Purifyable access control payment scheme against malicious data publishers

Abstract

The present application provides a purifiable access control payment scheme which can resist malicious data publishers, and safely and efficiently resists malicious data publishers through a purification algorithm. Through the purification operator to perform decryption outsourcing operation, relying on the strong computing power of the purification operator to complete most of the heavy pairing operations, it is beneficial for the legal users to only need to perform a small amount of operation, so as to realize fast and complete decryption, thereby improving the overall decryption efficiency of the system, and is very suitable for application scenarios with limited computing resources. The present application aims to complete an efficient and safe outsourcing purifiable access control payment scheme which can resist malicious data publishers in a secure cloud storage environment, and plays a positive promoting role in the controllability and practicability of the online payment service system.

Description

Technical Field

[0001] This invention relates to the fields of information security technology and cloud storage technology, and in particular to a clean access control payment scheme that can resist malicious data publishers. Background Technology

[0002] With the rapid development of internet technology, online paid services have emerged. Due to the large amount of data in these payment systems, migrating this data to cloud servers for storage is essential. This avoids cumbersome local data management and provides more convenient services. Providing a secure and fair cloud storage trading environment has become a current research hotspot. Most online paid services employ encryption technology to ensure security; that is, the data publisher encrypts copyrighted content. Only after a legitimate payment process is completed will an authoritative institution issue the correct key to the user. The user can then use this key to decrypt and obtain the copyrighted content. This method not only effectively protects legitimate copyrights but also provides service guarantees for users.

[0003] Attribute-based encryption (ABE) aims to associate ciphertext, keys, and sets of attributes with an access structure. A user can successfully decrypt the data if and only if the set of attributes satisfies the access structure. Attribute-based encryption can be divided into two categories: Key Policy-ABE (KP-ABE) and Ciphertext Policy-ABE (CP-ABE). CP-ABE embeds the access policy into the ciphertext, meaning that data publishers can set policies to determine which attributes allow access to the ciphertext. In online paid service transactions, using CP-ABE to encrypt the data publisher's key enables fine-grained access control and improves data security. However, the decryption process involves computationally expensive pairing operations. Users with limited computing resources need to frequently decrypt large amounts of data, causing a surge in time-consuming pairing operations, which becomes a significant bottleneck restricting system efficiency. Decryption outsourcing is one way to solve the above problems. By outsourcing the CP-ABE decryption operation to a cloud service center with powerful computing capabilities, the computational pressure on users can be effectively alleviated and the decryption efficiency can be improved while making full use of the powerful computing power of external devices.

[0004] Typical online payment systems assume data publishers are honest and trustworthy. However, this approach lacks universality. If a data publisher is malicious, it can cause incalculable damage to the entire system. The ciphertext constructed by a malicious data publisher can easily be decrypted by unauthorized users without a valid key. Simply put, a malicious data publisher can leak their key, allowing anyone without authorization to decrypt the data. Therefore, effectively defending against malicious data publishers in a system is a very real and urgent problem, and has significant research value. Summary of the Invention

[0005] Based on existing technology research and secure cloud storage, this invention designs an efficient and secure outsourced sanitized access control payment scheme that is resistant to malicious data publishers. The technical problem this invention aims to solve is: to resist malicious data publishers in a secure cloud storage environment, thereby achieving secure and efficient outsourced sanitized access control payment.

[0006] In online payment systems, malicious data publishers can cause incalculable damage to the entire system. The ciphertext constructed by malicious publishers can easily be decrypted by unauthorized users without valid keys. Simply put, malicious publishers can leak keys, allowing anyone without authorization to decrypt the data. This solution uses a purification algorithm to securely and efficiently resist malicious data publishers. Furthermore, this solution outsources decryption operations to a purifier, leveraging its powerful computing capabilities to handle most of the heavy-duty pairing calculations. This allows legitimate users to perform only a small amount of computation, enabling rapid and complete decryption, thus improving the overall decryption efficiency of the system. This is particularly suitable for applications with limited computing resources. This application aims to develop an efficient and secure outsourced, purifier-enabled access control payment solution that resists malicious data publishers in a secure cloud storage environment, positively promoting the controllability and practicality of online payment systems.

