Key management method and device suitable for nuclear power instrument control system

Abstract

The invention provides a key management method and device suitable for a nuclear power instrument control system. The method comprises the following steps: acquiring an identity public key in an identity public and private key pair of a node; generating a communication public and private key pair and a storage key corresponding to each node and a communication key shared by all nodes according to a preset rule; encrypting a communication public-private key pair by using the identity public key, and distributing the communication public-private key pair to a corresponding node; and encrypting the storage key and the communication key by using a communication public key in the communication public-private key pair, and distributing the storage key and the communication key to the corresponding nodes for each node to perform data encryption storage and transmission. According to the secret key management method, an identity public and private key pair is set for each node to serve as first encryption, a communication public and private key pair is specially generated to serve as second encryption, and finally a storage secret key and a communication secret key are set to encrypt stored and transmitted data. And the reliability of key management of the nuclear power instrument control system and the security during data storage and communication can be fully protected.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power control technology, and in particular to a key management method and device suitable for a nuclear power instrumentation and control system. Background Art

[0002] In the nuclear power instrumentation and control system, important data needs to be encrypted and stored. When encryption technology is applied, a key is required. At present, a single key is mostly used to encrypt data. The key is used in the software running memory, that is, the key is loaded when the software is running, and the key is in the software binary file after the software exits. When the nuclear power instrumentation and control system is started, the key is loaded into the memory. During the encryption and decryption operations, the key can be directly called and used without delay. This key management method has many shortcomings: First, there is a lack of key management mechanism in the nuclear power instrumentation and control system. The key is built into the system during research and development, and only a single key is used during storage. The key is not used in other aspects. In addition, the key is in plain text and is determined at the product development stage, so the key cannot be replaced later; the other is that the key management system only has the key management function and cannot cooperate with the nuclear power instrumentation and control system. The transmission and replacement of the key requires manual processing, which is inefficient. Summary of the invention

[0003] In view of the above defects of the prior art, the present invention provides a key management method and device suitable for a nuclear power instrumentation and control system to solve the technical problems of low efficiency and low security of key management in the nuclear power instrumentation and control system.

[0004] To achieve the above-mentioned purpose and other related purposes, the present invention provides a key management method suitable for a nuclear power instrumentation and control system, comprising: obtaining an identity public key in a node's identity public-private key pair; generating a communication public-private key pair and a storage key corresponding to each node, as well as a communication key shared by all nodes according to preset rules; encrypting the communication public-private key pair using the identity public key, and distributing them to corresponding nodes; encrypting the storage key and the communication key using the communication public key in the communication public-private key pair, and distributing them to corresponding nodes, so that each node can perform data encryption storage and transmission.

[0005] In one embodiment of the present invention, a communication public-private key pair and a storage key corresponding to each node, as well as a communication key shared by all nodes are generated according to preset rules, including: generating a certificate corresponding to each node based on the identity public key of each node, and distributing it to the corresponding node; generating the communication public-private key pair, the storage key and the communication key based on the certificate.

[0006] In one embodiment of the present invention, the method also includes: when receiving a key request or a key update request from a node, authenticating the identity of the node based on the certificate and random number signature provided by the node, and the identity public key corresponding to the node, and responding to the key request or key update request issued by the node after the identity authentication is successful.

[0007] In one embodiment of the present invention, distributing to the corresponding node includes: distributing to the corresponding node via a message, wherein the message includes a protocol header, a control area, and a data area, and the control area contains a first preset character for characterizing the key function and a second preset character for characterizing the key type.

[0008] In one embodiment of the present invention, the method further includes: regenerating the communication public-private key pair, the storage key and the communication key according to a preset time, and updating the existing keys.

[0009] In one embodiment of the present invention, the method further includes: when receiving a key update request from a node, regenerating the communication public-private key pair, or the storage key, or the communication key, and updating the existing key.

