WO2011041933A1

WO2011041933A1 - Method for key pre-distribution and key establishment in a sensor network

Info

Publication number: WO2011041933A1
Application number: PCT/CN2009/076172
Authority: WO
Inventors: 杜志强; 曹军; 铁满霞; 黄振海
Original assignee: 西安西电捷通无线网络通信股份有限公司
Priority date: 2009-10-10
Filing date: 2009-12-29
Publication date: 2011-04-14
Also published as: CN101674179A; CN101674179B

Abstract

A method for key pre-distribution and key establishment in a sensor network is characterized in that the method includes the following steps: 1) keys are pre-distributed, the step 1) includes: 1.1) a disposition server generates a key pool KP before a network disposition, the key pool KP comprises multiple keys and the key identifiers thereof, the key number in the key pool is denoted as ¦KP¦, and the disposition server is secure; 1.2) the degree d of a node is calculated,; 1.3) according to the degree d of the node and the number n' of the adjacent nodes of the node after the expected network disposition, the probability p of pairwise pre-shared keys between the adjacent nodes is calculated,; 1.4) the disposition server pre-distributes the keys for the node; 2) the keys are established, the step 2) includes: 2.1) establishing a key pair; 2.2) establishing a key group.

Description

A sensor network key pre-distribution and key establishment method is submitted to the Chinese Patent Office on October 10, 2009, and the application number is 200910024214.1. The invention name is "a sensor network key pre-distribution and key establishment method" The priority of the Chinese Patent Application, the entire contents of which is incorporated herein by reference.

Technical field

The present invention belongs to the field of network security technologies, and in particular, to a key pre-distribution and key establishment method for a sensor network, which can be applied to a large-scale sensor network.

Background technique

The sensor network consists of a large number of small, inexpensive, battery-powered sensor nodes with wireless communication and monitoring capabilities. These nodes are densely deployed in the monitoring area for the purpose of monitoring the physical world. Wireless sensor networks are a new field in information technology and have broad application prospects in environmental monitoring, military, homeland security, traffic control, community security, forest fire prevention, and target location.

The key management mechanism is the basis of sensor network security and should have the following features:

1) Scalability. As the size of the sensor network node expands, the computational, storage, and communication overhead required for the key agreement process will increase. The key management mechanism must be able to adapt to sensor networks of different sizes.

2) Effectiveness. Since the storage, computing, and communication capabilities of sensor nodes are strictly limited, the following aspects should be considered when designing the sensor network key management mechanism: storage complexity, storage space usage for storing communication keys; computational complexity, The amount of computation that must be performed to generate the communication key; communication complexity, the amount of information that needs to be transmitted during the communication key negotiation process;

3) Key connectivity. Key connectivity refers to the probability of establishing a communication key directly between nodes. Maintaining a high enough key connection probability is a necessary condition for the sensor network to perform its function. Since the sensor node cannot communicate directly with other nodes that are far away, there is no need to ensure that the node can maintain a secure connection with all other nodes, and only need to ensure a high key connection between adjacent nodes;

4) Invulnerability. Invulnerability refers to the ability of a key management mechanism to protect against damage to a node. Resistance Destructiveness can be expressed as the probability that a key of an undamaged node will be exposed when part of the node is damaged. The better the invulnerability, the lower the link damage.

Since the sensor nodes are vulnerable to capture attacks, once captured, the secret information loaded in the nodes will be leaked, so the key management method in which all nodes share a master key cannot meet the security requirements of the sensor network. The key management method in which each pair of nodes share one key can provide identity authentication service while providing confidential communication between nodes, but this method does not support the joining of new nodes, so it does not have scalability, and for the existence of "nodes" For large-scale networks, this method requires each node to store "-1 keys, which consumes a large amount of node storage space, and is difficult to apply to large-scale sensor networks. At present, the key management method of random key pre-distribution is widely used in sensor networks. This method only generates small overhead and is more practical, but the key it distributes does not support point-to-point identity authentication between nodes. Because the key in the method key pool may be distributed to different nodes multiple times, point-to-point identity authentication based on pre-shared key cannot be realized even if the key is shared between the two nodes. For example, assume that node A shares a key with node B. Since the same key of the key pool in the random key pre-distribution method may be fetched and distributed to different nodes multiple times, node C may also be distributed with a key. K, at this time, node A is unable to determine the identity of the other node based on the key ^:. The consequences are as follows: During communication, Node A cannot determine whether it is communicating with Node B or Node C. There is a great security risk when communicating with it without being able to confirm the identity of the other party.