[0007] The specific technical solution adopted is as follows:

[0008] A sanitized access control payment scheme that can resist malicious data publishers provides a secure, fine-grained access control payment solution in the event of malicious data publishers. The sanitization algorithm consists of three parts: First, the sanitizer checks the received encrypted ciphertext to ensure it was generated from a specified access structure. Second, the sanitizer performs a decryption outsourcing operation, using an outsourced conversion key to partially decrypt the encrypted ciphertext, completing the pairing operation using the sanitizer's computing power without requiring data to be sent as input. Finally, the sanitizer uses a sanitization key to purify the encrypted ciphertext and encapsulates the sanitization key using the ElGamal public-key encryption algorithm to resist malicious data publishers.

[0009] Furthermore, the specific steps include:

[0010] Step S101: The authoritative center, knowing the security parameter κ and the size U of the attribute set, runs the system initialization function to generate the system public parameter Params and the master private key MSK, sends the system public parameter to all participants, and secretly saves the master private key.

[0011] Step S102: The authority center uses the attribute set S and the master private key MSK to generate an outsourced conversion key TK and an outsourced decryption key DK. The outsourced conversion key is sent to the purifier, and the outsourced decryption key is sent to the user whose attributes satisfy the access structure.

[0012] Step S103: Based on the payment voucher submitted by the user, the authority center generates a public-private key pair (pk, sk) for each legitimate user who has paid. The public key pk assigned to the paid user is sent to the purifier, while the private key sk is secretly kept by the user who has completed the payment.

[0013] Step S104: The data publisher selects an encryption key K and encrypts the original data according to the access structure, and sends the generated ciphertext CT to the purifier.

[0014] Step S105: The purifier selects the purification key K', uses the conversion key and the public key allocated to the paid user, calls the purification algorithm to convert the encrypted ciphertext CT into the purified ciphertext CT', and sends it to the cloud service provider for storage.

[0015] Step S106: Users whose attributes meet the access structure and who have completed the legitimate payment process download the purified ciphertext from the cloud service provider, decrypt it using an outsourced decryption key and a secret private key, and recover the original data.

[0016] Further, step S101 specifically includes:

[0017] The authoritative center knows the security parameter κ and the size U of the attribute set; using the security parameter κ, it constructs an additive cyclic group G1 of prime order p and generator q, as well as a bilinear group D = (e, G, G) T (g,p); Select random numbers h1,...,h U ∈G and α, a∈G1; select a pseudo-random generator, the pseudo-random generator having the form PRG(K)=H(K,1)||H(K,2)||...||H(K,n), where H is a hash function; construct the system public parameters Params=(g,q,h1,h2,...,h) according to the size of the attribute set. U ,g a ,e(g,g) α (,PRG), and generate the master private key MSK=gα Keep it secret;

[0018] Where g is a generator of group G; q is a generator of group G1; h1,...h U It is a random value belonging to group G; e is a value from G×G to G. T The bilinear mapping; a and α are random values ​​belonging to group G1; PRG is a pseudo-random generator.

[0019] Furthermore, step S102 specifically includes:

[0020] The authoritative center randomly selects α',t∈G1, and uses the attribute set S and the master private key MSK to generate the outsourced conversion key. Send it to the Sanitizer; in addition, send the outsourced decryption key DK=α' to the user whose attributes satisfy the access structure.

[0021] Where α' and t are random values ​​belonging to group G1.

[0022] Furthermore, in step S103:

[0023] The authoritative center randomly selects d∈[1,p-1] and generates a public-private key pair (pk,sk) for legitimate users who have completed the payment process, based on the payment credentials submitted by the user; the authoritative center sets the public key pk=q d Send to the purifier, where q is the generator of group G1, and the private key sk=d is secretly kept by the paid user;

[0024] Here, [1, p-1] represents the set of integers that are not less than 1 and not greater than p-1.

