Self-adaptive access control method based on block chain

Abstract

The invention provides an adaptive access control method based on a block chain, and belongs to the technical field of access control, and the method comprises the steps: deploying the metadata of an access control strategy into a block chain smart contract in a block chain system initialization stage; the specific content of the access control policy is stored in the TEE; when a user initiates an access request, the block chain system obtains metadata of a current strategy from the chain, and loads a corresponding access control rule in the TEE under the chain; the TEE performs access legality judgment according to the multi-dimensional information to generate an access decision; and the decision result is subjected to digital signature and then returned to the on-chain smart contract for verification, and an access log is recorded. According to the method, the execution logic of the access control strategy is moved to the under-chain trusted execution environment, so that the occupation of computing resources on the chain is remarkably reduced, the delay of access control operation and the Gas cost are reduced, the throughput capacity and the expansibility of the system are improved, and the method is suitable for access control scenes with high-frequency access and complicated strategies.

Description

Technical Field

[0001] The present invention belongs to the field of access control technology, and specifically relates to an adaptive access control method based on blockchain. Background Art

[0002] As mentioned in the prior art patent publication "CN120259009A," blockchain access control is a key aspect of blockchain technology. Existing blockchain-based access control methods typically deploy access control policies directly within smart contracts. Each access request requires the execution of policy judgment logic on the blockchain to ensure the immutability and traceability of blockchain access control. However, this design consumes a significant amount of on-chain computing resources, impacting the throughput of the blockchain system. This is particularly true in scenarios with complex policies or high access frequency, significantly reducing on-chain execution efficiency and causing network congestion and response delays. Summary of the Invention

[0003] In order to address the defects in the existing technology, the present invention provides an adaptive access control method based on blockchain. In view of the problems in the existing technology that access control policies are directly deployed in smart contracts and each access request requires policy judgment to be executed on the blockchain, resulting in high on-chain computing resource usage and low blockchain system throughput, an adaptive access control method based on blockchain is proposed. The policy judgment logic is moved to the off-chain trusted execution environment, and only the access decision results are recorded on the chain, thereby reducing the on-chain computing load of the blockchain and improving the throughput of the blockchain system.

[0004] A blockchain-based adaptive access control method, comprising:

[0005] Step 1: Register the policy metadata on-chain;

[0006] Step 2: Off-chain policy matching during access request;

[0007] Step 3: Verify and record access decision chain;

[0008] Step 4: When the access control policy needs to be updated, update the policy and ensure consistency.

[0009] Furthermore, step 1 includes: in the initialization phase of the blockchain system, deploying the metadata of the access control policy into the blockchain smart contract, storing the specific content of the access control policy in the off-chain trusted execution environment, and identifying it by the hash value of the corresponding policy hash.

[0010] Furthermore, in step 1, the metadata of the access control policy includes the policy ID, version number, and policy hash of the access control policy.

[0011] Furthermore, in step 1, the blockchain smart contract is only responsible for verifying the integrity of the policy hash and does not participate in the execution process of the policy logic of the access control policy.

[0012] Furthermore, in step 1, for the cross-organizational medical data sharing platform, during the initialization phase of the blockchain system, the administrator deploys the access control policy P to the off-chain TEE and calculates its hash value H(P). Then, the policy metadata, that is, the metadata of the access control policy (ID, V, H(P)), is submitted to the on-chain smart contract, where ID represents the policy ID of the access control policy, V represents the version number of the access control policy, and H(P) represents the policy hash of the access control policy. The specific content of the access control policy P can be expressed as: P = {if S∈G doctor and A=read and O∈R clinical , then allow}, where S represents the access subject, O represents the access object, G doctor represents the doctor user group, R clinical represents a collection of clinical data;

[0013] The on-chain smart contract only accesses the metadata of the control policy (ID, V, H(P)) and does not execute the policy logic of the access control policy P.