[0010] In one embodiment of the present invention, when a key update request from a node is received, the communication public-private key pair, or the storage key, or the communication key is regenerated, and the existing key is updated, including: when the key update request from the node is received to update the storage key, the storage key of the corresponding node is regenerated, and the storage key of the node is updated; when the key update request from the node is received to update the communication key, the communication key shared by all nodes is regenerated, and the communication keys of all nodes are updated; when the key update request from the node is received to update the communication public-private key pair, the communication public-private key pair of the corresponding node is regenerated, and the communication public key in the new communication public-private key pair of the node is synchronized to other nodes.

[0011] To achieve the above-mentioned purpose and other related purposes, the present invention also provides a key management device suitable for a nuclear power instrumentation and control system, comprising: a data acquisition unit, used to acquire the identity public key in the identity public-private key pair of the node; a key generation unit, used to generate the communication public-private key pair and storage key corresponding to each node, and the communication key shared by all nodes according to preset rules; a first distribution unit, used to encrypt the communication public-private key pair using the identity public key, and distribute it to the corresponding nodes; and a second distribution unit, used to encrypt the storage key and the communication key using the communication public key in the communication public-private key pair, and distribute them to the corresponding nodes, so that each node can perform encrypted storage and transmission of data.

[0012] Beneficial effects of the invention: The invention proposes a key management method and device suitable for a nuclear power instrumentation and control system. The method sets a respective identity public-private key pair for each node as the first encryption, then specifically generates a communication public-private key pair as the second encryption, and finally sets a storage key and a communication key to encrypt the stored and transmitted data respectively. Specifically, when applied, the identity public-private key pair can be imported and exported in the form of an offline file, and the communication public-private key pair, the storage key and the communication key can be distributed and transmitted online. Through such a key management method, the reliability of the key management of the nuclear power instrumentation and control system and the security of data storage and communication can be fully protected. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A flowchart of a key management method provided by an embodiment of the present invention;

[0015] Figure 2 A detailed flow chart of step S200 provided in one embodiment of the present invention;

[0016] Figure 3 A detailed flow chart of step S700 provided in one embodiment of the present invention;

[0017] Figure 4 A schematic diagram of an initialization phase provided by an embodiment of the present invention;

[0018] Figure 5 A schematic diagram of an operation phase provided by an embodiment of the present invention;

[0019] Figure 6 A schematic diagram of a periodic key update phase provided by an embodiment of the present invention;

[0020] Figure 7 A schematic diagram of an active key update phase provided by an embodiment of the present invention;

[0021] Figure 8 A schematic diagram of a key management device provided by an embodiment of the present invention;

[0022] Fig. 9 A schematic diagram of a nuclear power instrumentation and control system provided by an embodiment of the present invention;

[0023] Fig.10A logic diagram of a nuclear power instrumentation and control system provided in one embodiment of the present invention.

[0024] Explanation of reference numerals: 101, data acquisition unit; 102, key generation unit; 103, first distribution unit; 104, second distribution unit. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention through specific specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. It should be noted that the following embodiments and the features in the embodiments can be combined with each other without conflict. In addition to the specific methods, equipment, and materials used in the embodiments, according to the technical personnel in this technical field's grasp of the prior art and the records of the present invention, any methods, equipment, and materials of the prior art that are similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to implement the present invention.

[0026] It should be understood that the terms used in the embodiments of the present invention are for describing specific embodiments rather than for limiting the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art.

[0027] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented, so they have no substantive technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. In addition, the drawings only show the components related to the present invention rather than the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be changed arbitrarily, and the component layout type may also be more complicated.

[0028] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In some of the embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0029] The flowchart and block diagram in the accompanying drawings illustrate the system architecture, functions and operations that may be implemented according to the methods and computer program products of various embodiments disclosed in the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment, or a part of a code, and the module, program segment, or a part of a code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0030] Before describing the technical solution in the present invention, a brief description is first given of the keys and their abbreviations involved in the present invention.

