CN105812132A - Group password negotiation method based on Vehicle to X (V2X) network - Google Patents

Abstract

The invention discloses a group password negotiation method based on a Vehicle to X (V2X) network. The method comprises: an initiating node broadcasts a negotiation operating message comprising a group communication queue to surrounding nodes agreeing to join a group, vehicle nodes sequentially generate and broadcast negotiation password messages according to the sequence of unique identifiers of the surrounding nodes in the group communication queue, the initiating node generates and broadcasts a final negotiation password message after receiving the negotiation password message of the last vehicle node, and the surrounding nodes generate group passwords using the final negotiation password message, thereby realizing secret communication with the vehicle nodes in the group. By using the characteristics of the V2X network, the method realizes a group password negotiation process among the vehicle nodes and ensures secure communication among the vehicle nodes.

Description

Group cipher machinery of consultation based on vehicle-mounted short haul connection net

Technical field

The present invention relates to a kind of group cipher machinery of consultation based on vehicle-mounted short haul connection net, belong to vehicle-carrying communication network technology field.

Background technology

Vehicle-mounted short haul connection (VehicletoX:V2X) network is (CAN-ControllerAreaNetwork), bus or train route (Vehicle-2-RSU) in the car by short-range communication technique realizations such as radio communication, GPS/GIS, sensings, workshop (Vehicle-2-Vehicle), the outer communication between (vehicle-2-Infrastructure), people's car (Vehicle-2-Person) of car.

V2X, as a kind of mobile radio network being core node with the vehicle in constantly moving, has the fast-changing feature of topological structure, and especially the opening of its communication media causes that channel safety is poor, compares legacy network and is more subject to attack.Simultaneously as V2X is the core of following intelligent transportation system (ITS), relating to the high-security applications such as safety and automatic Pilot, relatively conventional network, the loss that its safety brings can be bigger, and therefore, safety is had higher requirement by V2X.

Group key agreement method is to be generated a shared group key by joint consultation in many ways, and any participant is unable to pre-determine the value of group key.Characteristic by means of V2X network, as all vehicles are in equal standing, vehicle-mounted node periodic broadcasting heartbeat message etc., application group cryptographic key negotiation method in V2X network, both vehicle advantage quantitatively can have been played, again can secure communication between support vehicles, improve the safety of V2X network.

Summary of the invention

In view of the foregoing, it is an object of the invention to provide a kind of group cipher machinery of consultation based on vehicle-mounted short haul connection net, the method is the characteristic utilizing V2X network, it is achieved the group cipher negotiations process between vehicle-mounted node, it is ensured that the secure communication between vehicle-mounted node.

For achieving the above object, the present invention is by the following technical solutions:

A kind of group cipher machinery of consultation based on vehicle-mounted short haul connection net, comprises the following steps:

S1: initiate node node towards periphery and send the request message consulting group key；

S2: surroundings nodes receives this request message, sends, to initiating node, the response message adhereed to；

S3: initiation node sets up group communication queue after receiving this response message, this group communication queue includes unique mark of surroundings nodes and the marker bit of correspondence；

S4: initiate node node broadcasts negotiation message towards periphery, this negotiation message includes the information such as unique mark of group communication queue, initiation node；

S5: after surroundings nodes receives this negotiation message, is stored in this locality by the group communication queuing message in message；

S6: according to the uniquely identified order of surroundings nodes in group communication queue, after first vehicle-mounted node receives this negotiation message, utilize random function to generate secret exponent x₁, and generate negotiation code message [ID₁, Z₁, Y₁], wherein,Then code message is consulted to node broadcasts about by what generate；

S7: after receiving the negotiation code message of first vehicle-mounted node, node around first vehicle-mounted node, updates group communication queue, is updated to by the marker bit of first vehicle-mounted node and sends, meanwhile, initiate node and preserve the negotiation code message that first vehicle-mounted node sends；

S8: the vehicle-mounted node of i-th receives the negotiation code message [ID of the i-th-1 vehicle-mounted node_i-1, Z_i-1, Y_i-1] after, utilize random function to generate secret exponent x_i, and generate negotiation code message [ID_i, Z_i, Y_i], wherein,

