Low-altitude big data access control method and system based on comparable attributes in low-altitude trusted data space

Abstract

The invention discloses a low-altitude big data access control method and system based on comparable attributes in a low-altitude trusted data space. The method comprises the steps that a data user DU sends an access request for target data to the low-altitude trusted data space LADS; the access request comprises an attribute set and a label set of the DU; the low-altitude trusted data space LADS judges whether the attribute set of the DU is matched with the target data access strategy or not; if yes, the ciphertext of the target data is returned to the DU; the DU checks whether a puncture label set contained in the ciphertext of the target data is matched with the target decryption key or not; and if the target decryption key is not matched with the target decryption key and the target time trap door in the ciphertext of the target data is determined to be released, decrypting the ciphertext of the target data based on the target decryption key to obtain the target data. According to the method, flexible and efficient user revocation is realized to ensure forward security, flexible decision can be made for access behaviors of data users according to access time and attribute comparison, and correctness verification of a decryption process is supported.

Description

Technical Field

[0001] This invention belongs to the field of low-altitude data security technology, and in particular relates to a method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space. Background Technology

[0002] With the advent of a new wave of digital transformation, technologies such as 5G, cloud computing, artificial intelligence, and the Internet of Things are being widely applied, driving profound changes in the drone industry and the vigorous development of the low-altitude economy. Data, as a key production factor in the low-altitude economy era, is increasingly valuable and has become an important driving force for global economic growth and value creation. The explosive growth of data and the demand for its circulation and utilization have brought new challenges to low-altitude big data management, access control, and data mining and analysis. Data space, as a new data organization and management model, focuses on the mining, analysis, and secondary utilization of data value by protecting data sovereignty, ensuring data security, and promoting cross-domain data circulation, thereby promoting unified standards and interoperability of data within industry sectors. In the low-altitude domain, a trusted low-altitude data space provides an effective solution for the orderly release of the value of low-altitude data elements and has become an important infrastructure in the low-altitude economy era.

[0003] In the low-altitude trusted data space, the process of data owners sharing data with data users is often accompanied by the risk of low-altitude big data being stolen, tampered with, and misused, leading to the loss of data sovereignty. Data access control, by uniformly managing the digital identities and data access policies of all participating entities, can achieve precise delivery and access management during the sharing of low-altitude big data, and has become one of the key technologies for realizing the circulation and trusted sharing of low-altitude big data in the low-altitude trusted data space.

[0004] Currently, low-altitude trusted data spaces extensively employ ciphertext-policy attribute-based encryption (CP-ABE) technology to achieve data confidentiality and access control. This involves data providers specifying specific access policies for their data and encrypting it across large low-altitude datasets. Only data users with permissions matching the access policy can decrypt the data to obtain the correct plaintext. While CP-ABE enables flexible, fine-grained access control over encrypted data, directly applying it to secure data sharing within a data space faces several challenges. First, traditional attribute-based encryption schemes incur significant computational overhead when a user withdraws, making them unsuitable for scenarios with numerous dynamic user additions and exits in low-altitude trusted data spaces. Second, low-altitude trusted data spaces require flexible access control based on user attribute comparisons and access times for their shared low-altitude big data, and the ability to verify decryption results. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method and system for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space, comprising: Data user DU sends an access request for target data to the Low Altitude Trusted Data Space (LADS); the access request contains a set of attributes and a set of tags of data user DU. The Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the target data access policy; if they match, it returns the ciphertext of the target data to the data user (DU); wherein, the target data access policy and the ciphertext of the target data are received in advance from the data owner (DO). Data user DU checks whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, then the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data; wherein, the target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of data user DU.

