A blockchain-based method for sharing data security of internet of things

Abstract

The application discloses a kind of based on blockchain's Internet of Things data security sharing method, attribute-based access control smart contract framework, equipment owner makes attribute and strategy, and smart contract interaction process handles access request;Device in system needs to carry out data interaction by communication tunnel, and the control field of communication tunnel needs to be set by equipment owner negotiation, and the establishment, update, deletion of communication tunnel can only be completed by equipment owner;Set access permission, formulate strategy;Set communication tunnel, carry out data exchange.The application establishes fine-grained access control mechanism using blockchain on one hand, and the owner of Internet of Things device can master the substantial equipment control right without passing through third party;On the other hand, communication tunnel mechanism is proposed, and the owner of equipment sets tunnel information, controls the data interaction between devices, to prevent malicious users from abusing communication resources.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of computer software, and particularly relates to a blockchain-based Internet of Things data security sharing method. BACKGROUND

[0002] Nowadays is the era of everything connected, Internet of Things and sensor technology are developing rapidly. Internet of Things devices not only realize the connection between people and things, things and things, and people and people, but also are further applied in intelligent factories, smart agriculture, intelligent medical treatment and many other fields. Internet of Things devices cooperate with each other, share information, change production mode, improve production efficiency, and play an important role in the development of human society. However, with the continuous expansion of the Internet of Things, its network structure becomes more and more complex, and the data interaction frequency between devices becomes higher and higher. Among them, the data security problem attracts people's attention. How to establish a safe and effective data sharing mechanism between different organizations under the Internet of Things system environment has become the focus of researchers.

[0003] Internet of Things devices generate and exchange a large amount of data, and confidential or private information may be contained in the transmitted data. Once an unauthenticated or unauthorized user uses the system function, it is extremely likely to bring data security risks. In addition, if there is an unscrupulous user, after obtaining authorization, misusing the system function, maliciously exchanging data, or sending meaningless data, or eavesdropping data, it may also bring economic or personal harm to other users. Traditional data sharing mechanisms often transmit the data generated by the device to a trusted third-party entity, which uses a series of methods to analyze the data and provide services for users. However, once the user submits his own data, he loses control over the data, and the user cannot know whether the data is leaked or traded. The centralized data management mechanism is not transparent to the data owner, and there is a risk of personal privacy leakage. In addition to this, the data security problem of the third-party entity occurs frequently, resulting in an untrustworthy network environment at the present stage, and a part of users have a distrustful attitude towards the third-party entity, so it is necessary to propose a trusted and secure data sharing mechanism.

[0004] The emergence of blockchain technology provides a new method to solve such problems. Unlike traditional centralized architecture, a tamper-proof, decentralized system can be built using blockchain technology. Compared with role-based access control, attribute-based access control is more flexible and can provide different granularity of permission control on demand, providing a reliable and dynamic identity authentication and permission control mechanism in Internet of Things data sharing. Combined with the characteristics of blockchain, a communication management mechanism between devices is realized on the smart contract to prevent users from misusing system functions.

[0005] This invention proposes a blockchain-based information sharing mechanism for Internet of Things (IoT) devices. This mechanism leverages the immutability and decentralization of blockchain, integrating attribute-based access control to prevent unauthorized users from maliciously accessing others' devices and data, and using smart contracts to implement an inter-device communication management mechanism to address malicious communication during data sharing. Summary of the Invention

[0006] Purpose of the invention: To address the issues of data leakage and unauthorized access in the Internet of Things (IoT), as well as the problem of fine-grained access control, this invention proposes a blockchain-based IoT data security sharing method to achieve a decentralized access control mechanism, enabling resource owners to truly control resource ownership.

[0007] Technical Solution: This invention provides a blockchain-based method for secure data sharing in the Internet of Things (IoT), comprising the following steps:

[0008] (1) IoT access control: Attribute-based access control smart contract architecture, where the device owner sets attributes and policies, and the smart contract interaction process handles access requests;

[0009] (2) Communication tunnel mechanism: Devices in the system need to interact with each other through a communication tunnel. The control field settings of the communication tunnel need to be negotiated by the device owner. The establishment, updating and deletion of the communication tunnel can only be completed by the device owner.