Summary of the invention

In order to solve the above technical problems existing in the background art, the present invention provides a key pre-distribution that supports both identity authentication, relatively low overhead, and has excellent invulnerability and scalability and can be applied to a large-scale sensor network. And key establishment method.

The technical solution of the present invention is that the present invention provides a key pre-distribution and key establishment method for a sensor network, which is special in that the method includes the following steps:

1) Key pre-distribution, the specific implementation is:

1.1) Before the network is deployed, the deployment server generates a key pool. The key pool KP contains multiple keys and their key identifiers. The number of keys in the key pool is recorded as I PI is large enough, and the deployment server is assumed to be secure; 1.2) Assuming the default network connectivity is, the number of nodes in the network is ", each node has a corresponding identification ID, and the degree of the node is calculated according to the classical random graph theory d = (n - l) * (ln«- Ln(-lnP _c ))/«;

1.3) Calculate the probability p=dln of the two-way pre-shared key between adjacent nodes according to the degree d of the node and the number of neighbor nodes of the node after the desired network deployment.

1.4) The deployment server pre-distributes the key for the node;

2) Key establishment, the specific implementation is:

2.1) the establishment of a key;

2.2) Establishment of a group key.

The specific implementation of step 1.4) above is:

1.4.1) For the node Ni, the deployment server first constructs an ID list for the M, and the ID list includes: an N_ID field, a K_ID field, a K_STA field, a K_ATTR field, a K_ATTR_EX field, and a K_VAL field;

among them:

N_ID field: a node ID indicating a node identity value that shares a key with the node M;

K_ID field: Key ID, which indicates the identification value of the shared key between the node identified by the node M and the N_ID field;

K_STA field: Key status, indicating the status of the key identified by the K_ID field. When the node identified by the node M and the N_ID field has established a pair key, the value of the K_STA field is established, otherwise it is not established, the field is The initial value is not established;

K_ATTR field: Key attribute, when the value in the K_STA field is established, the value of the field is meaningful, indicating whether the key identified by the K_ID field is a shared key or a path key, and the default representation of the field is shared. Key

K_ATTR_EX field: Key attribute extension. When the key represented by the K_ATTR field is the path key, the value of this field is meaningful. It is used to indicate whether the path key is a direct key or a multi-hop connected key. The province indicates that the key is a direct key;

K_VAL field: Key value, used to store the key value identified by the _ field; After establishing the ID list on M, the deployment server randomly selects nodes from the remaining n-1 nodes, and inserts their node IDs into M respectively. ID list; then, department The server selects a key from the key pool for each item in the ID list, and inserts the key identifier and the corresponding key value into the corresponding K_ID field and K_VAL field in the ID list of M respectively. And delete these keys and identifiers from the key pool KP; finally, the deployment server generates ( < «,) spare key IDs, where the alternate key ID and the key ID in the key pool KP are not Repeatedly, also loaded into Νί; the deployment server records all the information in the node's ID list; the alternate key ID here is used to identify the pair of keys established by the independent negotiation between the nodes;

1.4.2) For the node ^, the deployment server pre-distributes the key for the node ^ after pre-distributing the key for the node M: First, the deployment server randomly selects the nodes from the remaining "-1 nodes, respectively, and nodes thereof The ID is inserted into the ID list of Ny; then, the deployment server selects a key from the key pool for each item in the Ny ID list, and inserts the key identifier and the corresponding key value respectively. Ny's ID list corresponds to the K_ID field and the K_VAL field, but when M is randomly selected for Ny, the key is no longer reassigned for Ny and M, but is allocated for M before it is allocated. The shared key between the two, and the ID and key value of the shared key are inserted in the K_ID field and the K_VAL field of the item corresponding to Ni in the ID list of Nj; deployment server generation ( < «,) The key IDs that are not duplicated with the key ID in the key pool and the alternate key ID of M are also loaded into Ny; the deployment server records all the information in the ID list of the node Ny;

1.4.3) For the remaining nodes, after deploying the key, the deployment server distributes the keys for all remaining nodes in turn, and the distribution method is the same as that of node ^; the deployment server records the ID list information of all remaining nodes.

The specific implementation of the above steps 2.1) is:

2.1.1) establishment of a shared key;

2.1.2) Establishment of a path key.

