Quantum-resistant secure communication system and method for an edge terminal system using a hardware security architecture and post-quantum cryptography software

Abstract

The present invention discloses a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software.A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software according to the present invention is a quantum-resistant secure communication system of an Edge terminal system connected to one or more field sensors, comprising: a sensor interface unit that receives measurement data and sensor status information from the one or more field sensors; a hardware security unit that stores at least one of device unique information, a root key, an authentication key, key protection information, and a security random number of the Edge terminal system within a hardware-based security area; a quantum-resistant cryptographic processing unit that performs at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security unit; a quantum-resistant key exchange unit that performs quantum-resistant key exchange with an external server based on information protected by the hardware security unit and the processing result of the quantum-resistant cryptographic processing unit, and derives a session key used for secure transmission of the measurement data based on the quantum-resistant key exchange; and the occurrence of a field event including at least one of a physical risk event, a sensor abnormality event, a communication abnormality event, and an equipment replacement event based on at least one of the measurement data, the sensor status information, the communication status information of the Edge terminal system, and the connection status information of the one or more field sensors. The method is characterized by comprising: an event determination unit for determining whether; a security policy control unit for dynamically changing at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for the measurement data, and the transmission security policy for the measurement data based on the determination result of the event determination unit; and a security communication unit for adding at least one of encryption information, integrity verification information, electronic signature information, timestamp, nonce, and sensor identification information to the measurement data and transmitting it to the external server according to the policy changed by the security policy control unit.

Description

Technology Field

[0001] The present invention relates to a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, and more specifically, to a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software that can be applied to the secure transmission of heterogeneous field sensor data, such as radar water level gauges, flow meters, slope collapse detection systems, and weather observation sensors. Background Technology

[0002] Recently, multiple field measurement sensors are being installed at various sites, such as rivers, dams, reservoirs, drainage facilities, slopes, bridges, roads, mountainous areas, and weather observation points, to monitor disaster and environmental conditions, including water level, flow velocity, rainfall, wind direction, wind speed, temperature, humidity, ground displacement, slope angle, vibration, cracks, and soil moisture. These field measurement sensors can be configured in various forms, such as radar-type water level gauges, ultrasonic-type water level gauges, flow meters, rainfall meters, weather observation sensors, slope collapse detection sensors, underground displacement sensors, vibration sensors, and hydrological condition detection sensors. Measurement data collected from each sensor is transmitted to a control server, disaster management server, or integrated monitoring platform via field terminals, data loggers, gateways, or Edge terminals.

[0003] In conventional field measurement systems, RS485, Modbus, UART, CAN, Ethernet, LoRa, LTE, 5G, Wi-Fi, or dedicated wireless networks are used for communication between sensors and field terminals, while mobile communication networks, wired internet networks, dedicated networks, or satellite communication networks are used for communication between field terminals and servers. Field terminals generally operate by receiving measurement data collected from multiple sensors at regular intervals, and then transmitting the received data to a server after performing simple format conversion, filtering, threshold comparison, or packetization. This structure has the advantage of making the installation and maintenance of field sensors relatively easy and allowing multiple sensor data to be managed integrally by a central server.

[0004] Meanwhile, conventional measurement data security methods have primarily relied on encryption of communication channels, terminal authentication for server access, VPN-based connections, TLS-based secure communication, pre-shared key-based encryption, or device certificate-based authentication. Some systems are configured to protect device identification information, certificates, secret keys, or root keys by applying security chips, security elements, TPMs, secure storage areas, or trusted execution environments within field terminals, and to perform authentication procedures with the server using these. Additionally, in certain systems, methods that append message authentication codes, hash values, digital signatures, or serial numbers to data frames may be used to verify the integrity of sensor data.

[0005] However, conventional field measurement systems are generally designed around the functions of collecting and transmitting sensor data, and the security processing of field measurement data is often treated as an auxiliary function to protect the communication channel. In other words, when a secure channel is established between a server and a field terminal, all sensor data transmitted within that channel is often treated at the same level of security; consequently, the type of individual sensor, the importance of the measurement data, the occurrence of physical risk events, communication anomalies, sensor replacement status, or sudden changes in the field environment are frequently not directly reflected in security policies.

[0006] Furthermore, conventional secure communication methods generally focus on session-based authentication or channel-based encryption. In these methods, security is determined based on whether a communication session between the field terminal and the server has been successfully established; consequently, it can be difficult to make a precise determination regarding whether individual sensor data generated within the session was legitimately acquired from the actual sensor, whether past data has been retransmitted, whether data from a specific sensor channel has been tampered with, or whether an unauthorized device was connected during sensor replacement or field maintenance. Particularly in the fields of disaster and environmental measurement, where a single piece of data can be directly utilized for issuing alarms, controlling water gates, determining evacuation, operating facilities, or assessing risk, it is difficult to sufficiently guarantee the reliability of measurement data through simple communication channel security alone.

[0007] In conventional field measurement systems, even when multiple sensors are connected to a single field terminal, data is often transmitted using the same communication session or key scheme without establishing independent security contexts for each sensor. In this scenario, even if a specific sensor channel is attacked or its identification information is stolen, it is difficult to independently isolate that specific channel or update only the key corresponding to that sensor. Furthermore, the same authentication, encryption, and key update policies may be applied despite differences in measurement cycles, data importance, risk levels, field locations, and event types among the sensors. This structure limits the integrated operation of sensors with varying data characteristics and risk levels, such as water level gauges, flow meters, slope failure detection sensors, and weather observation sensors.

[0008] Furthermore, conventional key management methods typically update keys based on pre-set cycles or administrator commands. However, in field measurement environments, various events can occur, such as sudden changes in water level, rapid increases in flow velocity or rainfall, abnormal ground displacement, increased slope vibration, communication errors, authentication failures, sensor detachment, sensor replacement, or an increase in abnormal packets. These events are not merely simple measurement anomalies but may also be associated with data forgery, equipment impersonation, field equipment hijacking, retransmission attacks, or man-in-the-middle attacks. Nevertheless, conventional systems often do not link physical measurement events with security key management procedures, allowing existing session keys or security policies to remain unchanged even when a risk event occurs.

[0009] In particular, field measurement systems often experience unstable communication quality due to the characteristics of their installation locations. In mountainous areas, rivers, reservoirs, remote weather stations, slope monitoring zones, or facilities on the outskirts of cities, mobile communication networks may be temporarily disconnected, power supplies may be unstable, or systems may remain offline for extended periods. While conventional secure communication methods may be suitable for protecting secure channels when the server and field terminal are normally connected, they have limitations in reliably verifying the order, omission, tampering, and retransmission status of sensor data generated during communication interruptions. For instance, if data stored during a communication outage is subsequently partially deleted, the order of the data is altered, or it is replaced with past valid data, the server may find it difficult to accurately verify the authenticity and continuity of the data based solely on the reception time.

[0010] Furthermore, existing public-key cryptography is often based on RSA, ECC, or similar mathematical challenges. While these methods are currently widely used, there are concerns that their security may be compromised in the face of quantum computer-based attacks from a long-term security perspective. Since disaster and environmental measurement data can be utilized not only for real-time response but also for long-term historical analysis, facility safety assessment, disaster cause analysis, and as a basis for administrative decisions, long-term data reliability is just as important as short-term transmission security. Nevertheless, conventional field measurement systems often fail to adequately incorporate key generation, key exchange, device authentication, and data integrity protection structures that account for quantum computer environments.

[0011] Furthermore, even in conventional systems equipped with hardware security modules, such modules are often primarily used for storing existing certificates, authenticating devices based on existing public keys, protecting private keys, or for secure boot functions. In such cases, the structure in which quantum-resistant cryptographic software and the hardware security module interact to protect key materials and derive or update session keys by combining device unique information, sensor identification information, field events, and server authentication results is not sufficiently considered. Consequently, if the hardware security module is used merely as a storage device or an auxiliary authentication method, problems may arise where key materials are exposed in memory or cannot be linked to sensor-specific security policies, even if quantum-resistant cryptographic algorithms are applied in software.

[0012] Furthermore, in conventional field sensor systems, security authentication procedures are sometimes not sufficiently sophisticated during operational situations such as sensor replacement, maintenance, temporary sensor connection, or field equipment relocation. When a field operator replaces a sensor or connects a new one, it may be difficult for the server to determine whether the sensor was connected through normal maintenance procedures, is an unauthorized device connected by an attacker, or is a device that has duplicated the identification information of an existing sensor. Particularly in structures where multiple sensors are connected to a single Edge terminal, if the connection history, authentication status, risk level, and security context of individual sensors are not managed independently, there is a risk that data generated by unauthorized sensors will be transmitted to the server along with legitimate data.

[0013] Ultimately, while conventional field measurement systems are suitable for the collection and transmission of sensor data itself, they have limitations in independently managing sensor-specific security contexts in Edge environments where heterogeneous sensors are connected, dynamically linking physical risk events with security key management procedures, guaranteeing data continuity and integrity even in environments with communication disconnection, and securing long-term security considering quantum computing environments. In particular, in fields such as disaster and environmental monitoring where the reliability of measurement data directly impacts human life, facility safety, and public decision-making, there is a problem in that simple channel encryption or general IoT device authentication alone is insufficient to adequately counter risks such as data forgery, equipment impersonation, replay attacks, sensor replacement attacks, and key exposure.

[0014] Therefore, measures to address the aforementioned problems are required. Prior art literature

[0015] Republic of Korea Published Patent Application No. 10-2025-0158935 (Published Nov. 07, 2025) The problem to be solved

[0016] Accordingly, the present invention was created to solve the above-mentioned problems, and the objective of the present invention is to provide a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software that can secure the security of field measurement data even in a quantum computer-based attack environment by linking a hardware security module and quantum-resistant cryptographic software to perform quantum-resistant key generation and key exchange with a server in an Edge terminal system connected to one or more field measurement sensors, such as a radar water level gauge, a flow meter, a slope collapse detection system, and a weather observation sensor.

[0017] Furthermore, the present invention provides a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, which can effectively prevent falsification, retransmission, and impersonation of heterogeneous sensor data by setting a security context including at least one of sensor identification information, sensor type, measurement time, risk level, and communication status for each of a plurality of field measurement sensors connected to an Edge terminal system, and differentially applying session key derivation, data encryption, integrity verification, and transmission policies according to said security context.

[0018] Furthermore, the present invention provides a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, which can improve the reliability and security continuity of measurement data in disaster and environmental measurement environments by performing quantum-resistant key exchange, session key renewal, sensor channel isolation, or security policy reinforcement in conjunction with field events such as sudden changes in water level, sudden changes in flow velocity, slope displacement anomalies, sudden surge in rainfall, sensor replacement, communication errors, or authentication failures.

[0019] The purpose of the invention is not limited to the purposes mentioned above, and other unmentioned purposes will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0020] A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software according to the first aspect of the present invention for achieving the above objective is a quantum-resistant secure communication system of an Edge terminal system connected to one or more field sensors, comprising: a sensor interface unit that receives measurement data and sensor status information from the one or more field sensors; a hardware security unit that stores at least one of device unique information, a root key, an authentication key, key protection information, and a security random number of the Edge terminal system within a hardware-based security area; a quantum-resistant cryptographic processing unit that performs at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security unit; a quantum-resistant key exchange unit that performs quantum-resistant key exchange with an external server based on information protected by the hardware security unit and the processing result of the quantum-resistant cryptographic processing unit, and derives a session key used for secure transmission of the measurement data based on the quantum-resistant key exchange; and, based on at least one of the measurement data, the sensor status information, the communication status information of the Edge terminal system, and the connection status information of the one or more field sensors, a physical risk event, a sensor abnormality event, a communication abnormality event, and an equipment replacement event The method is characterized by comprising: an event determination unit that determines whether a field event including at least one of the following occurs; a security policy control unit that dynamically changes at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for the measurement data, and the transmission security policy for the measurement data based on the determination result of the event determination unit; and a security communication unit that adds at least one of encryption information, integrity verification information, electronic signature information, timestamp, nonce, and sensor identification information to the measurement data and transmits it to the external server according to the policy changed by the security policy control unit.