[0010] (3) Data sharing process: set access permissions and formulate strategies; set up communication tunnels and exchange data.

[0011] Further, step (1) includes the following steps:

[0012] (11) The permission management framework consists of access control contracts, subject attribute contracts, object attribute contracts and policy contracts. The device owner needs to set various device attributes. The subject and object attribute contracts can only be called by the device administrator. At the same time, access control policies also need to be set.

[0013] (12) Access control contract handles access requests: The subject sends a transaction containing the subject ID and the object ID to the access control contract. After receiving the request, the access control contract will obtain the corresponding subject's real attributes, object attributes, and strategies from the subject attribute contract, object attribute contract, and strategy contract respectively, and return the results.

[0014] Furthermore, the operation of the access control contract is as follows:

[0015] Input the address of the subject attribute contract, the object attribute contract, the policy contract, the subject ID of the access request, the access target object ID, and the access action; query the corresponding subject and object attributes from the subject attribute contract and the object attribute contract through the subject ID and the object ID; after obtaining the attributes, query the access control policy that meets the conditions from the policy contract through the subject and object attributes, and return the corresponding error information if there is no such policy; return the access control result according to the policy.

[0016] Further, the control field of the communication tunnel in step (2) includes a communication direction and a communication number.

[0017] Further, the establishment process of the communication tunnel in step (2) is as follows:

[0018] The source device sends a communication request transaction Tx1 to the source owner, which contains the ID of the destination device and the group ID of the destination device, and Tx1 is as follows:

[0019] Tx1 = (DG||DO) (1)

[0020] The source owner adds the source device information and the tunnel information, including the group ID, the device ID, the direction flag, and the communication duration, and signs it as a transaction Tx2 and sends it to the destination owner, and Tx2 is as follows:

[0021] Tx2 = ((DG||DO||SG||SO||TTC||DF) signedbySM ) (2)

[0022] The destination owner verifies the signature after receiving the transaction Tx2, and decides whether to establish the tunnel according to the requirements of the source owner, and if agrees to establish, the destination owner signs the Tx2 with the destination device information to form a transaction Tx3 and sends it to the communication tunnel contract, and Tx3 is as follows:

[0023] Tx3 = (((DG||DO||SG||SO||TTC||DF) signedbySM )) signedbyDM ) (3)

[0024] The communication tunnel contract verifies the signature in Tx3, checks whether there is a duplicate tunnel, and if there is, updates the information, and then the tunnel is established, and the source owner returns the information to the source device to inform whether the communication can be performed.

[0025] Further, the data sharing in step (3) is divided into a permission granting phase and a data exchange phase; in the permission granting phase, the device owner needs to first set device attributes and access strategies, and then the device issues an access application, and the permission management related and permission granting process is performed; in the data exchange phase, after the device obtains authorization, if the communication parties do not belong to the same owner, a communication tunnel needs to be established for data exchange, and the establishment of the tunnel needs to be completed by negotiation of both parties, and after the tunnel is established, communication can be performed.

[0026] Further, the data exchange implementation process is as follows:

[0027] The tunnel ID, the source device ID, the destination device ID and the message to be sent are input; it is inquired whether the communication duration of the corresponding tunnel is 0, if yes, an error is returned to the source device, the setting information of the corresponding tunnel is inquired, if the source device ID and the destination device ID match the setting information of the tunnel, the message is sent, the tunnel communication duration is reduced by one, if not, an error is returned; the direction flag of the corresponding tunnel is checked, if it is 1, the destination device can send the message, if it is 0, the destination device can only receive the message.

[0028] Advantages: Compared with the prior art, the advantages of the present application are: on the one hand, the present application establishes a fine-grained access control mechanism based on a block chain, and the owner of the Internet of Things device can master the substantial device control right without the need for a third party; on the other hand, a communication tunnel mechanism is proposed, the tunnel information is set by the device owner, the data interaction between devices is controlled, and the abuse of communication resources by malicious users is prevented. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a block chain-based Internet of Things device information sharing system framework diagram;

[0030] Figure 2 It is an attribute-based access control contract framework diagram;

[0031] Figure 3 It is a communication tunnel establishment process schematic diagram;

[0032] Figure 4 It is a data sharing flowchart. DETAILED DESCRIPTION

[0033] The present application will be further described in detail below in combination with the drawings.

