A searchable registration attribute base encryption method

Abstract

A searchable registration attribute-based encryption method includes: generating a public reference string using a public reference string generator; users generating their own public and private keys; a key manager collecting and aggregating the public keys of all registered users to generate a unified master public key and auxiliary decryption keys; the data owner encrypting the original data while generating a searchable ciphertext index, uploading it to a cloud server for storage, thus achieving data encryption and searchability; the user generating a search trapdoor based on the keywords to be searched, sending it to the cloud server through a secure channel, with the trapdoor bound to the user's own attributes to ensure fine-grained search permissions; the cloud server verifying whether the user's attributes meet the access policy without decrypting the data, then performing keyword matching and returning the successfully matched ciphertext; the user using their private key, the ciphertext returned by the cloud server, and the search component to decrypt the ciphertext and recover the original data.

Description

Technical Field

[0001] This invention belongs to the field of cloud computing and Internet of Things security technology, and specifically relates to a searchable registration attribute base encryption method. Background Technology

[0002] With the widespread adoption of Cloud-based Internet of Things (Cloud-IoT), massive amounts of data are being outsourced for storage on cloud servers, including sensitive information such as medical records, industrial data, and personal privacy data. Attribute-based encryption (ABE) technology is favored for its ability to achieve fine-grained "one-to-many" access control, allowing data owners to define attribute-based access policies so that only users meeting specific attributes can decrypt ciphertext. However, traditional ABE solutions face significant challenges in the specific scenario of Cloud-IoT.

[0003] The primary concern is key escrow risk. In centralized ABE systems, the Key Generation Center (KGC) holds the system master key and all users' private keys. This centralized key management approach presents a single point of failure. If the KGC is compromised by malicious attackers or if internal personnel abuse their privileges, the entire system will collapse, and all encrypted data may be at risk of being leaked. This risk is particularly pronounced in sensitive data areas such as healthcare and finance.

[0004] Secondly, ABE encryption and decryption operations involve a large number of complex cryptographic calculations such as bilinear pairing and exponential operations, which place a heavy burden on IoT terminal devices with limited computing power, storage space, and battery capacity. For example, in resource-constrained environments such as wearable medical devices and industrial sensors, traditional ABE solutions are often difficult to deploy in practice due to excessive computational overhead, which seriously restricts their feasibility in large-scale IoT applications.

[0005] Furthermore, traditional ABE solutions have functional limitations, namely, they do not support efficient keyword searches. After data encryption, the content is completely invisible to the cloud server; users must download and decrypt the entire dataset before they can perform searches, which is virtually impractical in cloud IoT environments with massive data volumes. Taking smart city video surveillance data as an example, the terabytes of encrypted data generated daily makes traditional retrieval methods extremely inefficient, greatly limiting the practicality of ABE in data retrieval scenarios.

[0006] To address the key escrow issue, Registered Attribute-Based Cryptography (RABE) effectively reduces complete reliance on a centralized Key Controller (KGC) by allowing users to generate and manage a portion of their private keys. In a RABE system, users generate a portion of their private key and only need to register the public key component with the KGC, thus significantly reducing key escrow risks. However, existing RABE solutions still lack built-in keyword search functionality, failing to meet the efficient retrieval needs of cloud environments.

[0007] Meanwhile, while searchable encryption (SE) technology can achieve encrypted searching, its access control mechanism is usually relatively simple, making it difficult to achieve the fine-grained access control capabilities of ABE. When SE and ABE are simply combined, there is often a disconnect between access control and search permission management, making it impossible to achieve attribute-based search permission control. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a searchable registration attribute base encryption method that is safe, reliable, efficient in retrieval, and has low overall computational overhead.

[0009] The technical solution adopted to solve the above technical problems is: a searchable registration attribute base encryption method, including the following steps:

[0010] Step 1. Generate a common reference string

[0011] Input security parameters Size of the complete set of attributes The number of slots L, representing the number of users, is used to generate a common reference string through a common reference string generator. And output,

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[0020] In the formula, and It is a prime number. Multiplication cyclic group, and It is a multiplication cyclic group The generator, e, is a bilinear mapping function. All from The random number selected from the data. For model The multiplication group;

[0021] Step 2. Users generate public and private keys themselves.