[0025] Furthermore, in step S104:

[0026] The data publisher transforms access structure A into access structure (M, ρ) of a linear secret-sharing scheme, where M is an l×n matrix and ρ is a function that associates each row of matrix M with an attribute; the data publisher sets a vector Where s is the shared secret value, y2, y3, ... y n It is a random value belonging to G1, and for each i∈[1,l] it has Randomly select encryption key K∈G T Random values ​​r1, r2, ..., r l ∈G1, generate encrypted ciphertext CT:

[0027]

[0028]

[0029] Where m represents the original data.

[0030] Furthermore, in step S105:

[0031] First, the Purifier settings Select ω i ∈G1 such that ∑ i∈I ω i λ i =s; randomly select γ, Calculate the inspection key sk' S , The purifier examines the received encrypted ciphertext CT to determine whether the encrypted ciphertext was generated by the specified access structure;

[0032]

[0033]

[0034] in, It is a random value belonging to group G1;

[0035] By calculating and judging the equation e(C”,g γ )=e(g,g) γs Check if the equation is true; if it is true, it means that the encrypted ciphertext was generated by the specified access structure; if the equation is false, then the opposite is true, and the ciphertext that does not meet the requirements is discarded.

[0036] Then, the purifier uses the outsourced conversion key TK to partially decrypt the encrypted ciphertext, obtaining the partially decrypted ciphertext CT. OUT ;

[0037]

[0038] Finally, the purifier randomly selects a purification key K'∈G1 and a random number b∈[1,p-1] to purify the encrypted ciphertext and generate the purified ciphertext CT'.

[0039] CT'=(V0,V1,CT out ),

[0040]

[0041] Furthermore, in step S106:

[0042] Legitimate users compute e(g,g) using an outsourced decryption key. αs ;

[0043] (CT out ) DK =e(g,g) αs

[0044] Then, the user can calculate the encryption key of the data publisher and the purification key of the purifier;

[0045] K = C' / e(g,g) αs ,K'=K'q bd / (q b ) d

[0046] Finally, the original data was recovered from the purified ciphertext;

[0047]

[0048] Compared to existing technologies, the advantages of this invention and its preferred solutions are as follows: A fine-grained access control payment scheme is implemented in a secure cloud storage environment, addressing security threats posed by malicious data publishers through a secure and efficient purification algorithm. The purification algorithm consists of three main parts: First, the purifier checks the received encrypted ciphertext to ensure it was generated from the specified access structure; second, the purifier performs decryption outsourcing operations, using the outsourced conversion key to partially decrypt the encrypted ciphertext. Without requiring data as input, the purifier's powerful computing capabilities complete most of the heavyweight pairing operations, allowing legitimate users, knowing the outsourced decryption key, to decrypt the outsourced results with minimal computation, achieving rapid and complete decryption and improving the overall system decryption efficiency; finally, the purifier uses the purification key to purify the encrypted ciphertext and encapsulates the purification key using the ElGamal public-key encryption algorithm, efficiently and securely resisting malicious data publishers. Attached Figure Description

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0050] Figure 1 A flowchart illustrating a clean access control payment scheme that can resist malicious data publishers, provided as an embodiment of the present invention.

[0051] Figure 2 This is a schematic diagram of a clean access control payment process that can resist malicious data publishers, provided as an embodiment of the present invention. Detailed Implementation

[0052] To make the features and advantages of this patent more apparent and understandable, specific embodiments are provided below, along with accompanying drawings, for detailed explanation:

[0053] The most crucial concept of this invention lies in achieving a secure, fine-grained access control payment scheme through a highly efficient purification algorithm, even when the data publisher is malicious. The purification algorithm consists of three main parts: First, the purifier checks the received encrypted ciphertext to ensure it was generated from a specified access structure. Second, the purifier performs decryption outsourcing operations, using the outsourced conversion key to partially decrypt the encrypted ciphertext. Without requiring the sent data as input, the purifier's powerful computing capabilities complete most of the heavyweight pairing operations, allowing legitimate users, knowing the outsourced decryption key, to decrypt the outsourced results with minimal computation, achieving rapid and complete decryption and improving the overall system decryption efficiency. Finally, the purifier uses the purification key to purify the encrypted ciphertext and encapsulates the purification key using the ElGamal public-key encryption algorithm, efficiently and securely resisting malicious data publishers.