$Z_i={\left(Z_{i-1}\right)}^{x_i}={\left(g^{\underset{k=1}{\overset{i-1}{\mathrm{\Π}}}{x}_k}\right)}^{x_i}=g^{\underset{k=1}{\overset{i}{\mathrm{\Π}}}{x}_k}$

$Y_i=\underset{k=1,...,i-1}{\∪}\left\{Z_{i-1}^{x_i/x_k}\right\}\∪\left\{Z_{i-1}\right\}=\underset{k=1,...,i}{\∪}\left\{Z_{i-1}^{x_i/x_k}\right\}=\underset{k=1,...,i}{\∪}\left\{Z_i^{1/x_k}\right\}$

And the negotiation code message [ID that will generate_i, Z_i, Y_i] to node broadcasts about；

S9: after receiving the negotiation code message of the vehicle-mounted node of i-th, the surroundings nodes of the vehicle-mounted node of i-th updates group communication queue, meanwhile, initiates node and preserves the negotiation code message that the vehicle-mounted node of i-th sends；

S10: initiate node and receive in group communication queue after the negotiation code message of last vehicle-mounted node transmission, initiation node stochastic generation secret exponent x_N, and generate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\Π}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\Π}}}{x}_k}$

$Y_N=\underset{k=1,...,N-1}{\∪}\left\{Z_{N-1}^{x_N/x_k}\right\}\∪\left\{Z_N\right\}=\underset{k=1,...,N}{\∪}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\∪}\left\{Z_N^{1/x_k}\right\}$

Then, initiate node node towards periphery and send final negotiation code message [IDF, Y_N], wherein, IDF is uniquely identified, by surroundings nodes, the index queue formed；

S11: surroundings nodes receives negotiation code message [IDF, the Y that this is final_N] after, it is thus achieved that the group cipher after negotiation $K=g^{x_1{x}_2...x_N}.$

Further,

Surroundings nodes sends interval time by one, updates the group communication queue that this locality preserves.

Arrive described transmission interval time time, according to the marker bit of the i-th-1 vehicle-mounted node in group communication queue, the vehicle-mounted node of i-th judges that the i-th-1 vehicle-mounted node is not as sending state, the vehicle-mounted node of i-th utilizes the negotiation code message of the i-th-2 vehicle-mounted nodes, generate and consult code message, and the negotiation code message of generation is broadcasted.

Arrive described transmission interval time time, judge that the i-th-1 vehicle-mounted node is not as sending state according to the marker bit in group communication queue, the information of this i-th-1 vehicle-mounted node is deleted by surroundings nodes from the group communication queue that this locality preserves.

When having new vehicle-mounted node to add group, perform following steps:

S21: initiate node to being newly added vehicle-mounted node and send the request message consulting group key；

S22: be newly added vehicle-mounted node to initiating node and send the response message adhereed to；

S23: this negotiation code message is sent to and is newly added vehicle-mounted node after receiving the negotiation code message that in group communication queue, last vehicle-mounted node sends by initiation node, is newly added vehicle-mounted node and utilizes random function to generate secret exponent x_N, and generate negotiation code message [ID_N, Z_N, Y_N], wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\Π}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\Π}}}{x}_k}$

$Y_N=\underset{k=1,...,N-1}{\∪}\left\{Z_{N-1}^{x_N/x_k}\right\}\∪\left\{Z_{N-1}\right\}=\underset{k=1,...,N}{\∪}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\∪}\left\{Z_N^{1/x_k}\right\}$

Then the negotiation code message [ID that will generate_N, Z_N, Y_N] to node broadcasts about；

S24: initiate node and receive negotiation code message [ID_N, Z_N, Y_N] after, utilize random function to generate secret exponent x_N+1, and generate Y_N+1、Z_N+1, wherein,

$Z_{N+1}={\left(Z_N\right)}^{x_{N+1}}={\left(g^{\underset{k=1}{\overset{N}{\mathrm{\Π}}}{x}_k}\right)}^{x_{N+1}}=g^{\underset{k=1}{\overset{N+1}{\mathrm{\Π}}}{x}_k}$