[0021] In addition, in a quantum-resistant security communication system of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the one or more field sensors include at least one of a radar water level gauge, a flow meter, a slope collapse detection sensor, a weather observation sensor, a rain gauge, an underground displacement sensor, a vibration sensor, and a hydrological condition detection sensor; the security policy control unit sets a sensor-specific security context for each of the one or more field sensors, which includes at least one of sensor identification information, sensor type, measurement cycle, risk grade, data importance, and communication status; and the quantum-resistant key exchange unit sets different session keys, sub-session keys, or key update conditions for each of the one or more field sensors based on the sensor-specific security context.

[0022] In addition, in a quantum-resistant security communication system of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the quantum-resistant cryptographic processing unit selects a quantum-resistant cryptographic algorithm for key exchange and a quantum-resistant cryptographic algorithm for digital signature based on at least one of the computational performance, memory capacity, power state, communication state, key exchange frequency, and risk class of measurement data of the Edge terminal system, wherein the quantum-resistant cryptographic algorithm for key exchange includes at least one of ML-KEM, Kyber, HQC, NTRU family algorithms and lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signatures includes at least one of ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+ and hash-based digital signature algorithms.

[0023] In addition, in a quantum-resistant security communication system of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the event determination unit determines whether a physical risk event or a sensor abnormality event occurs based on at least one of the change amount, change rate, threshold exceedance, correlation between multiple sensors, and sensor status information of measurement data received from one or more field sensors, and the security policy control unit controls the quantum-resistant key exchange unit to re-perform quantum-resistant key exchange with an external server or to discard an existing session key and derive a new session key when it is determined that the physical risk event or the sensor abnormality event has occurred.

[0024] In addition, in a quantum-resistant secure communication system of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the secure communication unit adds session key-based encryption information or integrity verification information to normal measurement data according to a transmission security policy set by the security policy control unit, and when it is determined by the event judgment unit that a physical risk event, a sensor abnormality event, a communication abnormality event, or an equipment replacement event has occurred, at least one of electronic signature information, an increment counter value, a timestamp, a nonce, and sensor identification information is additionally added to the measurement data related to the event and transmitted to an external server.

[0025] And, a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software according to a second aspect of the present invention for achieving the above objective is a quantum-resistant secure communication method performed in an Edge terminal system connected to one or more field sensors, comprising: receiving measurement data and sensor status information from the one or more field sensors; the hardware security structure of the Edge terminal system storing at least one of device unique information, root key, authentication key, key protection information, and security random number of the Edge terminal system within a hardware-based security area; quantum-resistant cryptographic software executed in the Edge terminal system performing at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security structure; the Edge terminal system performing a quantum-resistant key exchange with an external server based on information protected by the hardware security structure and the processing result of the quantum-resistant cryptographic software, and deriving a session key used for secure transmission of the measurement data based on the quantum-resistant key exchange; and the Edge terminal system, the measurement data, the sensor status information, the communication status information of the Edge terminal system, and the one or more field sensors A step of determining whether a field event has occurred, including at least one of a physical risk event, a sensor abnormality event, a communication abnormality event, and an equipment replacement event, based on at least one of connection status information; a step in which the Edge terminal system dynamically changes at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for the measurement data, and the transmission security policy for the measurement data, based on whether the field event has occurred; and a step in which the Edge terminal system, according to the dynamically changed policy, provides encryption information, integrity verification information, etc. to the measurement data.The method is characterized by including the step of transmitting to the external server at least one of electronic signature information, timestamp, nonce, and sensor identification information.

[0026] In addition, in a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software of the present invention, the step of determining whether the field event occurs comprises: a step in which the Edge terminal system generates a sensor-specific security context for each of the one or more field sensors, the context including at least one of sensor identification information, sensor type, measurement cycle, risk level, data importance, and communication status; and a step in which the Edge terminal system sets different session keys, sub-session keys, or key update conditions for each of the one or more field sensors based on the sensor-specific security context.

[0027] In addition, in a quantum-resistant secure communication method of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the step of determining whether the field event has occurred includes the step of determining whether a physical risk event has occurred by using at least one of the change amount, rate of change, threshold exceedance, and correlation between multiple sensors of measurement data received from at least one of a radar water level gauge, a flow meter, a slope collapse detection sensor, and a weather observation sensor, wherein the step of dynamically changing includes the step of, when the Edge terminal system determines that the physical risk event has occurred, discarding the existing session key and re-performing the quantum-resistant key exchange with the external server to derive a new session key, or updating the sub-session key corresponding to the field sensor associated with the physical risk event.

[0028] In addition, in a quantum-resistant secure communication method of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the step of transmitting to the external server comprises: a step of adding and storing continuity verification information, which includes at least one of a monotonically increasing counter value, a timestamp, sensor identification information, and a hash value of a previous measurement data protected by the hardware security structure, for each measurement data generated while the Edge terminal system is disconnected from the external server; and a step of transmitting a plurality of measurement data with the added continuity verification information when the Edge terminal system restores communication with the external server, and performing integrity and order verification of the plurality of measurement data through quantum-resistant key exchange or the derivation of a new session key.

[0029] In addition, in a quantum-resistant secure communication method of an Edge terminal system using the hardware security structure and quantum-resistant cryptographic software of the present invention, the step of performing at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on the quantum-resistant cryptographic algorithm comprises the step of the Edge terminal system selecting a quantum-resistant cryptographic algorithm for key exchange and a quantum-resistant cryptographic algorithm for digital signature based on at least one of the computational performance, memory capacity, power state, communication state, key exchange frequency, and risk class of measurement data of the Edge terminal system, wherein the quantum-resistant cryptographic algorithm for key exchange includes at least one of ML-KEM, Kyber, HQC, NTRU family algorithms and lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signature includes at least one of ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+, and hash-based digital signature algorithms. Effects of the invention

[0030] Accordingly, the present invention has the effect of improving the confidentiality, integrity, and authentication reliability of field measurement data even in environments where existing public-key cryptographic systems may be vulnerable to quantum computer-based attacks, by linking a hardware security structure with quantum-resistant cryptographic software in an Edge terminal system to perform quantum-resistant key exchange with an external server and deriving a session key used for the secure transmission of measurement data based on this.

[0031] Furthermore, since the present invention can dynamically change the execution conditions for quantum-resistant key exchange, session key renewal conditions, electronic signature policies, and transmission security policies depending on the occurrence of field events such as sudden changes in water level, flow velocity, slope displacement abnormalities, sudden surges in rainfall, sensor malfunctions, communication abnormalities, or equipment replacement, it has the effect of responding more rapidly and adaptively to hazardous situations at disaster and environmental measurement sites compared to a simple periodic key renewal method.

[0032] Furthermore, the present invention can transmit measurement data collected from multiple types of field sensors, such as radar level gauges, flow meters, slope collapse detection sensors, and weather observation sensors, to an external server by adding sensor identification information, timestamps, nonces, integrity verification information, or electronic signature information. This effectively prevents data forgery, retransmission attacks, equipment impersonation, and sensor replacement attacks, and has the effect of improving the reliability and security continuity of heterogeneous field sensor data.

[0033] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0034] FIG. 1 is a configuration diagram showing a quantum-resistant security communication system according to one embodiment of the present invention. Figure 2 is an example diagram showing an example of applying the quantum-resistant security communication system of Figure 1 to a radar level gauge. Figure 3 is an example diagram illustrating an event-based security policy change mechanism through the quantum-resistant security communication system of Figure 1. Figure 4 is an example diagram illustrating a change to the mechanism of Figure 3. And, FIG. 5 is a flowchart illustrating a quantum-resistant secure communication method according to one embodiment of the present invention. Specific details for implementing the invention

[0035] Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, the scope of the patent application is not limited or restricted by these embodiments. Identical reference numerals in each drawing indicate identical components.

[0036] Various modifications may be made to the embodiments described below. The embodiments described below are not intended to limit the forms of practice and should be understood to include all modifications, equivalents, and substitutions thereof.

[0037] Terms such as "first" or "second" may be used to describe various components, but these terms should be understood solely for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, a second component may be named a first component.

[0038] The terms used in the embodiments are used merely to describe specific embodiments and are not intended to limit the embodiments. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this specification, phrases such as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B or C,” “at least one of A, B and C,” and “at least one of A, B, or C” may each include any one of the items listed together with the corresponding phrase, or any possible combination thereof. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0039] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0040] Furthermore, in the description referring to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. In describing the embodiments, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the embodiments, such detailed description is omitted.

[0041] Additionally, in describing the embodiments of the present invention, if it is determined that a detailed description of known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the embodiments of the present invention, and these may vary depending on the intentions or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification.

[0042] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement functions in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the functions described in the flow diagram block(s). Since computer program instructions can also be loaded onto a computer or other programmable data processing equipment, the instructions that execute the computer or other programmable data processing equipment by creating a process in which a series of operation steps are performed on the computer or other programmable data processing equipment are flow diagrams It is also possible to provide steps for executing the functions described in the block(s).

[0043] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). Also, it should be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0044] In this case, the term '~part' used in this embodiment refers to software or hardware components such as FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~part' performs certain roles. However, the meaning of '~part' is not limited to software or hardware. The 'part' may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the 'part' includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and 'parts' may be combined into a smaller number of components and 'parts' or further separated into additional components and 'parts'. In addition, the components and 'parts' may be implemented to run one or more CPUs within a device or secure multimedia card.

[0045] In describing the embodiments of the present invention in detail, the focus will be on examples of specific systems, but the main point claimed in this specification is applicable to other communication systems and services having a similar technical background without significantly departing from the scope disclosed in this specification, and this will be possible at the judgment of a person with skilled technical knowledge in the relevant technical field.

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0048] FIG. 1 is a configuration diagram showing a quantum-resistant security communication system according to one embodiment of the present invention.

[0049] As illustrated in FIG. 1, the quantum-resistant security communication system (100) of the present invention may include one or more field sensors (110), a terminal system (120), and an external server (130). In the present invention, the terminal system (120) may be configured as an Edge terminal system positioned between the field sensor (110) and the external server (130), and may be configured to receive measurement data and sensor status information from the field sensor (110), perform security processing on the received measurement data and sensor status information using a hardware security structure and quantum-resistant cryptographic software, and then transmit the security-processed data to the external server (130).

[0050] The field sensor (110) may be composed of one or more measuring devices installed at the site for disaster monitoring, environmental measurement, water resource management, facility safety management, or weather observation. For example, the field sensor (110) may include at least one of a radar water level gauge, a flow meter, a slope collapse detection sensor, a weather observation sensor, a rain gauge, an underground displacement sensor, a vibration sensor, and a hydrological condition detection sensor. If the field sensor (110) is a radar water level gauge, the field sensor (110) may generate water level data of a river, dam, reservoir, drainage facility, or waterway; if the field sensor (110) is a flow meter, it may generate flow velocity data or measurement data for calculating flow rate; and if the field sensor (110) is a slope collapse detection sensor, it may generate data related to slope angle, underground displacement, vibration, cracks, or soil moisture. In addition, if the field sensor (110) is a weather observation sensor, it can generate data related to rainfall, wind direction, wind speed, temperature, humidity, or atmospheric pressure.