[0031] (1) Identity public-private key pair (IDKP);

[0032] a) Identity private key (IDSK);

[0033] b) Identity public key (IDPK);

[0034] (2) Communication public-private key pair (CKP);

[0035] a) Communication private key (CSK);

[0036] b) Communication public key (CPK);

[0037] (3) Storage Key (STK);

[0038] (4) Communication key (CMK);

[0039] (5) Session key (SSK).

[0040] The key management system (KMS) manages these keys, and the certificate management system manages and authenticates certificates. They can be collectively referred to as key and certificate management modules.

[0041] See also Figure 1 , Figure 1 A key management method applicable to a nuclear power instrumentation and control system provided in an embodiment of the present invention includes steps S100 to S400.

[0042] Step S100, obtain the identity public key in the node's identity public-private key pair. A node refers to each business device in a nuclear power instrumentation and control system, such as the engineer station, operator station, server, control station, gateway, etc. mentioned below. These devices can all be regarded as nodes. The node's identity public-private key pair is generated by each node itself, for example, it can be generated by the node's own cryptographic product, wherein the identity private key is saved by each node itself, and the identity public key is disclosed to the key management system and other interactive objects. The identity public key can be disclosed in an offline import manner, which can ensure security. The identity private key is generated by the node, which effectively guarantees the authenticity of the node identity and eliminates the possibility of the node identity being counterfeited.

[0043] Step S200, according to the preset rules, generate the communication public-private key pair and storage key corresponding to each node, as well as the communication key shared by all nodes. The preset rules are pre-set rules, in which the generated keys may be related to the identity public key or not. It can be understood that the communication public-private key pair and the storage key correspond to the node, that is, each node corresponds to a communication public-private key pair (including a communication public key and a communication private key) and a storage key; the communication key is different, it is a key shared by all nodes under the same security network.

[0044] See also Figure 2 In a specific embodiment of the present invention, step S200 includes: S201, generating a certificate corresponding to each node according to the identity public key of each node, and distributing it to the corresponding node; S202, generating a communication public-private key pair, a storage key, and a communication key according to the certificate. In this embodiment, the certificate is first generated by the identity public key. The certificate can be used to generate a communication public-private key pair, a storage key, and a communication key on the one hand, and can be used for identity authentication on the other hand.

[0045] Step S300, encrypt the communication public-private key pair using the identity public key and distribute it to the corresponding nodes. This step is considered the first encryption, using the identity public key to encrypt the communication public-private key pair, and then distribute it. The distribution here can be distributed over the network, and when the nuclear power instrumentation and control system is initialized for the first time, it can also be distributed offline. After receiving the encrypted communication public-private key pair, each node can use the identity private key to decrypt it, thereby obtaining the communication public-private key pair and saving it.

[0046] Step S400: Use the communication public key in the communication public-private key pair to encrypt the storage key and the communication key, and distribute them to the corresponding nodes for each node to perform data encryption storage and transmission. The first step is equivalent to the second encryption, that is, the storage key and the communication key are encrypted using the communication public key. After receiving the encrypted key, each node can use the communication private key obtained in step S300 to decrypt it, thereby obtaining the unencrypted storage key and communication key. After that, the storage key can be used to encrypt and store the data, and the communication key can also be used to encrypt and transmit the data.

[0047] In a specific embodiment of the present invention, for example, the data to be stored can be directly encrypted using the storage key, and then the encrypted ciphertext can be saved. When decryption is required later, the ciphertext can be decrypted using the storage key to obtain the previously encrypted and stored data.

[0048] In a specific embodiment of the present invention, for example, encrypted communication can be performed through the following steps: (1) The communication initiator uses the generated random number salt and the communication key generated according to the above-mentioned key management method to derive a session key; (2) The communication initiator encrypts the data to be sent according to the session key, and sends the encrypted ciphertext together with the random number salt to the communication receiver; (3) After receiving the data, the communication receiver first separates the random number salt, and then combines it with the locally stored communication key to derive the session key; (4) The communication receiver decrypts the ciphertext according to the session key to obtain the data to be sent. At this point, an encrypted communication is completed. When replying to the message, the received random number salt can be used directly, or the random number salt can be regenerated to derive a new session key to reply.