[0022] user Select secret value As a private key and generate partial public key components. and public key components required for cross-slot collaboration , , From The random number selected from the data. Obtain the public key The key is then output to the key administrator for registration, and the user retains the private key. ;

[0023] Step 3. The key manager collects and aggregates the public keys of all registered users to generate a unified master public key and auxiliary decryption keys;

[0024] Step 4. The data owner encrypts the original data while generating a searchable ciphertext index, which is then uploaded to the cloud server for storage, thus achieving data encryption and searchability;

[0025] Step 5. The user generates a search trap based on the keywords to be searched and sends it to the cloud server through a secure channel. The trap is bound to the user's own attributes to ensure fine-grained search permissions.

[0026] Step 6. Without decrypting the data, the cloud server first verifies whether the user attributes meet the access policy, then performs keyword matching and returns the encrypted text of the successful match;

[0027] Step 7. The user uses their private key, the ciphertext returned by the cloud server, and the search component. Complete the decryption of the encrypted data and restore the original data.

[0028] As a preferred technical solution, the method for generating a unified master public key and auxiliary decryption key in step 3 is as follows:

[0029] Step 3.1. Integrate the partial public key components of all users according to the following formula. Generate aggregate public key ,

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[0031] Aggregate all other users according to the following formula. i-generated cross-slot collaboration public key component ,

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[0033] in, User For users The public key component required for the generated cross-slot collaboration, , For users The private key;

[0034] Step 3.2. For each attribute Aggregate all those having the following formula User attributes Attribute components Thus obtain Aggregate property component ,

[0035] ,

[0036] In the formula, Let j be the set of attributes for user j;

[0037] For each user Aggregator users Combining user j's attributes Parameter-generated cross-slot elimination component Get users For attributes Cross-slot aggregation components , ;

[0038] Step 3.3. Output the master public key and auxiliary decryption key .

[0039] As a preferred technical solution, step 4 specifically involves the following steps:

[0040] Step 4.1. The data owner from Select random session key Random elements Keywords ;

[0041] Step 4.2. Settings Make common parameters , ;

[0042] Step 4.3. Generate encrypted data , , and searchable index components , , ;

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[0050] In the formula, All The random value selected from the middle For the access matrix, It is the hash value of the keyword K. It accesses the attribute mapped to the i-th row of matrix M. The corresponding aggregated attribute component;

[0051] Step 4.4. Generate searchable ciphertext ,in , To access the row number of the matrix, It is a mapping function.

[0052] As a preferred technical solution, step 5 specifically involves the following steps:

[0053] Step 5.1. The user from Select random number Generate trapdoor components ;

[0054] Output keyword search trap Initiate a search request to the cloud server.

[0055] As a preferred technical solution, step 6 specifically involves the following steps:

[0056] Step 6.1. The cloud server verifies the user's attribute set. Does the access structure satisfy? Unauthorized users will have their search requests rejected outright.

[0057] Step 6.2. For authorized users, generate the attribute matching component. Slot matching components ,

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[0060] Step 6.3. Keyword matching test, if If true, return the matching ciphertext. Decryption and reusable property matching components .

[0061] As a preferred technical solution, step 7 specifically involves the user using their private key. Decryption slot matching component And combine the attribute matching component returned by the cloud server Restore original data ,

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[0063] .

[0064] The beneficial effects of this invention are as follows:

[0065] This invention adopts a registration-based key management mechanism where users generate their own private keys. Users independently generate and store their private keys, and only submit their public keys to the key manager for registration. This completely eliminates the traditional centralized attribute-based encryption model where the key generation center (KGC) holds all users' private keys. It avoids the risk of system-wide data leakage caused by single point of failure of the KGC, abuse of internal permissions, or attacks, and significantly improves the security boundary of the system in sensitive data fields such as healthcare, finance, and industrial IoT.

[0066] This invention integrates the fine-grained access control features of attribute-based encryption with the ciphertext retrieval function of searchable encryption. Data owners can define attribute access policies for ciphertext through access structures. Before executing a retrieval, the cloud server must first verify whether the attribute set of the data user meets the policy. Only authorized users can initiate valid retrievals, avoiding invalid retrievals and permission abuse by unauthorized users. This solves the problems of simple access control in traditional searchable encryption and lack of retrieval function in attribute-based encryption.

[0067] This invention allows data owners to simultaneously generate a searchable ciphertext index bound to keywords when encrypting data. Data users initiate searches by generating keyword search traps. The cloud server completes attribute verification and keyword matching without decrypting the ciphertext or obtaining plaintext keywords, and directly returns the successfully matched ciphertext. This eliminates the need for users to download and decrypt the entire dataset, completely solving the problem of low retrieval efficiency for massive encrypted data and significantly enhancing the practical value of cloud-encrypted data.

[0068] This invention features a targeted design for the computation process, outsourcing a large number of computationally intensive operations such as attribute verification and keyword matching calculations on the server side to the cloud server. Data owners and users only need to perform simple parameter selection and component calculations, which significantly reduces the computation, storage, and energy consumption burden on terminal devices. It solves the problem that traditional attribute-based encryption is difficult to deploy on IoT terminals due to excessive computational overhead, and is suitable for large-scale cloud IoT application scenarios. Attached Figure Description

[0069] Figure 1 This is a flowchart illustrating the searchable registration attribute base encryption method of the present invention. Detailed Implementation

[0070] 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.

[0071] exist Figure 1 In this embodiment, a searchable registration attribute base encryption method is characterized by comprising the following steps:

[0072] Step 1. Generate a common reference string

[0073] Input security parameters Size of the complete set of attributes The number of slots L, representing the number of users, is used to generate a common reference string through a common reference string generator. And output,

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[0082] In the formula, and It is a prime number. Multiplication cyclic group, and It is a multiplication cyclic group The generator, e, is a bilinear mapping function. All from The random number selected from the data. For model The multiplication group;

[0083] Step 2. Users generate public and private keys themselves.

[0084] user Select secret value As a private key and generate partial public key components. and public key components required for cross-slot collaboration , , From The random number selected from the data. Obtain the public key The key is then output to the key administrator for registration, and the user retains the private key. ;

[0085] Step 3. The key manager collects and aggregates the public keys of all registered users to generate a unified master public key and auxiliary decryption keys.

[0086] Step 3.1. Integrate the partial public key components of all users according to the following formula. Generate aggregate public key ,

[0087]

[0088] Aggregate all other users according to the following formula. i-generated cross-slot collaboration public key component ,

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[0090] in, User For users The public key component required for the generated cross-slot collaboration, , For users The private key;

[0091] Step 3.2. For each attribute Aggregate all those having the following formula User attributes Attribute components Thus obtain Aggregate property component ,

[0092] ,

[0093] In the formula, Let j be the set of attributes for user j;

[0094] For each user Aggregator users Combining user j's attributes Parameter-generated cross-slot elimination component Get users For attributes Cross-slot aggregation components , ;

[0095] Step 3.3. Output the master public key and auxiliary decryption key .

[0096] Step 4. The data owner encrypts the original data while generating a searchable ciphertext index, which is then uploaded to the cloud server for storage, achieving both data encryption and searchability. The specific steps are as follows:

[0097] Step 4.1. The data owner from Select random session key Random elements Keywords ;

[0098] Step 4.2. Settings Make common parameters , ;

[0099] Step 4.3. Generate encrypted data , , and searchable index components , , ;

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[0107] In the formula, All The random value selected from the middle For the access matrix, It is the hash value of the keyword K. It accesses the attribute mapped to the i-th row of matrix M. The corresponding aggregated attribute component;

[0108] Step 4.4. Generate searchable ciphertext ,in , To access the row number of the matrix, It is a mapping function.

[0109] Step 5. The user generates a search trap based on the keywords to be searched and sends it to the cloud server through a secure channel. The trap is bound to the user's own attributes to ensure fine-grained search permissions. The specific operation is as follows:

[0110] Step 5.1. The user from Select random number Generate trapdoor components ;

[0111] Output keyword search trap Initiate a search request to the cloud server.

[0112] Step 6. Without decrypting the data, the cloud server first verifies whether the user attributes meet the access policy, then performs keyword matching and returns the ciphertext of the successful match. The specific operation is as follows:

[0113] Step 6.1. The cloud server verifies the user's attribute set. Does the access structure satisfy? Unauthorized users will have their search requests rejected outright.

[0114] Step 6.2. For authorized users, generate the attribute matching component. Slot matching components ,

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[0117] Step 6.3. Keyword matching test, if If true, return the matching ciphertext. Decryption and reusable property matching components .

[0118] Step 7. The user uses their own private key The encrypted text returned by the cloud server and the search component Complete the decryption and recover the original data. ,

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Claims

1. A searchable registration attribute base encryption method, characterized in that, Includes the following steps: Step 1. Generate a common reference string Input security parameters Size of the complete set of attributes The number of slots L, representing the number of users, is used to generate a common reference string through a common reference string generator. And output, In the formula, and It is a prime number. Multiplication cyclic group, and It is a multiplication cyclic group The generator, e, is a bilinear mapping function. All from The random number selected from the data. For model The multiplication group; Step 2. Users generate public and private keys themselves. user Select secret value As a private key and generate partial public key components. and public key components required for cross-slot collaboration , , From The random number selected from the data. Obtain the public key The key is then output to the key administrator for registration, and the user retains the private key. ; Step 3. The key manager collects and aggregates the public keys of all registered users to generate a unified master public key and auxiliary decryption keys; Step 4. The data owner encrypts the original data while generating a searchable ciphertext index, which is then uploaded to the cloud server for storage, thus achieving data encryption and searchability; Step 5. The user generates a search trap based on the keywords to be searched and sends it to the cloud server through a secure channel. The trap is bound to the user's own attributes to ensure fine-grained search permissions. Step 6. Without decrypting the data, the cloud server first verifies whether the user attributes meet the access policy, then performs keyword matching and returns the encrypted text of the successful match; Step 7. The user uses their private key, the ciphertext returned by the cloud server, and the search component. Complete the decryption of the encrypted data and restore the original data.

2. The searchable registration attribute base encryption method according to claim 1, characterized in that, In step 3, the method for generating the unified master public key and auxiliary decryption key is as follows: Step 3.

1. Integrate the partial public key components of all users according to the following formula. Generate aggregate public key , Aggregate all other users according to the following formula. i-generated cross-slot collaboration public key component , in, User For users The public key component required for the generated cross-slot collaboration, , For users The private key; Step 3.

2. For each attribute Aggregate all those having the following formula User attributes Attribute components Thus obtain Aggregate property component , , In the formula, Let j be the set of attributes for user j; For each user Aggregator users Combining user j's attributes Parameter-generated cross-slot elimination component Get users For attributes Cross-slot aggregation components , ; Step 3.

3. Output the master public key and auxiliary decryption key .

3. The searchable registration attribute base encryption method according to claim 2, characterized in that, The specific operation of step 4 is as follows: Step 4.

1. The data owner from Select random session key Random elements Keywords ; Step 4.

2. Settings Make common parameters , ; Step 4.

3. Generate encrypted data , , and searchable index components , , ; In the formula, All The random value selected from the middle For the access matrix, It is the hash value of the keyword K. It accesses the attribute mapped to the i-th row of matrix M. The corresponding aggregated attribute component; Step 4.

4. Generate searchable ciphertext ,in , To access the row number of the matrix, It is a mapping function.

4. The searchable registration attribute base encryption method according to claim 3, characterized in that, The specific operation of step 5 is as follows: Step 5.

1. The user from Select random number Generate trapdoor components ; Output keyword search trap Initiate a search request to the cloud server.

5. The searchable registration attribute base encryption method according to claim 4, characterized in that, The specific operation of step 6 is as follows: Step 6.

1. The cloud server verifies the user's attribute set. Does the access structure satisfy? Unauthorized users will have their search requests rejected outright. Step 6.

2. For authorized users, generate the attribute matching component. Slot matching components , Step 6.

3. Keyword matching test, if If true, return the matching ciphertext. Decryption and reusable property matching components .

6. The searchable registration attribute base encryption method according to claim 5, characterized in that, The specific operation of step 7 is as follows: the user uses the private key. Decryption slot matching component And combine the attribute matching component returned by the cloud server Restore original data , 。

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