[0014] Furthermore, in step 2, when the user initiates an access request, the blockchain system obtains the metadata of the current access control policy from the on-chain smart contract, which is the blockchain smart contract, and loads the specific content of the corresponding access control policy into the off-chain trusted execution environment, that is, the off-chain TEE. The off-chain TEE performs policy matching based on the multi-dimensional information of the access request triplet to determine the applicable access control rules.

[0015] Furthermore, in step 2, after the specific content of the corresponding access control policy P is loaded into the off-chain TEE, it also includes: verifying whether its hash value is consistent with the policy hash H(P) of the access control policy recorded by the on-chain smart contract. If consistent, continue with the subsequent steps of the blockchain-based adaptive access control method. If inconsistent, terminate the execution of the subsequent steps of the blockchain-based adaptive access control method.

[0016] Furthermore, in step 2, for the cross-organizational medical data sharing platform, user a initiates an access request to request access to the clinical data set R as a resource. clinical When , the blockchain system performs the following steps:

[0017] Step 2-1: Extract the triplet of the access request initiated by user a:

[0018] (S=a,A=read,O=R clinical), read indicates read access;

[0019] Step 2-2: Get the current policy metadata, that is, get the metadata of the current access control policy (ID, V, H(P)) from the on-chain smart contract;

[0020] Step 2-3: Load the access control policy P and perform matching, that is, load the access control policy P in the off-chain TEE and perform the policy matching logic match(S,A,O) as shown below based on the access request:

[0021]

[0022] Step 2-4: After the policy is matched, an access decision is generated to determine the applicable access control rule. That is, if the value of match(S,A,O) is true, it means that the policy is matched successfully, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=allow, and then the access permission message is output to execute the access control on the clinical data set R. clinical If the value of match(S,A,O) is false, it means that the policy match is unsuccessful, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=refuse, and then the access prohibition message is output to execute the access control of the clinical data set R clinical The access control rule that applies is the access decision result.

[0023] Furthermore, in step 3, the access decision result is signed by the off-chain TEE and returned to the on-chain smart contract for verification, and the access decision result, access time, and access subject information are written into the blockchain log.

[0024] Furthermore, in step 3, for the cross-organizational medical data sharing platform, the off-chain TEE generates a digital signature σ=Sign for Decision(S,A,O) TEE (Decision(S,A,O)), Sign TEE (Decision(S,A,O)) means applying the RSA method to generate a digital signature for Decision(S,A,O), and then submitting the digital signature σ to the on-chain smart contract. After the on-chain smart contract verifies the validity of the digital signature σ, it writes the access decision result, access time, and access subject information into the blockchain log.

[0025] Furthermore, in step 4, when the access control policy needs to be updated, the blockchain system verifies the update permission in the on-chain TEE. If there is update permission, it updates the local policy copy and submits the hash value and version information of the new policy to the on-chain smart contract. The on-chain smart contract records the policy update event and automatically matches the latest version of the access control policy in subsequent access requests.

[0026] Furthermore, in step 4, for the cross-organizational medical data sharing platform, when the access control policy needs to be updated, the administrator updates the specific content of the new access control policy P' in the on-chain TEE, calculates the hash value H(P') of the new access control policy, and then submits the metadata (ID, V', H(P')) of the updated new access control policy to the on-chain smart contract. V' represents the version information of the new access control policy. The new policy P' is expressed as: P'=if S∈G specialist and A=read and O∈R clinical , then allow, where G specialist Represents the specialist user group. The on-chain smart contract records policy update events and automatically matches the latest version of the access control policy in subsequent access requests.