[0054] Symbols and definitions

[0055] G: An additive cyclic group of order p.

[0056] G1: An additive cyclic group of order p.

[0057] G T : A multiplicative cyclic group of order p.

[0058] g: a generator of group G.

[0059] q: generator of group G1.

[0060] e: From G×G to G T A bilinear mapping.

[0061] D: Bilinear group (e, G, G) T ,g,p).

[0062] [1, p-1]: The set of integers that are not less than 1 and not greater than p-1.

[0063] [1,l]: The set of integers that are not less than 1 and not greater than l.

[0064] κ; safety parameter.

[0065] PRG: Pseudo-random generator.

[0066] H: Hash function.

[0067] U: Size of the attribute set.

[0068] Params: System-exposed parameters.

[0069] MSK; System encryption master private key.

[0070] h1,...hU ; a random value belonging to group G.

[0071] α: A random value belonging to group G1.

[0072] a: A random value belonging to group G1.

[0073] α': A random value belonging to group G1.

[0074] t: A random value belonging to group G1.

[0075] γ: A random value belonging to group G1.

[0076] Random values ​​belonging to group G1.

[0077] S: Attribute set.

[0078] TK; Outsourced conversion key.

[0079] DK; Outsourced decryption key.

[0080] d; a random integer, where d∈[1,p-1].

[0081] b: A random integer, where k∈[1,p-1].

[0082] pk: The public key assigned to users who have already paid.

[0083] sk: The private key assigned to users who have already paid.

[0084] A; Access structure.

[0085] M: Access control matrix.

[0086] ρ: A function that maps each row of matrix M to an attribute.

[0087] s: The secret value shared.

[0088] y2, y3, ... y n : Random values ​​belonging to group G1.

[0089] A random vector composed of random values.

[0090] M i The i-th row of M.

[0091] λ i : Elements belonging to group G1.

[0092] ω i :∑ i∈I ω i λ i=s, an element belonging to group G1.

[0093] K: The encryption key chosen by the data publisher.

[0094] sk' S : The inspection key generated by the Purifier.

[0095] K': The purification key chosen by the purifier.

[0096] m: Raw data.

[0097] CT: Encrypted ciphertext generated by the data publisher.

[0098] CT OUT : Semi-decrypted ciphertext.

[0099] CT': Purification cipher generated by the Purifier.

[0100] Please refer to Figure 1 This embodiment provides a cleansing access control payment solution that can resist malicious data publishers, including the following steps:

[0101] S101. The authoritative center, knowing the security parameter κ and the size of the attribute set U, runs the system initialization function to generate the system public parameter Params and the master private key MSK, sends the system public parameter to all participants, and secretly saves the master private key.

[0102] S102. The Authority Center uses the attribute set S and the master private key MSK to generate the outsourcing conversion key TK and the outsourcing decryption key DK. It sends the outsourcing conversion key to the Sanitizer and the outsourcing decryption key to the user whose attributes satisfy the access structure.

[0103] S103. Based on the payment vouchers submitted by users, the Authority Center generates a public-private key pair (pk, sk) for each legitimate user who has paid. The public key pk of the paid user is sent to the Purifier, while the private key sk is secretly kept by the user who has completed the payment.

[0104] S104. The data publisher selects an encryption key K and encrypts the original data according to the access structure, and sends the generated ciphertext CT to the purifier.

[0105] S105. The purifier selects the purification key K', uses the conversion key and the public key allocated to the paid user, calls the purification algorithm to convert the encrypted ciphertext CT into the purified ciphertext CT', and sends it to the cloud service provider for storage.

[0106] S106. Users whose attributes meet the access structure and who have completed the legitimate payment process download the purified ciphertext from the cloud service provider, decrypt it using an outsourced decryption key and a secret private key, and recover the original data.

