Chemical process control system network risk analysis method and system based on multilayer business process modeling

Abstract

The invention belongs to the field of safety engineering in chemical industry production, and discloses a chemical process control system network risk analysis method based on multilayer business process modeling and application, and the method comprises the steps: analyzing the business process and data interaction relation of a chemical process, and constructing a multilayer business process model based on a BPMN2.0 standard; according to the method, an original equipment-centered method is replaced, an improved failure mode and consequence analysis centered on a business basic unit is provided, a potential failure mode of a task is identified, failure reasons and consequences under different attack intentions are clarified, and generation of an attack fault tree model is guided conveniently; and finally, risk analysis of the business activity is carried out. According to the method, the effect and importance of the assets in the task execution process are considered, the whole complete failure path under the integration of information security and function security can be comprehensively covered, the security risk in each task link can be more comprehensively identified, and then the accuracy of risk analysis is improved.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the field of safety engineering technology in chemical industry production, and in particular relates to a chemical process control system network risk analysis method and system based on multi-layer business process modeling. Background Art

[0002] With the deepening of industrial automation and digitalization, chemical process control systems are not only facing the original failure problems, but also facing security issues caused by threats such as network attacks. Therefore, how to ensure the safe and stable operation of the system has become a key research issue.

[0003] At present, most of the risk assessment methods for business are analyzed from the information security domain, including the assessment of information generation, display, access, transmission, use and storage in information security (such as invention patent 201710994902.5), risk assessment of relevant business functions and data of network domain infrastructure in information security (such as invention patent 2017110120552.X), etc.; However, for chemical process control systems, it is far from enough to consider business process risk assessment only from the perspective of information layer. Some of them also consider physical layer business nodes, but they are mainly aimed at e-commerce, power and manufacturing industries (such as invention patent 202010923638.8, the paper "Information Security Risk Assessment Based on Business Process Modeling" in the 23-4 issue of the journal "Journal of Beijing Institute of Graphic Communication", etc.). Due to the continuity and complexity of chemical process production business, these methods lack consideration of the complex interactive relationship between process variables and equipment-tasks in continuous operation, so they are difficult to apply directly.

[0004] In view of the above analysis, the technical problems that need to be solved urgently in the prior art are:

[0005] The business process risk assessment method based on the information security domain lacks consideration of the scenario in which information layer network attacks cascade downward and cause functional safety failure.

[0006] The traditional risk assessment method of chemical process control system based on equipment assets lacks consideration of the role and importance of chemical equipment in the task execution process. In addition, there is no one-to-one correspondence between equipment assets and business tasks, making it difficult to discover key failure paths that affect the safe operation of the business.

[0007] Therefore, a method is needed that takes into account the role and importance of assets in the task execution process and can comprehensively cover the entire failure path under the integration of information security and functional safety, and more comprehensively identify and identify security risks in each task link. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a chemical industry risk analysis method and system based on a multi-layer business process model.

[0009] The present invention is implemented as follows: a chemical process control system network risk analysis method based on multi-layer business process modeling, the method specifically comprising:

[0010] S1: Construct a multi-layer business security model for chemical process control systems based on the Business Process Model and Notation 2.0 (BPMN2.0) standard;

[0011] S2: Conduct potential safety failure analysis of business activities based on the improved failure mode and effects analysis method to guide the construction of attack fault tree models;

[0012] S3: Risk analysis of conducting business activities.

[0013] Further, the S1 comprises the following steps:

[0014] (1) Analyze the business production types in the chemical process control system, mainly including two types of business: management business model and production business, and determine the business scope and objectives.

[0015] Specifically, the production management business model includes sub-business processes such as production planning and scheduling management, equipment management, safety and environmental management, and the production business model includes sub-businesses such as production process operation, equipment operation and monitoring, and raw material and product processing.

[0016] (2) Clarify the system topology level to which each sub-business process belongs, and analyze the dynamic and static information related to the BPMN2.0 business model.

[0017] Specifically, the dynamic information of a business includes business processes and business activities, where a business process is a group of activities combined according to certain rules, business relationships and their sequence; a business activity is a collection of one or more tasks. The static information of a business includes the supporting components or dependent resources and executors that complete the goals of the business activities.

[0018] (3) Analyze the system hierarchy of the distribution of four types of data flows, namely business flow, information flow, control flow and material flow, included in the business activities of the management business model and the production business model, the connection relationship between devices, and the data transmitted interactively.