[0049] In a specific embodiment of the present invention, the key management method further includes step S500, when receiving a key request or a key update request from a node, the identity of the node is authenticated according to the certificate and random number signature provided by the node, and the identity public key corresponding to the node, and the key request or key update request issued by the node is responded to after the identity authentication is successful. This step belongs to the identity authentication process, and the identity authentication is performed only when a key request or a key update request sent by a node is received to ensure that the node is safe and reliable.

[0050] In a specific embodiment of the present invention, the identity authentication process may be, for example, that a node provides a certificate and a random number signature, wherein the random number signature is signed by the node calling the identity private key in its own cryptographic product, and then the certificate management system calls the corresponding identity public key to verify the signature, thereby completing the identity authentication process.

[0051] In a specific embodiment of the present invention, the distribution to the corresponding node in step S300 and step S400 includes: distribution to the corresponding node via a message, wherein the message includes a protocol header, a control area, and a data area, and the control area includes a first preset character for characterizing the key function and a second preset character for characterizing the key type. The protocol header can be, for example, TCP, UDP, etc., and the data area generally corresponds to the data to be transmitted, such as key data, reply information of transmission success or failure, node identity information, etc.

[0052] In a specific embodiment of the present invention, the first preset character and the function it represents can be set as follows:

[0053] 0x01, key distribution;

[0054] 0x11, key distribution reply;

[0055] 0x02, key request;

[0056] 0x12, key request reply;

[0057] 0x22, key request reply confirmation;

[0058] 0x03, key synchronization;

[0059] 0x13, key synchronization reply.

[0060] The second preset character is used to represent the key type, that is, the key function represented by the first preset character is specifically performed for that key, for example, it can be set as follows:

[0061] 0x01, communication public and private key pair;

[0062] 0x02, storage key;

[0063] 0x03, communication key;

[0064] Among them, key distribution, key distribution reply, key request, key request reply, and key request reply confirmation can be operated on communication public-private key pairs, storage keys, and communication keys, while key synchronization and key synchronization reply can only be operated on communication public-private key pairs and communication keys. The details are shown in Table 1.

[0065] Table 1: Message format and content

[0066]

[0067]

[0068] It can be understood that the specific settings of the first preset character and the second preset character are only for illustration and can be represented in other ways.

[0069] In a specific embodiment of the present invention, the method further includes step S600, regenerating the communication public-private key pair, storage key and communication key according to a preset time, and updating the existing key. In this embodiment, other keys except the identity public-private key pair are actively updated regularly according to the preset time. The active update function can be initiated by the key management system, that is, steps S200 to S400 are executed regularly to regenerate and distribute new communication public-private key pairs, storage keys and communication keys.

[0070] In a specific embodiment of the present invention, the method further includes step S700, when a key update request from a node is received, a communication public-private key pair, or a storage key, or a communication key is regenerated, and the existing key is updated. In this step, when a node fails, an accident occurs, or a security risk is encountered, the node requests a new key from the key management system, and different keys are updated according to different requested key types.

[0071] See also Figure 3 In a specific embodiment of the present invention, step S700 includes steps S701 to S703.

[0072] Step S701: When a key update request from a node is received to update a storage key, a storage key of the corresponding node is regenerated and the storage key of the node is updated. The storage key of each node is different, so when updating, only the storage key of the node needs to be updated separately.

[0073] Step S702: When the key update request received from the node is to update the communication key, regenerate the communication key shared by all nodes and update the communication keys of all nodes. The communication key is shared by all nodes, so when updating, the communication keys of all nodes need to be updated.

[0074] Step S703: When the key update request received from the node is to update the communication public-private key pair, the communication public-private key pair of the corresponding node is regenerated, and the communication public key in the new communication public-private key pair of the node is synchronized to other nodes. The communication public-private key pair of each node is different, and the communication private key in the communication public-private key pair is saved by each node, but the communication public key of each node needs to be synchronized to all nodes.