[0007] Secondly, this invention provides a low-altitude big data access control system based on comparable attributes in a low-altitude trusted data space, comprising a data user (DU), a low-altitude trusted data space (LADS), a data owner (DO), and a key generation center (KGC); wherein... Data user (DU) is used to send access requests for target data to the Low Altitude Trusted Data Space (LADS); the access request contains a set of attributes and a set of tags of the data user (DU); The Low Altitude Trusted Data Space (LADS) is used to determine whether the attribute set of a data user (DU) matches the target data access policy. If they match, the encrypted target data is returned to the data user (DU). The target data access policy and the encrypted target data are received in advance from the data owner (DO). The data user DU is also used to check whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data; wherein, the target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of the data user DU.

[0008] This invention provides a method and system for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space. It achieves flexible and efficient user revocation to ensure forward security, can make flexible decisions on data user access behavior based on access time and attribute comparison, and supports the verification of the correctness of the decryption process. This invention is applicable to applications such as secure sharing and circulation of low-altitude big data in a low-altitude trusted data space. It not only improves the flexibility and efficiency of user revocation in the process of low-altitude big data sharing, but also enables data access control based on comparable attributes and time sensitivity under the same performance conditions.

[0009] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating an application scenario of a low-altitude big data access control method based on comparable attributes in a low-altitude trusted data space, as provided in an embodiment of the present invention. Figure 2 This is a structural block diagram of a low-altitude big data access control system based on comparable attributes in a low-altitude trusted data space, according to an embodiment of the present invention. Detailed Implementation

[0011] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0012] In a first aspect, embodiments of the present invention provide a method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space. See also... Figure 1 The method includes the following steps: S10, Data user DU sends an access request for the target data to the Low Altitude Trusted Data Space (LADS).

[0013] The access request includes the attribute set and tag set of the data user DU.

[0014] S20. The Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the target data access policy; if they match, it returns the ciphertext of the target data to the data user (DU).

[0015] The target data access policy and the encrypted target data are received in advance from the data owner (DO).

[0016] In one optional embodiment, the method further includes: the data owner (DO) encrypts the target data based on a symmetric encryption algorithm and a predefined target data access strategy to obtain the ciphertext of the target data and key verification parameters, and then entrusts the ciphertext to the Low Altitude Trusted Data Space (LADS).

[0017] For example, during the system initialization phase, Setup (1 λ ,d ) → ( PK K ,MK K ) , ( SPK,SMK First, the key generation center KGC generates a bilinear group, which includes two prime groups of order 2. p Multiplication cyclic group and Bilinear mapping ,and The generator g is defined. Two collision-resistant hash functions are also defined. Attribute set U ={1,2, , n} and a unified time format F T and tags Where n represents the number of attributes in the attribute set. This is the only tag that won't be used; it's used to mark whether the initial keys before and after the puncture are consistent. Secondly, the key generation center (KGC) randomly selects a random number. , α , β , γ ∈ ,calculate Define polynomial ,in, , Meanwhile, the Key Generation Center (KGC) randomly selects a random number. and construct a length of Key export function KDF 1. Finally, the Key Generation Center (KGC) stores the system master key. MK K =( ,γ, ), public system public key PK K =( , , , , , , , KDF 1, F T , , , ),in, This represents a bilinear mapping. Simultaneously, the Low Altitude Reliable Data Space (LADS) is randomly selected. Calculate the LADS signature public key and private key .

[0018] Subsequently, during the stage where the data owner (DO) encrypts the target data, Encrypt ( , M , PK K )→( CT ): When DO targets data M ∈ During encryption, select a symmetric encryption / decryption algorithm pair ( E , D Random selection s,ρ ∈ p ,calculate and To obtain the symmetric key Then, the target data was calculated. M ciphertext and key verification parameters to verify the symmetric key. The key verification parameter can be a Pedersen commitment. The specific process is as follows: First, DO randomly selects... r 0∈ p Generate an initial key for puncture-proof encryption. SK 0 ={ , D 0 = , F 0 = ,Q 0 = } and embed it into the ciphertext.