[0019] Specifically, business flow describes the process and sequence of various business activities within the enterprise; information flow is effectively transmitted between different departments and links through networks and systems to provide data support for decision-making; control flow refers to the data flow process for monitoring and adjusting each link in the production process; material flow refers to the flow and transfer of materials from raw materials to finished products in the production process.

[0020] (4) Based on the interactive dependency between business processes and business data, the business construction standard BPMN2.0 is used to generate a fine-grained chemical process control system business process model, and the chemical process control system business model is verified and optimized.

[0021] Furthermore, S2 replaces the original device-centric method and proposes a safety failure analysis method for improving failure mode and effect analysis centered on a business basic unit, including the following steps:

[0022] (1) Define the scope of failure analysis, determine the system losses and hazards caused by business activities, analyze the failure events that cause losses and hazards, and use improved failure mode and effect analysis methods to identify failure modes that occur under network attack intentions.

[0023] Specifically, the business failure mode is composed of the following aspects, that is, business failure mode = {business attribute + deviation guide word},

[0024] Specifically, business attributes can be divided into the following four categories: business services, business values, business execution time, and business execution sequence. Deviation guide words are determined according to different failure types of business attributes, among which, deviation words of business service type = {lack, excess}, a total of two categories; deviation words of business value type = {too much, too little}, a total of two categories; deviation words of business execution time type = {too early, too late}, a total of two categories; deviation words of business execution sequence type = {omission, repetition, wrong order}, a total of three categories.

[0025] (2) Analyze the failure causes and consequences of the business process failure of the chemical process control system to guide the construction of subsequent attack fault trees.

[0026] Further, the S3 comprises the following steps:

[0027] (1) The failure modes, failure causes and failure consequences obtained by the above safety failure analysis module are mapped with the elements in the attack fault tree model, and then the attack fault tree model is constructed.

[0028] (2) Decompose the attack fault tree model into static subtrees. Analyze the basic events of the attack fault subtrees in different topological structure levels associated with the business process;

[0029] (3) Solve the minimum cut set of static subtrees at each topological level according to the principle of the smallest event set that cannot cause the top event to occur after removing any event;

[0030] (4) Risk analysis is performed through minimum cut sets and structural importance.

[0031] Another object of the present invention is to provide a chemical process control system risk analysis system based on a multi-layer business process model, the system specifically comprising:

[0032] Model building module, building a multi-layer business model of chemical process based on the business building standard BPMN2.0;

[0033] The safety failure analysis module analyzes the business processes / behaviors that cause losses and harm to chemical process control systems, uses an improved failure mode and effect analysis method to identify the failure modes of each basic unit of business activities, namely, tasks, under different network attack intentions, and analyzes the failure causes and failure results;

[0034] The risk analysis module analyzes the related events that lead to the failure of the business process, builds an attack fault tree model from the perspective of business process failure-task failure-equipment failure, and performs risk analysis based on the minimum cut set and structural importance.

[0035] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0036] First, in terms of business process modeling, it provides a business process model construction solution for the chemical industry, which effectively fills the technical gap in this field, meets the basic needs of chemical production and management business process description, and provides effective support for the collaborative work of business analysts and system safety engineers.

[0037] In analyzing the supporting role of equipment assets in the business process of the chemical process system, it is possible to identify the complex many-to-many relationship between equipment and tasks, so that equipment assets and business tasks can be flexibly configured to adapt to the diversified business needs.

[0038] In terms of failure process analysis, the traditional failure mode and effect analysis method is equipment-centric and easily limited to the failure mode and risk of the equipment. The improved failure mode and effect analysis method provided is guided by the business basic unit, accurately identifies the task failure mode, pays more attention to the key links and business continuity in the business process, identifies potential risks from the business level, and is more in line with actual application needs.

[0039] Through a comprehensive business process risk analysis solution that integrates information security and functional safety, we can ensure that the complete system failure path of the attack propagation can be effectively identified when facing a cyber attack. This will more comprehensively identify the security risks in each business link, thereby improving the accuracy of risk analysis and supporting enterprises to improve their ability to resist cyber attacks in an increasingly research environment.

[0040] Second, the technical solution of the present invention effectively solves the following technical problems in the prior art in industrial applications and has achieved significant technical progress:

[0041] 1. Technical issues

[0042] 1) Limitations of risk analysis of traditional chemical process control systems

[0043] Existing technologies mainly focus on risk analysis at a single level and lack correlation analysis between business processes, task units, and equipment levels, and are unable to fully reveal the potential risks in chemical processes.