[0051] The terminal system (120) may include a sensor interface unit (121), a hardware security unit (122), a quantum-resistant cryptographic processing unit (123), a quantum-resistant key exchange unit (124), an event determination unit (125), a security policy control unit (126), and a security communication unit (127). The terminal system (120) may be implemented as a single gateway device, a data logger, an industrial edge computer, a field control panel, a communication terminal, or a sensor-embedded security terminal, and may be connected to a battery power source, a solar power source, a commercial power source, or an emergency power source depending on the field installation environment.

[0052] The sensor interface unit (121) is electrically or telecommunicationally connected to one or more field sensors (110) and can receive measurement data and sensor status information from the field sensors (110). The sensor interface unit (121) can be connected to the field sensors (110) via at least one of RS485, Modbus, UART, CAN, Ethernet, LoRa, Wi-Fi, BLE, LTE, 5G, or dedicated wired and wireless interfaces. The sensor interface unit (121) can convert raw measurement values ​​received from the field sensors (110) into a standard data frame within the terminal system (120) along with at least one of sensor identification information, sensor type, measurement time, measurement cycle, location information, sensor status information, and communication status information. Here, the sensor status information may include whether the sensor is operating normally, power status, battery status, communication quality, whether the equipment is disconnected, whether the equipment is replaced, self-diagnosis results, or sensor error codes.

[0053] The hardware security unit (122) may be configured to store at least one of the device unique information, root key, authentication key, key protection information, and security random number of the terminal system (120) within a hardware-based security area. The hardware security unit (122) may be implemented as at least one of a security element, a security chip, a TPM, an HSM, a TEE, a security storage area, or a security MCU, and may be implemented as a hardware security module such as, for example, SE050. The hardware security unit (122) may store key material or key protection information in a security area that cannot be directly read from an external processor or general memory area of ​​the terminal system (120), and accordingly, may provide the trust point, random number, key wrapping information, or device authentication information required in the software-based cryptographic processing process performed by the quantum-resistant cryptographic processing unit (123).

[0054] The quantum-resistant cryptographic processing unit (123) may correspond to quantum-resistant cryptographic software executed in the terminal system (120) and may perform at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security unit (122). The quantum-resistant cryptographic processing unit (123) may execute the quantum-resistant cryptographic algorithm in the MCU, MPU, security processor, or Edge computing unit of the terminal system (120), and the hardware security unit (122) may provide the device unique information, root key, authentication key, key protection information, or security random number used at this time in a protected form. Accordingly, the quantum-resistant cryptographic processing unit (123) can reduce the long-term exposure of the core key material used in the operation as plaintext in the general memory area while performing quantum-resistant cryptographic operations.

[0055] The quantum-resistant cryptographic processing unit (123) may select a quantum-resistant cryptographic algorithm for key exchange and a quantum-resistant cryptographic algorithm for digital signatures based on at least one of the computational performance, memory capacity, power status, communication status, key exchange frequency, and risk level of measurement data of the terminal system (120). For example, the quantum-resistant cryptographic algorithm for key exchange may include at least one of ML-KEM, Kyber, HQC, NTRU family algorithms and lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signatures may include at least one of ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+, and hash-based digital signature algorithms. In this case, the terminal system (120) may be configured to select a relatively lightweight key exchange or integrity verification method to reduce computational and communication volumes during normal operation, and to select a digital signature or enhanced integrity verification method when a risk event occurs.

[0056] The quantum-resistant key exchange unit (124) can perform quantum-resistant key exchange with an external server (130) based on information protected by the hardware security unit (122) and the processing result of the quantum-resistant cryptographic processing unit (123). The quantum-resistant key exchange unit (124) can set a shared secret value through a key encapsulation and key decapsulation procedure with the external server (130), and can derive a session key used for secure transmission of measurement data by combining the set shared secret value with the device unique information, sensor identification information, time information, nonce, or risk level of the terminal system (120). Here, the session key may be a communication session key that is commonly applied to the entire terminal system (120), or a sub-session key corresponding to a specific field sensor (110).

[0057] The security policy control unit (126) can set a sensor-specific security context for each of one or more field sensors (110). The sensor-specific security context may include at least one of sensor identification information, sensor type, measurement cycle, risk level, data importance, and communication status. For example, for a radar water level gauge, the water level change rate, critical water level, flood risk level, and communication delay time may be included in the sensor-specific security context; for a flow meter, the flow velocity change rate, whether there is backflow, and whether there is a surge in flow rate may be included in the sensor-specific security context; and for a slope collapse detection sensor, the amount of change in slope angle, the amount of change in underground displacement, vibration pattern, and crack change information may be included in the sensor-specific security context. Based on these sensor-specific security contexts, the quantum-resistant key exchange unit (124) can set different session keys, sub-session keys, or key update conditions for each of one or more field sensors (110).

[0058] The event determination unit (125) can determine whether a field event has occurred based on at least one of measurement data, sensor status information, communication status information of the terminal system (120), and connection status information of one or more field sensors (110). Here, the field event may include at least one of a physical hazard event, a sensor malfunction event, a communication malfunction event, and an equipment replacement event. A physical hazard event may be an event indicating a rapid change in the actual field condition, such as a rapid rise in water level, a rapid fall in water level, a rapid change in flow velocity, a rapid increase in rainfall, an increase in slope displacement, an abnormal vibration, an abnormal opening / closing of a sluice gate, or a rapid change in weather. A sensor malfunction event may include an abnormal fixation of the sensor output value, a discontinuous change in the sensor output value, a self-diagnosis error, a low battery voltage, a sensor disconnection, or a sensor communication error. A communication malfunction event may include a disconnection of communication with an external server (130), an increase in packet loss, an increase in the number of retransmissions, an authentication failure, an abnormal connection attempt, or an increase in latency. Equipment replacement events may include the new connection of a field sensor (110), replacement of an existing sensor, reinstallation of a terminal system (120), or entry into a maintenance mode.

[0059] The event determination unit (125) can determine whether a physical danger event or a sensor malfunction event has occurred based on at least one of the change amount, change rate, threshold value exceeded, correlation between multiple sensors, and sensor status information of measurement data received from one or more field sensors (110). For example, if the water level data of a radar water level gauge increases by more than a reference change amount within a unit time, or if the rainfall data and water level data of a weather observation sensor increase simultaneously, the event determination unit (125) can determine that a physical danger event corresponding to a sudden change in water level has occurred. Conversely, if only the water level data changes rapidly while the rainfall, flow velocity, or adjacent sensor data is within the normal range, the event determination unit (125) can determine that it is an event with a possibility of sensor malfunction or data falsification.

[0060] The security policy control unit (126) can dynamically change at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for measurement data, and the transmission security policy for measurement data based on the judgment result of the event judgment unit (125). For example, if the event judgment unit (125) determines that a physical risk event or a sensor abnormality event has occurred, the security policy control unit (126) can control the quantum-resistant key exchange unit (124) to re-perform quantum-resistant key exchange with the external server (130), or control it to discard the existing session key and derive a new session key. Additionally, the security policy control unit (126) may control the update of the sub-session key only for the field sensor (110) related to the event, and may control the maintenance of the existing session key or existing transmission policy for other field sensors (110) unrelated to the event.

[0061] The security policy control unit (126) can apply different security policies depending on the type and risk level of field events. For example, it can be configured to add session key-based encryption information or integrity verification information to normal measurement data, and in the event of a physical risk event, sensor abnormality event, communication abnormality event, or equipment replacement event, it can be configured to add at least one of electronic signature information, increment counter value, timestamp, nonce, and sensor identification information to the measurement data related to the event. By dynamically changing the security policy in this way, the terminal system (120) can strengthen the security level in dangerous situations or situations with a high possibility of tampering, without applying the same high-load security processing to all measurement data.

[0062] The secure communication unit (127) can transmit measurement data to an external server (130) by adding at least one of encryption information, integrity verification information, digital signature information, timestamp, nonce, and sensor identification information according to a policy changed by the security policy control unit (126). The secure communication unit (127) can communicate with the external server (130) using at least one of LTE, 5G, Ethernet, RS485, LoRa, Wi-Fi, a satellite communication network, a private network, or a public network. Normally, the secure communication unit (127) transmits data centered on session key-based encryption and integrity verification information for efficient transmission of measurement data, and when an event occurs, it can generate and transmit a secure data frame that additionally includes digital signature information, an increment counter value, timestamp, nonce, and sensor identification information. Accordingly, the external server (130) can verify the source, creation time, retransmission status, order change status, and tampering status of the received measurement data.

[0063] The external server (130) receives measurement data securely transmitted from the terminal system (120) and can perform decryption of the measurement data, integrity verification, digital signature verification, sensor identification information verification, and event history management using a server-side session key corresponding to the result of key exchange with the quantum-resistant key exchange unit (124). The external server (130) can be implemented as a disaster control server, a water resource management server, an environment monitoring server, a facility safety management server, or an integrated control platform. The external server (130) can detect retransmission attacks, delayed transmission, order change, or forged data using the timestamp, nonce, increment counter value, and sensor identification information included in the data received from the terminal system (120).

[0064] In one embodiment, when the field sensor (110) is a radar level gauge, the sensor interface unit (121) receives level data and sensor status information from the radar level gauge, and the event determination unit (125) can determine a rapid rise or rapid fall in level event based on the amount of change, rate of change, and whether the threshold level of the level data is exceeded. At this time, if the security policy control unit (126) determines that a rapid change in the level has occurred, it can control the quantum-resistant key exchange unit (124) to re-perform a quantum-resistant key exchange with the external server (130) by considering the possibility that the level data may be tampered with or past data may be retransmitted. Additionally, the security policy control unit (126) can control the existing session key to be discarded and a new session key to be derived, and the security communication unit (127) can use the new session key to add electronic signature information, timestamp, nonce, increment counter value, and sensor identification information of the radar level gauge to the level data and transmit it to the external server (130).

[0065] In another embodiment, when the field sensor (110) includes a plurality of different sensors, the security policy control unit (126) may set different security levels for each sensor according to the security context for each sensor. For example, measurement data from radar level gauges and flow meters used directly for hydrological control or evacuation judgment may be set to have high data importance, while auxiliary weather observation data may be set to have relatively low data importance. In this case, the quantum-resistant key exchange unit (124) may set the update cycle of the sub-session key corresponding to the radar level gauge or flow meter to be short, and for the slope collapse detection sensor, may be set to update the sub-session key immediately upon the occurrence of an abnormal displacement or vibration event.

[0066] In another embodiment, the terminal system (120) may be installed at a remote site where the communication status is unstable. In this case, the event judgment unit (125) may determine that a communication disconnection with the external server (130) or an increase in packet loss is a communication abnormality event, and the security policy control unit (126) may be configured to re-perform quantum-resistant key exchange or update the session key after communication is restored. Additionally, the secure communication unit (127) may store the measurement data generated during the communication disconnection by adding an increment counter value, timestamp, nonce, and sensor identification information, and then transmit it in bulk to the external server (130) upon communication restoration. Through this, the external server (130) can verify the order, omission, and tampering of the measurement data generated during the communication disconnection period.

[0067] In another embodiment, when replacement or new connection of a field sensor (110) is detected, the event determination unit (125) may determine that an equipment replacement event has occurred. In this case, the security policy control unit (126) may discard or update the existing sensor-specific security context for the replaced field sensor (110) and set the measurement data received from the sensor to be isolated and stored until approval from the external server (130). Subsequently, the quantum-resistant key exchange unit (124) may perform a re-authentication procedure or a new session key derivation procedure with the external server (130) based on the device unique information protected by the hardware security unit (122) and the key exchange result of the quantum-resistant cryptographic processing unit (123). Accordingly, even if an unauthorized sensor is connected to the terminal system (120), the measurement data of the sensor may be prevented from being processed as normal data.

[0068] As such, the quantum-resistant security communication system (100) according to FIG. 1 is not limited to a structure that simply encrypts measurement data from a field sensor (110) and transmits it to an external server (130), but is configured to perform quantum-resistant key exchange and session key derivation by combining trust information protected by a hardware security unit (122) within the terminal system (120) with cryptographic operations of a quantum-resistant cryptographic processing unit (123), and to dynamically change key exchange conditions, session key update conditions, electronic signature policies, and transmission security policies according to the judgment result of an event judgment unit (125). Accordingly, the quantum-resistant security communication system (100) of the present invention can be extended to various field sensors (110), such as radar water level gauges, flow meters, slope collapse detection sensors, and weather observation sensors, and can more effectively suppress the risk of falsification, retransmission, equipment impersonation, and key exposure of measurement data when a field event occurs.

[0069] Figure 2 is an example diagram showing an example of applying the quantum-resistant security communication system of Figure 1 to a radar level gauge.

[0070] As illustrated in FIG. 2, the quantum-resistant security communication system of the present embodiment may be configured to include a radar level gauge (110), a terminal system (120), a network, and an external server (130). In the present embodiment, the radar level gauge (110) is installed near a river, reservoir, drainage channel, sluice gate, dam, or urban flood-prone area to measure the distance to the water surface in a non-contact manner and generate water level data based on this. The radar level gauge (110) may output sensor status information indicating the sensor's operating status, measurement cycle, power status, communication status, self-diagnosis results, or abnormality along with the water level data. Accordingly, the terminal system (120) receives not only a simple water level value from the radar level gauge (110) but also additional information necessary for determining the reliability of the water level data, which can be utilized for security processing and event determination.

[0071] The terminal system (120) may be configured as a field edge terminal that collects measurement data and status information received from a radar level gauge (110), performs quantum-resistant security processing on the data, and then transmits it to an external server (130) via a network. The terminal system (120) may include a sensor interface unit (121), a hardware security unit (122), a quantum-resistant cryptographic processing unit (123), an event judgment unit (124), a security policy control unit (125), and a security communication unit (126). In this case, the terminal system (120) may be embedded inside a field control box or implemented in the form of a standalone data collection device, a remote terminal device, or an industrial edge computer. Additionally, the terminal system (120) may be powered by commercial power, battery power, solar power, or a combination thereof, and may include a waterproof and environmentally resistant structure to enable operation even in field environments with significant flooding, condensation, vibration, or temperature changes.

[0072] The sensor interface unit (121) is configured to provide a data input / output interface between the radar level gauge (110) and the terminal system (120), and can receive measurement data and sensor status information from the radar level gauge (110). The sensor interface unit (121) can be connected to the radar level gauge (110) via RS485, UART, Modbus, Ethernet, SDI-12, CAN, wireless low-power communication methods, or similar sensor communication standards. The sensor interface unit (121) can convert the received raw data into a standard data format that can be processed within the terminal system (120), and, if necessary, can add sensor identification information, measurement time, installation location, measurement unit, or error detection code. Additionally, the sensor interface unit (121) is not limited to a single radar level gauge (110) but can be expanded to be connected in parallel or serially to multiple radar level gauges, flow meters, rain gauges, etc.

[0073] The hardware security unit (122) is a component that forms a security trust point of the terminal system (120) and can store at least one of device unique information, root key, authentication key, key protection information, and security random number within a hardware-based security area. The hardware security unit (122) can be implemented in the form of a security element, a dedicated security chip, a TPM, a TEE-based security area, or a hardware cryptographic module. By managing sensitive key materials in a protection area separated from the general memory area, the hardware security unit (122) can reduce the risk of key theft even in a field environment where the terminal system (120) is physically exposed. Additionally, the hardware security unit (122) can additionally perform functions such as generating security random numbers, controlling key access rights, verifying boot integrity, or device authentication, thereby improving the overall security of the terminal system (120).

[0074] The quantum-resistant cryptographic processing unit (123) is configured to perform security operations based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security unit (122), and can perform at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification. The quantum-resistant cryptographic processing unit (123) may be implemented as a software module running on the processor of the terminal system (120), and if necessary, some operations may be linked with a hardware acceleration structure. The quantum-resistant cryptographic processing unit (123) may select an appropriate quantum-resistant cryptographic algorithm according to the computational performance, memory capacity, power status, communication status, or security level requirements of the terminal system (120). For example, for key exchange, ML-KEM, Kyber, HQC, NTRU family algorithms or similar lattice-based key encapsulation algorithms may be applied, and for digital signatures, ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+, or hash-based digital signature algorithms may be applied. In this way, the quantum-resistant cryptographic processing unit (123) can perform security processing capable of responding to future quantum computer-based attacks while taking into account the limited resource environment of the field terminal.

[0075] The event determination unit (124) can determine whether a field event has occurred by analyzing measurement data and sensor status information received from the radar water level gauge (110). The event determination unit (124) can determine events such as a rapid rise in water level, a rapid drop in water level, a sensor malfunction, a disconnection in communication, or equipment replacement by considering the amount of change in water level, the rate of change in water level, whether a preset threshold is exceeded, a change in the pattern of continuous measurement values, whether the sensor status information is abnormal, or the communication response status. For example, if the water level rises rapidly over a short period of time, it can be determined as a rapid rise in water level event corresponding to a flood risk or a situation of rapid inflow, and if the water level drops rapidly over a short period of time, it can be determined as a rapid drop in water level event corresponding to drainage, discharge, sensor error, or the possibility of abnormal data occurrence. In addition, if the water level data is abnormally fixed or changes discontinuously, it can be determined as a sensor malfunction event, and if the connection with the external server (130) fails for a certain period of time or longer, it can be determined as a disconnection in communication event. Furthermore, if sensor identification information or device registration information is changed or a new sensor is connected, it can be determined as an equipment replacement event.

[0076] The security policy control unit (125) can dynamically change the security policy based on the judgment result of the event judgment unit (124). That is, the security policy control unit (125) can change at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy, and the transmission security policy according to the state of the water level data, the type of event, the risk level, or the communication status. For example, under normal circumstances, it can be set to transmit the water level data with only session key-based encryption or integrity verification information added, and in the event of a rapid rise in water level, rapid fall in water level, sensor malfunction, communication disconnection, or equipment replacement, it can be set to additionally include electronic signature information, an increment counter value, timestamp, nonce, and sensor identification information. In addition, when an event occurs, the security policy control unit (125) can discard the existing session key and induce the creation or renewal of a new session key, and can control the re-execution of the quantum-resistant key exchange procedure with the external server (130) as needed. Through such dynamic policy control, the terminal system (120) can perform adaptive security operations that strengthen the security level in dangerous situations, instead of uniformly applying a high security load to all data.

[0077] In particular, a mechanism to change the key may be applied to prevent data tampering in the event of a rapid change in water level. For example, if the event judgment unit (124) determines that the rate of increase in water level per unit time is above a reference value or that the pattern of continuously measured water level values ​​deviates from the normal range, the security policy control unit (125) may determine that the water level data is critical data indicating a disaster situation or data with a high probability of tampering. In this case, the security policy control unit (125) may discard or restrict the use of the session key currently in use, and control the generation of new key material or a new session key through the linkage of the quantum-resistant cryptographic processing unit (123) and the hardware security unit (122). Additionally, the security policy control unit (125) may strengthen the authentication procedure with the external server (130) or configure it to ensure that an electronic signature is applied to the data in the relevant section. Accordingly, the problem of core water level data being forged during transmission or past normal data being retransmitted and mistaken for the current state can be reduced.

[0078] The secure communication unit (126) is configured to transmit water level data to an external server (130) according to a transmission security policy set or changed by the security policy control unit (125). The secure communication unit (126) may add at least one of encryption information, integrity verification information, digital signature information, timestamp, nonce, and sensor identification information to the measurement data and transmit it to the external server (130) via a network. The network may be implemented as LTE, 5G, NB-IoT, Wi-Fi, LoRa, wired internet, satellite communication network, or a combination thereof. The secure communication unit (126) can efficiently transmit data using a lightweight security frame under normal conditions, and can ensure a higher level of authentication and integrity by using an enhanced security frame when an event occurs. Additionally, in the event of a communication interruption, the secure communication unit (126) can temporarily store the data that could not be transmitted, and then, when communication is restored, retransmit the stored data to the external server (130), including sequence information, time information, and integrity verification information.

[0079] The external server (130) can receive, store, decrypt, verify, and analyze water level data transmitted from the terminal system (120). By verifying the electronic signature information, increment counter value, timestamp, nonce, and sensor identification information included in the received data, the external server (130) can determine whether the data was generated by a legitimate terminal system (120), whether it was not tampered with during transmission, or whether it is a retransmission of past data. Additionally, when an event such as a rapid rise or fall in water level is detected, the external server (130) can trigger an alarm, display a control screen, notify relevant agencies, or request additional verification. The external server (130) can be implemented as a disaster control server, a water resource management server, a smart city integrated platform, or a cloud-based analysis server, and can be configured to manage data received from multiple field terminal systems (120) in an integrated manner.

[0080] In one embodiment, the radar water level gauge (110) may be installed near a bridge pier of a river or on the side of an embankment, and may generate water level data at regular intervals and transmit it to a terminal system (120). Under normal circumstances, the terminal system (120) may transmit the corresponding water level data to an external server (130) after encryption and integrity verification, and the external server (130) may utilize this as real-time control information. Subsequently, if the water level rises rapidly in a short period of time due to the influence of heavy rain or discharge, the event judgment unit (124) may determine the water level rapid rise event, and the security policy control unit (125) may control the application of session key updates and enhanced electronic signature policies. At this time, the security communication unit (126) may transmit to the external server (130) electronic signature information, timestamp, nonce, and sensor identification information added to the water level data according to the new policy. Accordingly, the external server (130) can more reliably verify whether the received water level data reflects the actual rapid rise situation and whether it is forged or retransmitted data.

[0081] In another embodiment, if the radar level gauge (110) causes abnormal operation and repeatedly outputs only the same value or outputs unrealistically rapidly changing values, the event judgment unit (124) may determine this as a sensor abnormal event. In this case, the security policy control unit (125) may set the trust level for the data to be lowered or to apply an enhanced digital signature policy during transmission. Additionally, if necessary, the hardware security unit (122) and the quantum-resistant cryptographic processing unit (123) may be used to generate a new session key or authentication information and control the transmission of sensor status information indicating the equipment status together. Accordingly, the external server (130) recognizes that the received data was generated in a sensor abnormal state and can perform control judgments or maintenance instructions more accurately.

[0082] In another embodiment, when a communication disconnection event occurs due to network instability or a remote communication failure, the event determination unit (124) can detect a failure to transmit or receive with an external server (130) for a certain period of time or longer and determine this as a communication disconnection event. The security policy control unit (125) can control the addition of a creation time, sequence information, or nonce to each data while temporarily storing data collected during the communication disconnection period, and when communication is restored, the quantum-resistant security policy can be reset to ensure the reliability of data transmission after restoration. By configuring it in this way, continuous water level monitoring can be performed even in a remote installation environment while reducing concerns about data loss or tampering.

[0083] In another embodiment, when the radar level gauge (110) is replaced or a new device is connected due to maintenance work, the event determination unit (124) can determine an equipment replacement event. The security policy control unit (125) can control the execution of an authentication procedure, a key renewal procedure, or an identification information re-registration procedure for the new sensor when an equipment replacement event occurs. Through this, it is possible to detect cases where an unauthorized device is arbitrarily connected to the terminal system (120) and ensure that data is transmitted to an external server (130) only after the newly connected device has undergone a normal approval procedure. Thus, security vulnerabilities associated with field equipment replacement can be effectively reduced.

[0084] Additionally, FIG. 2 illustrates an example in which a radar water level gauge (110) is applied, but the present invention is not limited thereto. That is, the structure and security processing method of the same terminal system (120) can be applied in the same or similarly to a flow meter, a rain gauge, a slope collapse detection sensor, a weather observation sensor, a hydrological condition detection sensor, or similar disaster and environmental measurement sensors. For example, when applied to a flow meter, an event can be determined based on a sudden change in flow velocity or an increase in flow rate; when applied to a slope collapse detection sensor, an event can be determined based on a change in slope, underground displacement, or a change in vibration pattern; and when applied to a weather observation sensor, an event can be determined based on a sudden increase in rainfall, an abnormal wind speed, or a change in atmospheric pressure. In this case as well, depending on the type of event, session key renewal, electronic signature policy change, or transmission security policy strengthening can be performed using the same principle.

[0085] Figure 3 is an example diagram illustrating an event-based security policy change mechanism through the quantum-resistant security communication system of Figure 1.

[0086] As illustrated in FIG. 3, the quantum-resistant secure communication system (100) of the present invention may be configured to perform periodic key exchange, session maintenance, and general secure transmission under normal circumstances, and to dynamically strengthen quantum-resistant key exchange, session key management, data signing policy, and transmission security policy when a field event is detected. Here, the field event may include physical risk events detected by the field sensor (110), sensor abnormality events, communication abnormality events between the terminal system (120) and the external server (130), or equipment replacement events such as replacement, disconnection, or new connection of the field sensor (110). Accordingly, the quantum-resistant secure communication system (100) of the present invention may not have a structure that simply updates keys at regular intervals or transmits all measurement data at the same security level, but may have a structure that adaptively changes security operations according to the risk level of the field and the possibility of data tampering.

[0087] Under normal conditions, the terminal system (120) performs quantum-resistant key exchange with the external server (130) according to a pre-set period or communication session setting condition, and can derive a session key used for secure transmission of measurement data based on the result. In this case, the quantum-resistant key exchange can be performed using device unique information, root key, authentication key, key protection information, or security random number protected by the hardware security unit (122), and a key encapsulation value, key decapsulation value, or shared secret value generated by the quantum-resistant cryptographic processing unit (123). Under normal conditions, secure transmission can be performed based on session key-based encryption information or integrity verification information to reduce the transmission load of measurement data and the computational load of the terminal system (120), and the secure communication unit (127) can transmit the measurement data to the external server (130) by adding at least one of sensor identification information, timestamp, or nonce.

[0088] The event determination unit (125) can determine whether an event has occurred by continuously monitoring normal measurement data and sensor status information. The event determination unit (125) can use at least one of water level change, sensor malfunction, communication malfunction, and equipment replacement as an event determination item. For example, if the field sensor (110) is a radar water level gauge, the event determination unit (125) can determine a water level change event by using the amount of increase in water level per unit time, the amount of decrease in water level, the rate of change in water level, whether the critical water level is exceeded, the discontinuity of continuous measurement values, or the deviation from previous measurement values. Additionally, the event determination unit (125) can determine a sensor malfunction event if the sensor output value remains fixed at the same level for a certain period of time or longer, if a sudden value that is physically difficult to occur is repeated, if a sensor self-diagnosis error occurs, or if the sensor response is abnormal. Additionally, the event judgment unit (125) can determine that a failure to connect with an external server (130), an increase in packet loss, an increase in the number of retransmissions, an authentication failure, or an abnormal connection request are communication abnormal events, and can determine that a change in the identification information of a field sensor (110), a connection of a new sensor, a disconnection of an existing sensor, or entry into a maintenance mode are equipment replacement events.

[0089] When an event is detected by the event judgment unit (125), the security policy control unit (126) can dynamically change the security policy based on the type of event, risk level, related sensor identification information, data importance, and communication status. At this time, the security policy control unit (126) can determine the conditions for performing quantum-resistant key exchange, whether to maintain the existing session key, whether to derive a new session key, whether to apply the electronic signature policy, and whether to strengthen the transmission security policy. For example, for low-risk events such as simple communication delay, the response can be to maintain the session key while adding a nonce or increment counter value, and for high-risk events such as a rapid rise or fall in water level, sensor malfunction, or equipment replacement, the control can be to immediately re-perform quantum-resistant key exchange or discard the existing session key and derive a new session key.

[0090] In the security processing process when an event occurs, the quantum-resistant key exchange unit (124) may re-perform quantum-resistant key exchange with the external server (130). In this case, the quantum-resistant key exchange unit (124) may verify the legitimacy of the terminal system (120) using the device unique information, root key, authentication key, key protection information, or security random number stored in the hardware security unit (122), and may set a new shared secret value with the external server (130) using the result of key encapsulation or key decapsulation processing of the quantum-resistant cryptographic processing unit (123). Once the new shared secret value is set, the quantum-resistant key exchange unit (124) may derive a new session key or an event-specific sub-session key by combining the shared secret value with sensor identification information, event type, risk level, timestamp, nonce, or session identification information. Accordingly, even if the existing session key used before the event occurred is exposed or there is a possibility that it may be used for a retransmission attack, important data transmitted after the event occurs can be protected by the new session key.

[0091] The process of discarding an existing session key is not limited to simply generating a new key, but may include a procedure to stop the use of the existing session key and restrict additional encryption, decryption, or integrity verification processing using the key. For example, the security policy control unit (126) may mark the session identifier of the existing session key as discarded and control the security communication unit (127) so that it cannot transmit data after the event using the existing session key. Additionally, the hardware security unit (122) may invalidate the existing session key or the key wrapping information that protected the existing session key, or generate new key protection information to protect the new session key. When the existing session key is explicitly discarded in this way, the risk of an attacker forging or retransmitting current event data using the past session key or past data frame can be reduced.

[0092] After a new session key is derived, the security policy control unit (126) can strengthen the electronic signature policy. Normally, only session key-based encryption information or integrity verification information may be added considering data transmission efficiency, but when an event occurs, it may be configured to additionally add electronic signature information to the measurement data related to the event. For example, if a water level surge event occurs, the security communication unit (127) may add electronic signature information to a data frame containing water level data at the time of the event, the previous water level data, the next water level data, and the rate of change of the water level. At this time, the electronic signature information may be generated by the quantum-resistant cryptographic processing unit (123), and the data to be signed may include sensor identification information, measurement data, timestamp, nonce, increment counter value, event type, and risk grade. Accordingly, the external server (130) can verify that the received data was generated by a legitimate terminal system (120), was not tampered with during transmission, and is not a retransmission of past data.

[0093] Additionally, the security policy control unit (126) may strengthen the transmission security policy when an event occurs. Strengthening the transmission security policy may include adjusting the data encryption level, changing whether to add a digital signature, mandating the addition of a nonce or increment counter value, limiting the number of data retransmissions, requiring re-authentication from the external server (130), prioritizing the transmission of event data, delaying the transmission of general data, or transmitting event data through a separate secure channel. For example, if a communication anomaly event occurs, the security policy control unit (126) may set the quantum-resistant key exchange to be performed again after communication is restored, and control the addition of sequence information, timestamp, nonce, and integrity verification information to the measurement data stored during the communication interruption. Subsequently, the secure communication unit (127) may transmit the stored data to the external server (130) using a new session key upon communication restoration, and the external server (130) may verify the creation order, whether there are omissions, and whether there is tampering with each data.

[0094] In particular, when a sudden change in water level is detected, a key change mechanism may be performed in consideration of concerns regarding data falsification. For example, if the field sensor (110) is a radar water level gauge and the event judgment unit (125) determines that the rate of increase in water level per unit time is above a reference value or the rate of decrease in water level is above a reference value, the security policy control unit (126) may classify the situation as a sudden change in water level event. A sudden change in water level event can indicate actual disaster risks, and at the same time, it can be viewed as a situation where there is a high possibility that an attacker may tamper with measurement data to generate a false alarm or conceal an actual alarm. Accordingly, the security policy control unit (126) may discard the existing session key and control the quantum-resistant key exchange unit (124) to re-perform quantum-resistant key exchange with the external server (130). Additionally, the security policy control unit (126) may control the transmission of the event data to be suspended until a new session key is derived, or to be temporarily stored and then transmitted using the new session key.

[0095] Key changes resulting from sudden water level changes can be configured so that they are not excessively repeated due to temporary noise or momentary sensor errors. For example, the event judgment unit (125) may set an event candidate state when the amount of change in water level exceeds a first reference value, and may confirm it as an actual sudden water level change event if the rate of change is maintained in a number of consecutive measurement cycles or if a correlation is confirmed with data from an adjacent sensor, rain gauge, or flow meter. Additionally, the security policy control unit (126) may be configured to use an event-dedicated sub-session key or perform a new key exchange after approval from an external server (130) instead of immediately repeating the key exchange when the number of key updates within a certain period exceeds a reference value. This allows for the application of an enhanced security policy in actual dangerous situations while reducing the computational and communication loads of the terminal system (120).

[0096] Even when a sensor abnormal event occurs, the security policy control unit (126) can strengthen the security policy. For example, if the output value of the field sensor (110) is abnormally fixed, if the sensor status information contains a self-diagnosis error, or if the sensor identification information is abnormally changed, the event judgment unit (125) can determine a sensor abnormal event. In this case, the security policy control unit (126) can discard or update the sub-session key corresponding to the sensor, assign a low trust level to the measurement data received from the sensor, or control it to be isolated and stored until additional verification by the external server (130) is completed. Additionally, the security communication unit (127) can transmit to the external server (130) a data frame related to the sensor abnormal event that includes sensor status information, an error code, a timestamp, a nonce, and digital signature information.

[0097] In the event of a communication anomaly, the security policy control unit (126) may apply a policy to ensure security continuity after communication is restored. For example, if communication with an external server (130) is interrupted for a certain period of time or longer, the security communication unit (127) may store measurement data generated during the communication interruption in a local storage area and add continuity verification information to each data, including an increment counter value, timestamp, nonce, or hash value of previous data. When communication is restored, the quantum-resistant key exchange unit (124) may re-perform quantum-resistant key exchange with the external server (130) or reconfirm the validity of the existing session key, and the security communication unit (127) may transmit the stored measurement data to the external server (130) along with the continuity verification information. The external server (130) may use this to determine whether data was deleted, changed in order, or replaced with past data during the communication interruption.

[0098] When an equipment replacement event occurs, the security policy control unit (126) may control the execution of a security onboarding procedure for the new equipment or the replacement equipment. For example, if a field sensor (110) is replaced and the sensor identification information is changed or communication response characteristics different from the existing sensor are confirmed, the event judgment unit (125) may determine an equipment replacement event. In this case, the security policy control unit (126) may discard or update the existing sensor-specific security context and set a new sensor-specific security context including sensor identification information, sensor type, measurement cycle, risk level, and communication status for the new sensor. Additionally, the quantum-resistant key exchange unit (124) may perform a re-authentication procedure with an external server (130) using the device unique information of the hardware security unit (122) and the key exchange result of the quantum-resistant cryptographic processing unit (123), and may be configured to store the measurement data of the new sensor separately from general control data until approval by the external server (130).

[0099] The mechanism of FIG. 3 is not applied only to a single radar level gauge, but can be extended to an Edge environment where various types of field sensors (110) are connected. For example, if a flow meter is connected, a sudden change in flow velocity or the occurrence of backflow may be determined as a physical risk event; if a slope collapse detection sensor is connected, a change in slope angle, an increase in underground displacement, or an abnormal vibration pattern may be determined as a physical risk event; and if a weather observation sensor is connected, a sudden increase in rainfall, an abnormal wind speed, or a sudden change in atmospheric pressure may be determined as a physical risk event. In this case, the security policy control unit (126) may control the update of only the sub-session key corresponding to the sensor according to the security context for each sensor, or, if the events of multiple sensors are correlated, to re-perform quantum-resistant key exchange for the entire communication session.

[0100] Additionally, when multiple field sensors (110) are connected to a single terminal system (120), the event judgment unit (125) can determine whether to change the security policy by utilizing the correlation between the multiple sensors. For example, if the water level data rises rapidly but the rainfall data and flow velocity data are within the normal range, the event judgment unit (125) may determine that the event is likely to be a sensor malfunction or data falsification rather than an actual physical danger event. Conversely, if rainfall increases, flow velocity increases, and water level rises simultaneously, the event judgment unit (125) may determine that the reliability of the actual physical danger event is high. Based on the results of such determination, the security policy control unit (126) may selectively apply not only simple key renewal but also mandatory electronic signatures, adjustment of data transmission priority, a re-authentication request from an external server (130), or transmission of event data through a separate secure channel.

[0101] Figure 4 is an example diagram illustrating a change to the mechanism of Figure 3.

[0102] As illustrated in FIG. 4, the quantum-resistant secure communication system (100) of the present invention may be configured to maintain an existing session key (K1) according to the temporal change of measurement data collected from a field sensor (110), or to discard the existing session key (K1) and apply a new session key (K2) when an event such as a sudden change in water level occurs. FIG. 4 shows a state in which the water level changes over time, and sequentially illustrates the process in which an event is detected in a section where the water level exceeds a critical water level or a critical rate of change, and in response thereto, a key exchange and a session key change are performed.

[0103] Specifically, in the first stage, the existing session key (K1) may be used in the normal state. At this time, the terminal system (120) periodically receives water level data from a field sensor (110), for example, a radar water level gauge, and the secure communication unit (127) may generate encryption information or integrity verification information for the water level data based on the existing session key (K1) and transmit it to an external server (130). The normal state may refer to a state where the water level is below a preset threshold level, or where the amount of water level change per unit time or the rate of water level change is within the normal range. In this case, the terminal system (120) may apply a general secure transmission policy while maintaining the existing session key (K1) to reduce computational load and communication load.

[0104] In the second stage, a sudden change in water level may be detected. The event determination unit (125) can determine whether a sudden change in water level event has occurred by using at least one of the current value, previous value, average value within a certain time interval, moving average value, amount of change, rate of change, or whether the critical water level is exceeded, of the water level data received from the field sensor (110). For example, if the current water level value increases by more than the reference amount of change compared to the previous water level value, or the rate of increase in water level per unit time is greater than or equal to the reference rate of change, or the water level value exceeds the critical water level line, the event determination unit (125) can determine that a sudden change in water level event has occurred. Additionally, to prevent unnecessary key changes from being repeated due to temporary noise, the event determination unit (125) can further determine whether the rate of change in water level is maintained above the reference value in a plurality of consecutive measurement cycles, or whether the water level data is maintained stably near the critical water level for a preset time.

[0105] A sudden change in water level event can indicate a physical danger situation such as an actual flood, sudden discharge, change in drainage conditions, or risk of inundation, while at the same time being treated as a section where an attacker is highly likely to falsify or retransmit water level data to generate a false alarm or conceal an actual danger situation. Therefore, the present invention does not stop at simply reporting a sudden change in water level event to a control server, but uses the event as a trigger for changing the security policy. Accordingly, when the event judgment unit (125) determines a sudden change in water level event, the security policy control unit (126) can control the security level of the measurement data related to the event to be strengthened compared to the existing normal security level.

[0106] In the third stage, key exchange and new key generation may be performed. When the security policy control unit (126) determines that a rapid change in water level event has occurred, it may control the quantum-resistant key exchange unit (124) to re-perform quantum-resistant key exchange with the external server (130). At this time, the quantum-resistant key exchange unit (124) may establish a new shared secret value with the external server (130) using the device unique information, root key, authentication key, key protection information, or security random number protected by the hardware security unit (122), and the results of key generation, key encapsulation, or key decapsulation processing of the quantum-resistant cryptographic processing unit (123). The quantum-resistant key exchange unit (124) may derive a new session key (K2) based on the new shared secret value, and at this time, sensor identification information, event type, risk level, timestamp, nonce, session identification information, or key generation information may additionally be used as key derivation input values.

[0107] The discarding of the existing session key (K1) can be explicitly performed by the security policy control unit (126). The security policy control unit (126) can restrict the usable range of the existing session key (K1) based on the time when a water level sudden change event occurs, and control the security communication unit (127) so that the existing session key (K1) is not used for water level data generated after that time. Additionally, the hardware security unit (122) can invalidate key protection information or key wrapping information that protected the existing session key (K1), or mark the session identifier corresponding to the existing session key (K1) as discarded. By discarding the existing session key (K1) in this way, the risk of an attacker forging or retransmitting data in the water level sudden change section using past session keys or past data frames can be reduced.

[0108] In the fourth step, a new session key (K2) may be applied. The secure communication unit (127) may use the new session key (K2) to encrypt measurement data related to a rapid change in water level event or generate integrity verification information for said data. Additionally, the security policy control unit (126) may strengthen the transmission security policy in the section where the new session key (K2) is applied, thereby controlling the addition of at least one of electronic signature information, increment counter value, timestamp, nonce, and sensor identification information to the water level data. In this case, the electronic signature information may be generated by the quantum-resistant cryptographic processing unit (123), and the data to be signed may include a water level value, amount of change in water level, rate of change in water level, time of event occurrence, sensor identification information, key generation information, and session identification information corresponding to the new session key (K2).

[0109] The external server (130) can perform decryption of the received data, integrity verification, and digital signature verification using a server-side key or shared secret value corresponding to the new session key (K2). The external server (130) can distinguish whether the data was generated during the period of using the existing session key (K1), the period of using the new session key (K2), or whether past data has been retransmitted by using the timestamp, nonce, increment counter value, and key generation information included in the received data. Accordingly, the external server (130) can more accurately determine the source, time of creation, and integrity of the data received during the period of rapid change in water level.

[0110] In the fifth stage, normal mode may be performed after the water level has stabilized. The event judgment unit (125) may determine that the water level change event has ended if the water level value is maintained within a stable range for a certain period of time after the water level change, if the rate of change in water level decreases below a reference value, or if the state of exceeding the critical water level is resolved. At this time, the security policy control unit (126) may decide whether to maintain the enhanced electronic signature policy or the transmission security policy, return to the normal security policy, or maintain the observation mode for a certain period of time. For example, immediately after the water level stabilizes, the new session key (K2) may be continuously used, but the electronic signature addition cycle may be gradually lowered, or after the risk level is lowered, it may be configured to return to the general security transmission policy.

[0111] The new session key (K2) can be maintained even after returning to normal mode. That is, in the present invention, key change is not limited to a security measure used temporarily only during the event period, but can be performed by switching the key generation from K1 to K2 based on the water level sudden change event. In this case, when the external server (130) manages the history of water level data, data prior to the water level sudden change event can be managed as data corresponding to the existing session key (K1) or the first key generation, and data after the event can be managed as data corresponding to the new session key (K2) or the second key generation. Accordingly, data history and key history can be managed together based on the time of the water level sudden change, and the falsification or alteration of data in a specific section can be verified more clearly during post-analysis.

[0112] In one embodiment, the critical water level can be set as an absolute water level value. For example, if a water level of interest, a water level of caution, a water level of warning, or a water level of danger is pre-set for a specific point in a river or drainage channel, the event judgment unit (125) can determine whether the current water level value exceeds any of the critical water levels. If the current water level value exceeds the caution level, only the transmission security policy is strengthened, and if the current water level value exceeds the warning level or the water level of danger, the existing session key (K1) is discarded and a new session key (K2) is derived. In this way, by setting different levels of security policy strengthening according to the critical water level stage, the disaster risk and the security processing strength can be linked.

[0113] In another embodiment, the critical condition may be set as the rate of change in water level. For example, the difference between the current water level and the previous water level is divided by the measurement interval to calculate the rate of rise in water level per unit time, and if the calculated rate of rise in water level is greater than or equal to the reference rate of change, it can be determined that a rapid change in water level event has occurred. This method has the advantage of being able to detect a rapid rise occurring over a short period of time early, even if the absolute water level has not yet reached a dangerous level. Additionally, if the rate of fall in water level is greater than the reference value, it can be determined as a separate rapid drop in water level event by considering the possibility of rapid discharge, drainage, sensor error, or falsified data.

[0114] In another embodiment, the event judgment unit (125) may combine multiple conditions when determining a rapid change in water level event. For example, it may be determined that the key change condition is satisfied only when the current water level value approaches a critical water level, the rate of change in water level is simultaneously greater than or equal to a reference value, and the same rising pattern is confirmed in a series of consecutive measurement data. Additionally, when the terminal system (120) is operated together with a flow meter, a rain gauge, or a weather observation sensor, the event judgment unit (125) may additionally determine the correlation between the rise in water level and the increase in rainfall or flow velocity. If only the water level data changes rapidly while the rainfall or flow velocity data is within the normal range, it is determined that there is a higher possibility of sensor malfunction or data falsification rather than an actual physical danger event, and the electronic signature policy can be further strengthened along with the application of a new session key (K2).

[0115] In another embodiment, the key change mechanism may be configured to prevent excessive repetition of key exchanges. Since water level data may fluctuate instantaneously due to noise, waves, water surface reflection conditions, rainfall influence, or sensor installation environment, immediately re-performing quantum-resistant key exchanges for every instantaneous change may increase the computational load, power consumption, and communication load of the terminal system (120). To prevent this, the security policy control unit (126) may set a re-key exchange time limit for a certain period after a key change, or set it to maintain a new session key (K2) during the same event period. Additionally, if multiple water level sudden change events occur consecutively within a short period, instead of repeatedly updating the entire session key, it may be configured to use an event-specific sub-session key or a derived key at the data frame level.

[0116] In another embodiment, the new session key (K2) may be a session key applied to the entire terminal system (120), or a sub-session key applied only to a specific field sensor (110). For example, if a radar water level gauge, a flow meter, a rain gauge, and a slope collapse detection sensor are connected together to a single terminal system (120), when a sudden change in water level event occurs only at the radar water level gauge, the security policy control unit (126) may control the system to change only the sub-session key corresponding to the radar water level gauge from K1 to K2, while maintaining the existing sub-session key for the other sensors. Conversely, in the case of a complex risk event where rainfall increases, flow velocity increases, and water level rises occur simultaneously, the communication session key of the entire terminal system (120) may be configured to be changed to the new session key (K2).

[0117] In another embodiment, key generation information may be included in the data frames before and after the key change. For example, the data frame using the existing session key (K1) may include first key generation identification information, and the data frame using the new session key (K2) may include second key generation identification information. The external server (130) can use the key generation information to identify which key the received data is protected by and perform a verification procedure corresponding to the key generation. Additionally, the external server (130) can store the transition history between the first key generation and the second key generation based on the time when a water level sudden change event occurred, so that the correlation between the data and the key can be tracked during post-audit or failure analysis.

[0118] In another embodiment, event data may be stored in a temporary protection state until a new session key (K2) is derived. For example, if quantum-resistant key exchange with an external server (130) is delayed or the network is temporarily unstable immediately after a sudden change in water level event is detected, the secure communication unit (127) may store water level data at the time of the event and a certain number of water level data before and after it in a local storage area. At this time, at least one of a timestamp, nonce, increment counter value, and hash value of previous data may be added to each data. Subsequently, when a new session key (K2) is derived or communication with the external server (130) is restored, the secure communication unit (127) may securely transmit the stored data based on the new session key (K2). Accordingly, the continuity and integrity of the event data can be preserved even in situations of key exchange delay or communication delay.

[0119] In another embodiment, the disposal of the existing session key (K1) can be performed using an immediate disposal method or a deferred disposal method. In the immediate disposal method, the existing session key (K1) is configured to no longer be used as soon as the event of a sudden change in water level is confirmed, and subsequent data can be transmitted only through the new session key (K2). In the deferred disposal method, the existing session key (K1) is used for limited purposes only until the quantum-resistant key exchange is completed and the new session key (K2) is successfully derived, and electronic signature information, timestamp, nonce, and increment counter value can be mandatorily added to the data in that section. Such a deferred disposal method may be advantageous for ensuring the continuity of data transmission in sites where the network condition is unstable or the computational resources of the terminal system (120) are limited.

[0120] In another embodiment, the security policy control unit (126) may set conditions for returning to normal mode after stabilization in multiple stages. For example, it may be configured to return to normal mode only when the water level drops below a critical level, the rate of change in water level is maintained below a reference value, and the data verification result of the external server (130) is confirmed to be normal. Additionally, even after returning to normal mode, the new session key (K2) may be maintained for a certain period of time, and the digital signature addition cycle may be set to be kept high for a certain period immediately after the event. Accordingly, the level of defense against data falsification or retransmission attacks can be maintained even during the unstable period immediately after a sudden change in water level.

[0121] The embodiment according to FIG. 4 illustrates a key change process in response to a sudden change in water level of a radar water level gauge, but the present invention is not limited thereto. For example, when applied to a flow meter, the existing session key (K1) can be discarded and a new session key (K2) derived when a sudden change in flow velocity or backflow is detected; when applied to a slope collapse detection sensor, the new session key (K2) can be applied when a change in slope angle, an increase in underground displacement, or an abnormal vibration pattern is detected; and when applied to a weather observation sensor, security policies can be strengthened when a sudden increase in rainfall, a sudden change in wind speed, or a sudden change in atmospheric pressure is detected. In this way, the present invention can apply an event-based key change mechanism to various changes in physical quantities in the fields of disaster and environmental measurement as well as water level data.

[0122] And, FIG. 5 is a flowchart illustrating a quantum-resistant secure communication method according to one embodiment of the present invention.

[0123] As illustrated in FIG. 5, the quantum-resistant secure communication method of the present invention can be performed in a terminal system (120), preferably an Edge terminal system, connected to one or more field sensors (110). In this embodiment, the terminal system (120) is not merely a relay device that transmits measurement data and sensor status information collected from the field sensors (110) to an external server (130), but can operate as a secure communication entity that performs quantum-resistant key exchange, session key derivation, event determination, security policy change, and secure data transmission by linking a hardware security structure with quantum-resistant cryptographic software. Accordingly, the method of the present invention can be applied to various sensor devices installed in the field, such as radar water level gauges, flow meters, slope collapse detection sensors, weather observation sensors, rain gauges, underground displacement sensors, vibration sensors, or hydrological condition detection sensors.

[0124] First, in step S100, the terminal system (120) can receive measurement data and sensor status information from one or more field sensors (110). Here, the measurement data may include water level data, flow velocity data, rainfall data, wind direction data, wind speed data, temperature data, humidity data, inclination angle data, underground displacement data, vibration data, crack data, or hydrological status data, depending on the type of field sensor (110). Additionally, the sensor status information may include sensor identification information, sensor type, measurement cycle, battery status, power status, self-diagnosis result, communication response status, error code, installation location information, whether the equipment is disconnected, whether the equipment is replaced, or whether it has entered maintenance mode. The terminal system (120) can convert the received measurement data and sensor status information into data frames suitable for internal processing, and each data frame may include sensor identification information, measurement time, data sequence information, or validity information of the measurement value.

[0125] In step S200, the hardware security structure of the terminal system (120) may store at least one of device unique information, a root key, an authentication key, key protection information, and a security random number within a hardware-based security area. The hardware security structure may be implemented by a hardware security unit (122) and may include a security element, a security chip, a TPM, an HSM, a TEE, a security MCU, or an equivalent hardware-based trusted area. By managing sensitive information in a security area separated from a general computation area or a general memory area, the hardware security structure may ensure that device authentication and key protection functions are maintained even when the terminal system (120) is installed outdoors or in a remote location where there is a risk of physical access. Additionally, the hardware security structure may directly store key materials used by quantum-resistant cryptographic software, store key protection information to protect key materials, and generate or provide security random numbers used in the quantum-resistant key exchange process.

[0126] In step S300, quantum-resistant cryptographic software executed on the terminal system (120) can perform at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with a hardware security structure. The quantum-resistant cryptographic software can be executed on a processor, microcontroller, security processor, or edge computing unit of the terminal system (120), and can perform quantum-resistant cryptographic operations by referencing device unique information, authentication key, key protection information, or security random number stored in the hardware security structure. For example, the quantum-resistant cryptographic software can perform key encapsulation or key decapsulation for key exchange with an external server (130), and can generate a digital signature or verify authentication information received from the external server (130) to prove the source and integrity of the measurement data.

[0127] At this time, the quantum-resistant cryptographic software may select a quantum-resistant cryptographic algorithm to apply based on the computational performance, memory capacity, power status, communication quality, key exchange frequency, risk level of measurement data, or whether an event occurs of the terminal system (120). For example, in normal times, a relatively lightweight key exchange or integrity verification method may be applied to reduce power consumption and communication load of the terminal system (120), and when an event such as a sudden change in water level, a sudden change in flow velocity, an anomaly in slope displacement, or a communication anomaly occurs, a key exchange method or digital signature method with high security strength may be applied. In this case, the quantum-resistant cryptographic algorithm for key exchange may include ML-KEM, Kyber, HQC, NTRU family algorithms or lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signatures may include ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+, or hash-based digital signature algorithms.

[0128] In step S400, the terminal system (120) performs quantum-resistant key exchange with the external server (130) based on information protected by a hardware security structure and the processing result of quantum-resistant cryptographic software, and can derive a session key used for secure transmission of measurement data based on the quantum-resistant key exchange. Specifically, the terminal system (120) can exchange or process a key encapsulation value, key decapsulation value, or shared secret value generated through the quantum-resistant cryptographic software with the external server (130), and can generate a session key by combining device unique information protected by the hardware security structure, a security random number, key protection information, sensor identification information, timestamp, or nonce. The session key may be a common session key applied to the entire communication session between the terminal system (120) and the external server (130), or a sub-session key corresponding to a specific field sensor (110).

[0129] In step S500, the terminal system (120) can determine whether a field event has occurred based on at least one of measurement data, sensor status information, communication status information of the terminal system (120), and connection status information of one or more field sensors (110). Here, the field event may include at least one of a physical hazard event, a sensor malfunction event, a communication malfunction event, and an equipment replacement event. A physical hazard event may be an event indicating a sudden change in the actual field condition, such as a sudden rise in water level, a sudden drop in water level, a sudden change in flow velocity, a sudden increase in rainfall, an increase in slope displacement, an abnormal vibration, an abnormal hydrological condition, or a sudden change in weather. A sensor malfunction event may include a fixed sensor output value, an output of an unrealistically rapidly changing value, a self-diagnosis error, a sensor response delay, a power malfunction, or a mismatch in sensor identification information. A communication malfunction event may include a disconnection of communication with an external server (130), an increase in packet loss, an increase in the number of retransmissions, an authentication failure, or an abnormal connection attempt. Equipment replacement events may include the new connection of the field sensor (110), replacement of the existing sensor, sensor disconnection, or entry into maintenance mode.

[0130] Additionally, at step S500, the terminal system (120) may generate a sensor-specific security context for each of one or more field sensors (110). The sensor-specific security context may include at least one of sensor identification information, sensor type, measurement cycle, risk level, data importance, and communication status. For example, in the case of a radar water level gauge, the water level change rate, critical water level, flood risk level, and importance of water level data may be included in the sensor-specific security context; in the case of a flow meter, the flow velocity change rate and whether the flow rate increases or reverses may be included; and in the case of a slope collapse detection sensor, the amount of change in inclination angle, the amount of change in underground displacement, vibration pattern, or crack change information may be included. Based on these sensor-specific security contexts, the terminal system (120) may set different session keys, sub-session keys, or key update conditions for each field sensor (110).

[0131] If it is determined that no event occurred at step S500, the terminal system (120) may proceed to step S700 while maintaining the existing session key and existing security policy. In this case, the terminal system (120) may add session key-based encryption information or integrity verification information to the measurement data according to the normal security policy, and, if necessary, add timestamp, nonce, or sensor identification information and transmit it to an external server (130). In this way, by omitting or minimizing excessive key exchange or digital signature operations during normal operation, critical computational load, memory usage, power consumption, and communication volume in the Edge environment can be reduced.

[0132] On the other hand, if it is determined that an event has occurred at the S500 stage, the terminal system (120) at the S600 stage may dynamically change at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for measurement data, and the transmission security policy for measurement data based on whether a field event has occurred. For example, if a physical risk event such as a sudden rise in water level, a sudden change in flow velocity, or an increase in slope displacement occurs, the terminal system (120) may discard the existing session key and re-perform quantum-resistant key exchange with the external server (130) to derive a new session key. Additionally, if an event occurs only at a specific field sensor (110), the entire communication session key may not be changed, and only the sub-session key corresponding to that field sensor (110) may be updated.

[0133] The process of discarding the existing session key in step S600 may include not only simply stopping the use of the existing session key, but also updating key generation information or session identification information so that the existing session key is not applied to measurement data generated after the time of the event. The terminal system (120) may limit the scope of use of the existing session key to data prior to the event and apply a new session key or an updated sub-session key to critical data after the event. Accordingly, the risk of retransmission attacks using past session keys or past normal data frames, insertion of forged data, or false alarm generation can be reduced.

[0134] Additionally, at stage S600, the electronic signature policy may be strengthened according to the type of event and the risk level. Normally, only encryption information or integrity verification information may be added to the measurement data; however, if a physical risk event, sensor anomaly event, communication anomaly event, or equipment replacement event occurs, the policy may be changed to additionally add electronic signature information to the measurement data related to the event. In this case, the data subject to the electronic signature may include at least one of measurement data, sensor identification information, timestamp, nonce, increment counter value, event type, risk level, key generation information, or session identification information. Accordingly, the external server (130) can verify whether the data in the event interval was generated by a legitimate terminal system (120), whether it was not tampered with during transmission, or whether past data was retransmitted.

[0135] In step S700, the terminal system (120) can transmit measurement data to an external server (130) by adding security information according to the changed policy. At this time, the terminal system (120) can add at least one of encryption information, integrity verification information, digital signature information, timestamp, nonce, and sensor identification information to the measurement data. The external server (130) can perform decryption, integrity verification, digital signature verification, sensor identification information verification, timestamp verification, checking for nonce duplication, or key generation information verification using the security information included in the received data. Accordingly, the external server (130) can determine the creator of the measurement data, the time of creation, the order of the data, whether it has been retransmitted, and whether it has been tampered with.

[0136] In one embodiment, when the field sensor (110) is a radar level gauge, the terminal system (120) receives level data and sensor status information from the radar level gauge at step S100, and at step S500, determines whether a sudden level change event has occurred using the amount of change in level, the rate of change in level, or whether the threshold level has been exceeded. If no sudden level change event has occurred, a general secure transmission can be performed while maintaining the existing session key, and if a sudden level change event has occurred, the existing session key can be discarded or a sub-session key corresponding to the level gauge can be updated at step S600. Subsequently, at step S700, the terminal system (120) can transmit to an external server (130) the level data with added electronic signature information, timestamp, nonce, increment counter value, and sensor identification information based on the new session key.

[0137] In another embodiment, when communication with the external server (130) is interrupted, the terminal system (120) may store continuity verification information for each measurement data generated during the communication interruption, including at least one of a monotonically increasing counter value, a timestamp, sensor identification information, and a hash value of previous measurement data, which are protected by a hardware security structure. In this case, the monotonically increasing counter value may indicate the data generation order, and the hash value of previous measurement data may form a hash chain between the data generated during the communication interruption period. Subsequently, when communication is restored, the terminal system (120) may re-perform a quantum-resistant key exchange with the external server (130) or derive a new session key, and then transmit a plurality of measurement data with continuity verification information attached to the external server (130). The external server (130) may use this to verify whether the data was deleted, the order was changed, or it was replaced with past data during the communication interruption.

[0138] In another embodiment, when an equipment replacement event occurs, the terminal system (120) may not immediately process the data of the new equipment as normal data, but may store it in isolation until approval or re-authentication by the external server (130) is completed. For example, if sensor identification information is changed, communication response characteristics different from the existing sensor are confirmed, or if a new sensor is connected after entering maintenance mode, the terminal system (120) may determine that an equipment replacement event has occurred. In this case, the terminal system (120) may discard or update the security context for the existing sensor, create a security context for the new sensor, and perform a quantum-resistant key exchange or re-authentication procedure with the external server (130). Accordingly, it is possible to prevent unauthorized equipment from arbitrarily connecting and transmitting false measurement data to the external server (130).

[0139] In another embodiment, when a plurality of field sensors (110) are connected to a single terminal system (120), the terminal system (120) can determine the reliability of a field event by utilizing the correlation between the plurality of sensors. For example, if the water level data of a radar water level gauge rises rapidly while the rainfall data of a rain gauge and the flow velocity data of a flow meter increase together, the terminal system (120) can determine that an actual physical danger event has occurred. Conversely, if only the water level data changes rapidly while the rainfall or flow velocity data remains within the normal range, the terminal system (120) can determine that the event is likely to be a sensor malfunction or data falsification. Based on the results of such determination, the terminal system (120) can update the entire session key, update only the sub-session key corresponding to a specific sensor, or change the policy to mandatorily add an electronic signature to the data.

[0140] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Industrial applicability

[0141] Furthermore, the present invention provides a quantum-resistant secure communication system for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software that can secure the security of field measurement data even in a quantum computer-based attack environment by linking a hardware security module with quantum-resistant cryptographic software to perform quantum-resistant key generation and key exchange with a server in an Edge terminal system connected to one or more field measurement sensors, such as a radar water level gauge, a flow meter, a slope collapse detection system, and a weather observation sensor. Since the invention is not only sufficiently capable of commercialization or business but is also clearly and practically implementable, it is an invention with industrial applicability. Explanation of the symbols

[0142] 100: Quantum-resistant secure communication system 110: Field sensor 120 : Edge terminal system 130 : External server

Claims

Claim 1 A quantum-resistant secure communication system for an Edge terminal system connected to one or more field sensors, comprising: a sensor interface unit that receives measurement data and sensor status information from the one or more field sensors; a hardware security unit that stores at least one of the device unique information, root key, authentication key, key protection information, and security random number of the Edge terminal system within a hardware-based security area; a quantum-resistant cryptographic processing unit that performs at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security unit; a quantum-resistant key exchange unit that performs quantum-resistant key exchange with an external server based on information protected by the hardware security unit and the processing result of the quantum-resistant cryptographic processing unit, and derives a session key used for secure transmission of the measurement data based on the quantum-resistant key exchange; an event determination unit that determines whether a field event, including at least one of a physical risk event, a sensor abnormality event, a communication abnormality event, and an equipment replacement event, occurs based on at least one of the measurement data, the sensor status information, the communication status information of the Edge terminal system, and the connection status information of the one or more field sensors; and the execution of the quantum-resistant key exchange based on the determination result of the event determination unit. A quantum-resistant security communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, characterized by comprising: a security policy control unit that dynamically changes at least one of a condition, a condition for updating the session key, an electronic signature policy for the measurement data, and a transmission security policy for the measurement data; and a security communication unit that transmits the measurement data to an external server by adding at least one of encryption information, integrity verification information, electronic signature information, timestamp, nonce, and sensor identification information according to the policy changed by the security policy control unit. Claim 2 A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, wherein, in claim 1, the one or more field sensors include at least one of a radar water level gauge, a flow meter, a slope collapse detection sensor, a weather observation sensor, a rain gauge, an underground displacement sensor, a vibration sensor, and a hydrological condition detection sensor, and the security policy control unit sets a sensor-specific security context for each of the one or more field sensors, which includes at least one of sensor identification information, sensor type, measurement cycle, risk grade, data importance, and communication status, and the quantum-resistant key exchange unit sets different session keys, sub-session keys, or key update conditions for each of the one or more field sensors based on the sensor-specific security context. Claim 3 A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, wherein, in claim 1, the quantum-resistant cryptographic processing unit selects a quantum-resistant cryptographic algorithm for key exchange and a quantum-resistant cryptographic algorithm for digital signatures based on at least one of the computational performance, memory capacity, power state, communication state, key exchange frequency, and risk class of measurement data of the Edge terminal system, wherein the quantum-resistant cryptographic algorithm for key exchange includes at least one of ML-KEM, Kyber, HQC, NTRU family algorithms and lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signatures includes at least one of ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+ and hash-based digital signature algorithms. Claim 4 A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, wherein, in claim 1, the event determination unit determines whether a physical risk event or a sensor abnormality event has occurred based on at least one of the amount of change, rate of change, threshold exceedance, correlation between multiple sensors, and sensor status information of measurement data received from one or more field sensors, and the security policy control unit controls the quantum-resistant key exchange unit to re-perform quantum-resistant key exchange with an external server or to discard an existing session key and derive a new session key when it is determined that the physical risk event or the sensor abnormality event has occurred. Claim 5 A quantum-resistant secure communication system of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, wherein, in the first paragraph, the security communication unit adds session key-based encryption information or integrity verification information to normal measurement data according to a transmission security policy set by the security policy control unit, and when the event judgment unit determines that a physical risk event, sensor abnormality event, communication abnormality event, or equipment replacement event has occurred, at least one of electronic signature information, increment counter value, timestamp, nonce, and sensor identification information is additionally added to the measurement data related to the event and transmitted to an external server. Claim 6 A quantum-resistant secure communication method performed in an Edge terminal system connected to one or more field sensors, comprising: receiving measurement data and sensor status information from the one or more field sensors; a step in which a hardware security structure of the Edge terminal system stores at least one of the device unique information, root key, authentication key, key protection information, and security random number of the Edge terminal system within a hardware-based security area; a step in which quantum-resistant cryptographic software executed in the Edge terminal system performs at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on a quantum-resistant cryptographic algorithm in conjunction with the hardware security structure; a step in which the Edge terminal system performs a quantum-resistant key exchange with an external server based on information protected by the hardware security structure and the processing result of the quantum-resistant cryptographic software, and derives a session key used for secure transmission of the measurement data based on the quantum-resistant key exchange; and a step in which the Edge terminal system determines whether a field event, including at least one of a physical risk event, a sensor abnormality event, a communication abnormality event, and an equipment replacement event, occurs based on at least one of the measurement data, the sensor status information, the communication status information of the Edge terminal system, and the connection status information of the one or more field sensors. A step of determining; a step in which the Edge terminal system dynamically changes at least one of the conditions for performing quantum-resistant key exchange, the conditions for updating the session key, the electronic signature policy for the measurement data, and the transmission security policy for the measurement data based on whether the field event occurs; and a step in which the Edge terminal system adds at least one of encryption information, integrity verification information, electronic signature information, timestamp, nonce, and sensor identification information to the measurement data according to the dynamically changed policy and transmits it to the external server.A quantum-resistant secure communication method for an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software, characterized by including... Claim 7 In claim 6, the step of determining whether the field event occurs comprises: the step of the Edge terminal system generating a sensor-specific security context for each of the one or more field sensors, the sensor-specific security context including at least one of sensor identification information, sensor type, measurement cycle, risk level, data importance, and communication status; and the step of the Edge terminal system setting different session keys, sub-session keys, or key update conditions for each of the one or more field sensors based on the sensor-specific security context; characterized in that it is a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software. Claim 8 In claim 6, the step of determining whether the field event has occurred includes the step of determining whether the physical risk event has occurred by using at least one of the change amount, change rate, threshold exceedance of measurement data received from at least one of a radar water level gauge, a flow meter, a slope collapse detection sensor, and a weather observation sensor, and the correlation between multiple sensors; and the step of dynamically changing includes the step of, when the Edge terminal system determines that the physical risk event has occurred, discarding the existing session key and re-performing quantum-resistant key exchange with the external server to derive a new session key, or updating the sub-session key corresponding to the field sensor related to the physical risk event. This characterizes a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software. Claim 9 In claim 6, the step of transmitting to the external server comprises: a step of adding and storing continuity verification information, which includes at least one of a monotonically increasing counter value, a timestamp, sensor identification information, and a hash value of a previous measurement data protected by the hardware security structure, for each measurement data generated while the Edge terminal system is disconnected from the external server; and a step of transmitting a plurality of measurement data with the added continuity verification information, and performing integrity and sequence verification of the plurality of measurement data through the quantum-resistant key exchange or the derivation of a new session key, when the Edge terminal system restores communication with the external server. This characterizes a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software. Claim 10 In claim 6, the step of performing at least one of key generation, key encapsulation, key decapsulation, digital signature, and verification based on the quantum-resistant cryptographic algorithm comprises the step of the Edge terminal system selecting a quantum-resistant cryptographic algorithm for key exchange and a quantum-resistant cryptographic algorithm for digital signature based on at least one of the computational performance, memory capacity, power state, communication state, key exchange frequency, and risk class of measurement data of the Edge terminal system, wherein the quantum-resistant cryptographic algorithm for key exchange includes at least one of ML-KEM, Kyber, HQC, NTRU family algorithms and lattice-based key encapsulation algorithms, and the quantum-resistant cryptographic algorithm for digital signatures includes at least one of ML-DSA, Dilithium, Falcon, SLH-DSA, SPHINCS+, and hash-based digital signature algorithms. This characterizes a quantum-resistant secure communication method of an Edge terminal system using a hardware security structure and quantum-resistant cryptographic software.

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