[0075] It should be noted that the step division of the above methods is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they contain the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0076] For example, in a specific embodiment of the present invention, the above process can be divided into four stages.

[0077] See also Figure 4 ,Phase 1: Initialization process. The nuclear power instrumentation and control system is in an unstarted state, and the cryptographic devices of each node in the system need to be initialized. First, the cryptographic products of each node need to generate an identity public-private key pair, and export the identity public key and provide it to the certificate management system to generate a certificate; then provide the certificate to the key management system to generate a communication public-private key pair, storage key and communication key, and import the above three keys into the cryptographic products of the corresponding nodes to complete the key initialization process.

[0078] In the first part of the phase, the keys are transferred offline through files, mainly on-site, and strict key protection can be implemented in management by establishing strict processes.

[0079] See also Figure 5 , Phase 2: Operation phase. It mainly involves the use of various keys, which can be divided into three processes, mainly the identity authentication process (corresponding to the above step S500), the encrypted communication process and the encrypted storage process (corresponding to the above step S400).

[0080] In the second phase, the key is mainly in the node's cryptographic product and is restricted from going out. The salt value is only transmitted in the communication part, which will not leak the complete key, effectively protecting the session key and thus data security. In the complete communication message, the original data area needs to be reserved for the salt value area for transmission.

[0081] See also Figure 6 , Phase 3: Periodic key update phase. This phase corresponds to the above step S600. After all nodes confirm receipt of the new key, the new key is enabled. The key is sensitive data and needs to be encrypted and transmitted using an asymmetric key. For the interaction of the communication public and private key pairs, the identity public key needs to be encrypted and transmitted; for storage keys and communication keys, the communication public key needs to be encrypted and transmitted.

[0082] See also Figure 7 ,Phase 4: Active key update phase. This phase corresponds to the above step S700, and it also needs to use asymmetric key encryption transmission.

[0083] Through the above design, the key usage and management functions are added to the nuclear power instrumentation and control system, and the keys are protected during the key generation, transmission and use stages, which effectively protects the security of the keys. At the same time, it also improves the security, real-time and reliability of the system, thereby protecting the security of the system and data.

[0084] The use of multiple keys in different scenarios in the present invention fully protects the security of the system. Combined with the key periodic update strategy and key online distribution mechanism set by the system, the key protection function is improved and the efficiency of the key is also improved. Nodes can update keys at any time according to the actual business operation situation to prevent data leakage. At the same time, all keys are backed up in the key management system to prevent data loss due to accidental or single failure of a single node in the system, thereby improving the reliability of the system.

[0085] See also Figure 8 , Figure 8 A key management device for a nuclear power instrumentation and control system provided in an embodiment of the present invention includes a data acquisition unit 101, a key generation unit 102, a first distribution unit 103, and a second distribution unit 104. The data acquisition unit 101 is used to acquire the identity public key in the identity public-private key pair of the node; the key generation unit 102 is used to generate the communication public-private key pair and storage key corresponding to each node and the communication key shared by all nodes according to preset rules; the first distribution unit 103 is used to encrypt the communication public-private key pair using the identity public key and distribute it to the corresponding node; the second distribution unit 104 is used to encrypt the storage key and the communication key using the communication public key in the communication public-private key pair, and distribute it to the corresponding node, so that each node can perform encrypted storage and transmission of data.

[0086] It should be noted that the key management device of this embodiment is a device corresponding to the key management method described above, and the functional modules in the key management device may correspond to the corresponding steps in the key management method. The key management device of this embodiment can be implemented in conjunction with the key management method, that is, in the absence of conflict, the relevant technical details mentioned in the key management method of the above embodiment can also be applied to the key management device of this embodiment.