[0044] 2) Insufficient identification of failure modes in cyber attack scenarios

[0045] Chemical control systems face complex cyber attack scenarios. Existing technologies make it difficult to accurately identify failure mode analysis of task units under attack intent, resulting in non-targeted defense measures.

[0046] 3) Risk assessment models lack hierarchy and dynamism

[0047] Traditional risk assessment methods lack multi-level modeling capabilities from the equipment layer to the business process, and cannot dynamically reflect the complexity of the system and the real-time changing risk status.

[0048] 2. Significant technological progress

[0049] 1) Multi-layer business process modeling for comprehensive analysis

[0050] The present invention builds a multi-layer business model of the chemical process control system based on BPMN2.0, combines business processes, task units and equipment status to form a hierarchical analysis framework that comprehensively covers all aspects of the chemical process. This modeling method makes risk analysis more accurate and efficient.

[0051] 2) Improve failure mode analysis to improve targeting

[0052] By introducing an improved failure mode and effects analysis (FMEA), the present invention can identify the failure mode of each task unit under the intention of a network attack, and deeply analyze the causes and consequences of the failure, thereby providing targeted security protection suggestions.

[0053] 3) Attack the fault tree model to enhance the depth of risk assessment

[0054] The present invention structures the relationship between business process failure and task and equipment failure by attacking the fault tree model, and can qualitatively analyze the event path leading to chemical process failure, providing a scientific basis for system security optimization.

[0055] 4) Combining qualitative and quantitative risk analysis

[0056] By using minimum cut sets and structural importance analysis, the present invention not only qualitatively reveals the key risk points, but also quantitatively evaluates the impact of each event on the system, thereby achieving comprehensive and accurate risk assessment.

[0057] 5) Dynamic risk assessment supports real-time monitoring

[0058] The present invention supports real-time updating and dynamic risk assessment, can timely update the model according to system operation data, make a rapid response to risk status, and improve the safety and adaptability of chemical control systems.

[0059] 6) Industrial application value

[0060] This invention significantly improves the safety, stability and reliability of chemical process control systems in complex scenarios, promotes the digital transformation of the industry, and has important practical application value, especially in the fields of network security, chemical process optimization and risk management. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is an overall flow chart of a risk analysis method based on a chemical process control system business model provided by an embodiment of the present invention;

[0062] Figure 2 It is a schematic diagram of a production process operation business model of a chemical process control system provided by an embodiment of the present invention;

[0063] Figure 3 It is a relationship diagram of enterprise levels involved, tasks related to each level, and dependent equipment assets in an example of risk analysis for fractionation tower top temperature control execution provided by an embodiment of the present invention;

[0064] Figure 4 It is an attack-fault tree diagram of the temperature control execution of the distillation tower top provided by an embodiment of the present invention;

[0065] Figure 5 A chemical process control system risk analysis system based on a multi-layer business process model is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0067] like Figure 1 As shown, an embodiment of the present invention provides a chemical process control system network risk analysis method based on multi-layer business process modeling, the method specifically includes:

[0068] S1: Build a multi-layer business security model for a chemical process control system based on the BPMN2.0 standard;

[0069] S2: Conduct potential safety failure analysis of business activities based on the improved failure mode and effects analysis method to guide the construction of attack fault tree models;

[0070] S3: Risk analysis of conducting business activities.

[0071] 1. Data collection and modeling of multi-layer business security model

[0072] First, based on the key signal data of the chemical process control system, such as sensor data, control signals and operating instructions, they are classified and organized according to the logical relationship between business activities and processes. The BPMN2.0 standard is used to define the multi-layer structure of management and production business activities, generate a multi-layer business security model, and map the key signal data to the nodes of each business activity to form a dynamic and traceable model.

[0073] 2. Failure mode extraction and analysis of signal data

[0074] At the nodes of business activities, combined with the characteristics of signal data, the potential signal failure modes of each node are identified through the improved failure mode and effects analysis (FMEA) method. For example, the failure causes and consequences such as signal transmission delay, wrong operation instructions or sensor failure are analyzed one by one through this method. The results of the analysis record the association between failure modes and signal characteristics, providing basic data for subsequent risk modeling.