$Y_{N+1}=\underset{k=1,...,N}{\∪}\left\{Z_N^{x_{N+1}/x_k}\right\}\∪\left\{Z_{N+1}\right\}=\underset{k=1,...,N+1}{\∪}\left\{Z_N^{x_{N+1}/x_k}\right\}=\underset{k=1,...,N+1}{\∪}\left\{Z_{N+1}^{1/x_k}\right\}$

Then, initiate node node towards periphery and be newly added negotiation code message [IDF`, the Y that the transmission of vehicle-mounted node is final<sub>N+1</sub>], wherein, IDF` be by surroundings nodes and be newly added vehicle-mounted node uniquely identify the index queue formed；

S25: surroundings nodes and be newly added vehicle-mounted node and receive final negotiation code message [IDF`, Y_N+1] after, it is thus achieved that the group cipher after negotiation

When having vehicle-mounted node to exit group, perform following steps:

S31: initiate, the negotiation code message of each surroundings nodes that node preserves from this locality, to delete the negotiation code message exiting vehicle-mounted node, then utilize random function to generate secret exponent x_N, and generate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}$

$Y_N=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_N\right\}=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_N^{1/x_k}\right\}$

Afterwards, initiate node and send final negotiation code message [IDF``, Y to all surroundings nodes except exiting vehicle-mounted node<sub>N</sub>], wherein, IDF`` is uniquely identified, by surroundings nodes all except exiting vehicle-mounted node, the index queue IDF`` formed；

S32: the surroundings nodes except exiting vehicle-mounted node receives final negotiation code message [IDF``, Y_N] after, it is thus achieved that the group cipher after final negotiationWherein, exiting vehicle-mounted node is the vehicle-mounted node of m-th.

It is an advantage of the current invention that:

The group cipher machinery of consultation based on vehicle-mounted short haul connection net of the present invention, utilize the characteristic of V2X network, as vehicle-mounted node periodic broadcasting heartbeat message, all vehicles are on an equal footing, achieve in V2X network the group cipher negotiations process between vehicle-mounted node in communication range, ensure that the secure communication between vehicle-mounted node, improve the safety of V2X network.

Accompanying drawing explanation

Fig. 1 is the method flow diagram of the present invention.

Detailed description of the invention

Below in conjunction with drawings and Examples, the present invention is further detailed explanation.

In V2X network, the regular node broadcasts towards periphery of each node comprises the heartbeat message of the oneself state information such as geographical position, state, unique mark, travel direction, each node receives the heartbeat message that surroundings nodes sends simultaneously, know the situation of surroundings nodes according to the heartbeat message received, realize communicating with surroundings nodes.By means of the heartbeat message of periodic broadcasting between each node, can realize that the vehicle-mounted node in communication range is formed group, initiate group cipher negotiation, monitor group negotiation message transmission situation and group's maintenance etc., and then complete group cipher negotiations process, it is ensured that secure communication between vehicle-mounted node in group.

Fig. 1 is the method flow diagram of the present invention.As it can be seen, the group cipher machinery of consultation based on vehicle-mounted short haul connection net disclosed by the invention, comprise the following steps:

1, initiate node node towards periphery and send the request message consulting group key, this request message includes initiating the information such as unique mark (ID) of node, the sequence number (initiate node send the serial number of request message to identify different initiation requests, calculating of again making zero when this sequence number is more than certain value for recording) of request message and request flag position (flag bit for mark request message)；

2, surroundings nodes receives this request message, if adhereing to group, then to initiating node transmission response message, this response message includes the information such as the sequence number of request message, response flag bit；

3, after initiating the response message adhereing to group that node receives surroundings nodes reply, setting up group communication queue, this group communication queue includes unique mark of each surroundings nodes and the marker bit (for whether flag node has sent negotiation message) of correspondence；

4, when arriving the access request threshold time of default, initiating node node broadcasts negotiation message towards periphery, this negotiation message includes group communication queue, initiates unique mark of node, asks the sequence number of message, consults the information such as flag bit (for indicating the flag bit of negotiation message)；

5, after each node in group receives negotiation message, the group communication queuing message in this message is stored in this locality；

6, according to the uniquely identified order of surroundings nodes in group communication queue, as first vehicle-mounted node (ID₁) receive this negotiation message after, utilize random function generate secret exponent x₁, generate on this basis and consult code message [ID₁, Z₁, Y₁], and by this negotiation code message to node broadcasts about；Wherein,G is a primitive element on a mould p；

7, after receiving the negotiation code message of first vehicle-mounted node, node around first vehicle-mounted node, update the group communication queue that this locality preserves, specifically, it is revised as sends group communication queue uniquely identifies with first vehicle-mounted node corresponding marker bit, it was shown that in group, first vehicle-mounted node has been successfully transmitted negotiation code message；Meanwhile, initiate node and the negotiation code message that first vehicle-mounted node sends is stored in this locality；

8, the vehicle-mounted node of i-th is receiving the negotiation code message [ID of the i-th-1 vehicle-mounted node_i-1, Z_i-1, Y_i-1] after, utilize random function to generate secret exponent x_i, generate on this basis and consult code message [ID_i, Z_i, Y_i], wherein,

$Z_i={\left(Z_{i-1}\right)}^{x_i}={\left(g^{\underset{k=1}{\overset{i-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_i}=g^{\underset{k=1}{\overset{i}{\mathrm{\&Pi;}}}{x}_k}---\left(1\right)$

$Y_i=\underset{k=1,...,i-1}{\&cup;}\left\{Z_{i-1}^{x_i/x_k}\right\}\&cup;\left\{Z_{i-1}\right\}=\underset{k=1,...,i}{\&cup;}\left\{Z_{i-1}^{x_i/x_k}\right\}=\underset{k=1,...,i}{\&cup;}\left\{Z_i^{1/x_k}\right\}---\left(2\right)$

And the negotiation code message [ID that will generate_i, Z_i, Y_i] to node broadcasts about；

9, after receiving the negotiation code message of the vehicle-mounted node of i-th, the surroundings nodes of the vehicle-mounted node of i-th updates the group communication queue that this locality preserves, namely, it is revised as sends group communication queue uniquely identifies with the vehicle-mounted node of i-th corresponding marker bit, it was shown that in group, the vehicle-mounted node of i-th has been successfully transmitted negotiation code message；Meanwhile, initiate node and the negotiation code message that vehicle-mounted for i-th node sends is stored in this locality；

10, after initiation node receives the negotiation code message that last vehicle-mounted node in group communication queue (N-1 vehicle-mounted node) sends, node stochastic generation secret exponent x is initiated_N, and utilize this secret exponent x_NGenerate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}---\left(3\right)$

$Y_N=\underset{k=1,...,N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_N\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{1/x_k}\right\}---\left(4\right)$

Then, initiating node and send, to the oriented initiation node of institute, the surroundings nodes (N-1 in group vehicle-mounted node) consulting code message and send final negotiation code message, what this was final consult code message includes the Y of generation_N, and uniquely identify, by N-1 vehicle-mounted node, the index queue IDF formed, i.e. initiation node is to final negotiation code message [IDF, the Y of the individual vehicle-mounted node broadcasts of N-1 about_N]；

11, N-1 vehicle-mounted node receives final negotiation code message [IDF, the Y initiating node broadcasts_N] after, the group cipher after final negotiation can be obtained

Considering that in V2X network, vehicle is in the state being continually changing, in fact it could happen that because of the reason such as network delay or link failure, code message is consulted in the unsuccessful transmission of certain vehicle-mounted node or the situations such as packet loss occurs in the negotiation code message of transmission；For solving this problem, set one and send interval time, by the group communication queue that vehicle-mounted node this locality preserves, it may be judged whether there is vehicle-mounted node there is a problem；Specifically, when arriving the transmission interval time set, the vehicle-mounted node of i-th reads in the group communication queue of its preservation the i-th-1 vehicle-mounted node and uniquely identifies and the marker bit of correspondence, find but without the negotiation code message receiving the i-th-1 vehicle-mounted node, now, the vehicle-mounted node of i-th is no longer waiting for, and directly utilizes the negotiation code message of the i-th-2 received vehicle-mounted nodes, generate the negotiation code message of self, then the negotiation code message of generation is broadcasted；Meanwhile, each vehicle-mounted node is by group communication queue and sends interval time, updates the group communication queue that this locality preserves, the relevant information of the i-th-1 vehicle-mounted node is deleted from group communication queue.

When the vehicle change in group, e.g., there is new vehicle-mounted node to add group, or when vehicle-mounted node rolls the communication range of group away from, process in accordance with the following methods:

When there being new vehicle-mounted node request to add group:

21, after initiation node is perceived by heartbeat message and around has new vehicle-mounted node, it is newly added vehicle-mounted node to this and sends the request message consulting group key；

22, it is newly added vehicle-mounted node and adheres to group, send, to initiating node, the response message adhereed to；

23, after initiating the negotiation code message that node receives the individual vehicle-mounted node transmission of N-1 in group communication queue, this negotiation code message is sent to and is newly added vehicle-mounted node (now, it is newly added vehicle-mounted node and is designated as node N, initiate node and be designated as node N+1), it is newly added vehicle-mounted node and utilizes random function to generate secret exponent x_N, generate on this basis and consult code message [ID_N, Z_N, Y_N], wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}---\left(5\right)$

$Y_N=\underset{k=1,...,N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_{N-1}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{1/x_k}\right\}---\left(6\right)$

And the negotiation code message [ID that will generate_N, Z_N, Y_N] to node broadcasts about；

24, after initiation node receives and is newly added the negotiation code message that vehicle-mounted node sends, random function is utilized to generate secret exponent x_N+1, and utilize this secret exponent x_N+1Generate Y_N+1、Z_N+1, wherein,

$Z_{N+1}={\left(Z_N\right)}^{x_{N+1}}={\left(g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_{N+1}}=g^{\underset{k=1}{\overset{N+1}{\mathrm{\&Pi;}}}{x}_k---\left(7\right)}$

$Y_{N+1}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{x_{N+1}/x_k}\right\}\&cup;\left\{Z_{N+1}\right\}=\underset{k=1,...,N+1}{\&cup;}\left\{Z_N^{x_{N+1}/x_k}\right\}=\underset{k=1,...,N+1}{\&cup;}\left\{Z_{N+1}^{1/x_k}\right\}---\left(8\right)$

Then, initiating node and send, to the oriented initiation node of institute, the surroundings nodes (N-1 in group vehicle-mounted node and be newly added vehicle-mounted node N) consulting code message and send final negotiation code message, what this was final consult code message includes the Y of generation_N+1, and uniquely identified, by N number of vehicle-mounted node, the index queue IDF` formed, i.e. initiate node to final negotiation code message [IDF`, the Y of N number of vehicle-mounted node broadcasts about_N+1]；

25, N number of vehicle-mounted node receives final negotiation code message [IDF`, the Y initiating node broadcasts_N+1] after, the group cipher after final negotiation can be obtainedIt is newly added the vehicle-mounted node that vehicle-mounted node may utilize in this group cipher and group to securely communicate.

When there being vehicle-mounted node to exit group (vehicle-mounted node rolls group communication scope away from, initiation node forbids that some node participates in group communication etc.), it is assumed that the vehicle-mounted node of m-th exits group, then process in accordance with the following methods:

31, initiate, the negotiation code message of each vehicle-mounted node that node preserves from this locality, to delete the negotiation code message of the vehicle-mounted node of m-th, then utilize random function to generate secret exponent x_N, and utilize this secret exponent x_NGenerate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}---\left(9\right)$

$Y_N=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_N\right\}=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_N^{1/x_k}\right\}---\left(10\right)$

Then, initiate node to send, to the oriented initiation node of institute except vehicle-mounted node m, the surroundings nodes (N-2 in group individual vehicle-mounted node) consulting code message and send final negotiation code message, what this was final consults the YN that code message includes generating, and uniquely identified, by N-2 vehicle-mounted node, the index queue IDF`` formed, namely, initiate node to final negotiation code message [IDF``, the Y of the vehicle-mounted node broadcasts of N-2 about_N]；

32, N-2 vehicle-mounted node receives final negotiation code message [IDF``, the Y initiating node broadcasts_N] after, the group cipher after final negotiation can be obtainedVehicle-mounted node m cannot continue other nodes in same group and carry out secret communication.

The group cipher machinery of consultation based on vehicle-mounted short haul connection net of the present invention, it it is the characteristic utilizing V2X network, in network each vehicle be on an equal footing, each vehicle-mounted node periodic broadcasting heartbeat message etc., vehicle-mounted node within certain communication range is formed group, vehicle-mounted node in group sends negotiation code message according to the order of sequence, ultimately generate group cipher, it is achieved that the secret communication of vehicle-mounted node in group, improve the safety of V2X network.

The above is presently preferred embodiments of the present invention and the know-why used thereof; for a person skilled in the art; when without departing substantially from the spirit and scope of the present invention; any based on apparent changes such as the equivalent transformation on technical solution of the present invention basis, simple replacements, belong within scope.

Claims (6)

1. based on the group cipher machinery of consultation of vehicle-mounted short haul connection net, it is characterised in that comprise the following steps:

S1: initiate node node towards periphery and send the request message consulting group key；

S2: surroundings nodes receives this request message, sends, to initiating node, the response message adhereed to；

S3: initiation node sets up group communication queue after receiving this response message, this group communication queue includes unique mark of surroundings nodes and the marker bit of correspondence；

S4: initiate node node broadcasts negotiation message towards periphery, this negotiation message includes the information such as unique mark of group communication queue, initiation node；

S5: after surroundings nodes receives this negotiation message, is stored in this locality by the group communication queuing message in message；

S6: according to the uniquely identified order of surroundings nodes in group communication queue, after first vehicle-mounted node receives this negotiation message, utilize random function to generate secret exponent x₁, and generate negotiation code message [ID₁, Z₁, Y₁], wherein,Then code message is consulted to node broadcasts about by what generate；

S7: after receiving the negotiation code message of first vehicle-mounted node, node around first vehicle-mounted node, updates group communication queue, is updated to by the marker bit of first vehicle-mounted node and sends, meanwhile, initiate node and preserve the negotiation code message that first vehicle-mounted node sends；

S8: the vehicle-mounted node of i-th receives the negotiation code message [ID of the i-th-1 vehicle-mounted node_i-1, Z_i-1, Y_i-1]After, utilize random function to generate secret exponent x_i, and generate negotiation code message [ID_i, Z_i, Y_i], wherein,

$Z_i={\left(Z_{i-1}\right)}^{x_i}={\left(g^{\underset{k=1}{\overset{i-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_i}=g^{\underset{k=1}{\overset{i}{\mathrm{\&Pi;}}}{x}_k}$

$Y_i=\underset{k=1,...,i-1}{\&cup;}\left\{Z_{i-1}^{x_i/x_k}\right\}\&cup;\left\{Z_{i-1}\right\}=\underset{k=1,...,i}{\&cup;}\left\{Z_{i-1}^{x_i/x_k}\right\}=\underset{k=1,...,i}{\&cup;}\left\{Z_i^{1/x_k}\right\}$

And the negotiation code message [ID that will generate_i, Z_i, Y_i] to node broadcasts about；

S9: after receiving the negotiation code message of the vehicle-mounted node of i-th, the surroundings nodes of the vehicle-mounted node of i-th updates group communication queue, meanwhile, initiates node and preserves the negotiation code message that the vehicle-mounted node of i-th sends；

S10: initiate node and receive in group communication queue after the negotiation code message of last vehicle-mounted node transmission, initiation node stochastic generation secret exponent x_N, and generate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}$

$Y_N=\underset{k=1,...,N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_N\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{1/x_k}\right\}$

Then, initiate node node towards periphery and send final negotiation code message [IDF, Y_N], wherein, IDF is uniquely identified, by surroundings nodes, the index queue formed；

S11: surroundings nodes receives negotiation code message [IDF, the Y that this is final_N] after, it is thus achieved that the group cipher after negotiation $K=g^{x_1{x}_2...x_N}.$

2. the group cipher machinery of consultation based on vehicle-mounted short haul connection net as claimed in claim 1, it is characterised in that surroundings nodes sends interval time by, updates the group communication queue that this locality preserves.

3. the group cipher machinery of consultation based on vehicle-mounted short haul connection net as claimed in claim 2, it is characterized in that, arrive described transmission interval time time, according to the marker bit of the i-th-1 vehicle-mounted node in group communication queue, the vehicle-mounted node of i-th judges that the i-th-1 vehicle-mounted node is not as sending state, the vehicle-mounted node of i-th utilizes the negotiation code message of the i-th-2 vehicle-mounted nodes, generate and consult code message, and the negotiation code message of generation is broadcasted.

4. the group cipher machinery of consultation based on vehicle-mounted short haul connection net as claimed in claim 3, it is characterized in that, arrive described transmission interval time time, judging that the i-th-1 vehicle-mounted node is not as sending state according to the marker bit in group communication queue, the information of this i-th-1 vehicle-mounted node is deleted by surroundings nodes from the group communication queue that this locality preserves.

5. the group cipher machinery of consultation based on vehicle-mounted short haul connection net as claimed in claim 4, it is characterised in that when having new vehicle-mounted node to add group, perform following steps:

S21: initiate node to being newly added vehicle-mounted node and send the request message consulting group key；

S22: be newly added vehicle-mounted node to initiating node and send the response message adhereed to；

S23: this negotiation code message is sent to and is newly added vehicle-mounted node after receiving the negotiation code message that in group communication queue, last vehicle-mounted node sends by initiation node, is newly added vehicle-mounted node and utilizes random function to generate secret exponent x_N, and generate negotiation code message [ID_N, Z_N, Y_N], wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}$

$Y_N=\underset{k=1,...,N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_{N-1}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{1/x_k}\right\}$

Then the negotiation code message [ID that will generate_N, Z_N, Y_N] to node broadcasts about；

S24: initiate node and receive negotiation code message [ID_N, Z_N, Y_N] after, utilize random function to generate secret exponent x_N+1, and generate Y_N+1、Z_N+1, wherein,

$Z_{N+1}={\left(Z_N\right)}^{x_{N+1}}={\left(g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_{N+1}}=g^{\underset{k=1}{\overset{N+1}{\mathrm{\&Pi;}}}{x}_k}$

$Y_{N+1}=\underset{k=1,...,N}{\&cup;}\left\{Z_N^{x_{N+1}/x_k}\right\}\&cup;\left\{Z_{N+1}\right\}=\underset{k=1,...,N+1}{\&cup;}\left\{Z_N^{x_{N+1}/x_k}\right\}=\underset{k=1,...,N+1}{\&cup;}\left\{Z_{N+1}^{1/x_k}\right\}$

Then, initiate node node towards periphery and be newly added negotiation code message [IDF ', the Y that the transmission of vehicle-mounted node is final_N+1], wherein, IDF ' for by surroundings nodes and be newly added vehicle-mounted node uniquely identify the index queue formed；

S25: surroundings nodes and be newly added vehicle-mounted node and receive final negotiation code message [IDF ', Y_N+1] after, it is thus achieved that the group cipher after negotiation

6. the group cipher machinery of consultation based on vehicle-mounted short haul connection net as claimed in claim 4, it is characterised in that when having vehicle-mounted node to exit group, perform following steps:

S31: initiate, the negotiation code message of each surroundings nodes that node preserves from this locality, to delete the negotiation code message exiting vehicle-mounted node, then utilize random function to generate secret exponent x_N, and generate Y_N、Z_N, wherein,

$Z_N={\left(Z_{N-1}\right)}^{x_N}={\left(g^{\underset{k=1}{\overset{N-1}{\mathrm{\&Pi;}}}{x}_k}\right)}^{x_N}=g^{\underset{k=1}{\overset{N}{\mathrm{\&Pi;}}}{x}_k}$

$Y_N=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}\&cup;\left\{Z_N\right\}=\underset{k=1,...,m-1,m+1,...N}{\&cup;}\left\{Z_{N-1}^{x_N/x_k}\right\}=\underset{k=1,...,m-1,m+1,...N-1}{\&cup;}\left\{Z_N^{1/x_k}\right\}$

Afterwards, initiate node to all surroundings nodes except exiting vehicle-mounted node send final negotiation code message [IDF ", Y_N], wherein, IDF " for uniquely being identified, by surroundings nodes all except exiting vehicle-mounted node, the index queue IDF formed "；

S32: the surroundings nodes except exiting vehicle-mounted node receive final negotiation code message [IDF ", Y_N] after, it is thus achieved that the group cipher after final negotiationWherein, exiting vehicle-mounted node is the vehicle-mounted node of m-th.