[0019] Secondly, the target data access strategy Each node x Associated with 3 parameters, including and .in, Participate in parent node sharing, Shared by its child nodes, It is a node x The time-related parameters. The values ​​of these three parameters depend on the target data access strategy. The allocation is performed in a top-down manner. Specifically: ① If the node... x It is the root node R ,but ; ② For each having nodes x If the node x If there is no time trapdoor, then If the node x If a time trapdoor exists, then , When a time trapdoor exists on a non-leaf node, the subtree of that node is locked until the release time is reached. This applies to time points. t ∈ F T and parameters Related time traps TS x Random selection r t ∈ And calculate TS x = ( A x = ,B x = ( + .

[0020] Furthermore, in an optional embodiment, the method of this embodiment further includes: the data owner DO encodes and converts the attributes of each leaf node according to the size relationship between the attributes of each leaf node in the target data access strategy and a preset threshold, to obtain a strategy-encoded attribute set; wherein, the strategy-encoded attribute set includes 0 encoding and 1 encoding, where 0 encoding indicates that the size relationship is greater than, and 1 encoding indicates that the size relationship is not greater than.

[0021] Specifically, in the target data access strategy In the middle, each leaf node x Represents an attribute y The DO process converts each leaf node into a 0-encoded or 1-encoded subtree based on the relationship between its attributes and a preset threshold. Specifically, ">" relationships are replaced with 0 encoding; otherwise, they are encoded with 1. S 1 represents the expanded attribute set (i.e., the policy-encoded attribute set). The policy-encoded attribute set enables flexible attribute comparison-based access control for data users (DUs).

[0022] Finally, the ciphertext of the target data MCT The calculation is as follows:

[0023] .

[0024] Data owner DO obtains the encrypted text CT Then, it is hosted in the Low Altitude Trusted Data Space (LADS) for data users (DU) to access.

[0025] In one optional embodiment, the Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the target data access policy, including: the Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the policy-encoded attribute set.

[0026] For example, after receiving an access request from a data user (DU), the Low Altitude Trusted Data Space (LADS) first determines the attribute set of the data user (DU). S Is it related to ciphertext? CT The target data access policy matching involves determining whether the modified extended set S2 of the data user DU (S2 represents the extended set of attributes of DU after 0-1 encoding) matches the policy-encoded attribute set. If they match, the ciphertext of the target data is then... CT Returning data to user DU.

[0027] In one optional embodiment, the method further includes: the data owner DO sending a puncture strategy to the Low Altitude Trusted Data Space (LADS); the LADS puncturing the ciphertext of the target data based on the puncture strategy to obtain the ciphertext of the punctured target data, the ciphertext of the punctured target data including a puncture key and a puncture tag set; signing the puncture key using a pre-generated LADS signing private key to generate a puncture signature, and sending the puncture signature to the data owner DO for verification; and the data owner DO verifying the puncture signature based on a pre-generated LADS signing public key.

[0028] For example, when the data owner DO encrypts the data... CT After hosting to the Low Altitude Trusted Data Space (LADS), a puncture strategy can be sent to the LADS at any time to target ciphertext. CT The puncture is performed. The specific procedure is as follows: Puncture ( PK K ,PP K ,SMK,CT ) → ( ,ζWhen LADS receives the puncture strategy from DO: PP K The ciphertext is then punctured, but no other operations are performed directly on the CP-ABE ciphertext.

[0029] First, the puncture strategy PP K Convert to access policy AP K .for PP K For each non-leaf node in the array, convert the OR gate to an AND gate, and the AND gate to an OR gate. m,n The door then becomes ( n m + 1,n (Door.) For each leaf node, the label associated with that leaf node. Change to the negative form NOT t (For example: puncture strategy) PP K The j The label of each node t k,j , converted AP K Postscript: t k,j ), This is the tag set for the data user DU. The initial key embedded in the ciphertext is... SK K 1 = { sk 0 ,sk 1 , ,sk k 1}, sk 0 = { ,D 0 ,F 0 ,Q 0}. At this time, LADS randomly selects... λ k , r k ∈ p and calculate: =( , = , , ), Thus, the puncture key is obtained. And so on, we can obtain the...k Secondary puncture key.