[0075] 3. Construction of attack fault tree model driven by signal data

[0076] According to the failure mode analysis results, the chemical process control system signal data is used as node input, and the attack fault tree model is constructed layer by layer from business activity failure to equipment failure. Signal data is used to quantify the failure probability of the critical path in the fault tree, and combined with the minimum cut set analysis, potential network attack intentions and the path of failure of key business activities are identified.

[0077] 4. Risk analysis and assessment of signal data

[0078] The fault tree model is used to analyze the structural importance and probability of key signal data nodes and assess the risk level of each node. At the same time, combined with real-time monitoring of signal data, the possible failure risks in business activities are dynamically assessed. Finally, signal data is used to generate risk analysis reports to guide the formulation of risk mitigation strategies and the safety optimization of chemical process control systems.

[0079] S1, based on the business, builds a standard BPMN2.0 chemical process control system business model, including:

[0080] (1) The business production types in the chemical process control system are analyzed, mainly including two types of business: management business model and production business, and the business goals and specific business processes are determined.

[0081] Among them, the production management business model includes production planning and scheduling management, equipment management, safety and environmental management and other sub-businesses. The risk analysis of the chemical process control system based on the multi-layer business process model, the production business model includes production process operation, equipment operation and monitoring, raw material and product processing and other sub-businesses.

[0082]

[0083] (2) Clarify the system topology structure level to which each sub-business process belongs, and analyze the dynamic information and static information related to the BPMN2.0 business model. The dynamic information of the business includes business processes and business activities. Among them, the business process is a group of activities combined according to certain rules, business relationships and their sequence; the business activity is a collection of one or more tasks. The static information of the business includes the supporting components or dependent resources and executors to complete the business activity goals.

[0084] The business processes, business activities, tasks involved, and dependent resources of the production management business are as follows:

[0085]

[0086]

[0087] The business process, business activities, tasks involved, and dependent resources of the production execution business are as follows:

[0088]

[0089] (3) Based on the overall structure of the business process of the chemical process control system, the data types of business activities are divided into four types: business flow, control flow, information flow and material flow, and the characteristics of different data types are analyzed. The issuing role and execution role of the business data flow are analyzed, and the interaction relationship between the resources that the business activities at different system topology levels depend on is determined, so as to develop a detailed business process diagram and verify and optimize the business model of the chemical process control system.

[0090] Specifically, business flow describes the process and sequence of various business activities within the enterprise; information flow is effectively transmitted between different departments and links through networks and systems to provide data support for decision-making; control flow refers to the data flow process for monitoring and adjusting each link in the production process; material flow refers to the flow and transfer of materials from raw materials to finished products in the production process.

[0091]

[0092] (4) Draw a high-level flowchart based on the business construction standard BPMN2.0 to show the overall structure of the main business processes of the chemical process control system. Taking the production process operation business process as an example, the business process model is constructed based on the BPMN2.0 standard. Figure 2 shown.

[0093] The S2 comprises the following steps:

[0094] Taking the catalytic cracking fractionation unit as an example, the chemical process control system is used to analyze the enterprise levels, tasks related to each level, and dependent equipment assets involved in the temperature control execution process of the fractionation tower top, as follows: Figure 3 shown.

[0095] (1) Clarify the scope of failure analysis, determine the system losses and hazards caused by mission failure, improve the failure mode and effect analysis method with the mission as the center, and identify the failure mode that occurs.

[0096] Specifically, the service failure mode is composed of the following aspects, that is, service failure mode = {service attribute + deviation guide word}.

[0097] Specifically, business attributes can be divided into the following four categories: business services, business values, business execution time, and business execution sequence. Deviation guide words are determined according to different failure types of business attributes, among which, deviation words of business service type = {lack, excess}, a total of two categories; deviation words of business value type = {too much, too little}, a total of two categories; deviation words of business execution time type = {too early, too late}, a total of two categories; deviation words of business execution sequence type = {omission, repetition, wrong order}, a total of three categories.

[0098]

[0099] (2) Based on the improved failure mode and effect analysis method, the causes and consequences of task failure are analyzed, and the scenario of task failure is constructed. Taking the catalytic cracking fractionation unit, a chemical process control system, as an example, the failure modes, causes and consequences of the related tasks in the temperature control execution process of the distillation tower top are analyzed in detail, which is convenient for guiding the construction of subsequent attack fault trees.

