Ciphertext encryption and decryption method and system

Abstract

The invention provides a ciphertext encryption and decryption method and system, and the method comprises the steps: firstly achieving the fine-grained access control based on attributes, and employing a multi-authority distributed architecture to improve the system expansibility and load balancing capability; secondly, a password reverse firewall is deployed at a key communication node, and attack and key ciphertext leakage threats are replaced by a real-time re-randomization operation defense algorithm; meanwhile, an independent auditing center is introduced, plaintext data can be recovered through a safety process under the supervision requirement, and it is ensured that data use is compliant and controllable.

Description

Technical Field

[0001] This application relates to the field of data processing technology, and in particular to a method and system for ciphertext encryption and decryption. Background Technology

[0002] Against the backdrop of increasingly severe global climate change, building an efficient and reliable carbon emission monitoring system has become a key task in achieving the "dual carbon" strategic goals. With the widespread deployment of Industrial Internet of Things (IIoT) technology, systems covering the entire process of carbon emission monitoring, reporting, and verification are gradually being improved, forming a carbon monitoring network integrating multi-source data collection, cross-domain flow, and collaborative processing. In this process, carbon emission data possesses the dual attributes of being both a core asset for enterprises and a basis for government regulation, making the issues of secure sharing and privacy protection increasingly prominent. Therefore, there is an urgent need to build a data security system that supports fine-grained access control and has high scalability.

[0003] Attribute-based encryption technology, based on ciphertext policies, is an effective way to achieve fine-grained access control. By using user attributes as the basis for access permissions, it ensures that only users with the corresponding attributes can decrypt and obtain data, thereby significantly reducing the risk of data leakage. However, traditional attribute-based encryption architectures with single-authority ciphertext policies suffer from significant performance bottlenecks and single points of failure. Once the attribute authority is attacked, the entire system's security will collapse. Furthermore, existing mechanisms generally lack robust security authentication and auditing capabilities, making it difficult to effectively verify the identity of visitors. They also cannot achieve compliant decryption during regulatory reviews or dispute resolution, making it difficult to meet the stringent requirements for operational compliance and data auditability in carbon regulatory scenarios. Summary of the Invention

[0004] This application proposes a method and system for ciphertext encryption and decryption, which can solve one of the problems existing in the background technology.

[0005] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for encrypting and decrypting text is provided. This method is based on an encryption / decryption system, which includes: a key generation center, a key reverse firewall, an audit center, several attribute authority centers, a data collection terminal, a cloud server, and users. Each attribute authority center independently manages a non-overlapping subset of user attributes. The encryption part includes: The key generation center generates the master public key and the master private key; The key reverse firewall rerandomizes the master public key and the master private key, and publishes the rerandomized master public key; The audit center uses the rerandomized master private key to construct an audit key; The attribute authority center constructs an attribute key using the rerandomized master private key and the user attributes; The key reverse firewall rerandomizes the audit key and the attribute key; The audit center constructs a user token based on the user's identity identifier and the user's attributes; The data acquisition terminal constructs ciphertext based on the collected data, the user attributes, and the rerandomized master public key; The key reverse firewall rerandomizes the ciphertext; and The cloud server stores the rerandomized ciphertext. The decryption process includes: The cloud server verifies the user token. After successful verification, the user uses the audit key and the attribute key to decrypt the ciphertext obtained from the cloud server.

[0006] Based on the above technical solutions, firstly, fine-grained access control is implemented based on attributes, and a multi-authority distributed architecture is adopted to improve system scalability and load balancing capabilities; secondly, cryptographic reverse firewalls are deployed at key communication nodes, and real-time re-randomization operation defense algorithms are used to replace attack and key ciphertext leakage threats; at the same time, an independent audit center is introduced to support the recovery of plaintext data through secure processes under regulatory requirements, ensuring that data use is compliant and controllable.

[0007] In one possible design of the first aspect, the key generation center generates the master public key and the master private key, specifically including: The key generation center determines the generator in a ternary bilinear group, wherein the generator order of the ternary bilinear group is a prime number p. In Z p The first parameter, Z, is randomly selected from the given parameters. p Let P be an integer ring modulo a prime number P; and, Using the generator and the first parameter, the master public key and the master private key are calculated.