[0030] Secondly, λ k As a secret value, according to AP K Divide the data into sections, and assign labels to the leaf nodes. t k,j , λ k The secret value on it is λ k,j Random selection r k,j ∈ p And calculate: sk k,j = ( l k,j , D k,j = ,Q k,j = ) in, The leaf node t represents the puncture strategy. k,j The corresponding tag value.

[0031] The puncture key obtained after multiple punctures is represented as follows: SK k = ({ PP i ,AP i} i∈[1,k] , ,sk 1 , ,sk k 1 ,sk k ).

[0032] Again, LADS uses the LADS signing private key. Generate a new key component N k = sk k puncture signature ζ = Send to DO for verification. DO receives the puncture signature ζ generated during the puncture operation using LADS and uses the LADS signing public key. SPK The following formula is used to verify whether the ciphertext has been correctly punctured, based on the puncture strategy:

[0033] If the above equations are equal, then the verification is successful.

[0034] Finally, LADS will use the puncture key. SK k Embedded into the ciphertext, and output as follows ciphertext after piercing. Forward security of shared data ciphertext is achieved through punctured ciphertext.

[0035] = ( SK k , , , , , TS x = ( A x ,B x ) , ).

[0036] S30. Data user DU checks whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, then the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data.

[0037] The target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of the data user DU.

[0038] For example, after receiving the ciphertext of the target data, the data user DU checks whether the set of puncture tags in the ciphertext of the target data is the target decryption key. DK u All of them. Among them, the target decryption key. DK u It is generated during the system initialization phase, specifically... KeyGen ( S , PKK , MK K , T )→( DK u KGC randomly selects rx ∈ p Based on the attribute set of data user DU S The set S2 is expanded by modifying the comparable attributes, where S2 represents the expanded set of attributes of DU after 0-1 encoding, and the tag set. T ={ Generate target decryption key DK u , is represented as:

[0039] in, , , , Random selection .

[0040] If there is no match, it is determined whether the target time trapdoor in the ciphertext of the target data has been released. The specific process is as follows: In an optional embodiment, the method further includes: the Key Generation Center (KGC) sends a time token to the Low Altitude Trusted Data Space (LADS) at a preset time interval; the LADS determines whether the time token matches the release time of the target time trap in the target data access policy; if it matches, the target time trap is calculated based on the time token to obtain the released target time trap, and the released target time trap is embedded in the ciphertext of the corresponding target data.

[0041] For example, the Key Generation Center (KGC) sends time tokens to the Low Altitude Trusted Data Space (LADS) at preset time intervals. Specifically, TokenGen ( t,MK K ) → ( TK t KGC acts as a time proxy, at each preset time point. t ∈ F T Generate and publicly release a time token This token is used by LADS to release the target time trapdoor in its shared ciphertext-associated target data access policy.

[0042] The release process of the target time trapdoor is as follows: TrapdoorExposure ( ) →( ): If the ciphertext of the target data is associated with the target data access policy A certain node x It is associated with a target time trap. TS x When the target time trapdoor is not released, the value of the target time trapdoor is... TS x = ( A x = ,B x = ( + At this point, for a DU that has obtained the ciphertext of the target data, since the node cannot be obtained... x The corresponding target time trapdoor value However, the decryption calculation could not be completed. Meanwhile, LADS obtained a time token issued by KGC. TK t Query all time traps in the target data access policy and determine the time token. TK t Does it match the release time of the target time trapdoor in the target data access policy? t If a match is found, LADS is based on the time token. TK t ,calculate .like Then the target time trapdoor is successfully exposed, and it is used in its corresponding ciphertext. replace TS x At this point, any DU with sufficient privileges can, according to... Decryption calculation complete.