[0087] See also Fig. 9 and Fig.10 , Fig. 9 and Fig.10 A nuclear power instrumentation and control system provided in one embodiment of the present invention includes nodes and a key and certificate management module. The nodes may include, for example, a control station, a gateway, an engineer station, an operator station, and a server; the key and certificate management module is connected to the node in communication and manages the key of each node according to the key management method. The key and certificate management module corresponds to Fig. 9 and Fig.10 The dotted box part includes a key management system and a certificate management system (also known as a certificate management and authentication system).

[0088] In a specific embodiment of the present invention, the gateway includes an L1 gateway, an L2 gateway and an L3 gateway; a plurality of control stations are provided, and the plurality of control stations, L1 gateways, engineer stations, servers and key and certificate management modules are connected in parallel to the system network; the engineer station, operator station, L2 gateway, L3 gateway, server and key and certificate management modules are connected in parallel to the management network.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A key management method applicable to a nuclear power instrumentation and control system, characterized in that: include: Get the public key of the node's public-private key pair; Generate the communication public and private key pairs and storage keys corresponding to each node, as well as the communication keys shared by all nodes according to the preset rules; Encrypt the communication public-private key pair using the identity public key and distribute it to the corresponding nodes; The storage key and the communication key are encrypted using the communication public key in the communication public-private key pair, and are distributed to corresponding nodes so that each node can perform data encryption storage and transmission.

2. The key management method applicable to nuclear power instrumentation and control systems according to claim 1 is characterized in that: According to the preset rules, the communication public and private key pairs and storage keys corresponding to each node, as well as the communication keys shared by all nodes, are generated, including: Generate the certificate corresponding to each node according to the identity public key of each node and distribute it to the corresponding node; The communication public-private key pair, the storage key and the communication key are generated according to the certificate.

3. The key management method applicable to nuclear power instrumentation and control systems according to claim 2 is characterized in that: The method further includes: When a key request or key update request from a node is received, the identity of the node is authenticated based on the certificate and random number signature provided by the node, and the identity public key corresponding to the node, and the key request or key update request issued by the node is responded to after the identity authentication is successful.

4. The key management method applicable to nuclear power instrumentation and control systems according to claim 1 is characterized in that: Distribute to the corresponding nodes, including: The message is distributed to the corresponding node via a message, wherein the message includes a protocol header, a control area, and a data area, and the control area includes a first preset character for representing the key function and a second preset character for representing the key type.

5. The key management method applicable to nuclear power instrumentation and control systems according to claim 1 is characterized in that: The method further includes: According to the preset time, the communication public-private key pair, the storage key and the communication key are regenerated, and the existing keys are updated.

6. The key management method applicable to nuclear power instrumentation and control systems according to claim 1 is characterized in that: The method further includes: When a key update request from a node is received, the communication public-private key pair, or the storage key, or the communication key is regenerated, and the existing key is updated.

7. The key management method applicable to nuclear power instrumentation and control systems according to claim 6 is characterized in that: When receiving a key update request from a node, regenerating the communication public-private key pair, or the storage key, or the communication key, and updating the existing key, including: When receiving a key update request from a node for updating a storage key, regenerate the storage key of the corresponding node and update the storage key of the node; When receiving a key update request from a node to update a communication key, regenerate a communication key shared by all nodes and update the communication keys of all nodes; When a key update request from a node is received to update a communication public-private key pair, the communication public-private key pair of the corresponding node is regenerated, and the communication public key in the new communication public-private key pair of the node is synchronized to other nodes.

8. A key management device suitable for a nuclear power instrumentation and control system, characterized in that: include: A data acquisition unit, used to acquire the identity public key of the identity public-private key pair of the node; A key generation unit, used to generate a communication public and private key pair and a storage key corresponding to each node, as well as a communication key shared by all nodes according to preset rules; A first distribution unit, configured to encrypt the communication public-private key pair using the identity public key, and distribute the encrypted key to corresponding nodes; as well as The second distribution unit is used to encrypt the storage key and the communication key using the communication public key in the communication public-private key pair, and distribute them to corresponding nodes so that each node can perform encrypted storage and transmission of data.

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