[0034] The present application proposes a block chain-based Internet of Things device information sharing method, as shown in the figure, which specifically includes the following steps: Figure 1

[0035] (1) Internet of Things permission management: attribute-based access control smart contract framework, the device owner formulates attributes and strategies, and the smart contract interaction process handles access requests.​

[0036] As Figure 2 shown, the attribute-based access control smart contract ABAC framework is composed of four smart contracts, namely, an access control contract (ACC), a subject attribute contract (SAC), an object attribute contract (OAC), and a policy contract (PC). Among them, the SAC and the OAC are used to manage and store the attributes of the subjects and objects, the PC is responsible for managing and storing the access control policies, and the ACC is responsible for the access control in the entire Internet of Things system.

[0037] The subject attribute contract and the object attribute contract are similar in function and are used to store and manage the attributes of the subjects and objects in the Internet of Things. Each group will have an owner, and the two contracts can only be called by the owner of the subject and object to which they belong. At the same time, each subject and object has a unique identifier, namely, an ObjID, which serves as a unique identifier for the subject and object in the contract. The group ID identifies the belonging relationship of each device, which will play a role in communication control in the subsequent data exchange stage. Each ID has various attributes associated with it. The SAC and the OAC also provide application binary interfaces (ABIs) such as SubAttriAdd / ObjAttriAdd, SubAttriDelete / ObjAttriDelete, SubDelete / ObjDelete, etc. to update or delete the attributes of the corresponding subjects and objects. When updating, adding, and deleting attributes, the owner needs to send the ID of the subject or object to be modified to the corresponding ABI of the SAC or OAC. If the contract does not find the attribute entry corresponding to the ID, the contract will automatically create a new entry and update the information. The same process is performed when deleting.

[0038] The policy contract is mainly used to store and manage the defined ABAC policy. The ABI of the policy in this contract can only be called by the owner. A policy contains a set of subject attributes, a set of object attributes, and a set of actions, for example, SA = {SubAttribute1: a1, SubAttribute2: a2}, OA = {ObjAttribute: b1, ObjAttribute: b2}, Action = {Action1, Action2}, this policy stipulates that any subject with attributes a1, a2 can perform the corresponding action on the object with attributes b1, b2. Similar to SAC and OAC, PC also provides policyAdd(), policyDelete(), policyUpdate() and other ABIs to add, delete and update policies respectively. The contract will record the last update time of each policy.

[0039] When searching for a policy, different search methods are used, one for deleting a policy and the other for finding a policy. When deleting a policy, a complete match search is used, which requires the owner to provide all the attribute information of the corresponding subject and object in the policy. This can accurately find the access control policy of the corresponding subject and object, avoiding the deletion of other similar but non-target policies. When searching for a policy, partial search is used, which requires the caller to provide part of the corresponding subject and object attributes. However, searching in this way will find multiple policies that meet the conditions. The found policies are a subset of all policies that meet the conditions. When determining the policy, the contract will first match the policy that only contains the provided attributes, and then return the most recently updated policy based on the policy update time. Partial search is mainly used when ACC processes access requests and searches for policies from PC.

[0040] When formulating a new policy, the more attributes the owner provides, the finer the granularity of the access control policy. When the owner adds a new policy, the contract will query whether there are any conflicting entries in the existing policy. If there are, the owner needs to modify or delete the policy content to eliminate the conflict before adding the new policy. In some cases, there is no need to add a new policy, and the existing policy will cover the new policy.

[0041] The access control contract provides the core function of the entire access control process. This contract controls the entire process of the Internet of Things system from the subject sending a request to returning the request result. The subject sends a transaction containing the subject ID and object ID to the access control contract. After receiving the request, the access control contract obtains the corresponding subject attributes, object attributes, and policies from the subject attribute contract, object attribute contract, and policy contract respectively, and verifies the access control rights of the subject. After confirming the access result, it is returned to the subject and object.

