information of the user's private key. A partial fragment of the user's key is as follows:

[0092] D u,i =(k f(i) )·(k h(i) )∈G

[0093] Finally, regarding attributes The attribute subkey components calculated for all attribute nodes are as follows:

[0094]

[0095] B3: The user reconstructs their complete private key SK from the received key component. u The specific generation process is as follows:

[0096] First, the user intervenes in the computation, defining the parameters of the Lagrange interpolation method as follows when the user reconstructs their key: and of Users rebuild their keys as follows:

[0097]

[0098] Finally, the user utilizes and D u Reconstruct your own key as follows:

[0099]

[0100] C: Encrypt;

[0101] The data owner executes the process. It uses system parameters Param, access tree Γ, plaintext M, and access structure. As input, the output is the ciphertext Cw associated with the plaintext M;

[0102] Step C includes the following specific steps:

[0103] C1: The data owner generates the necessary encrypted data and access tree structure. The specific generation process is as follows:

[0104] The data owner uses system parameters Param, the access tree Γ, and plaintext M as input. The data owner encrypts the plaintext M using SM3. This step encrypts M based on the access tree structure Γ and selects a polynomial q for each node x (including leaves) in the access tree Γ. x Choose polynomials from the root node R in a top-down manner. For each node x in the tree, let polynomial q... x $'s order d x It is the threshold k x Subtract node x, i.e., d x =k x -1.

[0105] C2: The data owner uses system parameters, encrypted data, and the access tree structure to encrypt plaintext data and embed it within the tree. The specific generation process is as follows:

[0106] First, plaintext M starts from the root node R, and the data owner is randomly selected. And set q R (0) = s. Then, randomly select the polynomial q. R b x Define the polynomial using other points. For any other node x, let q x (0)=q parent(x) (0) index(x) And randomly select polynomial q x b x Other points are used to define the polynomial.

[0107] Next, let Y be the set of leaf nodes of tree Γ. Then, the ciphertext of the plaintext is constructed by accessing the tree structure Γ. The plaintext and ciphertext are as follows:

[0108]

[0109] C = g βs ∈G

[0110] So,

[0111]

[0112] Finally, the ciphertext Cw of the plaintext is as follows:

[0113]

[0114] D: Decrypt;

[0115] The cloud server executes the command on behalf of the user. It will retrieve the encrypted data. If the attribute matches successfully, it returns 1. If the attribute does not match or the user is not authorized to execute the search, it returns ⊥.

[0116] Step D includes the following specific steps:

[0117] D1: The user performs a decryption operation using a cloud server. It will take the encrypted plaintext Cw as input. If S' satisfies the access structure... If the attributes match, the plaintext can be correctly searched and retrieved. For accessing a tree structure, the decryption process is recursive. The specific generation process is as follows:

[0118] First, let x be a leaf node in the tree structure Γ, i.e., x∈Γ. We define a recursive algorithm DecryptNode(Cw,Tw,x) for the leaf case. The input of this algorithm is the plaintext Cw and the leaf node x in tree Γ. Let i = att(x) and assume i∈S, then the following definition applies:

[0119]

[0120] Then, if Then we define DecryptNode(Cw,x) = ⊥.

[0121] Now consider the recursive case, where x is a non-leaf node. The algorithm DecryptNode(Cw,x) is calculated as follows: For all child nodes z of node x, call the function DecryptNode(Cw,z), and store the result as F. z Let S be the value of S. x It is of size k x Let F be any set z of its sub-items, such that F z ≠⊥ satisfies this condition. If such a set does not exist, the function will return ⊥.

[0122] If F is satisfied z ≠⊥, we define i = index(z), S' x ={index(z):z∈S x And calculate as follows:

[0123]

[0124] Secondly, by defining the function DecryptNode, we can define the decryption algorithm. This algorithm begins execution by simply calling the function at the root node R of the access tree Γ. If the set of attributes S' satisfies the access tree Γ, then let... The final decryption algorithm is as follows:

[0125]

[0126] Finally, if the access tree Γ is successfully satisfied, the above equation holds. The decryption result of the algorithm is plaintext M, proving that the attribute set S' satisfies the access tree Γ and the attribute match is successful. The cloud server will return the corresponding data to the user. Otherwise, the attribute match fails, and ⊥ is returned. Both are indispensable.

[0127] This invention proposes an attribute-based encryption method for decentralized key management, employing attribute-based encryption and Shamir (m,n)-threshold secret sharing technology. This method aims to address the single point of failure and security dependency issues present in traditional key management systems. By introducing attribute-based encryption, fine-grained access control for users is achieved. Furthermore, this method utilizes Shamir (m,n)-threshold secret sharing and blockchain technology, combined with decentralized characteristics, to enhance key management security. It provides an effective solution for market monitoring agencies to address key management challenges in open scenarios, and has been successfully applied, thus promoting technological advancement and application in the field of information security.

