Blockchain and covert communication-based lightweight authentication method for internet of things

Abstract

The application relates to a lightweight authentication method for Internet of Things based on a blockchain and covert communication, which comprises the following steps: an Internet of Things device generates an identity tag by using a key and a message, and broadcasts the tag and the message to a blockchain node according to a certain power distribution; a binary hypothesis is used to perform threshold testing on an extracted residual signal, so that a detected tag sequence is obtained; each blockchain node broadcasts the detected tag sequence to other nodes and receives and stores the tag sequences sent by other nodes; the tag sequences from other blockchain nodes are aggregated, and each node performs global decision on the tag sequences by using a global aggregation rule weighted by channel conditions and reputation; the reputation of the blockchain node is updated; and an authentication result and related information are stored on a chain by using an rPBFT consensus protocol, so that consistent identity verification and reputation management are guaranteed. The application uses a global aggregation rule weighted by channel conditions and reputation, and has stronger robustness and security.

Description

Technical Field

[0001] This invention belongs to the field of Internet of Things (IoT) security, and specifically relates to a lightweight IoT authentication method based on blockchain and covert communication. Background Technology

[0002] The Internet of Things (IoT) is an emerging communication network that enables interconnection and interoperability of any objects, including sensors, tags, and smart devices, based on the internet. IoT plays a crucial role in various application scenarios in people's lives and work, including smart cities, smart shopping malls, smart banks, smart agriculture, and home automation. With the widespread application of IoT technology in these fields, network security has become a critical issue, especially for IoT systems involving end-user privacy. The first network defense against malicious intrusion into IoT systems is the authentication mechanism, which checks the user's identity information by determining their access permissions. To protect the privacy of IoT terminals, various authentication mechanisms have been introduced into IoT systems. Generally, these authentication mechanisms rely on a central management system that establishes a cryptographic paradigm to protect identity information from leakage. However, the large number of small, low-powered, and resource-constrained terminal devices in the IoT makes it difficult for traditional, complex, user-driven security authentication protocols to function effectively in resource-constrained environments. To meet the information security needs of the IoT, adopting lightweight authentication mechanisms is an effective method to address the issue of authenticating device information with limited resources.

[0003] There are two information hiding schemes at the physical layer. In the first type, the covert information is hidden in background noise. In the second type, the covert information is embedded in an overlay signal. These two schemes have different applications and requirements. For example, the first is used for confidential communication, while the second is used for authentication or steganography. Hiding identity information in the physical layer avoids the need for resource-intensive cryptography and upper-layer processing; furthermore, it leverages the uncertainty created by noise in the wireless communication environment to protect identity information, preventing brute-force attacks by computationally powerful attackers.

[0004] Blockchain is an immutable and forgery-proof decentralized ledger that stores sequential data that can be verified within the system. As a data structure, a blockchain consists of many blocks linked together chronologically, containing transactions submitted to it. The addition of a consensus mechanism transforms the blockchain into a trusted network. Blockchain is characterized by transparency, decentralization, traceability, immutability, collective maintenance, and anonymity, features that can be used to address problems caused by the centralization of traditional authentication mechanisms. Summary of the Invention

[0005] The purpose of this invention is to provide a lightweight authentication method for the Internet of Things based on blockchain and covert communication.

[0006] The technical solution for achieving the objective of this invention is as follows: Firstly, this invention provides a tag-based physical layer authentication method with concealment, comprising the following steps:

[0007] IoT device authentication request: IoT devices use keys and messages to generate identity tags, and broadcast the tags and messages to blockchain nodes via wireless media according to a certain power allocation;

[0008] Local detection: Blockchain nodes use a binary assumption to perform a threshold test on the residual signal extracted from the transmitted signal to obtain a detection tag sequence;

[0009] Result broadcasting: Each blockchain node broadcasts the detected tag sequence to other nodes and receives and stores the tag sequences sent by other nodes;

[0010] Global aggregation: After aggregating the tag sequences from other blockchain nodes, each node makes a global decision on the tag sequences using a global aggregation rule weighted by channel conditions and reputation;

[0011] Reputation Update: Update the reputation of blockchain nodes using global aggregation results;

[0012] Information on-chain: The rPBFT consensus protocol is used to store authentication results and related information on the blockchain to ensure consistent identity verification and reputation management.

[0013] In a second aspect, the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method described in the first aspect.

[0014] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0015] Compared with existing technologies, the significant advantages of this invention are: 1) This invention overcomes the incompatibility problem caused by the reliance on a management center in traditional authentication technologies. By combining IoT terminal authentication with blockchain, it enables distributed collaborative authentication of IoT terminals. 2) This invention hides identity information in the physical layer, utilizing noise in the wireless communication environment to protect the identity information. This overcomes the security risks caused by transmitting identity information over public channels, avoids the resource consumption of cryptographic paradigms and upper-layer processing, and is more suitable for IoT terminals with lower capabilities. 3) This invention uses a global aggregation rule based on channel conditions and reputation weighting, which has stronger robustness and security than traditional tag-based physical layer authentication technologies. Attached Figure Description

[0016] Figure 1 This describes the tag embedding and transmission process in this invention.

[0017] Figure 2 This invention presents a technical framework for authenticating access nodes. Detailed Implementation

[0018] Combination Figure 1 , Figure 2 A lightweight authentication method for the Internet of Things (IoT) based on blockchain and covert communication, combining blockchain to achieve lightweight authentication of IoT devices, includes:

[0019] (1) IoT device authentication request: The IoT device uses a key and message agreed upon in advance with the receiver to generate a tag representing identity information, embeds the tag into the message according to the agreed power allocation, and then broadcasts it to the receiver through a wireless medium.

[0020] (1.1) Generating Identity Tags: Assuming the pre-agreed key between the sender and receiver is k, the message sent by the IoT device after encoding and BPSK modulation is represented as s, with a length of L. The generation of the tag representing identity information is given by the following formula.

[0021] t = g(s,k)

[0022] Where g is a hash function.

[0023] (1.2) Tag-embedded messages: IoT devices allocate transmit power to messages and tags, ρ s and ρ t Let these represent the energy allocation for messages and tags, respectively, and be subject to the following constraints:

[0024]

[0025] The transmitted signal of an IoT device can be represented as

[0026] x = ρ s *s+ρ t *t

[0027] Generally speaking, the minimum distance between the symbol and the modulation boundary determines the demodulation capability of the message, so the tag is embedded vertically into the message, i.e., s is an imaginary number and t is a real number.

[0028] (2) Local detection: Each blockchain node extracts the residual signal from the received signal according to the pre-agreed authentication scheme, and then uses the binary hypothesis to perform a threshold test on the residual signal to obtain the detection label sequence.

[0029] (2.1) Extracting the residual signal: The received signal of the i-th blockchain node is expressed by the following formula.

[0030] yi =h i *x+n i

[0031] Where h i This represents the channel status between the i-th blockchain node and the IoT device, n i This represents the noise at the i-th blockchain node.

[0032] Blockchain nodes estimate the channel using the following formula.

[0033]

[0034] Where p represents the pilot frequency, y p,i Let H represent the pilot signal received by the i-th blockchain node, and let H represent the transpose of the matrix. Channel equalization is performed using the estimated channel conditions.

[0035]

[0036] Where * denotes the conjugate of the matrix. The i-th blockchain node pair Demodulation, decoding, re-encoding, and remodulation are performed to obtain an estimate of the message. Then we can obtain an estimate of the label.

[0037]

[0038] Then, the residual signal is extracted using the following formula.

[0039]

[0040] (2.2) Threshold test: Blockchain nodes establish the following binary assumptions

[0041] H0:y i This is a normal signal

[0042] H1:y i It is a tag signal

[0043] The j-th bit of the residual signal is represented under different assumptions as

[0044]

[0045]

[0046] in In reliable wireless communication systems, the physical layer should provide error-free bit sequences to the upper layers. The i-th blockchain node takes the real part of the residual signal to construct the test statistic τ. i Then establish the following binary hypothesis.

[0047] H 10:t j =-1

[0048] H 11 :t j =1

[0049] Where j represents the j-th bit of the label.

[0050]

[0051]

[0052] Where N represents the number of blockchain nodes, P n This represents the noise power at the receiving end. The threshold test is expressed as...

[0053]

[0054] (3) Result broadcasting: Each blockchain node broadcasts the tag sequence obtained from the threshold test to other nodes, which will record the received tag sequence in their local memory.

[0055] (4) Global Aggregation: After aggregating the tag sequences from all other blockchain nodes, each blockchain node makes a global decision on the tag bit sequences using a global aggregation rule weighted by channel conditions and reputation. The reputation of the i-th blockchain node in the k-th round of authentication is represented as:

[0056]

[0057] in This represents the channel status between the i-th blockchain node and the IoT device in the k-th round of authentication. This reflects the accuracy of the authentication performed by the i-th blockchain node up to the k-th round. The global aggregation of the tag sequence can be expressed by the following formula:

[0058]

[0059] in This represents the j-th bit of the tag sequence detected locally by the m-th blockchain node. This represents the reputation of the m-th blockchain node in the k-th round of authentication.

[0060] If ultimately If the difference between the value of the device and the value of t is no more than 20%, the IoT device is considered to be legitimate and the authentication is successful.

[0061] (5) Reputation Update: Using the global aggregation results, update the local reputation of each blockchain node using the following formula.

[0062]

[0063] in This represents the j-th bit of the tag sequence detected locally by the m-th blockchain node. Let L represent the j-th bit of the tag sequence obtained from global aggregation, and L represent the length of the tag sequence.

[0064] Each blockchain node broadcasts its local reputation over the network, and other nodes can verify whether the reputation value received from the node matches their detection results.

[0065] Information on-chain: The rPBFT consensus protocol is used to store authentication results and related information on the blockchain, ensuring consistent authentication and reputation management. At each block height, rPBFT stipulates that a group of n blockchain nodes with the highest weights are selected as the consensus group, with weights determined by reputation and current channel status. The node with the highest weight is selected as the leader, and the weight of each consensus group member can be verified based on off-chain reputation management and channel status. The rPBFT algorithm operates in four phases: pre-preparation, preparation, commit, and response. First, in the block generation phase, the leader creates a block and broadcasts it to the consensus group. The block consists of a block header and a block body. Specifically, the block header includes metadata such as authentication requests, local detection results, reputation data, channel status, the leader's public address, timestamp, and the hash value of the previous block. The block body mainly includes the detected tag bit sequence and the local reputation values ​​of all consensus nodes. Consensus group members first verify the block content, such as the leader's legitimacy and local detection results, and then enter the preparation phase. Second, in the preparation phase, each member signs a specific verification time on the verified block and broadcasts a "ready" message within the consensus group. Third, if each member receives and verifies "ready" messages from 2f different members, the commit phase begins, where f is the number of Byzantine nodes in the system. Each member then sends a "committed" message to the other members. If each member receives and verifies "commit" messages from 2f+1 different members, consensus group members respond to accessing IoT devices with reply messages. If an IoT device collects f+1 reply messages from different consensus group members, the device is granted access to the IoT network. If the block content is unreliable, block proposals from malicious leaders will be rejected by honest consensus group members. Furthermore, similar to traditional PBFT, if the leader at the current block height is interrupted due to a crash, members will vote to change their opinion. The node with the second-highest reputation value in the consensus group becomes the leader for this round.

[0066] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A tag-based physical layer authentication method with concealment, characterized in that, Includes the following steps: IoT device authentication request: IoT devices use keys and messages to generate identity tags, and broadcast the tags and messages to blockchain nodes via wireless media according to a certain power allocation; Local detection: Blockchain nodes use a binary assumption to perform a threshold test on the residual signal extracted from the transmitted signal to obtain the detection tag sequence; the threshold test method is as follows: Blockchain nodes are established based on the following binary assumptions ； The j-th bit of the residual signal is represented under different assumptions as ； ； in Because in a reliable wireless communication system, the physical layer should provide error-free bit sequences to the upper layers; and These represent the energy allocation for messages and tags, respectively. This represents the channel condition between the i-th blockchain node and the IoT device; the i-th blockchain node takes the real part of the residual signal to construct the test statistic. Then establish the following binary hypothesis. ； Where j represents the j-th bit of the label; the distribution of the j-th bit of the test statistic under different hypotheses is expressed as follows: ； Where N represents the number of blockchain nodes, P n This represents the noise power at the receiving end; the threshold test is expressed as... ； Result broadcasting: Each blockchain node broadcasts the detected tag sequence to other nodes and receives and stores the tag sequences sent by other nodes; Global aggregation: After aggregating the tag sequences from other blockchain nodes, each node makes a global decision on the tag sequences using a global aggregation rule weighted by channel conditions and reputation; Reputation Update: Update the reputation of blockchain nodes using global aggregation results; Information on-chain: The rPBFT consensus protocol is used to store authentication results and related information on the blockchain to ensure consistent identity verification and reputation management.

2. The tag-based physical layer authentication method with concealment according to claim 1, characterized in that, The method for generating identity tags is as follows: Assuming the pre-agreed key between the sender and receiver is k, the message sent by the IoT device after encoding and BPSK modulation is represented as s, with a length of L; the generation of the tag representing identity information is given by the following formula. ； in, It is a hash function.

3. The tag-based physical layer authentication method with concealment according to claim 2, characterized in that, The method for embedding tags into messages is as follows: IoT devices allocate transmit power to messages and tags, subject to the following constraints. ； The transmitted signal of an IoT device can be represented as 。 4. The tag-based physical layer authentication method with concealment according to claim 3, characterized in that, The method for extracting residual signals is as follows: The received signal of the i-th blockchain node is represented by the following formula. ； in, This represents the noise at the i-th blockchain node; Blockchain nodes estimate the channel using the following formula. ； in Indicates pilot frequency, H represents the pilot signal received by the i-th blockchain node, and H represents the transpose of the matrix; channel equalization is performed using the estimated channel conditions. ； Where * denotes the conjugate of the matrix; the i-th blockchain node pair Demodulation, decoding, re-encoding, and remodulation are performed to obtain an estimate of the message. Then we can obtain an estimate of the label. ； Then, the residual signal is extracted using the following formula. 。 5. The tag-based physical layer authentication method with concealment according to claim 1, characterized in that, Each blockchain node broadcasts the tag sequence obtained from the threshold test to other nodes, which then record the received tag sequence in their local memory.

6. The tag-based physical layer authentication method with concealment according to claim 1, characterized in that, The reputation of the i-th blockchain node in the k-th round of authentication is represented as follows: ； in This represents the channel status between the i-th blockchain node and the IoT device in the k-th round of authentication. This represents the accuracy of the authentication performed by the i-th blockchain node before the k-th round; the global aggregation of the tag sequence can be expressed by the following formula. ； in This represents the j-th bit of the tag sequence detected locally by the m-th blockchain node. This represents the reputation of the m-th blockchain node in the k-th round of authentication; If ultimately and If the difference is no more than 20%, the IoT device is considered legitimate and the authentication is successful.

7. The tag-based physical layer authentication method with concealment according to claim 6, characterized in that, Using the global aggregation results, update the local reputation of each blockchain node using the following formula. ； in This represents the j-th bit of the tag sequence obtained from global aggregation. Indicates the length of the label sequence; Each blockchain node broadcasts its local reputation over the network, and other nodes can verify whether the reputation value received from the node matches their detection results.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method as described in any one of claims 1-7.

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