The specific implementation of step 2.1.1 above is:

2.1.1.1) After the network is deployed, each node broadcasts its own identity information to its neighbor nodes;

2.1.1.2) After the neighbor node receives the broadcast message of 2.1.1.1), according to its identity The identification information determines whether the key is shared with the broadcast node. If the same ID exists in the N_ID field of the ID list, it indicates that the key is shared with the node, that is, the key; the neighbor node corresponds to the ID list. The K_STA field in the set is set to establish that the key has been established with the broadcast node in 2.1.1.1), that is, a direct secure connection has been established.

The above steps 2.1.2) The process of establishing a key between nodes without a shared key but with a multi-hop secure connection is as follows:

2.1.2.1) When there is a secure path consisting of multiple nodes with shared keys between the source node and the destination node, the source node generates a path key and does not repeat from the alternate path key ID. Selecting an ID, passing the path between the path key PK and the corresponding key ID and the ID of the own node and the destination node through the hop-by-hop encryption and decryption transmission of the node on the secure path to the destination through the secure path with the destination node node;

2.1.2.2) After receiving the key message of the source node and decrypting the obtained path key PK, the destination node sends a key establishment success message to the source node through a secure path with the source node, indicating that the source node has been established. Secure connection; at this time, the source node and the destination node respectively insert the other party's identity ID as a new entry into their own ID list, and insert the PK ID and PK values into the corresponding K_ID field and K_VAL field, and The corresponding K_STA field is set to be established, and the K_ATTR field is set as the path key. If the path between the source node and the destination node when establishing the path key is a single hop, it indicates that the source node and the destination node are directly in the other party. Within the communication range, the corresponding K_ATTR_EX field is set as the direct key; otherwise, the corresponding K_ATTR_EX field is set to the multi-hop connected key.

The specific implementation of step 2.2) above is:

2.2.1) Establishment of a direct group key for establishing a group key between directly connected nodes; 2.2.2) Establishment of an indirect group key for establishing a group key between multi-hop connected nodes. The specific implementation of step 2.2.1 above is:

2.2.1.1) The multicast node generates a group key MSK, which is encrypted and sent to the multicast message receiving node by using a shared key or a direct connection key between the neighboring node, that is, the multicast message receiving node;

2.2.1.2) After the multicast message receiving node successfully decrypts the MSK, save it to the group. The broadcast node sends a group key establishment success message, and the direct group key establishment process ends.

The specific implementation of step 2.2.2 above is:

2.2.2.1) The multicast node generates the group key MSK, and uses the multi-hop connection key shared between the nodes connected to its multi-hop to encrypt the MSK and send it to the multicast message receiving node connected to the multicast node by multiple hops. ;

2.2.2.2) After the multicast message receiving node successfully decrypts M3⁄4: it is saved and sent to the group by using the direct key or shared key between the members of the group and the multicast message receiving node. The inner member then sends a group key setup success message to the multicast node.

The advantages of the present invention are: The communication capability of the sensor node is strictly limited, and the node can only communicate with its neighbor node after deployment, so that the security of the entire network can be ensured when the shared node and the neighbor node can share the key with a certain probability. Connectivity. Based on this characteristic of the sensor network, the present invention combines two key management methods, that is, each key pair and a random key pre-distribution, and uses a key-to-node binding method to propose a sensor network dense. The key management method enables the network to achieve preset network connectivity after deployment, and can support end-to-end identity authentication between nodes and generate only small node overhead. Compared with the key management method in which each pair of nodes share one key, the present invention can save the storage space of about twice the key size for the node; in the present invention, all the keys are only distributed to the two nodes without being repeated, even if A node is damaged, and the shared key between other nodes is not exposed, which has good invulnerability; the invention can realize end-to-end authentication while realizing sensor network key management, and has enhanced node resistance. Capturing attack capabilities, implementing distributed node revocation, and resisting node replication attacks. In addition, the present invention is also capable of supporting the joining of new nodes and has better scalability.

detailed description

The invention is based on the classical random graph theory, and combines two key network management methods, namely, a key and a random key pre-distribution for each pair of nodes, and adopts a method of binding a key with a node identifier to propose a capable Key pre-distribution and key establishment methods for large-scale sensor networks. According to a preferred embodiment of the invention, the method comprises the steps of: 1) Key pre-distribution

Before the network is deployed, the deployment server pre-distributes the communication key used to establish a secure connection between nodes to all nodes. The specific implementation is as follows:

1.1) Before the network is deployed, the deployment server generates a key pool. The key pool KP contains several keys and their key identifiers. The number of keys in the key pool is recorded as Ι ΡΙ , Ι ΡΙ is large enough, and the deployment server is assumed to be secure;

1.2) Assume that the preset network connectivity is , the number of nodes in the network is ", and each node has a corresponding ID. According to the classical random graph theory, the degree of the node ί =(«-1)*(1η«-1η(-1η 3⁄4)/« is calculated. In order to ensure better scalability, the number of preset network nodes is usually higher than The actual number of network nodes is slightly larger;

1.4) pre-distributing keys for nodes;

The deployment server assigns keys to all nodes. The specific implementation is:

1.4.1) For the node The deployment server first constructs a list of IDs for the M, including: N_ID field, K_ID field, K_STA field, K_ATTR field and

K_ATTR_EX field;

K_ID field: Key ID, indicating the identification value of the shared key between the node identified by the node M and the N_ID field;

K_STA field: Key status, indicating the status of the key identified by the K_ID field. When the node identified by the node M and the N_ID field has established a pair key, the value of the K_STA field is "established", otherwise it is "not established". The initial value of this field is "not established";

K_ATTR field: Key attribute. When the value in the K_STA field is "established", the value of this field is meaningful, indicating whether the key identified by the K_ID field is a shared key or a path key. The default representation of this field is the shared secret; K_ATTR_EX field: Key attribute extension. When the key represented by the K_ATTR field is a path key, the value of this field is meaningful to indicate whether the path key is a direct key or a multi-hop connected key. The default representation key of this field is the direct key;

K_VAL field: The key value used to store the key value identified by the _ field.

After the ID list is created on the M, the deployment server randomly selects the nodes from the remaining n-1 nodes, and inserts their node IDs into the ID list of M respectively; then, the deployment server is from the key pool ^ to the ID list. Each key is selected repeatedly without a key, and these key identifiers and corresponding key values are respectively inserted into the corresponding K_ID field and K_VAL field in the ID list of M, and these keys are deleted from the key pool. And logo. Finally, the deployment server generates ( < «,) alternate key IDs, where the alternate key ID is not duplicated with the key ID in the key pool KP and is also loaded into Νί. Deploy all information in the ID list of the node. The alternate key ID here is used to identify the pair of keys established by the independent negotiation between the nodes;

1.4.2) For node ^, the deployment server starts pre-distributing the key for the node ^ after pre-distributing the key for node M. First, the deployment server randomly selects nodes from the remaining "-1 nodes, and inserts their node IDs into the Ny ID list respectively; then, the deployment server does not list each item in the Ny ID list from the key pool. Repeatingly selecting a key, and inserting the key identifier and the corresponding key value into the corresponding K_ID field and K_VAL field in the ID list of Ny, respectively, but when M is randomly selected for Ny, then The key is no longer reassigned for Ny and M, but is assigned to the shared key that was previously assigned to M, and is in the K_ID field and K_VAL field of the item corresponding to Ni in the ID list of Nj. Insert the ID and key value of the shared key separately. The deployment server generates ( < «,) key IDs that do not duplicate the key ID in the key pool and the alternate key ID of M, and is also loaded into Ny. Deploy server record All information in the node Ny's ID list;

1.4.3) For the remaining nodes, after deploying the key, the deployment server distributes the keys for all remaining nodes in turn, and the distribution method is the same as that of node ^. Similarly, the deployment server records ID list information for all remaining nodes.

2) Key establishment After the network is deployed, the pair of keys and group keys for establishing a secure connection are established between the nodes. The specific implementation manner is as follows:

2.1) Establishment of the key

Used to establish a pairwise key between nodes. The specific implementation is:

2.1.1) Establishment of shared key

The specific implementation of establishing a key between neighbor nodes that have a shared key is:

2.1.1.2) After receiving the broadcast message of 2.1.1.1), the neighbor node determines whether to share the key with the broadcast node according to the identity information in it. If the same ID exists in the N_ID field in the ID list, it indicates that it Sharing a key with the node, that is, a pair of keys; the neighbor node sets the K_STA field in the corresponding item of the corresponding ID list to "established", and identifies that the key has been established with the broadcast node in 2.1.1.1), that is, Establish a direct secure connection.