[0043] In one optional embodiment, decrypting the ciphertext of the target data based on the target decryption key to obtain the target data includes: the data user DU decrypting the ciphertext of the target data based on the target decryption key to obtain a symmetric key; verifying the symmetric key based on key verification parameters; if the verification is successful, then using the symmetric key to decrypt the ciphertext of the target data to obtain the target data.

[0044] For example, when the set of puncture tags contained in the ciphertext of the target data does not match the target decryption key, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, then the ciphertext of the target data is decrypted based on the target decryption key. Specifically, for the target data access policy... leaf nodes x ∈S ,implement DecryptNode The algorithm is as follows: DecryptNode ( CT,TK u ,x ) , otherwise, DecryptNode ( CT,TK u ,x ) = ⊥.

[0045] For non-leaf nodes x , It is the set of its child nodes, and the process is executed recursively. DecryptNode Algorithm to obtain non-leaf nodes x Calculation results:

[0046]

[0047]

[0048] . And so on, for target data access strategies root node R The root node can be obtained. R Calculation results: W= DecryptNode ( CT,DK u ,R ) = = Next, calculate the intermediate value. :

[0049]

[0050]

[0051] for AP i leaf nodes in t i,j Find a set of Lagrange coefficients { w 1 ,w 2 , ,w d ,w }, making Calculate the leaf nodes t i,j Value:

[0052]

[0053]

[0054] according to{ J i,j} i,j∈[1,k] recover AP i root value As for SK K In Find a set of Lagrange coefficients { τ 1 ,τ 2 , ,τ d ,τ }, making ,calculate:

[0055] At this point, DU calculates the intermediate value using the following formula. :

[0056] Finally, DU calculates the ciphertext using the following formula. CT symmetric key And verify it:

[0057]

[0058] if Then the symmetric key Verification successful, based on Calculate target data And return the target data M Otherwise, return .

[0059] This embodiment presents a low-altitude big data access control method based on comparable attributes in a low-altitude trusted data space. By incorporating puncture-resistant encryption technology into CP-ABE, it dynamically controls the ability of data users to decrypt specified ciphertext, ensuring forward security—that is, a revoked data user no longer has the ability to decrypt previously ciphertext. Simultaneously, it supports the elimination of the need to update ciphertext and assign new keys to other data users when access rights are revoked for some data users, thereby reducing computational and communication overhead during the revocation process. Furthermore, it incorporates Pedersen commitments to verify the correctness of decryption results. Unlike traditional CP-ABE schemes that rely on precise matching of user attribute sets and policy attributes or embedding time factors into ciphertext for time-based access decisions, this embodiment's method achieves more flexible low-altitude big data access control decisions based on time and attribute comparison. It also combines time-release encryption and 0-1 encoding to encrypt shared low-altitude data, meeting the requirements for time-sensitive and finer-grained security access control in low-altitude trusted data spaces.

[0060] Secondly, embodiments of the present invention also provide a low-altitude big data access control system based on comparable attributes in a low-altitude trusted data space, referring to... Figure 2 The system specifically includes the data user (DU), the low-altitude trusted data space (LADS), the data owner (DO), and the key generation center (KGC); among them, Data user (DU) is used to send access requests for target data to the Low Altitude Trusted Data Space (LADS); the access request contains a set of attributes and a set of tags of the data user (DU); The Low Altitude Trusted Data Space (LADS) is used to determine whether the attribute set of a data user (DU) matches the target data access policy. If they match, the encrypted target data is returned to the data user (DU). The target data access policy and the encrypted target data are received in advance from the data owner (DO). The data user DU is also used to check whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data; wherein, the target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of the data user DU.