[0107] Furthermore, the detailed process of the above steps is as follows:

[0108] In step S101, the authoritative center, knowing the security parameter κ and the size U of the attribute set, runs the system initialization function to generate the system public parameters Params and the master private key MSK. The system public parameters are sent to all participants, and the master private key is secretly stored. Specifically, this includes:

[0109] The authoritative center knows the security parameter κ and the size U of the attribute set. Using the security parameter κ, construct an additive cyclic group G1 of order p with generator q, and a bilinear group D = (e, G, G) T (g,p). Select random numbers h1,...,h U ∈G and α, a∈G1. Select a pseudo-random generator of the form PRG(K)=H(K,1)||H(K,2)||...||H(K,n), where H is a hash function. Construct the system public parameters Params=(g,q,h1,h2,...,h) based on the size of the attribute set. U ,g a ,e(g,g) α (,PRG), and generate the master private key MSK=g α Keep it secret.

[0110] In step S102, the authority center uses the attribute set S and the master private key MSK to generate an outsourcing transformation key TK and an outsourcing decryption key DK. The outsourcing transformation key is sent to the Sanitizer, and the outsourcing decryption key is sent to users whose attributes satisfy the access structure. Specifically, this includes:

[0111] The authoritative center randomly selects α',t∈G1, and uses the attribute set S and the master private key MSK to generate the outsourced conversion key. Send it to the Sanitizer, and also send the outsourced decryption key DK=α' to the user whose attributes satisfy the access structure.

[0112] In step S103, the authoritative center generates a public-private key pair (pk, sk) for each legitimate user who has paid, based on the payment voucher submitted by the user. The public key pk of the paid user is sent to the purifier, while the private key sk is secretly stored by the user who has completed payment. Specifically, this includes:

[0113] The authoritative center randomly selects d∈[1,p-1] and generates a public-private key pair (pk,sk) for legitimate users who have completed the payment process, based on the payment credentials submitted by the user. The authoritative center then sets the public key pk = q. d Send to the purifier, where q is the generator of group G1, and the private key sk=d is secretly kept by the paid user.

[0114] In step S104, the data publisher selects an encryption key K and encrypts the original data according to the access structure, then sends the generated ciphertext CT to the purifier, specifically including:

[0115] The data publisher transforms access structure A into access structure (M, ρ) for a linear secret-sharing scheme, where M is an l×n matrix and ρ is a function that associates each row of matrix M with an attribute. The data publisher sets a vector... Where s is the shared secret value, y2, y3, ... y n It is a random value belonging to G1, and for each i∈[1,l] it has Randomly select encryption key K∈G T Random values ​​r1, r2, ..., r l ∈G1, generate encrypted ciphertext CT:

[0116]

[0117]

[0118] In step S105, the purifier selects the purification key K', uses the conversion key and the public key allocated to the paid user, calls the purification algorithm to convert the encrypted ciphertext CT into purified ciphertext CT', and sends it to the cloud service provider for storage. Specifically, this includes:

[0119] First, the Purifier settings Select ω i ∈G1 such that ∑ i∈I ω i λ i =s. Randomly select γ, Calculate the inspection key sk' S , The purifier examines the received encrypted ciphertext CT to determine whether the encrypted ciphertext was generated by the specified access structure.

[0120]

[0121]

[0122] By calculating and judging the equation e(C”,g γ )=e(g,g) γs Check if the equation is true. If the equation is true, it means that the encrypted ciphertext was generated by the specified access structure; if the equation is false, the opposite is true, and the invalid encrypted ciphertext is discarded.

[0123] Then, the purifier uses the outsourced conversion key TK to partially decrypt the encrypted ciphertext, obtaining the partially decrypted ciphertext CT. OUT .

[0124]

[0125] Finally, the purifier randomly selects a purification key K'∈G1 and a random number b∈[1,p-1] to purify the encrypted ciphertext and generate the purified ciphertext CT'.

[0126] CT'=(V0,V1,CT out ),

[0127]

[0128] In step S106, users whose attributes meet the access structure and who have completed the legitimate payment process download the purified ciphertext from the cloud service provider, decrypt it using an outsourced decryption key and a secret private key, and recover the original data. Specifically, this includes:

[0129] Legitimate users compute e(g,g) using an outsourced decryption key. αs .

[0130] (CT out ) DK =e(g,g) αs .

[0131] Then, the user can calculate the encryption key of the data publisher and the purification key of the purifier.

[0132] K = C' / e(g,g) αs ,K'=K'q bd / (q b ) d .

[0133] Finally, the original data was recovered from the purified ciphertext.

[0134]

[0135] Please refer to Figure 2 Based on the above design, a decryption process diagram of a clean access control payment scheme that can resist malicious data publishers is obtained. Figure 2 As can be seen, the decryption process consists of 17 steps, specifically: First, it is necessary to obtain the system security parameter κ and the size U of the attribute set, then proceed to step 1, generating random numbers h1,...,h. U ∈G and α, a∈G1; Perform step 2 to construct the system public parameters Params=(g,q,h1,h2,...,h U ,g a ,e(g,g) α PRG), and the master private key MSK=g α; Perform step 3 to generate random numbers α',t∈G1; Perform step 4 to calculate the outsourced conversion key. Outsource decryption key DK = α'; execute step 5 to generate random number d ∈ [1, p-1]; execute step 6 to calculate pk = q. d sk = d; execute step 7 to generate random numbers s, y2, y3, ... y n ∈G1, r1,r2,...,r l ∈G1, K∈G T Set vector Perform step 8 to calculate. C'=K·e(g,g) αs C” = g s , implement

[0136] Step 9, generate random number γ. ω i ∈G1 such that ∑ i∈I ω i λ i =s; After the first 9 steps are completed, the 10th step is executed to calculate. Begin executing step 11, calculation

[0137] Perform step 12 and evaluate the equation e(C”,g γ )=e(g,g) γs If the equation is not true, discard any ciphertext that does not conform to the equation; proceed to step 13 to calculate.

[0138] Execute step 14 to generate random numbers b∈[1,p-1], K'∈G1; Execute step 15 to calculate the cleaned ciphertext CT'=(V0,V1,CT out ), CT OUT =e(g,g) (α / α ' )s ; Perform step 16 to calculate (CT) out ) DK =e(g,g) αs K = C' / e(g,g) αs ,K'=K'q bd / (q b ) d ; Perform step 17 to recover the original data. As described above, this invention, based on a secure cloud storage environment, achieves a secure, fine-grained access control payment scheme through a highly efficient purification algorithm, even when the data publisher is malicious. The purification algorithm consists of three main parts: First, the purifier checks the received encrypted ciphertext to ensure it was generated from the specified access structure. Second, the purifier performs decryption outsourcing operations, using the outsourced conversion key to partially decrypt the encrypted ciphertext. Without requiring data as input, the purifier's powerful computing capabilities complete most of the heavyweight pairing operations, allowing legitimate users, knowing the outsourced decryption key, to decrypt the outsourced results with minimal computation, achieving rapid and complete decryption and improving the overall system decryption efficiency. Finally, the purifier uses the purification key to purify the encrypted ciphertext and encapsulates the purification key using the ElGamal public-key encryption algorithm, efficiently and securely resisting malicious data publishers. This design further broadens the application prospects of online payment services.

[0139] This patent is not limited to the above-described preferred embodiments. Anyone can derive other forms of clean access control payment solutions that can resist malicious data publishers based on the inspiration of this patent. All equivalent changes and modifications made within the scope of the patent application of this invention shall fall within the scope of this patent.

Claims

1. A cleanable access control payment scheme that can resist malicious data publishers, characterized in that: In cases where the data publisher is malicious, a sanitization algorithm is used to achieve a secure, fine-grained access control payment scheme. The sanitization algorithm consists of three parts: First, the sanitizer checks the received encrypted ciphertext to ensure it was generated from the specified access structure. Second, the sanitizer performs decryption outsourcing operations, using the outsourced conversion key to partially decrypt the encrypted ciphertext, completing the pairing operation using the sanitizer's computing power without requiring the data to be sent as input. Finally, the sanitizer uses the sanitization key to purify the encrypted ciphertext and encapsulates the sanitization key using the ElGamal public-key encryption algorithm to defend against malicious data publishers. Specifically, the following steps are included: Step S101, Authoritative Center Knows Safety Parameters and the size of the attribute set Run the system initialization function to generate public system parameters. and the master private key The system publicly sends the parameters to all participants and secretly stores the master private key; Step S102: The authority center utilizes attribute sets. and the master private key Generate outsourced conversion key and outsourced decryption keys The outsourcing conversion key is sent to the purifier, and the outsourcing decryption key is sent to the user whose attributes satisfy the access structure. Step S103: Based on the payment credentials submitted by the user, the authoritative center generates a public-private key pair for each legitimate user who has made payment. The public key will be assigned to users who have already paid. Send to the purifier, private key It will then be secretly stored by the user who has already completed the payment; Step S104: The data publisher selects an encryption key. The original data is encrypted according to the access structure, and the generated ciphertext is then processed. Send to the Purifier; Step S105: The purifier selects the purification key. Using the conversion key and the public key allocated to paid users, a purification algorithm is invoked to encrypt the ciphertext. Convert to purified ciphertext Send it to the cloud service provider for storage; Step S106: Users whose attributes meet the access structure and who have completed the legitimate payment process download the purified ciphertext from the cloud service provider, decrypt it using an outsourced decryption key and a secret private key, and recover the original data.

2. The cleanable access control payment scheme that can resist malicious data publishers according to claim 1, characterized in that: Step S101 is as follows: Authoritative center known security parameters and the size of the attribute set ; Utilizing safety parameters Construct order is a prime number Generator is addition cyclic group and bilinear group ; Select random number and ; Choose a pseudo-random generator, the pseudo-random generator having the following form: ,in Use a hash function; construct the system's public parameters based on the size of the attribute set. and the generated master private key Keep it secret; in, For the group Generators; For the group Generators; It belongs to the group Random values; From arrive a bilinear mapping; and Belonging to a group Random values; It is a pseudo-random generator.

3. The cleanable access control payment scheme that can resist malicious data publishers according to claim 2, characterized in that: Step S102 is as follows: Authoritative center randomly selected Using attribute sets and the master private key The generated outsourced conversion key Send to the Purifier In addition, outsource the decryption key. Send to users whose attributes match the access structure; in, , Belonging to a group The random value.

4. The cleanable access control payment scheme that can resist malicious data publishers according to claim 3, characterized in that: In step S103: Authoritative center randomly selected Based on the payment credentials submitted by the user, a public-private key pair is generated for legitimate users who have completed the payment process. The authoritative center will hold the public key. Send to the purifiers, among which For the group Generator, private key It is kept confidential by users who have already paid. in, It means not less than 1 and not greater than 1. The set of integers.

5. The cleanable access control payment scheme that can resist malicious data publishers according to claim 4, characterized in that: In step S104: Data publishers will access the structure Access structure transformed into a linear secret sharing scheme ,in It is The matrix, It is a matrix Each row is associated with a function for the attribute; the data publisher sets a vector. ,in It is a shared secret value. It belongs to The random value for each All Randomly select encryption key Random value Generate encrypted ciphertext : in, This is the original data.

6. The sanitizable access control payment scheme that can resist malicious data publishers according to claim 5, characterized in that: In step S105: First, the Purifier settings Select Make Random selection Calculate the inspection key , ; The purifier receives encrypted ciphertext Perform an inspection to determine whether the encrypted ciphertext was generated from the specified access structure; in, Belonging to a group Random values; Determine the equation by calculation. Check if the equation is true; if it is true, it means that the encrypted ciphertext was generated by the specified access structure; if the equation is false, then the opposite is true, and the ciphertext that does not meet the requirements is discarded. Then, the Purifiers used outsourced conversion keys. By partially decrypting the encrypted ciphertext, we obtain the partially decrypted ciphertext. ; Finally, the purifier randomly selects a purification key. random numbers The encrypted ciphertext is cleaned to generate cleaned ciphertext. ; 。 7. The sanitizable access control payment scheme that can resist malicious data publishers according to claim 6, characterized in that: In step S106: Legitimate users calculate decryption keys through outsourcing ; Then, the user can calculate the data publisher's encryption key and the purifier's purification key; Finally, the original data was recovered from the purified ciphertext; 。

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