[0100]

[0101] S3, taking the top temperature control of the fractionation tower of the fractionation unit in catalytic cracking as an example, provides a method for risk analysis of the business process of the chemical process control system, including the following steps:

[0102] (1) Map the failure modes, causes and consequences of failure obtained by the above safety failure analysis module with the elements in the attack fault tree model, and then construct a fault tree model. The failure consequence is the impact or result brought by the failure mode, mapped as the top event TE (Top Event); the failure mode represents the failure condition or deviation of the system, mapped as the intermediate event IE (Intermediate Events) of the fault tree; the failure cause is the direct factor that causes a specific failure mode, mapped as the basic event x in the fault tree i (Basic Events), which are the root causes of the failure.

[0103] (2) Based on the fault tree, the failure of the tower top temperature control caused by the network attack factor is taken into consideration and the attack fault tree is constructed as follows: Figure 4 As shown in the figure, the attack tree is composed of nodes and logical relationships. The nodes include root nodes and leaf nodes, and the logical relationships include AND, OR, and sequential AND. The root node is the hacked information or control device, and the leaf node is the attack method and the existing vulnerability.

[0104] (3) Decompose the attack fault tree model into static subtrees. Specifically, the attack fault tree basic event set X1 of the task in the enterprise layer is {x1, x2, ... x7}; the attack fault tree basic event set X2 of the task in the monitoring layer is {x8, x9, ... x 18}; The basic event set of the attack fault tree of the task in the control layer X3 = {x 19 ,x 20 ,…x 28}; The basic event set of the attack fault tree of the task in the physical layer X4 = {x 29}.

[0105] (4) Solve the minimum cut set of static subtrees at each level according to the following principles. Specifically, first perform logic gate analysis: the output event of the AND gate will only occur when all input events occur. Therefore, all input events connected to the AND gate constitute a cut set. The output event of the OR gate will occur when any input event occurs. Therefore, each input event of the OR gate can constitute a cut set separately. Second, solve the minimum cut set: the minimum set of events that can no longer cause the top event to occur after removing any event.

[0106] Specifically, there are 6 minimum cut sets of static attack fault subtrees in the enterprise layer, namely {x1}, {x2}, {x3}, {x4}, {x5, x6}, {x5, x7}; there are 9 minimum cut sets of static attack fault subtrees in the control layer, namely {x 19}、{x 23}、{x 26}、{x 27}、{x 28}、{x 20 , x 21}、{x 20 , x 22}、{x 20 , x 24}、{x 20 , x 25}.

[0107] (5) Risk analysis is performed through the minimum cut set and structural importance. The minimum cut set is used to solve and analyze the structural importance of a basic event. i The structural importance coefficient is represented by ST(i). The minimum cut set solution for structural importance must follow three rules:

[0108] The cut set structural importance of the minimum cut set with only one bottom event is the largest.

[0109] When the number of bottom events in the minimum cut set is equal, the bottom event that appears more times has a greater structural importance.

[0110] When the number of bottom events in the minimum cut set is unequal, the structural importance of the minimum cut set with fewer bottom events is greater than that with more.

[0111] Specifically, the importance of basic events in the enterprise layer and the control layer can be obtained:

[0112] ST(1)=ST(2)=ST(3)=ST(4)>ST(5)>ST(6)=ST(7) (Formula 1)

[0113] ST(19)=ST(23)=ST(26)=ST(27)=ST(28)>ST(20)>ST(21)=ST(22)=ST(24)=ST(25) (Equation 2)

[0114] (6) Information security risk analysis of business processes based on the attack fault tree model: According to Formula 1 and Formula 2, the structural importance of equipment failure events in functional safety is higher than the structural importance of network attack events in information security. The structural degree is positively correlated with the impact of the accident, and the greater the risk.

[0115] (7) Information security risk analysis of business processes based on the attack fault tree model: This risk analysis method takes into account the relationship between the topological levels, tasks, and devices associated with the business process. Multiple devices perform a task, such as management software and enterprise resource planning system. Both devices affect the control scheme design task. The greater the structural importance of the task, the greater the risk of task failure. A device performs multiple tasks, such as the controller device performs two tasks, namely, adjusting parameters and issuing instructions. The more tasks a device performs, the more task failures are affected by device damage, and the greater the risk of device failure.