Claims

1. A property-based encryption method for decentralized key management, characterized in that, The method comprises the following steps: A: Global initialization Setup, executed by a trusted genesis node, generates system parameters and private keys of attribute nodes; the genesis node divides the master key into key fragments as attribute nodes using Shamir's secret sharing scheme SSS ; After executing the Setup algorithm, the genesis node will permanently exit the global initialization program and no longer participate in any operation;​ B: User key generation Keygen, executed by attribute nodes within the blockchain; takes as input the system parameters , the user's global , the user attribute set , and the attribute node's private key ; the output is the user private key ; C: Encrypt, performed by data owner; takes system parameters , access tree and plaintext as input; output is ciphertext related to plaintext ; D: decryption, performed by the cloud server on behalf of the user, which will obtain the ciphertext; if the attribute matching is successful, a decryption success flag is returned; If the attribute match fails or the user is not authorized to perform the search, then return ; The step C comprises the following specific steps: C1: the data owner generates necessary ciphertext data and an access tree structure, and the specific generation process is as follows: Data owners utilize system parameters Visit tree He Mingwen As input, the data owner uses SM3 to process the plaintext. Encryption is performed; this step is based on the access tree structure. right Encryption is performed, and access to the tree is provided. Each node in Choose polynomial Starting from the root node in a top-down manner Choose a polynomial for each node in the tree. Let the polynomial The level Threshold Subtract nodes ,Right now ; C2: the data owner encrypts the plaintext into the tree by using the system parameters, the ciphertext data and the access tree structure, and the specific generation process is as follows: First, the plaintext From the root node Start, the data owner randomly selects And set ; Then, a polynomial is randomly selected of other points to define the polynomial, For any other node , let and randomly select a polynomial of degree other points to define the polynomial; second, let be a set of leaf nodes of a tree structure , then, by accessing the tree structure to construct the ciphertext of the plaintext, the ciphertext of the plaintext is as follows: ； Finally, the ciphertext of the plaintext As follows: ; The step D comprises the following specific steps: D1: the user performs a decryption operation using the cloud server; uses ciphertext As input, if If the access can be met and the attribute can be matched, the plaintext can be correctly searched and obtained, and the decryption process is a recursive process for the access tree structure, and the specific generation process is as follows: ; ； Now consider the recursive case, where... Non-leaf nodes, algorithm The calculation is as follows: For node All child nodes Calling the function The result is stored as ;set up It is the size of any set of its sub-items , making The function satisfies the condition; if such a set does not exist, the function will return [missing value]. If satisfied, We define And calculate as follows: ； Second, the decryption algorithm is defined by defining a function ; this algorithm begins execution by simply calling the function at the root node of the access tree ; if the attribute set can satisfy the access tree , set and finally execute the decryption algorithm as follows: ； Finally, if the access tree is satisfied, the above equation holds; the decryption result of the algorithm is plaintext , which proves that the attribute set satisfies the access tree , and the attribute matching is successful, in the case of returning the decryption success flag, the cloud server returns the decrypted plaintext data to the user; otherwise, the attribute matching fails, and is returned; both are indispensable.

2. The attribute-based encryption method of decentralized key management according to claim 1, characterized in that, The step A comprises the following specific steps; Second, the trusted genesis node in the private blockchain is randomly selected , As the master key of the system, let The attribute node is represented as ; Finally, the generation process of system parameters As follows: trusted genesis nodes in a private blockchain calculate And , system parameters As follows: ; System parameters After generation, the system parameters are broadcast to all users in the private blockchain; A2: The trusted genesis node of the private blockchain generates a public parameter of the private key of the attribute node, assuming that the total number of attribute nodes is , and the specific generation process is as follows: First, the trusted genesis node of the private blockchain uses The threshold secret sharing technique distributes fragments of the master key To the participants ; Second, the trusted genesis nodes of the private blockchain randomly select a polynomial of degree such that and are random elements in some finite field;​ Finally, the trusted genesis nodes of the private blockchain compute and distribute to the attribute nodes ; then, for each attribute , the algorithm randomly selects and generates a set of random numbers for the attribute; A3: The trusted genesis node of the private blockchain generates a respective private key for each attribute node Assuming the total number of attribute nodes is m, the specific generation process is as follows: The trusted genesis nodes of the private blockchain utilize the key fragments of the attribute nodes for the attribute nodes The private key is constructed and calculated The private key of the attribute node The private key formula of the attribute node is as follows: 。 3. The attribute-based encryption method of decentralized key management of claim 1, wherein, The step B comprises the following specific steps: B1: The user will... The information is sent to all attribute nodes, and the specific generation process is as follows: User calculation as well as Then, the user randomly selects a degree. polynomial , making and It is a random element in a finite field; user calculation Then, the user utilizes - Threshold secret sharing technology distribution and Give attribute nodes ; B2: Upon receiving the information from the user, the attribute node uses its private key to compute and send the key component to the user, the detailed generation process is as follows: First, each attribute node Using the private key Calculate the segment information of the user private key, and the partial key segment of the user is as follows: Finally, for the attribute , the attribute sub-key component calculated by all attribute nodes is as follows: ; B3: User intervention calculation, when the user rebuilds their key, define the parameters of the Lagrange interpolation method as and the ; The user reconstructs the key in the following manner: ； Finally, the user reconstructs his own key using , and as follows: .

4. The method of claim 1-3, wherein, Applied to the protection of data in market monitoring activities.

Images