[0061] For example, the system in this embodiment includes four entities: a key generation center (KGC), a data owner (DO), a data user (DU), and a low-altitude trusted data space (LADS). The detailed functions of each entity are as follows: 1) Key Generation Center (KGC): This entity is responsible for managing the keys and generating time tokens for the entire system, including generating public parameters for the system, generating decryption keys for DU, and acting as a time agent to release time tokens.

[0062] 2) Data Owner (DO): This entity is responsible for defining access and penetration policies for the data it owns, encrypting and outsourcing the data accordingly, and then sending the encrypted data to LADS for sharing, thereby achieving data confidentiality and fine-grained access control. When defining access policies, the DO can flexibly specify policies based on attribute size comparison, attribute range comparison, and access time sequence.

[0063] 3) Data User (DU): This entity sends an access request to LADS and downloads the corresponding encrypted data as needed. A DU can decrypt the encrypted data to obtain the plaintext only if its attribute set meets the flexible range comparison requirements of the access policy, the access time matches the time token release time, and its tag does not match the ciphertext piercing policy.

[0064] 4) Low Altitude Trusted Data Space (LADS): This entity is responsible for the sharing and circulation management of low-altitude big data within the Low Altitude Trusted Data Space. On one hand, it is responsible for the outsourced storage of encrypted data and the management of data access, circulation, and sharing. On the other hand, upon receiving a time token from the KGC, it is responsible for releasing access permissions in the access policy and performing encrypted data penetration upon receiving a penetration policy from the DO.

[0065] The system's processing is divided into four stages: initialization, data hosting, data access, and ciphertext penetration. 1) Initialization phase: KGC generates the system public key and master key, and distributes decryption keys to DU. LADS generates its signature public-private key pair.

[0066] 2) Data Hosting Phase: DO sets corresponding data access policies according to its data operation hosting needs. When defining access policies, DO can flexibly specify policies based on attribute size comparison, attribute range comparison, and access time sequence. Then, DO calculates the encrypted data according to the access policy and hosts the encrypted data to LADS so that LADS can provide sharing, circulation, and operation services to DU.

[0067] 3) During the data access phase, the DU requests relevant data from the LADS based on its actual needs. Upon receiving the access request, the LADS determines whether the access policy is satisfied based on the current DU's attribute set and returns the target ciphertext. The DU can only decrypt the ciphertext and obtain the plaintext if and only if its attribute set meets the flexible range comparison requirements of the access policy, the access time matches the time token release time, and its tag does not match the ciphertext piercing policy. To implement time-based access control, the KGC periodically issues time tokens to the LADS, which then exposes the time trapdoor of the access policy for the relevant ciphertext.

[0068] 4) Ciphertext Punishment Phase. Based on the context and changes in its needs, the DO performs punctures on the ciphertext data hosted on LADS to update the DU's access control permissions.

[0069] For details on the system, please refer to the steps of the "Low-Altitude Big Data Access Control Method Based on Comparable Attributes in a Low-Altitude Trusted Data Space" provided in the first aspect, which will not be repeated here.

[0070] This embodiment provides a low-altitude big data access control system based on comparable attributes in a low-altitude trusted data space. It achieves flexible and efficient user revocation to ensure forward security, can make flexible decisions on data user access behavior based on access time and attribute comparison, and supports the verification of the correctness of the decryption process. This invention is applicable to applications such as secure sharing and circulation of low-altitude big data in a low-altitude trusted data space. It not only improves the flexibility and efficiency of user revocation in the process of low-altitude big data sharing, but also enables data access control based on comparable attributes and time sensitivity under the same performance conditions.

[0071] It should be noted that the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention.

[0072] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0073] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings and the disclosure in carrying out the claimed invention. In the description of the invention, the word "comprising" does not exclude other components or steps, "a" or "an" does not exclude a plurality, and "a plurality" means two or more, unless otherwise explicitly specified. Furthermore, while different embodiments may describe certain measures, this does not mean that these measures cannot be combined to produce good results.