[0027] The beneficial effects of the present invention are as follows:

[0028] During the initialization phase of the blockchain system, the present invention deploys the metadata of the access control policy (including the policy ID, version number, and policy hash) into the blockchain smart contract. The specific content of the access control policy is stored in an off-chain trusted execution environment (TEE). When a user initiates an access request, the blockchain system obtains the metadata of the current policy from the chain and loads the corresponding access control rules into the off-chain TEE. The TEE makes an access legitimacy judgment based on multi-dimensional information and generates an access decision. The decision result is digitally signed and returned to the on-chain smart contract for verification, and the access log is recorded. By moving the execution logic of the access control policy to the off-chain trusted execution environment, the present invention significantly reduces the usage of on-chain computing resources, reduces the latency and gas cost of access control operations, and improves the system's throughput and scalability. It is suitable for access control scenarios with high-frequency access and complex policies. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the blockchain-based adaptive access control method in the present invention. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely express the technical solutions of the present invention. The embodiments expressed in this application are only part of the embodiments of the present invention, not all of the embodiments. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present invention.

[0031] like Figure 1 As shown, a blockchain-based adaptive access control method includes:

[0032] Step 1: Register the policy metadata on-chain;

[0033] In a preferred but non-limiting embodiment of the present invention, step 1 includes: in the initialization phase of the blockchain system, deploying the metadata of the access control policy into the blockchain smart contract, storing the specific content of the access control policy in the off-chain trusted execution environment (TEE), and identifying it by the hash value of the corresponding policy hash.

[0034] In a preferred but non-limiting embodiment of the present invention, in step 1, the metadata of the access control policy includes the policy ID, version number and policy hash of the access control policy.

[0035] In a preferred but non-limiting embodiment of the present invention, in step 1, the blockchain smart contract is only responsible for verifying the integrity of the policy hash and does not participate in the execution process of the policy logic of the access control policy.

[0036] Step 1 mainly involves registering the metadata of the access control policy in the on-chain smart contract, including the policy ID, version number, and hash value. The specific content of the access control policy is stored in the off-chain trusted execution environment (TEE).

[0037] In a preferred but non-restrictive embodiment of the present invention, in step 1, for a cross-organizational medical data sharing platform, multiple medical institutions hope to achieve controlled access to sensitive medical data while ensuring data security and access compliance. The cross-organizational medical data sharing platform requires that all access records cannot be tampered with, and at the same time hopes to reduce on-chain computing overhead and improve access control efficiency. During the initialization phase of the blockchain system, the administrator deploys the access control policy P to the off-chain TEE and calculates its hash value H(P), and then submits the policy metadata, that is, the metadata of the access control policy (ID, V, H(P)) to the on-chain smart contract, where ID represents the policy ID of the access control policy, V represents the version number of the access control policy, and H(P) represents the policy hash of the access control policy. For example, the specific content of the access control policy P can be expressed as: P = {if S∈G doctor and A=read and O∈Rclinical , then allow}, where S represents the access subject, O represents the access object, G doctor represents the doctor user group, R clinical represents a collection of clinical data;

[0038] The on-chain smart contract only accesses the metadata of the control policy (ID, V, H(P)) and does not execute the policy logic of the access control policy P.

[0039] Step 2: Off-chain policy matching during access request;

[0040] In a preferred but non-limiting embodiment of the present invention, in step 2, when a user initiates an access request, the blockchain system obtains the metadata of the current access control policy from the on-chain smart contract, which is a blockchain smart contract, and loads the specific content of the corresponding access control policy into the off-chain trusted execution environment, that is, the off-chain TEE. The off-chain TEE performs policy matching based on the multi-dimensional information of the access request triplet to determine the applicable access control rules.

[0041] In a preferred but non-limiting embodiment of the present invention, in step 2, after the specific content of the corresponding access control policy P is loaded into the off-chain TEE, it also includes: verifying whether its hash value is consistent with the policy hash H(P) of the access control policy recorded by the on-chain smart contract. If consistent, continue with the subsequent steps of the blockchain-based adaptive access control method. If inconsistent (such as the policy has been tampered with), terminate the execution of the subsequent steps of the blockchain-based adaptive access control method.

[0042] Step 2 mainly involves receiving user access requests, extracting information such as the request subject, access action, and access object, and matching applicable access control policies in the off-chain TEE.

[0043] In a preferred but non-limiting embodiment of the present invention, in step 2, user a initiates an access request to access the clinical data set R as a resource for the cross-organizational medical data sharing platform. clinical When , the blockchain system performs the following steps:

[0044] Step 2-1: Extract the triplet of the access request initiated by user a:

[0045] (S=a,A=read,O=R clinical ), read indicates read access;

[0046] Step 2-2: Get the current policy metadata, that is, get the metadata of the current access control policy (ID, V, H(P)) from the on-chain smart contract;

[0047] Step 2-3: Load the access control policy P and perform matching, that is, load the access control policy P in the off-chain TEE and perform the policy matching logic match(S,A,O) as shown below based on the access request:

[0048]

[0049] Step 2-4: After the policy is matched, an access decision is generated to determine the applicable access control rule. That is, if the value of match(S,A,O) is true, it means that the policy is matched successfully, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=allow, and then the access permission message is output to execute the access control on the clinical data set R. clinical If the value of match(S,A,O) is false, it means that the policy match is unsuccessful, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=refuse, and then the access prohibition message is output to execute the access control of the clinical data set R clinical The access control policy rules can be described in a formal policy language (such as XACML, ALFA or a custom DSL).

[0050] Step 3: Verify and record access decision chain;

[0051] In a preferred but non-limiting embodiment of the present invention, in step 3, the access decision result is signed by the off-chain TEE and returned to the on-chain smart contract for verification. The on-chain smart contract ensures the integrity and source credibility of the access decision result by verifying the signature, and writes the access decision result, access time, access subject information, etc. into the blockchain log to achieve traceability and non-tamperability of the access control process.

[0052] In a preferred but non-limiting embodiment of the present invention, in step 3, for the cross-organizational medical data sharing platform, the off-chain TEE generates a digital signature σ=Sign for Decision(S,A,O) TEE (Decision(S,A,O)), Sign TEE (Decision(S,A,O)) means applying the RSA method to generate a digital signature for Decision(S,A,O), and then submitting the digital signature σ to the on-chain smart contract. After the on-chain smart contract verifies the validity of the digital signature σ, it writes the access decision result, access time, access subject information, etc. into the blockchain log to achieve traceability and non-tamperability of the access control process.

[0053] Step 4: When the access control policy needs to be updated, update the policy and ensure consistency.

[0054] In a preferred but non-limiting embodiment of the present invention, in step 4, when the access control policy needs to be updated, the blockchain system verifies the update permission in the on-chain TEE. If there is update permission, it updates the local policy copy and submits the hash value and version information of the new policy to the on-chain smart contract. The on-chain smart contract records the policy update event and automatically matches the latest version of the access control policy in subsequent access requests, realizing dynamic update of the policy and on-chain synchronization to ensure policy consistency.

[0055] In a preferred but non-limiting embodiment of the present invention, in step 4, for a cross-organizational medical data sharing platform, when the access control policy needs to be updated, the administrator updates the specific content of the new access control policy P' in the on-chain TEE, calculates the hash value H(P') of the new access control policy, and then submits the metadata (ID, V', H(P')) of the updated new access control policy to the on-chain smart contract. V' represents the version information of the new access control policy. For example, the new policy P' can be expressed as:

[0056] P'=if S∈G specialist and A=readand O∈R clinical , then allow, where G specialist Representing the specialist user group, the on-chain smart contract records policy update events and automatically matches the latest version of the access control policy in subsequent access requests, realizing dynamic policy updates and on-chain synchronization to ensure policy consistency.

[0057] This invention significantly reduces on-chain computing resource usage and improves system throughput by moving the execution logic of access control policies from on-chain to off-chain TEEs. Furthermore, by storing policy metadata and access decision logs on-chain, the access control process is traceable and tamper-proof.

[0058] Specifically, the present invention has the following advantages:

[0059] Reduce on-chain resource consumption: The policy judgment logic is executed in TEE, and only the results are written to the chain, avoiding frequent on-chain calculations and saving gas fees.

[0060] Improve the flexibility of the blockchain system: Policy updates can be completed in TEE without redeploying smart contracts, supporting dynamic policy adjustments.

[0061] Enhanced security: On-chain TEE ensures that the access control policy execution process cannot be tampered with or spied on, protecting policy logic and data privacy.

[0062] Support fine-grained access control: Policy functions can define complex logic based on actual needs and support multi-level permissions and conditional judgments.

[0063] Achieve efficient access response: Avoid waiting for on-chain confirmation, significantly reduce access latency, and improve system response speed.

[0064] Therefore, the present invention effectively solves the shortcomings of the existing blockchain-based access control methods in terms of performance, flexibility and security, and is suitable for access control scenarios that require high security and traceability.

[0065] In summary, this invention provides an adaptive access control method based on blockchain, which aims to overcome the problem in the prior art of directly deploying access control policies in smart contracts, resulting in each access request requiring policy judgment to be executed on the chain, thereby causing high on-chain computing resource usage and low system throughput.

[0066] The beneficial effects of the present invention are as follows:

[0067] During the initialization phase of the blockchain system, the present invention deploys the metadata of the access control policy (including the policy ID, version number, and policy hash) into the blockchain smart contract. The specific content of the access control policy is stored in an off-chain trusted execution environment (TEE). When a user initiates an access request, the blockchain system obtains the metadata of the current policy from the chain and loads the corresponding access control rules into the off-chain TEE. The TEE makes an access legitimacy judgment based on multi-dimensional information and generates an access decision. The decision result is digitally signed and returned to the on-chain smart contract for verification, and the access log is recorded. By moving the execution logic of the access control policy to the off-chain trusted execution environment, the present invention significantly reduces the usage of on-chain computing resources, reduces the latency and gas cost of access control operations, and improves the system's throughput and scalability. It is suitable for access control scenarios with high-frequency access and complex policies.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not deviate from the spirit and scope of the present invention should be covered within the protection space of the claims of the present invention.

Claims

1. A blockchain-based adaptive access control method, characterized in that: include: Step 1: Register the policy metadata on-chain; Step 2: Off-chain policy matching during access request; Step 3: Verify and record access decision chain; Step 4: When the access control policy needs to be updated, update the policy and ensure consistency.

2. The blockchain-based adaptive access control method according to claim 1, characterized in that: Step 1 includes: deploying the metadata of the access control policy into the blockchain smart contract during the blockchain system initialization phase, storing the specific content of the access control policy in the off-chain trusted execution environment, and identifying it with the hash value of the corresponding policy hash; In step 1, the metadata of the access control policy includes the policy ID, version number, and policy hash of the access control policy; In step 1, the blockchain smart contract is only responsible for verifying the integrity of the policy hash and does not participate in the execution process of the policy logic of the access control policy.

3. The blockchain-based adaptive access control method according to claim 2, characterized in that: In step 1, for the cross-organizational medical data sharing platform, during the blockchain system initialization phase, the administrator deploys the access control policy P to the off-chain TEE and calculates its hash value H(P). Then, the policy metadata, that is, the metadata of the access control policy (ID, V, H(P)), is submitted to the on-chain smart contract. ID represents the policy ID of the access control policy, V represents the version number of the access control policy, and H(P) represents the policy hash of the access control policy. The specific content of the access control policy P can be expressed as follows: P={if S∈G doctor and A=read and O∈R clinical , then allow}, where S represents the access subject, O represents the access object, G doctor represents the doctor user group, R clinical represents a collection of clinical data; The on-chain smart contract only accesses the metadata of the control policy (ID, V, H(P)) and does not execute the policy logic of the access control policy P.

4. The blockchain-based adaptive access control method according to claim 3 is characterized in that: In step 2, when the user initiates an access request, the blockchain system obtains the metadata of the current access control policy from the on-chain smart contract, which is the blockchain smart contract, and loads the specific content of the corresponding access control policy into the off-chain trusted execution environment, that is, the off-chain TEE. The off-chain TEE performs policy matching based on the multi-dimensional information of the access request triplet and determines the applicable access control rules.

5. The blockchain-based adaptive access control method according to claim 4 is characterized in that: In step 2, after the specific content of the corresponding access control policy P is loaded into the off-chain TEE, it also includes: verifying whether its hash value is consistent with the policy hash H(P) of the access control policy recorded by the on-chain smart contract. If consistent, continue with the subsequent steps of the blockchain-based adaptive access control method. If inconsistent, terminate the execution of the subsequent steps of the blockchain-based adaptive access control method.

6. The blockchain-based adaptive access control method according to claim 5, characterized in that: In step 2, user a initiates an access request to access the clinical data set R as a resource on the cross-organizational medical data sharing platform. clinical When , the blockchain system performs the following steps: Step 2-1: Extract the triplet of the access request initiated by user a: (S=a,A=read,O=R clinical ), read indicates read access; Step 2-2: Get the current policy metadata, that is, get the metadata of the current access control policy (ID, V, H(P)) from the on-chain smart contract; Step 2-3: Load the access control policy P and perform matching, that is, load the access control policy P in the off-chain TEE and perform the policy matching logic match(S,A,O) as shown below based on the access request: Step 2-4: After the policy is matched, an access decision is generated to determine the applicable access control rule. That is, if the value of match(S,A,O) is true, it means that the policy is matched successfully, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=allow, and then the access permission message is output to execute the access control on the clinical data set R. clinical If the value of match(S,A,O) is false, it means that the policy match is unsuccessful, and the applicable access control rule is determined. The applicable access control rule is Decision(S,A,O)=refuse, and then the access prohibition message is output to execute the access control of the clinical data set R clinical The access control rule that applies is the access decision result.

7. The blockchain-based adaptive access control method according to claim 6, characterized in that: In step 3, the access decision result is signed by the off-chain TEE and returned to the on-chain smart contract for verification, and the access decision result, access time, and access subject information are written to the blockchain log.

8. The blockchain-based adaptive access control method according to claim 7, characterized in that: In step 3, for the cross-organizational medical data sharing platform, the off-chain TEE generates a digital signature σ=Sign for Decision(S,A,O) TEE (Decision(S,A,O)), Sign TEE (Decision(S,A,O)) means applying the RSA method to generate a digital signature for Decision(S,A,O), and then submitting the digital signature σ to the on-chain smart contract. After the on-chain smart contract verifies the validity of the digital signature σ, it writes the access decision result, access time, and access subject information into the blockchain log.

9. The blockchain-based adaptive access control method according to claim 8, characterized in that: In step 4, when the access control policy needs to be updated, the blockchain system verifies the update permission in the on-chain TEE. If there is update permission, it updates the local policy copy and submits the hash value and version information of the new policy to the on-chain smart contract. The on-chain smart contract records the policy update event and automatically matches the latest version of the access control policy in subsequent access requests.

10. The blockchain-based adaptive access control method according to claim 9, characterized in that: In step 4, for the cross-organizational medical data sharing platform, when the access control policy needs to be updated, the administrator updates the specific content of the new access control policy P' in the on-chain TEE, calculates the hash value H(P') of the new access control policy, and then submits the metadata of the updated new access control policy (ID, V', H(P')) to the on-chain smart contract. V' represents the version information of the new access control policy, and the new policy P' is expressed as: P'=if S∈G specialist and A=readand O∈R clinical , then allow, where G specialist Represents the specialist user group. The on-chain smart contract records policy update events and automatically matches the latest version of the access control policy in subsequent access requests.

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