[0116] like Figure 5 As shown, a chemical process control system network risk analysis system based on multi-layer business process modeling provided by an embodiment of the present invention specifically includes:

[0117] Model building module, building a multi-layer business model of chemical process control system based on business building standard BPMN2.0;

[0118] The safety failure analysis module analyzes the business processes / behaviors that cause losses and harm to chemical process control systems, uses an improved failure mode and effect analysis method to identify the failure modes of each basic unit of business activities, namely, tasks, under different network attack intentions, and analyzes the failure causes and failure results;

[0119] The risk analysis module analyzes the related events that lead to the failure of the business process, builds an attack fault tree model from the perspective of business process failure-task failure-equipment failure, and performs risk analysis based on the minimum cut set and structural importance.

[0120] The system builds a multi-layer business model of the chemical process control system based on the business process modeling standard BPMN2.0 (Business Process Model and Notation 2.0) through the model building module. The model covers multiple levels from high-level business goals to specific task activities, clearly describing the operating steps, resource allocation and the relationship between tasks in the chemical process, providing a structured framework and data support for subsequent risk analysis.

[0121] The safety failure analysis module of the system uses an improved failure mode and effects analysis (FMEA) method to identify failure modes of various business behaviors in the chemical process control system. This module uses tasks as the basic unit and combines the unique business processes of the chemical system to evaluate failure scenarios under different network attack intentions and deeply analyze the causes and potential consequences of failures. For example, the cause of failure is equipment failure, network communication interruption or instruction error, while the result of failure is the stagnation of critical tasks or unstable operation of chemical processes.

[0122] By combining the business process characteristics of chemical control systems, the safety failure analysis module identifies the intention of network attacks. The system can identify potential threat patterns at the business activity level for attack scenarios in chemical production (such as information tampering, instruction deception, or denial of service attacks), and then infer the intentions of attackers. The identification results are used to guide the risk analysis module to build a more targeted attack fault tree model.

[0123] The risk analysis module further analyzes the relationship between business process failure and task and equipment failure. By constructing an attack fault tree model, the complex risk factors of the chemical process control system are decomposed into sub-events that are easier to analyze. The fault tree model takes the chemical process failure as the top event, and gradually associates upward from the equipment layer and the task layer, comprehensively depicting the path leading to the top event.

[0124] Based on the attack fault tree model, the risk analysis module uses the minimum cut set and structural importance methods for analysis. The minimum cut set is used to identify the key event combination that causes business failure in the system, while the structural importance is used to evaluate the impact of each event on the overall system risk. These analysis results help to identify the weak links in the system and provide a specific technical basis for the optimization and protection of chemical process control systems.

[0125] Finally, the system combines the results of failure mode analysis and fault tree analysis to provide risk management recommendations for chemical process control systems. For example, task allocation can be adjusted, equipment maintenance can be strengthened, or network security configuration can be optimized based on the analysis results. At the same time, the system supports dynamic risk assessment, which can update the model and re-evaluate risks based on real-time data to ensure the safety and stability of chemical process control systems in complex environments.

[0126] The present invention belongs to the field of safety engineering technology in chemical industry production, and is applied to safety risk situation awareness equipment or safety assessment and management equipment of chemical process control systems. The present invention timely discovers potential high-risk points of the system under network attacks through full coverage analysis of equipment and task nodes. Combined with the analysis method of the multi-layer business process model, it can warn of risks in the system operation process, help managers take countermeasures in advance, and prevent accidents.

[0127] By testing different task flows of various chemical process control systems, potential risk points in each task node are identified, with a strong risk coverage rate. After risk identification, risk warning information can be effectively output to help managers understand and control risks in a timely manner.

[0128] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0129] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A chemical process control system network risk analysis method based on multi-layer business process modeling, characterized in that: The method specifically includes: S1: Based on the key signal data of the chemical process control system, including sensor data, control signals and operation instructions, data is classified and sorted according to the logical relationship between business activities and processes, a multi-layer business security model for management and production business activities is constructed, and key signal data is mapped to business activity nodes; S2: Using the improved Failure Mode and Effects Analysis (FMEA) method, combined with the signal data characteristics, identify the potential signal failure modes of business activity nodes, including signal transmission delay, erroneous operation instructions and sensor failure, and record the association between failure modes and signal characteristics; S3: Based on the failure mode analysis results, the attack fault tree model is constructed with signal data as input, which is expanded layer by layer from business activity failure to equipment failure. Through minimum cut set analysis and structural importance evaluation, potential network attack paths and key failure nodes of business activities are identified; S4: Based on the fault tree model, risk level assessment is performed on key signal data nodes. The risks of business activities are dynamically analyzed through real-time signal data monitoring. Risk analysis reports are generated to guide risk mitigation strategies and safety optimization of chemical process control systems.