2.1.2) Establishment of path key

The specific implementation of establishing a key between nodes that do not have a shared key but has a multi-hop secure connection is:

2.1.2.1) When there is a secure path consisting of multiple nodes with shared keys between the source node and the destination node, the method for establishing the path is not discussed in the present invention, and the source node generates a path dense. The key selects an ID from the alternate path key ID without repeating, and passes the secure path with the destination node, and passes the path key PK and the corresponding key ID and the ID of the own ID and the destination node through security. The hop-by-hop encryption and decryption transmission of the node on the path is sent to the destination node.

2.1.2.2) After receiving the key message of the source node and decrypting the obtained path key PK, the destination node sends a key establishment success message to the source node through a secure path with the source node, indicating that the source node has been established. Secure connection. At this time, the source node and the destination node respectively insert the identity ID of the other party into the ID list as a new entry, and insert the value of the PK and the value of the PK into the corresponding K_ID field and the K_VAL field, and the corresponding K_STA. The field is set to "established", and the K_ATTR field is set to "path key". If the path between the source node and the destination node when establishing the path key is a single hop, That is to say, both parties are within the direct communication range of the other party, and the corresponding K_ATTR_EX field is set to "direct connection key"; otherwise, the corresponding K_ATTR_EX field is set to "multi-hop connected key";

2.2) Establishment of group key

When a node needs to communicate with a multicast group, you need to establish a group key, including two types of establishment: direct group key establishment and indirect group key establishment. The specific implementation methods are as follows:

2.2.1) Direct group key establishment, used to establish a group key between neighbor nodes: 2.2.1.1) The multicast node generates a group key MSK, which utilizes a shared key with the neighbor node, ie, the multicast message receiving node. Or the direct connection key will be encrypted and sent to the multicast message receiving node;

2.2.1.2) After the multicast message receiving node successfully decrypts the MSK, it saves and sends a group key establishment success message to the multicast node, and the direct group key establishment process ends.

2.2.2) Indirect group key establishment, used to establish a group key between multi-hop nodes: 2.2.2.1) The multicast node generates a group key MSK, which uses a multi-hop connection secret shared between nodes connected to its multi-hop Key, the MSK is encrypted and sent to the multicast message receiving node connected to the multicast node by multiple hops;

2.2.2.2) After the multicast message receiving node successfully decrypts the MSK, save it and use the direct key or shared key between the members of the group, that is, the multicast message receiving node, to encrypt the MSK and send it to the members of the group. And then send a group key establishment success message to the multicast node.

The nodes in the present invention generally refer to various network entities in a sensor network, including a deployment server, a base station, a cluster head node, a common node, and the like.

The invention provides an execution flow of a sensor network key pre-distribution and key establishment method, and a key pre-distribution method based on random key pre-distribution and a pair of nodes sharing a key, and a density suitable for a large-scale sensor network is proposed. Key pre-distribution and key establishment methods. By binding the node ID to the key ID, this method enables end-to-end identity authentication between the nodes while helping the node establish the key. The present invention is also capable of providing a group key establishment service and supporting secure multicast communication between nodes.

Claims

Rights request

A key pre-distribution and key establishment method for a sensor network, characterized in that: the method comprises the following steps:

1) Key pre-distribution, the steps 1) include:

1.1) Before the network is deployed, the deployment server generates a key pool. The key pool KP contains multiple keys and their key identifiers. The number of keys in the key pool is recorded as I PI is large enough to ensure that it can be in the sensor network. The node provides enough keys to deploy the server is secure;

1.2) Calculate the degree of the node

Wherein, for the preset network connectivity, "for the number of nodes in the network, each node has a corresponding identification ID;

1.4) The deployment server pre-distributes the key for the node;

2) Key establishment, the step 2) includes:

2.1) the establishment of a key;

2.2) Establishment of a group key.

2. The key pre-distribution and key establishment method for a sensor network according to claim 1, wherein: the step 1.4) comprises:

among them:

The N_ID field is used to fill in a node ID, and the node ID represents a node identity value that shares a key with the node M;

The K_ID field is used to fill in the key ID, and the key ID represents the identification value of the shared key between the node identified by the node M and the N_ID field;

The K_STA field is used to fill in a key state indicating the state of the key identified by the K_ID field. When the node identified by the node M and the N_ID field has established a pair of keys, the value of the K_STA field is established. , otherwise it is not established, the initial value of this field is Not established;

The K_ATTR field is used to fill in the key attribute. When the value in the K_STA field is established, the value of the field is meaningful, indicating whether the key identified by the K_ID field is a shared key or a path key. Province represents a shared key;