[0042] The access control contract is implemented by the proposed access control algorithm: input the address of the subject attribute contract, the object attribute contract, the policy contract, the subject ID of the access request, the target object ID, and the access action. The subject and object IDs are used to query the corresponding subject and object attributes from the subject attribute contract and the object attribute contract. After obtaining the attributes, the subject and object attributes are used to query the access control policy that meets the conditions from the policy contract. If no policy is found, the corresponding error information is returned. The access control result is returned according to the policy.

[0043] (2) Communication tunnel mechanism: devices in the system need to interact through communication tunnels. The control fields of the communication tunnels (communication direction, communication times) need to be set by the device owner. The establishment, update, and deletion of the tunnels can only be completed by the device owner.

[0044] After the permission is granted, the data sharing of the Internet of Things device enters the data exchange phase. In the Internet of Things system, all data communication is completed by the smart contract. Each communication between devices needs to send a transaction to the smart contract responsible for data communication. Each communication data is stored in the block for auditing to ensure that the data cannot be tampered with.

[0045] To prevent dishonest users from making malicious behavior after obtaining access to the device, which may cause data leakage, tampering, and other problems. The system proposes a communication tunnel mechanism. Devices that meet the conditions and need data interaction must communicate after the communication tunnel is established. The communication tunnel contract (CTC) is used to complete this task.

[0046] In the Internet of Things system, the device that sends the communication is called the source device (SO), the group to which the source device belongs is called the source group (SG), and the owner of the source group is called the source master (SM). The target of the source device to be communicated is called the destiny object (DO). Similarly, the corresponding group and owner are called the destiny group (DG) and the destiny master (DM).

[0047] The communication tunnel contract manages the communication between devices. Each time a device needs to communicate, it needs to call the ABI of the contract and provide the corresponding information. If the SO and DO come from the same group, the two devices can directly exchange data without establishing a communication tunnel. If the SO and DO come from different groups, they need to exchange data in the case of establishing a communication tunnel. Establishing a communication tunnel requires SM and DM to negotiate. Both parties need to call the corresponding ABI in CTC to complete the negotiation. After negotiation, the tunnel setting information will be stored in the block. The characteristics of the block chain cannot be tampered with. Storing tunnel information into the block can record the entire process of tunnel establishment, update and deletion. The life cycle of all communication tunnels is stored in the block to prevent tampering and provide historical record queries. The contents that need to be negotiated are as follows:

[0048] 1) Direction flag (DF). The flag has two states, 0 and 1, representing one-way communication and two-way communication respectively. When the flag bit is 0, SO can only send data to DO. When the flag bit is 1, SO and DO can both send data.

[0049] 2) Time to communicate (TTC). This setting can limit the number of communications between two devices. This field will be recorded in the tunnel settings. Each time a device communicates, the field will be updated until its data is 0. After that, the two devices cannot continue to communicate. This field can be updated by the owner. The size of the field setting value needs to be negotiated and set by the owners of the two parties.

[0050] CTC also provides TunnelRequest(), TunnelInfoCheck() and CommViaTunnel() APIs, respectively, to apply for a tunnel, query tunnel information and use a tunnel to communicate. Figure 3 The process of establishing a communication tunnel is as follows:

[0051] The source device sends a communication request transaction Tx1 to the source owner, containing the ID of the destination device and the group ID of the destination device. Tx1 is as follows:

[0052] Tx1 = (DG || DO) (1)

[0053] The source owner adds source device information and tunnel information, including its group ID, device ID and direction flag, communication duration, and signs it as a transaction Tx2 sent to the destination owner. Tx2 is as follows:

[0054] Tx2 = ((DG || DO || SG || SO || TTC || DF) signedbySM ) (2)

[0055] The destination owner receives the transaction Tx2, verifies the signature, and decides whether to establish a tunnel according to the requirements of the source owner. If the destination owner agrees to establish a tunnel, the destination owner signs the Tx2 with the destination device information to form a transaction Tx3 and sends the transaction Tx3 to the communication tunnel contract. The Tx3 is as follows:

[0056] Tx3 = (((DG || DO || SG || SO || TTC || DF) signedbySM )) signedbyDM ) (3)

[0057] The communication tunnel contract receives the Tx3, verifies the signature, checks whether there is a duplicate tunnel, and updates the information if there is a duplicate tunnel. After the tunnel is established, the communication tunnel contract returns the information to the source owner. The source owner returns the information to the source device to inform whether the communication can be performed.

[0058] After the tunnel is established, the corresponding devices can communicate through the tunnel. Each communication updates the tunnel information until the tunnel cannot be used for communication.

[0059] The communication management mechanism requires that the devices exchange data through the communication tunnel. The devices in the same ownership relationship are considered to be trusted, and the devices in different ownership relationships are considered to be untrusted. The establishment of the communication tunnel requires the owners of the communication devices to negotiate. The control field information of each communication tunnel includes the communication direction and the communication times. The establishment, update, and deletion of the communication tunnel are completed by the smart contract. The communication tunnel information is stored on the block to ensure traceability and non-tamperability. Each time the device communicates, the device needs to send a transaction to the contract to check the tunnel control information and determine whether the tunnel can be used to exchange data.

[0060] (3) Data sharing process: First, the access permission needs to be set, the strategy needs to be formulated, and then the communication tunnel needs to be set. Only then can the devices exchange data.

[0061] The Internet of Things data sharing process is divided into two stages: the permission granting stage and the data exchange stage. In the permission granting stage, the device owner needs to first set the device attribute and the access strategy. Then, the device sends an access application to the permission management contract and executes the permission granting process. In the data exchange stage, after the device obtains the authorization, if the communication parties do not belong to the same owner, the communication tunnel needs to be established for data exchange. The establishment of the tunnel needs the cooperation of the owners of the two parties. After the tunnel is established, the devices can communicate.

[0062] Data exchange is realized through a communication tunnel: input tunnel ID, source device ID, destination device ID, and the message to be sent. First, check if the communication duration of the corresponding tunnel is 0. If it is 0, return an error to the source device. Query the setting information of the corresponding tunnel, such as the source device ID and the destination device ID. If the source device ID and the destination device ID match the tunnel setting, send the message, and reduce the tunnel communication duration by one. If they do not match, return an error. Check the direction flag of the corresponding tunnel. If it is 1, the destination device can send a message. If it is 0, the destination device can only receive a message.

[0063] Figure 4 The entire process of the subject requesting data sharing in the scheme is shown. The horizontal dashed line divides the permission management stage and the data exchange stage, and the vertical dashed line represents the operation or request of each entity. In the permission application stage, the subject needs to first make a request to the ACC, which will query the subject and object attributes according to the subject ID and object ID, and query the relevant strategy through the subject and object attributes, and then return the request result. If the request is successful, and the object and the subject are not in the same group, a communication tunnel needs to be applied to exchange data. The subject will send a communication request to the owner of the subject, and then the owner of the subject and the owner of the object will negotiate and determine the tunnel setting (communication direction, communication times) between the subject and the object. The owners of the subject and the object will sign the tunnel information to ensure the integrity of the information, make a request to the communication tunnel contract, and store the tunnel setting information in the block. After the tunnel is established, the subject can exchange data with the object, and the tunnel information is updated. During communication, all messages are encrypted by the public keys of the communication parties to ensure the confidentiality of the messages.

[0064] All interactions between devices are realized by smart contracts, and access control and communication management become distributed applications in the blockchain. All nodes in the system will execute, and the nodes interact with the contract and other nodes in the form of sending transactions. All access history and results are stored on the blockchain, so that the data sharing system can still work reliably even if some nodes are damaged or invaded.

[0065] In summary, the present application proposes an Internet of Things data sharing mechanism based on a blockchain, analyzes and designs different stages of data management and methods for realizing secure data exchange. The mechanism addresses the problem of centralized permission management in the current Internet of Things, which is not suitable for the development characteristics of the Internet of Things. It proposes an ABAC mechanism based on a blockchain, realizing a distributed and scalable permission management mechanism. Secondly, based on the above mechanism, a communication management mechanism based on a smart contract is proposed for the data exchange stage of the Internet of Things, realizing the management and control of device owners and communication between devices, and the effectiveness and usability of the mechanism are proved through experiments.

[0066] The above merely describes the preferred embodiments of the present application, and it should be pointed out that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1.A blockchain-based method for secure sharing of data in Internet of Things, characterized in that, The method comprises the following steps: (1) Internet of Things permission management: attribute-based access control smart contract framework, device owner sets attributes and strategies, smart contract interaction process handles access requests; (2) Communication tunnel mechanism: devices in the system need to interact through communication tunnels, and the control field of the communication tunnel needs to be set by the device owner, and the establishment, update and deletion of the communication tunnel can only be completed by the device owner; (3) Data sharing process: set access permissions and develop strategies; set communication tunnels and exchange data; The establishment process of the communication tunnel in step (2) is as follows: The source device sends a communication request transaction Tx1 to the source owner, which contains the ID of the destination device and the group ID of the destination device, Tx1 is as follows: Tx1=(DG||DO) (1) The source owner adds the source device information and tunnel information, including the group ID, device ID and direction flag, communication duration, and signs it as a transaction Tx2 sent to the destination owner, Tx2 is as follows: Tx2 = ((DG || DO || SG || SO || TTC || DF) signedbySM ) (2) The destination owner verifies whether the signature is correct after receiving the transaction Tx2, and decides whether to establish a tunnel according to the requirements of the source owner, if agrees to establish, the destination owner will sign the Tx2 with the destination device information to form a transaction Tx3 sent to the communication tunnel contract, Tx3 is as follows: Tx3 = (((DG || DO || SG || SO || TTC || DF) signedbySM )) signedbyDM )(3) The communication tunnel contract receives Tx3 and verifies the signature, checks whether there is a repeated tunnel, if yes, updates the information, and then the tunnel is established, and information is returned to the source owner; The source owner returns information to the source device to inform whether communication can be performed. 2.The blockchain-based IoT data security sharing method of claim 1, wherein, The step (1) comprises the following steps: (11) The permission management framework is composed of an access control contract, a subject attribute contract, an object attribute contract and a strategy contract, and the device owner needs to set the attributes of each device, and the subject and object attribute contracts can only be called by the device manager, and the access control strategy also needs to be set; (12) The access control contract processes access requests: the subject sends a transaction containing the subject ID and the object ID to the access control contract, and the access control contract receives the request and obtains the corresponding subject attribute, object attribute and strategy from the subject attribute contract, object attribute contract and strategy contract respectively and returns the result. 3.The blockchain-based IoT data security sharing method of claim 2, wherein, The working process of the access control contract is as follows: Input the addresses of the subject attribute contract, object attribute contract and strategy contract, the subject ID of the access request, the access target object ID and the access action; query the corresponding subject and object attributes through the subject and object IDs to the subject attribute contract and object attribute contract; After obtaining the attributes, query the access control strategy that meets the conditions through the subject and object attributes to the strategy contract, if not, return the corresponding error information; Return the access control result according to the strategy. 4.The blockchain-based IoT data security sharing method of claim 1, wherein, The control field of the communication tunnel in step (2) includes communication direction and communication times. 5.The blockchain-based IoT data security sharing method of claim 1, wherein, The data sharing in step (3) is divided into a permission granting phase and a data exchange phase; in the permission granting phase, the device owner needs to set the device attributes and access strategies first, and then the device sends an access application, which is related to the permission management and executes the permission granting process; Data exchange phase, after the device gets authorization, if the communication parties do not belong to the same owner, a communication tunnel needs to be established for data exchange. The establishment of the tunnel needs the negotiation of both owners. After the tunnel is established, the communication can be carried out. 6.The blockchain-based IoT data security sharing method of claim 5, wherein, The data exchange implementation process is as follows: Input tunnel ID, source device ID, destination device ID, and the message to be sent. Query whether the communication duration of the corresponding tunnel is 0. If it is 0, return an error to the source device. Query the setting information of the corresponding tunnel. If the source device ID and the destination device ID match the tunnel setting, send the message, and reduce the tunnel communication duration by one. If they do not match, return an error. Check the corresponding tunnel direction flag. If it is 1, the destination device can send a message. If it is 0, the destination device can only receive a message.

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