[0074] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space, characterized in that, include: Data user DU sends an access request for the target data to the Low Altitude Trusted Data Space (LADS). The access request includes the attribute set and tag set of the data user DU; The Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the target data access policy; if it matches, it returns the ciphertext of the target data to the data user (DU); wherein the target data access policy and the ciphertext of the target data are received in advance from the data owner (DO). The data user DU checks whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, then the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data; wherein, the target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of the data user DU.

2. The method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space according to claim 1, characterized in that, The method further includes: The Key Generation Center (KGC) sends time tokens to the Low Altitude Trusted Data Space (LADS) at preset time intervals. The Low Altitude Trusted Data Space (LADS) determines whether the time token matches the release time of the target time trap in the target data access policy; if it matches, it calculates the target time trap based on the time token to obtain the released target time trap and embeds the released target time trap into the ciphertext of the corresponding target data.

3. The method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space according to claim 1, characterized in that, The method further includes: The data owner (DO) encrypts the target data based on a symmetric encryption algorithm and a predefined target data access policy, obtaining the ciphertext of the target data and key verification parameters, and then entrusts the ciphertext to the Low Altitude Trusted Data Space (LADS).

4. A method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space according to any one of claims 3, characterized in that, The method further includes: The data owner (DO) sends a puncture strategy to the Low Altitude Trusted Data Space (LADS). The Low Altitude Trusted Data Space (LADS) performs a puncture on the ciphertext of the target data based on the puncture strategy to obtain the ciphertext of the target data after puncture. The ciphertext of the target data after puncture includes a puncture key and a puncture tag set. The puncture key is signed using a pre-generated LADS signing private key to generate a puncture signature, and the puncture signature is sent to the data owner (DO) for verification. The data owner (DO) verifies the puncture signature based on a pre-generated LADS signature public key.

5. A method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space according to claim 4, characterized in that, The process of decrypting the ciphertext of the target data based on the target decryption key to obtain the target data includes: The data user DU decrypts the ciphertext of the target data based on the target decryption key to obtain a symmetric key; the symmetric key is verified based on the key verification parameters. If the verification is successful, the symmetric key is used to decrypt the ciphertext of the target data to obtain the target data.

6. The method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space as described in claim 1, characterized in that, The method further includes: The data owner (DO) encodes and transforms the attributes of each leaf node according to the relationship between the attributes of each leaf node in the target data access strategy and the preset threshold, thus obtaining a strategy-encoded attribute set. The strategy encoding attribute set includes 0 encoding and 1 encoding, where 0 encoding indicates that the size relationship is greater than, and 1 encoding indicates that the size relationship is not greater than.

7. The method for low-altitude big data access control based on comparable attributes in a low-altitude trusted data space according to claim 6, characterized in that, The Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the target data access strategy, including: The Low Altitude Trusted Data Space (LADS) determines whether the attribute set of the data user (DU) matches the policy-encoded attribute set.

8. A low-altitude big data access control system based on comparable attributes in a low-altitude trusted data space, characterized in that, This includes the data user (DU), the Low Altitude Trusted Data Space (LADS), the data owner (DO), and the key generation center (KGC); among them, The data user (DU) is used to send an access request for target data to the Low Altitude Trusted Data Space (LADS); the access request includes the attribute set and tag set of the data user (DU); The Low Altitude Trusted Data Space (LADS) is used to determine whether the attribute set of the data user (DU) matches the target data access policy; if they match, the encrypted target data is returned to the data user (DU); wherein the target data access policy and the encrypted target data are received in advance from the data owner (DO). The data user DU is also used to check whether the set of puncture tags contained in the ciphertext of the target data matches the target decryption key; if they do not match, and it is determined that the target time trapdoor in the ciphertext of the target data has been released, then the ciphertext of the target data is decrypted based on the target decryption key to obtain the target data; wherein, the target decryption key is generated in advance by the key generation center KGC based on the attribute set and tag set of the data user DU.

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