The K_ATTR_EX field is used to fill in the key attribute extension. When the key represented by the K_ATTR field is the path key, the value of the field is meaningful, and is used to indicate whether the path key is a direct key or a multi-hop connected key. The default representation key of the field is a direct key;

The K_VAL field is used to fill in a key value for storing the key value identified by the K_ID field;

After the ID list is created on the M, the deployment server randomly selects the nodes from the remaining n-1 nodes, and inserts their node IDs into the ID list of M respectively; then, the deployment server is from the key pool ^ to the ID list. Each key is selected repeatedly without a key, and these key identifiers and corresponding key values are respectively inserted into the corresponding K_ID field and K_VAL field in the ID list of M, and these secrets are deleted from the key pool KP. Key and ID; Finally, the deployment server generates an alternate key ID, where, less than,, the alternate key ID here is not duplicated with the key ID in the key pool KP, and is also loaded into Νί; All the information in the ID list of the node Ni; the alternate key ID here is used to identify the pair of keys that are independently negotiated between the nodes;

1.4.2) For the node ^, the deployment server pre-distributes the key for the node ^ after pre-distributing the key for the node M: First, the deployment server randomly selects the nodes from the remaining "-1 nodes, respectively, and nodes thereof The ID is inserted into the ID list of Ny; then, the deployment server selects a key from the key pool for each item in the Ny ID list, and inserts the key identifier and the corresponding key value respectively. Ny's ID list corresponds to the K_ID field and the K_VAL field, but when M is randomly selected for Ny, the key is no longer reassigned for Ny and M, but is allocated for M before it is allocated. a shared key between the two, and insert the ID and key value of the shared key in the K_ID field and the K_VAL field of the item corresponding to Ni in the ID list of Nj; the deployment server generates a key pool The key ID in ^ and the key ID of the backup key ID of M are not loaded, and are also loaded into ^, where, less than ",; The server records all the information in the ID list of the node Nj;

The key pre-distribution and key establishment method of the sensor network according to claim 1 or 2, wherein: the step 2.1) comprises:

2.1.1) establishment of a shared key;

2.1.2) Establishment of a path key.

4. The key pre-distribution and key establishment method for a sensor network according to claim 3, wherein: the step 2.1.1) comprises:

2.1.1.2) After receiving the broadcast message in step 2.1.1.1), the neighbor node determines whether to share the key with the broadcast node according to the identity identification information therein. If the same ID exists in the N_ID field in the ID list, Indicates that the key is shared with the node, that is, the key; the neighbor node sets the K_STA field in the corresponding item of the corresponding ID list to be established, and the identifier has established a pair key with the broadcast node in step 2.1.1.1), that is, A direct secure connection has been established.

5. The method for key pre-distribution and key establishment of a sensor network according to claim 3, wherein: step 2.1.2) establishing a secret between nodes having no shared key but having a multi-hop secure connection. The key process is as follows:

2.1.2.1) When there is a secure path consisting of multiple nodes with shared keys between the source node and the destination node, the source node generates a path key and does not repeat from the alternate path key ID. Selecting an ID, passing the path between the path key PK and the corresponding key ID and the ID of the own node and the destination node through the hop-by-hop encryption and decryption transmission of the node on the secure path to the destination through the secure path with the destination node Node

2.1.2.2) After receiving the key message of the source node and decrypting the obtained path key PK, the destination node sends a key establishment success message to the source node through a secure path with the source node, indicating that the source node has been established. Secure connection; at this point, the source node and the destination node are divided into Do not insert the other party's identity ID as a new entry into its own ID list, and insert the PK ID and PK values into the corresponding K_ID field and K_VAL field, and set the corresponding K_STA field to established, K_ATTR The field is set to the path key. If the path between the source node and the destination node is a single hop when the path key is established, indicating that both the source node and the destination node are within the direct communication range of the other party, the corresponding K_ATTR_EX field is set. Is the direct key; otherwise, the corresponding K_ATTR_EX field is set to a multi-hop connected key.

The key pre-distribution and key establishment method of the sensor network according to any one of claims 1 to 5, wherein the step 2.2) comprises:

2.2.1) Establishment of a direct group key for establishing a group key between directly connected nodes; 2.2.2) Establishment of an indirect group key for establishing a group key between multi-hop connected nodes.

7. The key pre-distribution and key establishment method of a sensor network according to claim 6, wherein: the step 2.2.1) comprises:

8. The key pre-distribution and key establishment method of a sensor network according to claim 6, wherein: the step 2.2.2) comprises: