Intelligent water meter data secure transmission method and system based on NB-IoT and quantum random number generator

Abstract

The invention discloses an intelligent water meter data secure transmission method and system based on NB-IoT and a quantum random number generator, relates to the technical field of electronic information, and solves the problem that data security risks exist in the wireless data transmission process of an existing NB-IoT intelligent water meter. Bidirectional identity authentication is completed between the intelligent water meter and the cloud through the NB-IoT network, and a secure communication channel is established; a quantum random number generator of the intelligent water meter generates a true random number and generates an original quantum key; a key management module of the intelligent water meter provides a specified number of original quantum keys for a key synchronization module according to a key synchronization request sent by the cloud; the intelligent water meter and the cloud end realize original quantum key synchronization; and the intelligent water meter and the cloud carry out post-processing on the synchronized original quantum key to obtain a final security key for data encryption transmission between the intelligent water meter and the cloud, so that the data security risk existing in the wireless data transmission process of the intelligent water meter is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the field of electronic information technology, and in particular to a method and system for securely transmitting smart water meter data based on NB-IoT and a quantum random number generator. Background Art

[0002] With the rise of the Internet of Things (IoT), smart water meters based on narrowband IoT (NB-IoT) are becoming mainstream. As a low-power wide-area network (LPWAN) technology, NB-IoT offers advantages such as low power consumption, wide coverage, low cost, and high connection density. It enables remote transmission of water meter data without relying on on-site wiring, significantly improving meter reading efficiency. A typical solution integrates a complementary metal-oxide-semiconductor (CMOS) image sensor or a transmitter into the water meter to collect flow data. This is then combined with a microcontroller unit (MCU) controller and an NB-IoT communication module to upload the data to a cloud server, enabling remote meter reading and monitoring.

[0003] However, existing NB-IoT smart water meters still face the following technical bottlenecks: The risk of data interception and tampering during wireless transmission exists, especially in open public networks. Traditional encryption algorithms, such as the Advanced Encryption Standard (AES), rely on pseudorandom numbers to generate keys, which are predictable and vulnerable to attack. Some solutions use prepaid IC cards, but the IC card reading and writing processes lack bidirectional authentication, posing the risk of key leakage. Therefore, it is necessary to propose a secure data transmission method and system for smart water meters based on NB-IoT and a quantum random number generator to address these issues. Summary of the invention

[0004] The purpose of the present invention is to provide a smart water meter system and a data security transmission method and system based on NB-IoT and a quantum random number generator, so as to solve the problem of data security risks in the wireless data transmission process of existing NB-IoT smart water meters.

[0005] In a first aspect, the present invention provides a method for securely transmitting data of a smart water meter based on NB-IoT and a quantum random number generator, comprising: S1: After the smart water meter and the cloud are powered on, the terminal communication module of the smart water meter and the cloud communication module of the cloud complete two-way identity authentication through the NB-IoT network and establish a secure communication channel; S2: The quantum random number generator of the intelligent water meter generates true random numbers based on the principles of quantum mechanics and generates the original quantum key. S3: The key management module of the intelligent water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud. S4: The intelligent water meter and the cloud adopt the key encryption key scheme through the key synchronization module. The intelligent water meter encrypts and encapsulates the original quantum key using the built-in key, and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud decrypts it using the same built-in key to obtain the original quantum key, realizing the synchronization of the original quantum key between the intelligent water meter and the cloud. S5: The intelligent water meter and the cloud perform post-processing on the synchronized original quantum key, including error rate estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for data encryption transmission between the intelligent water meter and the cloud.

[0006] Further, step S1 includes: The intelligent water meter sends a connection request to the cloud. After receiving the connection request, the cloud generates a challenge code and sends the challenge code and the cloud certificate to the intelligent water meter. The intelligent water meter verifies the cloud certificate. If the cloud certificate verification passes, the intelligent water meter calculates a response value based on the challenge code. The intelligent water meter submits the intelligent water meter certificate and the response value to the cloud. The cloud verifies the intelligent water meter certificate. If the intelligent water meter certificate verification passes, the intelligent water meter and the cloud perform key negotiation, and the intelligent water meter sends an activation message to the cloud. The cloud verifies the activation message. If the activation message verification passes, the cloud performs key update and clock synchronization calibration, and the two-way identity authentication between the intelligent water meter and the cloud is successful, establishing a secure communication channel. If the cloud certificate verification fails, the intelligent water meter certificate verification fails, or the activation message verification fails, the authentication failure count is incremented by 1. Determine whether the consecutive authentication failure count is greater than or equal to 5. If the consecutive authentication failure count is greater than or equal to 5, the intelligent water meter is locked. If the consecutive authentication failure count is less than 5, the two-way identity authentication between the intelligent water meter and the cloud fails and an error is returned.

[0007] Further, step S3 includes: The intelligent water meter stores the original quantum key in the key storage module. After the intelligent water meter receives the key synchronization request sent by the cloud, it extracts a specified number of original quantum keys from the key storage module and outputs them to the key synchronization module.

[0008] Further, step S4 includes: The intelligent water meter initializes or periodically updates the built-in key with the cloud, and the built-in key is generated by using the RSA algorithm or the national cipher SM2 algorithm; The intelligent water meter encrypts and packages the original quantum key by using the updated built-in key to form an encrypted quantum key packet; The intelligent water meter transmits the encrypted quantum key packet to the cloud through the NB-IoT secure communication channel, and the cloud decrypts it by using the same built-in key to obtain the original quantum key.

[0009] Further, step S5 includes: The key synchronization modules of the intelligent water meter and the cloud respectively publish part of the original quantum keys and calculate the error rate; if the error rate exceeds the preset threshold, the intelligent water meter and the cloud discard the current original quantum keys; The intelligent water meter and the cloud divide the original quantum key into small segments of equal length, perform parity check on each segment, and locate and delete the error bits by segment-by-segment check; The intelligent water meter and the cloud randomly divide the corrected key into sub-segments of equal length, check the parity of each sub-segment to verify the consistency of the corrected key; The intelligent water meter and the cloud use a hash function to compress the verified key to eliminate potential eavesdropping information and obtain the final secure key.

[0010] Further, the preset threshold is pre-agreed by the intelligent water meter and the cloud. If the error rate exceeds this threshold, the intelligent water meter and the cloud determine that there are unacceptable error codes in the original quantum key and perform the discard operation.

[0011] Further, the intelligent water meter and the cloud divide the original quantum key into small segments of equal length, perform parity check on each segment, and locate and delete the error bits by segment-by-segment check, including: First, divide the original key into small segments according to a suitable size, then calculate the number of "1"s in each small segment and judge its parity according to the parity check rule, mark the small segments with inconsistent parity, then divide the marked error small segments into smaller sizes again, calculate the number of "1"s in the sub-segments and judge their parity, continuously narrow the range by subdivision to determine the error position, then delete the bit at the error position for error correction, and finally re-check the corrected key. If there are still errors, repeat all the above steps.

[0012] Furthermore, the smart water meter and the cloud use a hash function to compress the verified key to eliminate potential eavesdropping information and obtain the final secure key, including: First, an initial long key is generated. Then, a function is selected from the family of secure hash functions, and the selected function is used to perform a hash operation on the initial long key to obtain a short key. Next, the two parties determine the hash function through secure negotiation. Based on this, the two parties calculate the same new key as the final secure key.

[0013] On the second aspect, the present invention provides a smart water meter data secure transmission system based on NB-IoT and a quantum random number generator, including: a smart water meter and a cloud; The smart water meter is used to, after the smart water meter and the cloud are powered on, the terminal communication module of the smart water meter and the cloud communication module of the cloud complete two-way identity authentication through the NB-IoT network to establish a secure communication channel; the quantum random number generator of the smart water meter generates true random numbers based on the principles of quantum mechanics to generate an original quantum key; the key management module of the smart water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud; the smart water meter and the cloud adopt a key encryption key scheme through the key synchronization module. The smart water meter encrypts and packages the original quantum key using the built-in key and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud decrypts and obtains the original quantum key using the same built-in key to achieve the synchronization of the original quantum keys between the smart water meter and the cloud; the smart water meter and the cloud perform post-processing on the synchronized original quantum keys, including error estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for the secure data transmission between the smart water meter and the cloud; The cloud is used to send a key synchronization request to the smart water meter after the smart water meter and the cloud complete two-way identity authentication through the NB-IoT network to establish a secure communication channel, so as to achieve the synchronization of the original quantum keys between the smart water meter and the cloud; perform post-processing on the synchronized original quantum keys to obtain the final secure key for the secure data transmission between the smart water meter and the cloud.

[0014] The present invention has the following beneficial effects: For the smart water meter data secure transmission method and system based on NB-IoT and a quantum random number generator of the present invention, the quantum random number generator is arranged on the smart water meter, effectively avoiding the risk of the center being breached and large-scale key leakage. The post-processing idea of quantum key distribution is applied to the smart water meter and key distribution, further enhancing the security of smart water meter data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To more clearly illustrate the technical solution of the present invention, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a flowchart of the intelligent water meter data security transmission method based on NB-IoT and quantum random number generator provided by the present invention.

[0017] Figure 2 It is a schematic diagram of the intelligent water meter and the cloud. Specific embodiments

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments and corresponding accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention. The technical solutions provided by each embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Please refer to Figure 1 , an intelligent water meter data security transmission method based on NB-IoT and quantum random number generator provided by an embodiment of the present invention, includes: S1: After the intelligent water meter and the cloud are powered on, the terminal communication module of the intelligent water meter and the cloud communication module of the cloud complete two-way identity authentication through the NB-IoT network to establish a secure communication channel.

[0020] Specifically, step S1 includes: the intelligent water meter sends a connection request to the cloud; after receiving the connection request, the cloud generates a challenge code and sends the challenge code and the cloud certificate to the intelligent water meter; the intelligent water meter verifies the cloud certificate; if the cloud certificate verification is passed, the intelligent water meter calculates a response value according to the challenge code; the intelligent water meter submits the intelligent water meter certificate and the response value to the cloud.

[0021] The cloud verifies the smart water meter certificate; if the smart water meter certificate verification passes, the smart water meter and the cloud perform key negotiation, and the smart water meter sends an activation message to the cloud; the cloud verifies the activation message; if the activation message verification passes, the cloud performs key update and clock synchronization calibration, and the two-way authentication between the smart water meter and the cloud is successful, and a secure communication channel is established. If the cloud certificate verification fails, the smart water meter certificate verification fails, or the activation message verification fails, the authentication failure count is incremented by 1; it is determined whether the consecutive authentication failure count is greater than or equal to 5; if the consecutive authentication failure count is greater than or equal to 5, the smart water meter is locked; if the consecutive authentication failure count is less than 5, the two-way authentication between the smart water meter and the cloud fails and an error is returned.

[0022] Through the two-way certificate verification and challenge code mechanism, the present invention significantly improves communication security. The random challenge code generated by the cloud can effectively prevent replay attacks and ensure the uniqueness of each authentication response; the smart water meter and the cloud mutually verify the legitimacy of each other's certificates, such as device identification, CA signature, etc., to avoid illegal device access and ensure the authenticity of both communication parties from the identity level. The activation message verification and clock synchronization calibration mechanism improve the reliability of the system. After the smart water meter sends an activation message, the cloud verifies its validity to ensure that the device is in a normal working state; the clock synchronization calibration avoids authentication or data processing errors caused by time differences. The authentication failure counting and locking mechanism enhances the anti-attack ability of the system. If the consecutive authentication failure count exceeds 5 times, the smart water meter is locked, which can prevent malicious attacks such as brute force cracking and reduce the risk of illegal intrusion.

[0023] S2: The quantum random number generator of the smart water meter generates true random numbers based on the principles of quantum mechanics and generates the original quantum key.

[0024] The unpredictability of quantum random numbers ensures key security at the physical layer and resists classical and quantum attacks; the unbiasedness of true random numbers improves the accuracy of error detection and enhances the reliability of data transmission. The quantum random number generator is arranged on the smart water meter, effectively avoiding the risk of the center being breached and large-scale key leakage.

[0025] S3: The key management module of the smart water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud.

[0026] Specifically, step S3 includes: the smart water meter stores the original quantum key in the key storage module; after the smart water meter receives the key synchronization request sent by the cloud, it extracts a specified number of original quantum keys from the key storage module and outputs them to the key synchronization module.

[0027] S4: The intelligent water meter and the cloud adopt a key encryption key scheme through the key synchronization module. The intelligent water meter uses the built-in key to encrypt and encapsulate the original quantum key, and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud uses the same built-in key to decrypt and obtain the original quantum key, realizing the synchronization of the original quantum key between the intelligent water meter and the cloud.

[0028] Specifically, the intelligent water meter and the cloud initialize or periodically update the built-in key, and the built-in key is generated by using the RSA algorithm or the national cryptographic SM2 algorithm; the intelligent water meter uses the updated built-in key to encrypt and encapsulate the original quantum key through the encryption and decryption module to form an encrypted quantum key package; the intelligent water meter transmits the encrypted quantum key package to the cloud through the NB-IoT secure communication channel, and the cloud uses the same built-in key to decrypt through the encryption and decryption module to obtain the original quantum key.

[0029] Periodically updating the built-in key can dynamically resist the risk of key leakage. Combining the high-strength encryption characteristics of the RSA / SM2 asymmetric algorithm, it ensures that the original quantum key is not intercepted or tampered with during the NB-IoT transmission process; the cloud decrypts through the same built-in key to obtain the complete original quantum key, ensuring the accuracy and security of key synchronization, and providing a reliable basis for subsequent data encrypted transmission.

[0030] S5: The intelligent water meter and the cloud perform post-processing on the synchronized original quantum key, including error rate estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for data encrypted transmission between the intelligent water meter and the cloud.

[0031] Error rate estimation: The key synchronization modules of the intelligent water meter and the cloud respectively publish part of the original quantum key and calculate the error rate; error rate = (number of bits transmitted incorrectly ÷ total number of bits transmitted) × 100%. If the error rate exceeds the preset threshold, the intelligent water meter and the cloud discard the current original quantum key; among them, the preset threshold is pre-agreed by the intelligent water meter and the cloud. If the error rate exceeds this threshold, the intelligent water meter and the cloud determine that there are unacceptable error codes in the original quantum key and perform the discard operation.

[0032] Through the public comparison of part of the keys, it is possible to detect in a timely manner the error codes caused by signal interference, noise, or malicious interception during the wireless transmission process, avoid using defective keys for subsequent encryption, thereby preventing data transmission errors or leakage risks, and directly improving the security and reliability of the communication between the intelligent water meter and the cloud; actively discarding keys with a high error rate can effectively filter out invalid keys generated due to transmission anomalies or attacks, ensuring that the keys used subsequently have high reliability.

[0033] Key error correction: The smart water meter and the cloud divide the original quantum key into small segments of equal length, perform parity checks on each segment, and locate and delete the error bits by segment-by-segment verification. Specifically, first divide the original key into small segments of appropriate size, then calculate the number of "1"s in each small segment and determine its parity according to the parity check rule, mark the small segments with inconsistent parity, then divide the marked error small segments into smaller sizes again, calculate the number of "1"s in the sub-segments and determine their parity, continuously narrow down the range by continuous subdivision to determine the error location, then delete the bit at the error location for error correction, and finally re-check the corrected key. If there are still errors, repeat all the above steps.

[0034] The hierarchical and segmented parity check mechanism can effectively detect bit errors caused by signal interference, noise, or potential attacks during wireless transmission, avoid using defective keys for encryption, and directly reduce the risk of data transmission errors or leakage. Adapting to the low-power consumption characteristics, the computational complexity of segmented verification and location is small, and it can be efficiently completed under the limited computing resources of the smart water meter to ensure the real-time nature of key processing. By repeating verification and error correction, invalid keys caused by transmission anomalies or attacks can be filtered out.

[0035] Key verification: The smart water meter and the cloud randomly divide the corrected key into sub-segments of equal length, and check the parity of each sub-segment to verify the consistency of the corrected key.

[0036] By randomly dividing the sub-segments and checking the parity, bit errors that may be missed during the error correction process, such as local errors caused by signal interference or potential attacks, can be effectively detected, avoiding using defective keys for subsequent encryption, and directly reducing the risk of data transmission errors or leakage. The method of randomly dividing the sub-segments avoids the statistical bias that may be brought by fixed segmentation, ensuring that the verification result is more objective; the computational complexity of parity check is small and the efficiency is high, adapting to the low-power consumption characteristics of the smart water meter, and the verification can be quickly completed under limited computing resources.

[0037] Privacy amplification: The smart water meter and the cloud use a hash function to compress the verified key to eliminate potential eavesdropping information and obtain the final secure key.

[0038] Specifically, first generate an initial long key, then select a function from the family of secure hash functions, perform a hash operation on the initial long key using the selected function to obtain a short key, then the two parties determine this hash function through secure negotiation, and based on this, the two parties calculate the same new key as the final secure key.

[0039] The unpredictability of the combined quantum initial long key of the hash function effectively resists classical brute-force attacks and potential threats of quantum computing. The process of both parties negotiating and determining the hash function ensures the unity of the key generation rule, avoiding the key mismatch problem caused by differences in function selection; the fixed-length design of the short key reduces the storage and transmission costs, adapting to the low-resource and low-power characteristics of Internet of Things devices such as smart water meters. By performing a hash operation to compress the long key into a short key, the complexity of key storage and processing is reduced. Combining with the standardized process of the negotiation mechanism, secure keys that meet the encryption requirements can be quickly generated, improving the real-time performance and reliability of data transmission between the smart water meter and the cloud.

[0040] Please refer to Figure 2 , based on the above method, an embodiment of the present invention provides a smart water meter data secure transmission system based on NB-IoT and a quantum random number generator, including: a smart water meter and a cloud.

[0041] The smart water meter is used to, after the smart water meter and the cloud are powered on, the terminal communication module of the smart water meter and the cloud communication module of the cloud complete two-way authentication through the NB-IoT network to establish a secure communication channel; the quantum random number generator of the smart water meter generates true random numbers based on the principles of quantum mechanics to generate the original quantum key; the key management module of the smart water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud; the smart water meter and the cloud adopt a key encryption key scheme through the key synchronization module. The smart water meter encrypts and packages the original quantum key using the built-in key and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud decrypts it using the same built-in key to obtain the original quantum key, realizing the synchronization of the original quantum key between the smart water meter and the cloud; the smart water meter and the cloud perform post-processing on the synchronized original quantum key, including error code estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for data encrypted transmission between the smart water meter and the cloud; The cloud is used to, after the smart water meter and the cloud complete two-way authentication through the NB-IoT network to establish a secure communication channel, send a key synchronization request to the smart water meter to realize the synchronization of the original quantum key between the smart water meter and the cloud; perform post-processing on the synchronized original quantum key to obtain the final secure key for data encrypted transmission between the smart water meter and the cloud.

[0042] The above-described embodiments of the present invention do not constitute a limitation on the protection scope of the present invention.

Claims

1. An intelligent water meter data secure transmission method based on NB-IoT and quantum random number generator, characterized in that, Including: S1: After the intelligent water meter and the cloud are powered on, the terminal communication module of the intelligent water meter and the cloud communication module of the cloud complete two-way authentication through the NB-IoT network and establish a secure communication channel; S2: The quantum random number generator of the intelligent water meter generates true random numbers based on the principles of quantum mechanics to generate the original quantum key; S3: The key management module of the intelligent water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud; S4: The intelligent water meter and the cloud adopt the key encryption key scheme through the key synchronization module. The intelligent water meter encrypts and encapsulates the original quantum key using the built-in key and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud decrypts it using the same built-in key to obtain the original quantum key, realizing the synchronization of the original quantum key between the intelligent water meter and the cloud; S5: The intelligent water meter and the cloud perform post-processing on the synchronized original quantum key, including error code estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for data encrypted transmission between the intelligent water meter and the cloud.

2. The intelligent water meter data security transmission method based on NB-IoT and quantum random number generator according to claim 1, characterized in that Step S1 includes: The intelligent water meter sends a connection request to the cloud; After receiving the connection request, the cloud generates a challenge code and sends the challenge code and the cloud certificate to the intelligent water meter; The intelligent water meter verifies the cloud certificate; If the cloud certificate verification passes, the intelligent water meter calculates the response value according to the challenge code; The intelligent water meter submits the intelligent water meter certificate and the response value to the cloud; The cloud verifies the intelligent water meter certificate; If the intelligent water meter certificate verification passes, the intelligent water meter and the cloud perform key negotiation, and the intelligent water meter sends an activation message to the cloud; The cloud verifies the activation message; If the activation message verification passes, the cloud performs key update and clock synchronization calibration, and the two-way authentication between the intelligent water meter and the cloud is successful, establishing a secure communication channel; If the cloud certificate verification fails, the intelligent water meter certificate verification fails, or the activation message verification fails, the authentication failure count is incremented by 1; Judge whether the continuous authentication failure count is greater than or equal to 5; If the continuous authentication failure count is greater than or equal to 5, the intelligent water meter is locked; If the continuous authentication failure count is less than 5, the two-way authentication between the intelligent water meter and the cloud fails and an error is returned.

3. The intelligent water meter data security transmission method based on NB-IoT and quantum random number generator according to claim 1, characterized in that, Step S3 includes: The intelligent water meter stores the original quantum key in the key storage module; After receiving the key synchronization request sent by the cloud, the intelligent water meter extracts a specified number of original quantum keys from the key storage module and outputs them to the key synchronization module.

4. The intelligent water meter data security transmission method based on NB-IoT and quantum random number generator according to claim 1, characterized in that, Step S4 includes: The intelligent water meter and the cloud initialize or periodically update the built-in key, and the built-in key is generated using the RSA algorithm or the national cryptographic SM2 algorithm; The intelligent water meter encrypts and encapsulates the original quantum key using the updated built-in key to form an encrypted quantum key package; The intelligent water meter transmits the encrypted quantum key package to the cloud through the NB-IoT secure communication channel, and the cloud decrypts it using the same built-in key to obtain the original quantum key.

5. The intelligent water meter data security transmission method based on NB-IoT and quantum random number generator according to claim 1, characterized in that, Step S5 includes: The key synchronization module between the intelligent water meter and the cloud respectively discloses part of the original quantum key and calculates the error rate; if the error rate exceeds the preset threshold, the intelligent water meter and the cloud discard the current original quantum key; The intelligent water meter and the cloud divide the original quantum key into small segments of equal length, perform parity checks on each segment, and locate and delete the error bits by checking each segment one by one; The intelligent water meter and the cloud randomly divide the error-corrected key into sub-segments of equal length, check the parity of each sub-segment, and verify the consistency of the error-corrected key; The intelligent water meter and the cloud use a hash function to compress the verified key to eliminate potential eavesdropping information and obtain the final secure key.

6. The intelligent water meter data security transmission method based on NB-IoT and quantum random number generator as claimed in claim 5, wherein The preset threshold is pre-agreed between the intelligent water meter and the cloud. If the error rate exceeds this threshold, the intelligent water meter and the cloud determine that there are unacceptable error codes in the original quantum key and perform the discard operation.

7. The intelligent water meter data secure transmission method based on NB-IoT and quantum random number generator as claimed in claim 5, characterized in that The intelligent water meter and the cloud divide the original quantum key into small segments of equal length, perform parity checks on each segment, and locate and delete the error bits by checking each segment one by one, including: First, divide the original key into small segments according to a suitable size, then calculate the number of "1"s in each small segment and judge its parity according to the parity check rule, mark the small segments with inconsistent parity, then divide the marked error small segments into smaller sizes again, calculate the number of "1"s in the sub-segments and judge their parity, continuously narrow the range by continuous subdivision to determine the error position, then delete the bit at the error position for error correction, and finally re-check the error-corrected key. If there are still errors, repeat all the above steps.

8. The intelligent water meter data secure transmission method based on NB-IoT and quantum random number generator according to claim 5, characterized in that, The intelligent water meter and the cloud use a hash function to compress the verified key to eliminate potential eavesdropping information and obtain the final secure key, including: First, generate an initial long key, then select a function from the secure hash function family, use the selected function to perform a hash operation on the initial long key to obtain a short key, then the two parties determine this hash function through secure negotiation, and based on this, the two parties calculate the same new key as the final secure key.

9. An intelligent water meter data secure transmission system based on NB-IoT and a quantum random number generator, characterized in that, Including: Intelligent water meter and cloud; The intelligent water meter is used to complete two-way authentication between the terminal communication module of the intelligent water meter and the cloud communication module of the cloud through the NB-IoT network after the intelligent water meter and the cloud are powered on, and establish a secure communication channel; the quantum random number generator of the intelligent water meter generates true random numbers based on the principles of quantum mechanics to generate the original quantum key; the key management module of the intelligent water meter stores the original quantum key and provides a specified number of original quantum keys to the key synchronization module according to the key synchronization request sent by the cloud; the intelligent water meter and the cloud adopt the key encryption key scheme through the key synchronization module. The intelligent water meter encrypts and packages the original quantum key using the built-in key and transmits the encapsulated quantum key to the cloud through the NB-IoT secure communication channel. The cloud decrypts it using the same built-in key to obtain the original quantum key, realizing the synchronization of the original quantum key between the intelligent water meter and the cloud; the intelligent water meter and the cloud perform post-processing on the synchronized original quantum key, including error code estimation, key error correction, key verification, and privacy amplification, to obtain the final secure key for data encryption transmission between the intelligent water meter and the cloud. The cloud is used to send a key synchronization request to the intelligent water meter after the intelligent water meter and the cloud complete two-way authentication through the NB-IoT network and establish a secure communication channel, realizing the synchronization of the original quantum key between the intelligent water meter and the cloud; perform post-processing on the synchronized original quantum key to obtain the final secure key for data encryption transmission between the intelligent water meter and the cloud.

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