Decentralized attribute-based encryption method based on standard model

Abstract

A decentralized attribute-based encryption method based on a standard model includes: global initialization; an authority generating public and private keys associated with attributes; generating a user's attribute private key; message encryption; and verification of whether the identity and attribute satisfy the access policy. If they satisfy, the plaintext is decrypted and recovered; otherwise, decryption fails. This invention achieves flexible, fine-grained access control by combining LSSS access policies and provides dual security constraints through a global identity and attribute binding mechanism. It is suitable for various practical scenarios of secure data sharing and distributed attribute management, especially for multi-source authorization, privacy protection, and cross-domain collaborative environments. It features high security, high scalability, and good deployment feasibility. This invention requires no central authority or trusted initialization setup; each attribute authority can operate independently and be responsible for the key management and issuance of its own attribute, fundamentally eliminating single-point trust and system bottlenecks.

Description

Technical Field

[0001] This invention belongs to the field of cryptography and information security technology, specifically relating to a decentralized attribute-based encryption method based on a standard model. Background Technology

[0002] With the rapid development of cloud computing, the Internet of Things, and big data technologies, data sharing and access control have become key research directions in the field of information security. Attribute-Based Encryption (ABE), as a cryptographic technology that supports fine-grained access control, allows data owners to flexibly define access policies based on user attributes, thereby achieving efficient and secure data encryption and sharing. However, traditional ABE schemes mostly rely on a central authority for unified attribute management and key distribution. This centralized architecture not only brings serious single points of failure and trust bottleneck problems, but also makes the central authority a potential source of system privacy leaks and key abuse. At the same time, as the system scales up, the central authority faces exponentially increasing computational, communication, and storage pressures, making its scalability insufficient to meet the needs of large-scale applications. Furthermore, attribute updates, revocations, and management all rely on a central entity, which cannot adapt to the flexibility requirements of multi-domain collaboration and dynamic environments.

[0003] To alleviate the centralization problem, researchers have proposed the Multi-Authority Attribute-Based Encryption (ABE) scheme, which allows multiple attribute authorities to independently manage different attribute domains. However, existing multi-authority schemes still have significant limitations: most schemes still rely on trusted third parties for global parameter setting or master key escrow, making it difficult to achieve true decentralization; at the same time, their security is often built on a random oracle model, lacking the strict security guarantees under standard models. Furthermore, keys issued by different authorities may be used by malicious users in collusion to bypass access policies, and the lack of a global identity binding mechanism makes cross-authority key abuse difficult to track and prevent. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a decentralized attribute-based encryption method based on a standard model that features a decentralized architecture, high access control flexibility, and high security.

[0005] The technical solution adopted to solve the above-mentioned technical problems is: a decentralized attribute-based encryption method based on a standard model, comprising the following steps:

[0006] Step 1. Global Initialization

[0007] Input security parameter β, maximum length of global identity The maximum width of the access matrix is The system runs an initialization algorithm, defining the attribute space AU and the global identity space. It also runs a bilinear group generator to generate bilinear groups of order q. ,in and It is a cyclic group of order q. It is a bilinear mapping function. As a generator of a cyclic group G, output the public global parameter GP. , ),in Let G be a generator of the cyclic group G;

[0008] Step 2. Authoritative generation of public and private keys associated with the attributes.

[0009] Authority Selected Attribute And randomly select attributes Related secret parameters , Given an integer group modulo q, generate information about the attributes based on the global parameter GP. authoritative public key and authoritative private key ;

[0010] Step 3. Generate the user's attribute private key

[0011] User-held attributes The authoritative entity submits a global identity registration form to obtain the user's global identity GID, whose maximum length is [missing information]. Holding attributes The authoritative entity obtains the user's GID private key according to the following formula. And send it to the user,

[0012]

[0013] In the formula, , For generators of cyclic groups, The t-th character of the user's global identity (GID). Authority as an attribute The randomly selected secret parameter corresponds to the j-th column of the access matrix;

[0014] Step 4. Message Encryption

[0015] Step 4.1. The data owner obtains the global parameter GP and the message to be encrypted. LSSS access policy A set of public keys that map authority For message vector space, yes OK, Column access strategy matrix, For mapping functions, Access strategy matrix The authority of the attribute mapped in the i-th row;

[0016] Step 4.2. The data owner randomly selects the encryption parameter k. x , Used for secret sharing and anti-collusion protection, k is the secret sharing vector, and x is the anti-collusion vector. Generate a random number for the row;

[0017] Step 4.3. The data owner generates the master ciphertext component C and the matrix row ciphertext component C through bilinear mapping and group operations. Anti-collusion ciphertext component ;

[0018] Step 4.4. The data owner integrates the access policy and all encrypted components to generate the complete encrypted data.

[0019] ;

[0020] Step 5. Verify whether the identity and attributes meet the access policy. If they do, decrypt and recover the plaintext; otherwise, decryption fails.

[0021] Step 5.1. The user verifies whether their own attribute set satisfies the LSSS access policy in the ciphertext using the following formula.

[0022]

[0023] In the formula, I represents the set of matrix row indices corresponding to the attributes held by the user. For LSSS reconstruction coefficients, Access strategy matrix The i-th row;

[0024] Step 5.2. Verification passed. The plaintext data m is obtained according to the following formula.

[0025]

[0026] In the formula, To be consistent with user global identity and attribute authority The relevant private key.

[0027] As a preferred technical solution, the authoritative public key mentioned in step 2 The authoritative private key .

[0028] As a preferred technical solution, the master ciphertext component C is:

[0029]

[0030] In the formula, The first element of the secret shared vector k is used to hide the message;

[0031] The matrix row ciphertext component middle , ,in For attribute authority The secret parameters;

[0032] The anti-collusion ciphertext component middle ,in For attribute authority The secret parameters.

[0033] The beneficial effects of this invention are as follows:

[0034] This invention eliminates the need for a central authority or trusted third party. Each attribute authority operates independently and manages its own attributes and keys, thus eliminating single points of failure and trust bottlenecks. It fundamentally solves the risks of privacy leaks and key abuse that may arise from a central authority in traditional centralized ABE schemes. New attribute authorities can join or leave the system at any time without re-initializing the system or performing complex global coordination, greatly improving the system's flexibility and scalability.

[0035] This invention performs security proof under the standard model, avoiding security vulnerabilities caused by idealized assumptions. Through a global identity binding mechanism, all keys are bound to the user's global identity, and only legitimate users can use their attribute keys to decrypt. Even if malicious users share keys, they cannot bypass the access policy to decrypt unauthorized data, thereby ensuring the integrity and unavoidability of fine-grained access control and effectively preventing cross-user and cross-authority key abuse.

[0036] This invention eliminates the need for complex certificate issuance and revocation mechanisms, thus removing the burden of certificate management, reducing the difficulty of system implementation and deployment, improving overall operating efficiency, and supporting large-scale applications. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the decentralized attribute-based encryption method based on the standard model of this invention.

[0038] Figure 2 This is a schematic diagram of the decentralized attribute-based encryption method based on the standard model of the present invention. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0040] exist Figure 1 , 2 The decentralized attribute-based encryption method based on the standard model in this embodiment includes the following steps:

[0041] Step 1. Global Initialization

[0042] Input security parameter β, maximum length of global identity The maximum width of the access matrix is The system runs an initialization algorithm, defining the attribute space AU and the global identity space. It also runs a bilinear group generator to generate bilinear groups of order q. ,in and It is a cyclic group of order q. It is a bilinear mapping function. As a generator of a cyclic group G, output the public global parameter GP. , , ),in Let G be a generator of the cyclic group G;

[0043] Step 2. Attribute Authority generates public and private keys associated with the attribute.

[0044] Authority Selected Attribute And randomly select attributes Related secret parameters , Given an integer group modulo q, generate information about the attributes based on the global parameter GP. authoritative public key and authoritative private key This allows each attribute authority to independently manage its own attributes, avoiding single points of failure and trust bottlenecks caused by centralized authority.

[0045] Step 3. Generate the user's attribute private key

[0046] User-held attributes The authoritative entity submits a global identity registration form to obtain the user's global identity GID, whose maximum length is [missing information]. Holding attributes The authoritative entity obtains the user's GID private key according to the following formula. And send it to the user,

[0047]

[0048] In the formula, , For generators of cyclic groups, The t-th character of the user's global identity (GID). Authority as an attribute The randomly selected secret parameter corresponds to the j-th column of the access matrix;

[0049] This step binds the user's global identity GID to the attribute u, ensuring that only authorized users can use this attribute for decryption, preventing key abuse and unauthorized sharing, and enhancing system security.

[0050] Step 4. Message Encryption

[0051] Step 4.1. The data owner obtains the global parameter GP and the message to be encrypted. LSSS access policy A set of public keys that map authority For message vector space, yes OK, Column access strategy matrix, For mapping functions, Access strategy matrix The authority of the attribute mapped in the i-th row;

[0052] Step 4.2. The data owner randomly selects the encryption parameter k. x , Used for secret sharing and anti-collusion protection, where k is the secret sharing vector and x is the anti-collusion vector. Generate a random number for the row;

[0053] Step 4.3. The data owner generates the master ciphertext component C and the matrix row ciphertext component C through bilinear mapping and group operations. Anti-collusion ciphertext component ;

[0054] The main ciphertext component C is:

[0055]

[0056] In the formula, The first element of the secret shared vector k is used to hide the message;

[0057] Matrix row ciphertext component middle , In the formula For attribute authority The secret parameters;

[0058] Anti-collusion ciphertext component middle ,in For attribute authority The secret parameters;

[0059] Step 4.4. The data owner integrates the access policy and all encrypted components to generate the complete encrypted data.

[0060] ;

[0061] Step 5. Verify whether the identity and attributes meet the access policy. If they do, decrypt and recover the plaintext; otherwise, decryption fails.

[0062] Step 5.1. The user verifies whether their own attribute set satisfies the LSSS access policy in the ciphertext using the following formula.

[0063]

[0064] In the formula, I represents the set of matrix row indices corresponding to the attributes held by the user. For LSSS reconstruction coefficients, Access strategy matrix The i-th row;

[0065] Step 5.2. Verification passed. The plaintext data m is obtained according to the following formula.

[0066]

[0067] In the formula, To be consistent with user global identity and attribute authority The relevant private key.

Claims

1. A decentralized attribute-based encryption method based on a standard model, characterized in that, Includes the following steps: Step 1. Global Initialization Input security parameter β, maximum length of global identity The maximum width of the access matrix is The system runs an initialization algorithm, defining the attribute space AU and the global identity space. It also runs a bilinear group generator to generate bilinear groups of order q. ,in and It is a cyclic group of order q. It is a bilinear mapping function. As a generator of a cyclic group G, output the public global parameter GP. , ),in Let G be a generator of the cyclic group G; Step 2. Authoritative generation of public and private keys associated with the attributes. Authority Selected Attribute And randomly select attributes Related secret parameters , Given an integer group modulo q, generate information about the attributes based on the global parameter GP. authoritative public key and authoritative private key ; Step 3. Generate the user's attribute private key User-held attributes The authoritative entity submits a global identity registration form to obtain the user's global identity GID, whose maximum length is [missing information]. Holding attributes The authoritative entity obtains the user's GID private key according to the following formula. And send it to the user, In the formula, , For generators of cyclic groups, The t-th character of the user's global identity (GID). Authority as an attribute The randomly selected secret parameter corresponds to the j-th column of the access matrix; Step 4. Message Encryption Step 4.

1. The data owner obtains the global parameter GP and the message to be encrypted. LSSS access policy A set of public keys that map authority For message vector space, yes OK, Column access strategy matrix, For mapping functions, Access strategy matrix The authority of the attribute mapped in the i-th row; Step 4.

2. The data owner randomly selects the encryption parameter k. x , Used for secret sharing and anti-collusion protection, k is the secret sharing vector, and x is the anti-collusion vector. Generate a random number for the row; Step 4.

3. The data owner generates the master ciphertext component C and the matrix row ciphertext component C through bilinear mapping and group operations. Anti-collusion ciphertext component ; Step 4.

4. The data owner integrates the access policy and all encrypted components to generate the complete encrypted data. ； Step 5. Verify whether the identity and attributes meet the access policy. If they do, decrypt and recover the plaintext; otherwise, decryption fails. Step 5.

1. The user verifies whether their own attribute set satisfies the LSSS access policy in the ciphertext using the following formula. In the formula, I represents the set of matrix row indices corresponding to the attributes held by the user. For LSSS reconstruction coefficients, Access strategy matrix The i-th row; Step 5.

2. Verification passed. The plaintext data m is obtained according to the following formula. In the formula, To be consistent with user global identity and attribute authority The relevant private key.

2. The decentralized attribute-based encryption method based on the standard model according to claim 1, characterized in that, The authoritative public key mentioned in step 2 The authoritative private key .

3. The decentralized attribute-based encryption method based on the standard model according to claim 1, characterized in that, The master ciphertext component C is: In the formula, The first element of the secret shared vector k is used to hide the message; The matrix row ciphertext component middle , ,in For attribute authority The secret parameters; The anti-collusion ciphertext component middle ,in For attribute authority The secret parameters.

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