2. The chemical process control system network risk analysis method based on multi-layer business process modeling as claimed in claim 1 is characterized in that: S1, the chemical process control system business model is constructed in the following manner: (1) Analyze the key information of the business process of the chemical process control system, clarify the interactive relationship between the business processes within the topological hierarchy and between the hierarchies, and construct a coarse-grained business process relationship network; (2) Analyze the system level of the distribution of the four types of data flows, namely business flow, information flow, control flow and material flow, included in the business activities of the management business model and the production business model, the connection relationship between devices and the data transmitted interactively; (3) Based on the interactive dependency between business processes and business data, the business construction standard BPMN2.0 is used to generate a fine-grained chemical process control system business process model.

3. The chemical process control system business model as claimed in claim 2, characterized in that: The production management business model includes sub-business processes such as production planning and scheduling management, equipment management, safety and environmental management, etc. The production business model includes sub-businesses such as production process operation, equipment operation and monitoring, raw material and product processing, etc.; the dynamic information of the business includes business processes and business activities, among which the business process is a group of activities combined according to certain rules, business relationships and their sequence, and the business activity is a collection of one or more tasks. The static information of the business includes the supporting components or dependent resources and executors for completing the business activity goals; the business flow describes the process and sequence of various business activities within the enterprise, and the information flow is effectively transmitted between different departments and links through the network and system to provide data support for decision-making; the control flow refers to the data flow process for monitoring and adjusting each link of the production process; the material flow refers to the flow and transfer of materials from raw materials to finished products in the production process.

4. The chemical process control system network risk analysis method based on multi-layer business process modeling as claimed in claim 1 is characterized in that: S2 replaces the original equipment-centric method and proposes a safety failure analysis method for improving failure mode and effect analysis centered on the business basic unit, including the following steps: (1) Define the scope of failure analysis, determine the system losses and harms caused by business activities, analyze the failure events that cause losses and harms, and use improved failure mode and effect analysis methods to identify failure modes that occur under network attack intentions; (2) Analyze the failure causes and consequences of the business process failure of the chemical process control system to guide the construction of subsequent attack fault trees.

5. The safety failure analysis method for improving failure mode and effect analysis centered on the business basic unit as claimed in claim 4, characterized in that: The business failure mode is composed of the following aspects, namely, business failure mode = {business attributes + deviation guide words}, business attributes can be divided into the following four categories: business services, business values, business execution time, business execution order, and the deviation guide words are determined according to the different failure types of business attributes, among which the deviation words of the business service type = {lack, excess}, a total of two categories; the deviation words of the business value type = {too much, too little}, a total of two categories; the deviation words of the business execution time type = {too early, too late}, a total of two categories; the deviation words of the business execution order type = {omission, repetition, wrong order}, a total of three categories.

6. The chemical process control system network risk analysis method based on multi-layer business process modeling as claimed in claim 1 is characterized in that: The S3 comprises the following steps: (1) Mapping the failure modes, failure causes and failure consequences obtained by the safety failure analysis module with the elements in the attack fault tree model, and then constructing the attack fault tree model; (2) Decompose the attack fault tree model into static subtrees. Analyze the basic events of the attack fault subtrees in different topological structure levels associated with the business process; (3) Solve the minimum cut set of static subtrees at each topological level according to the principle of the smallest event set that cannot cause the top event to occur after removing any event; (4) Risk analysis is performed through minimum cut sets and structural importance.

7. A chemical process control system risk analysis system based on a multi-layer business process model as described in claims 1-6, characterized in that: The system specifically includes: Model building module, building a multi-layer business model of chemical process control system based on business building standard BPMN2.0; The safety failure analysis module analyzes the business processes / behaviors that cause losses and harm to chemical process control systems, uses an improved failure mode and effect analysis method to identify the failure modes of each basic unit of business activities, namely, tasks, under different network attack intentions, and analyzes the failure causes and failure results; The risk analysis module analyzes the related events that lead to the failure of the business process, builds an attack fault tree model from the perspective of business process failure-task failure-equipment failure, and performs risk analysis based on the minimum cut set and structural importance.

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