[0008] In one possible design of the first aspect, the key reverse firewall rerandomizes the master public key and the master private key, specifically including: The key reverse firewall in Z p The second parameter is randomly selected from the options. Construct a first randomization parameter using the first parameter and the second parameter, and rerandomize the generator; and, Using the first randomization parameter and the generator after rerandomization, the master public key and the master private key after rerandomization are calculated.

[0009] In one possible design of the first aspect, the audit center constructs an audit key using the re-randomized master private key, specifically including: The audit center is in Z p A third parameter is randomly selected, the third parameter including a first secret number; and, The audit key is calculated using the third parameter and the re-randomized master private key. The key reverse firewall rerandomizes the audit key, specifically including: The key reverse firewall in Z p The second randomization parameter is randomly selected; and, The audit key after re-randomization is calculated using the second randomization parameter and the audit key.

[0010] In one possible design approach of the first aspect, the attribute authority center constructs an attribute key using the re-randomized master private key and the user attributes, specifically including: The attribute authority center is in Z. p The fourth parameter is randomly selected from the data, and the first secret number is obtained; and, The attribute key is calculated using the fourth parameter, the first secret number, the re-randomized master private key, and the user attributes. The key reverse firewall rerandomizes the attribute key, specifically including: The key reverse firewall in Z p The third randomization parameter is randomly selected; and, The attribute key after re-randomization is calculated using the third randomization parameter and the attribute key.

[0011] In one possible design of the first aspect, the data acquisition terminal constructs ciphertext based on the acquired data, the user attributes, and the re-randomized master public key, specifically including: The data acquisition terminal defines an access structure (M, v), where M is the access strategy matrix and v is a function that maps rows of the access strategy matrix to the entire set of attributes. In Z p A fifth parameter is randomly selected, the fifth parameter including a second secret number; and, The ciphertext is constructed using the fifth parameter, the collected data, the user attributes, and the re-randomized master public key. The key-based reverse firewall rerandomizes the ciphertext, specifically including: The key reverse firewall obtains a fourth randomization parameter, which satisfies a predetermined relationship with the second randomization parameter; and, The ciphertext is rerandomized using the fourth randomization parameter.

[0012] In one possible design of the first aspect, the decryption section further includes: The cloud server calculates the reconstruction coefficient based on the access structure and the user attributes; Based on the reconstruction coefficients and the ciphertext aggregated ciphertext components, the aggregation result is obtained; and, The ciphertext, aggregation result, and reconstruction coefficients are sent to the user.

[0013] In one possible design of the first aspect, the encryption / decryption method further includes: The key reverse firewall in Z p The sixth parameter is randomly selected from the options. The third secret number is obtained by obfuscating the second secret number using the sixth parameter. Using the sixth parameter and the second secret number, calculate the integrity verification tag; and, Based on the sixth parameter, the integrity verification tag, the third secret number, the fourth randomization parameter, and the collected data portion of the ciphertext, an audit data packet is constructed. During the regulatory audit phase, the audit center recovers the plaintext based on the audit data packet.

[0014] In one possible design of the first aspect, the collected data is carbon emission data.

[0015] Secondly, a ciphertext encryption / decryption system is provided, including: as described above, a key generation center, a key reverse firewall, an audit center, several attribute authority centers, a data collection terminal, a cloud server, and users. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a multi-authority attribute-based encryption method for carbon emission monitoring that supports auditing and resists algorithm substitution attacks, provided in an embodiment of this application. Figure 2 This is a system architecture diagram provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0021] To address the aforementioned issues, this embodiment proposes a multi-authority attribute-based encryption and decryption method for carbon emission monitoring that supports auditing and resists algorithmic substitution attacks. First, this method implements fine-grained access control based on attributes, employing a multi-authority distributed architecture to enhance system scalability and load balancing capabilities. Second, it deploys cryptographic reverse firewalls at key communication nodes, using real-time re-randomization operations to defend against algorithmic substitution attacks and key ciphertext leakage threats. Simultaneously, it introduces an independent audit center to support the recovery of plaintext data through secure processes under regulatory requirements, ensuring compliant and controllable data usage. At the implementation level, the method employs asymmetric bilinear group-optimized cryptographic operations, significantly reducing computational and storage overhead. It also introduces a token generation and verification method based on short signatures using bilinear pairing, achieving strong, unforgeable verification of the data accessor's identity, attributes, and validity period, ensuring data security from the source. This embodiment's method ensures data privacy while also meeting regulatory auditing requirements, providing a secure, verifiable, efficient, and usable complete technical path for carbon emission monitoring in an IoT environment.

[0022] Figure 1 This embodiment illustrates a multi-authority attribute-based encryption and decryption method that supports auditing and resists algorithm substitution attacks. This method addresses several key issues faced by existing carbon emission data collection and sharing processes, such as privacy leaks, abuse of permissions, difficulties in regulatory auditing, and excessive system computational overhead. As a result, it ensures that carbon emission data can be used and analyzed securely, controllably, and compliantly in the industrial Internet of Things (IIoT) environment. Figure 2 The system architecture corresponding to the above method is shown.

[0023] Details are as follows: In step 1, during the system initialization phase, the key generation center generates a master public key and a master private key, and publishes the system parameters. The master public key and master private key are then given to the cryptographic reverse firewall for rerandomization, and the processed master private key is subsequently distributed to the audit center and the attribute authority center.

[0024] The specific implementation process of initialization in step 1 is as follows: Step 1.1: Key Generation Center Select security parameters The generating order is a prime number ternary bilinear group And determine the generator as Meanwhile, the bilinear mapping is defined as Furthermore, choose a secure cryptographic hash function. Among them, Z p It is an integer ring modulo a prime number p, by This finite set of p integers Map strings to group elements hash function, Mapping strings to finite fields hash function, A hash function that maps strings of arbitrary length to a fixed 256-bit output.

[0025] Step 1.2: Randomly select the first parameter And calculate the public key parameters. Private key parameters Finally, the system master public key... and the master private key Send to the corresponding password reverse firewall .

[0026] Step 1.3: Upon receiving and Then, the second parameter is randomly selected. Construct the first level of randomization parameters Then, rerandomized generators are generated. And calculate the rerandomized public key parameters in sequence. and private key parameters Finally, the rerandomized master public key is made public. and rerandomize the master private key Send to the Audit Center and attribute authority center .

[0027] In step 2, during the key generation and distribution phase, the attribute authority center generates attribute keys based on user attributes, and the audit center generates audit keys and user tokens; both types of keys are distributed to users after being rerandomized by their respective cryptographic reverse firewalls.

[0028] The specific implementation process of key generation and distribution in step 2 is as follows: Step 2.1: Received Afterwards, the audit center Randomly select the third parameter And based on the rerandomized master private key Constructing audit keys Specifically, it includes: Calculating the core key component 1: For dimensional indexes Calculate the key components respectively ;for Computation key component Finally, construct core key component 2: and the audit key Send to the corresponding password reverse firewall The First Secret Number Send to the Attribute Authority Center .

[0029] Step 2.2: Received Then, a second set of randomization parameters is randomly selected. Construct the rerandomized core key component 1: For dimensional indexes Calculate the rerandomized key components respectively ;for Calculate the rerandomized key components Constructing the rerandomized core key component 2: Generate the final rerandomized audit key. And send it to the user. Then, a random number will be generated. Send to the audit center.

[0030] Step 2.3: In the system's multi-authority architecture, each attribute has an authority center. Independently manage a disjoint subset of attributes. When Received Then, for the set of user attributes it manages Each attribute in Perform subsequent operations. First, randomly select the fourth parameter. Subsequently, for dimension indexes Calculate the key components respectively and for Computation key component Finally, combine the core key components. and attribute key Send to the corresponding password reverse firewall .

[0031] Step 2.4: Upon receiving Then, for each attribute Randomly select the third randomization parameter Subsequently, for dimension indexes Calculate the rerandomized key components respectively and for Calculate the rerandomized key components Finally, the core key components are re-randomized. And the rerandomized attribute key Send to the user.

[0032] Step 2.5: Audit Center Receive user identity token from user and attribute set Then, a signing private key is randomly selected. And calculate the signature public key Then, the hash value is calculated. ,in This represents the validity period. Finally, a signature is generated. Construct tokens And send it to the corresponding user.

[0033] In step 3, during the data encryption and uploading stage, the sensor collects carbon emission data, defines access policies and encrypts the data, and then uploads the generated ciphertext to the cloud server after being rerandomized by a cryptographic reverse firewall.

[0034] The specific implementation process of data encryption and uploading in step 3 is as follows: Step 3.1: The sensor receives... Then, define the access structure. Where M is a value of size Access strategy matrix, A function that maps matrix rows to the entire set of attributes.

[0035] Step 3.2: The sensor randomly selects the fifth parameter. And calculate the core component 1 of the ciphertext: Then, for each row of the access strategy matrix... and each dimension ciphertext computation component The symbol "a||b" means appending string b directly to the end of a, forming a new, longer string, 1||s|| ||1 converts the number 1 to its string or byte representation, and then sets the attribute. The string represents the concatenation, followed by the dimension. The string representation of the number 1 is then concatenated. Represents the variable from arrive Multiply all integer values ​​by the following expression in sequence. This does not represent the "attribute" itself, but rather the column index of the access strategy matrix M. The components of the same attribute are combined into the ciphertext core component 2: And calculate the ciphertext core component 3: ,in This is the raw data collected by the sensor. Finally, the complete ciphertext is constructed. and the second secret number and ciphertext Send to the corresponding password reverse firewall .

[0036] Step 3.3: Upon receiving the ciphertext The second secret number and Then, the extended Euclidean algorithm is run to obtain the fourth randomization parameters. To satisfy . ( Modulus The last equals 1, which is Divide by The remainder after that is 1, which is in the calculation. In the model Multiplicative inverse under . (This refers to the order of the group as defined earlier) for each row of the access policy matrix. 2. Computation of re-randomized ciphertext core component: Finally, the rerandomized ciphertext Send to cloud server .

[0037] Step 3.4: Randomly select the sixth parameter Calculate the third secret number after confusion. Then construct the components in the audit data package. And calculate integrity verification labels Finally, construct the audit data packet. And sent to the audit center .

[0038] In step 4, during the data access and decryption phase, the user requests data from the cloud server using a token; after the server verifies the data, it preprocesses the data and sends back the encrypted text, which the user then decrypts using the attribute key and the audit key.

[0039] The specific implementation process of data access and decryption in step 4 is as follows: Step 4.1: Cloud Server Receive user identity token and tokens Next, the validity of the token is verified. If the current time is not within the validity period... If the condition is met, a "reject" response is returned. The hash value is then calculated. And verify the bilinear mapping equation. The system checks whether the condition is true or false; if the verification fails, it returns "Reject". The process for verifying the bilinear mapping equation is as follows: Step 4.2: After successful token verification, the cloud server... According to the sensor's access structure and the user attribute set in the token Calculate reconstruction coefficients (in Then, for each dimension... The ciphertext is preprocessed, and the aggregated ciphertext components are calculated. Finally, the rerandomized ciphertext Aggregation results and reconstruction coefficient Send to the corresponding user.

[0040] Step 4.3: The user receives , and Then, use the audit key. and attribute key Execute the decryption process. For each dimension... Calculate the aggregate key components sequentially Then calculate the intermediate value. and median value Finally, the ratio calculation is performed. To recover the plaintext, the specific recovery steps are as follows: Because password reverse firewalls retain functionality, they can still correctly calculate intermediate values ​​using the original data (data before rerandomization). and The process is as follows: right Components in The simplification is based on the property of the monotonic span program (MSP): when the user attribute set... When the access policy is satisfied, its reconstruction coefficient (in ) makes linear combinations This means the column index of the matrix. hour, ; hour, .

[0041] Simplified components Substitute The process is as follows: Simplify The process is as follows: Through ratio calculation The process of restoring plaintext is as follows: In step 5, during the regulatory audit phase, the audit center can initiate a highest-level decryption process to securely restore the original plaintext data in specific scenarios such as compliance review.

[0042] The specific implementation process of regulatory audit in step 5 is as follows: Step 5.1: Audit Center Receive audit data packets and parameters Then, the extended Euclidean algorithm is run first to obtain the parameters. Then restore the intermediate secret value. ; thereby restoring the original secret number Then verify whether the integrity label meets the requirements. If the verification passes, the plaintext will be restored. .

[0043] The derivation process for recovering the original secret number is as follows: Restore Audit Center The derivation process for recovering the plaintext is as follows: One of the innovations of this embodiment is: In steps 1.3, 2.2, 2.4, and 3.3, cryptographic reverse firewalls are deployed at the key generation center, audit center, attribute authority center, and sensors to perform real-time rerandomization of the output public key, master key, audit key, attribute key, and ciphertext. This multi-level collaborative architecture effectively curbs systemic risks caused by single-point leaks and fundamentally defends against algorithm replacement attacks.

[0044] Innovation Two: Step 2 uses a token generation and verification mechanism based on bilinear pairing short signatures, namely steps 2.5 and 4.1, which bind and sign the user's identity, attribute set, and validity period to generate a token. The cloud server verifies the validity of the token through bilinear pairing operations, thereby achieving strong and unforgeable authentication of the data accessor's identity and permissions, ensuring the security and controllability of data access from the source.

[0045] Third innovation: Steps 3 and 5 incorporate a highest-level decryption mechanism to support regulatory auditing, namely steps 3.4 and 5.1. At the encryption end, the firewall constructs a dedicated audit data packet. This data packet linearly obfuscates and encapsulates the secret value required for decryption before sending it to the audit center. The audit center uses its unique private parameters to reverse-engineer the original secret value, thereby independently decrypting any ciphertext, ensuring the exclusivity and compliance of the highest-level decryption operation.

[0046] Fourth innovation: The proposed scheme is built on an asymmetric bilinear group, which has shorter group elements and higher computational efficiency. This significantly optimizes the computation and storage overhead of key operations such as steps 1.2, 2.1, and 2.3, making it more suitable for resource-constrained industrial IoT environments.

[0047] Innovation Five: Step 3 employs a ciphertext policy attribute-based encryption method based on monotonic span procedures, namely steps 3.1 and 3.2. This method defines complex access control policies using a monotonic span procedure matrix, maps attributes to rows of the matrix, and generates ciphertext components directly based on the row structure of the matrix during the encryption process. This achieves fine-grained access control that is more flexible and expressive than the traditional access tree structure.

[0048] This application also provides an electronic device, including: a processor, and a memory coupled to the processor, the memory being used to store a computer program; the processor being used to execute the computer program stored in the memory, so that the electronic device performs the method as described in any of the above embodiments.

[0049] Electronic devices can be computing devices such as desktop computers, laptops, handheld computers, and cloud servers. These electronic devices may include, but are not limited to, processors and memory.

[0050] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the electronic device, connecting various parts of the device via various interfaces and lines.

[0051] The memory can be used to store the computer program, and the processor implements various functions of the electronic device by running or executing the computer program stored in the memory and calling the data stored in the memory.

[0052] The memory may primarily include a program storage area and a data storage area. The program storage area may store the operating system, applications required for at least one function, etc.; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0053] This application also provides a storage medium, which is a computer-readable storage medium. The computer program is stored in the computer-readable storage medium, and when executed by a processor, the computer program can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0054] This application also provides a computer program product, including: a computer program or instructions that, when the computer program or instructions are run on a computer, cause the computer to perform any of the above possible implementation methods.

[0055] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A method for encrypting and decrypting ciphertext, characterized in that, The encrypted encryption / decryption method is based on an encryption / decryption system, which includes: a key generation center, a key reverse firewall, an audit center, several attribute authority centers, a data collection terminal, a cloud server, and users. Each attribute authority center independently manages a non-overlapping subset of user attributes. The encryption part includes: The key generation center generates the master public key and the master private key; The key reverse firewall rerandomizes the master public key and the master private key, and publishes the rerandomized master public key; The audit center uses the rerandomized master private key to construct an audit key; The attribute authority center constructs an attribute key using the rerandomized master private key and the user attributes; The key reverse firewall rerandomizes the audit key and the attribute key; The audit center constructs a user token based on the user's identity identifier and the user's attributes; The data acquisition terminal constructs ciphertext based on the collected data, the user attributes, and the rerandomized master public key; The key reverse firewall rerandomizes the ciphertext; and The cloud server stores the rerandomized ciphertext. The decryption process includes: The cloud server verifies the user token. After successful verification, the user uses the audit key and the attribute key to decrypt the ciphertext obtained from the cloud server.

2. The ciphertext encryption / decryption method as described in claim 1, characterized in that, The key generation center generates the master public key and master private key, specifically including: The key generation center determines the generator in a ternary bilinear group, wherein the generator order of the ternary bilinear group is a prime number p. In Z p The first parameter, Z, is randomly selected. p Let P be an integer ring modulo a prime number P; and, Using the generator and the first parameter, the master public key and the master private key are calculated.

3. The ciphertext encryption / decryption method as described in claim 2, characterized in that, The key reverse firewall rerandomizes the master public key and the master private key, specifically including: The key reverse firewall in Z p The second parameter is randomly selected from the options. Construct a first randomization parameter using the first parameter and the second parameter, and rerandomize the generator; and, Using the first randomization parameter and the generator after rerandomization, the master public key and the master private key after rerandomization are calculated.

4. The ciphertext encryption / decryption method as described in claim 3, characterized in that, The audit center constructs an audit key using the re-randomized master private key, specifically including: The audit center is in Z p A third parameter is randomly selected, the third parameter including a first secret number; and, The audit key is calculated using the third parameter and the re-randomized master private key. The key reverse firewall rerandomizes the audit key, specifically including: The key reverse firewall in Z p The second randomization parameter is randomly selected; and, The audit key after re-randomization is calculated using the second randomization parameter and the audit key.

5. The ciphertext encryption / decryption method as described in claim 4, characterized in that, The attribute authority center constructs an attribute key using the re-randomized master private key and the user attributes, specifically including: The attribute authority center is in Z. p The fourth parameter is randomly selected from the data, and the first secret number is obtained; and, The attribute key is calculated using the fourth parameter, the first secret number, the re-randomized master private key, and the user attributes. The key reverse firewall rerandomizes the attribute key, specifically including: The key reverse firewall in Z p The third randomization parameter is randomly selected; and, The attribute key after re-randomization is calculated using the third randomization parameter and the attribute key.

6. The ciphertext encryption / decryption method as described in claim 5, characterized in that, The data acquisition terminal constructs ciphertext based on the collected data, the user attributes, and the re-randomized master public key, specifically including: The data acquisition terminal defines an access structure (M, v), where M is the access strategy matrix and v is a function that maps rows of the access strategy matrix to the entire set of attributes. In Z p A fifth parameter is randomly selected, the fifth parameter including a second secret number; and, The ciphertext is constructed using the fifth parameter, the collected data, the user attributes, and the re-randomized master public key. The key-based reverse firewall rerandomizes the ciphertext, specifically including: The key reverse firewall obtains a fourth randomization parameter, which satisfies a predetermined relationship with the second randomization parameter; and, The ciphertext is rerandomized using the fourth randomization parameter.

7. The ciphertext encryption / decryption method as described in claim 6, characterized in that, The decryption section also includes: The cloud server calculates the reconstruction coefficient based on the access structure and the user attributes; Based on the reconstruction coefficients and the ciphertext aggregated ciphertext components, the aggregation result is obtained; and, The ciphertext, aggregation result, and reconstruction coefficients are sent to the user.

8. The ciphertext encryption / decryption method as described in claim 6, characterized in that, The encryption / decryption method also includes: The key reverse firewall in Z p The sixth parameter is randomly selected from the options. The third secret number is obtained by obfuscating the second secret number using the sixth parameter. Using the sixth parameter and the second secret number, calculate the integrity verification tag; and, Based on the sixth parameter, the integrity verification tag, the third secret number, the fourth randomization parameter, and the collected data portion of the ciphertext, an audit data packet is constructed. During the regulatory audit phase, the audit center recovers the plaintext based on the audit data packet.

9. The ciphertext encryption / decryption method according to any one of claims 1-8, characterized in that, The collected data is carbon emission data.

10. A ciphertext encryption / decryption system, characterized in that, include: The key generation center, key reverse firewall, audit center, several attribute authority centers, data collection terminal, cloud server and user as described in any one of claims 1-9.

Images