1 Trusted Nodes and Trusted Secure Routing Protocol Model 1. The definition of a trusted node Trust is an expectation. Under this expectation, the device operates in a specific way according to a specific purpose. Before putting forward the definition of the trusted node and the trusted secure routing protocol model, two assumptions must be made: 1 All vehicles are loaded with TPM chips, and the core code of the GPSR routing protocol is stored in the PCR of the TPM chip as a feature metric; 2 The on-board equipment of the TPM chip is capable of performing trusted calculations and sending and receiving information. The trusted node is loaded with a TPM chip, and can use the protection storage technology of the TPM chip to effectively protect the routing protocol and the neighbor location information table to prevent illegal access and modification; and ensure that the information can safely reach the intermediate node of the destination node. This article uses the TPM chip as the unique identifier of each vehicle, and binds the chip number to the driver's driver's license. If a traffic accident due to malicious transmission of a vehicle error is caused, the perpetrator may be directly held liable. 1.2 Trusted Security Routing Protocol Model The secure routing protocol should meet at least the following eight conditions: 1 is running a protocol that is not tampered with in accordance with the standards; 2 can prevent routing signals from being deceived; 3 malicious nodes cannot insert forged routing information in the network; 4 malicious nodes cannot modify routing information; 5 malicious routes cannot be generated. Number; 6 Malicious nodes cannot be redirected from the shortest path; 7 Unauthorized nodes do not participate in route calculation and route discovery; 8 The network topology contained in routing information cannot be exposed to malicious nodes or unauthorized nodes. The corresponding routing information of the GPSR protocol is the neighbor location table information. After joining the TPM chip, the proposed secure trusted routing protocol model can basically meet the above criteria. First, this security solution provides three basic attributes: 1) Each node has a unique identifier, namely the TPM chip number and its approval key (EK). The node that meets this condition is the authorized node, which satisfies conditions 7 and 8. 2) After authorizing the vehicle to join VANET, if it can be proved that the information was sent by a program that has not been tampered with, then the information is believed to be trustworthy. Therefore, the TPM chip must be able to authenticate each of the trusted node's runtime routing protocols and ensure the integrity and security of the protocol so that condition 1 can be met. 3) The credibility of the information content must be verified. Before adding or deleting the neighbor location table, verify the routing protocol and neighbor modification operations, and confirm that the node to be added or deleted is indeed the neighbor of the current node. This satisfies conditions 2 to 6. After satisfying the above 3 basic attributes, the security model works on two levels. After confirming the authenticity of the vehicle in the VENET, the base layer allows the establishment of a trust channel between any two cars. The second layer is the core layer. The purpose is to confirm the information. It ensures that the information exchanged by the vehicle is error-free. In this way, the TPM chip can prevent unintentional errors and intentional errors, can exclude the tampered vehicle of the routing protocol from outside the trusted node, thereby preventing the malicious modification of the neighbor position information table of the vehicle during driving, or sending the wrong one. Information destroys the entire network. The trusted security GPSR routing protocol framework is divided into two layers: the lower layer is the hardware layer and the upper layer is the software layer. The hardware layer contains the TPM chip and the neighbor location information table stored in the protected storage device. The software layer includes the TMS software abstraction TSS, security service agent SSA, trusted security GPSR routing protocol, and neighbor location information table stored in memory. . Feng San Cai 1 gives the working flow chart of the entire trusted security framework. When the protocol starts, the SSA informs the TPM to measure and compare the GPSR protocol at this time with the standard metric value stored in the PCR. After confirming that the GPSR is in a predetermined state, the key information EK in the TSS is used to list the neighbor location information. After decryption and decryption, it is read into memory from a place where TPM storage is protected (such as a hard disk) and sent to the GPSR protocol. If it is calculated that the GPSR protocol hash value is different from the PCR metric value, the TPM rejects the start of the protocol, and decrypts and accesses the neighbor location information table. When the neighbor location information table is modified, the information table in the memory is first modified, and then the SSA notifies the TPM. The TPM determines the correctness of the routing protocol and neighbor location modification operations through the integrity metrics, and at the same time, whether the node to be added or deleted is currently calculated. The neighbor of the node. When the above three items are confirmed to be correct, the information table can be modified and stored in the protection store to make it updated. The intermediate step from the integrity metrics to the integrity report is an integrity record, which stores the integrity metrics in the log to avoid plausibility or grievances after the malicious node is denied service. 2 simulation experiments and discussions 2. 1 algorithm description The TPM 1.2 specification specifies a hashing algorithm using SHA21. Based on experimental conditions and machine configuration and other factors, this paper uses the MD5 algorithm instead of the SHA21 algorithm to calculate the hash value, and takes the MD5 value of the complete GPSR protocol gpsr.cc as the integrity measure value. 2. 2 simulation platform and experimental parameters The machine used in the experiment was a Dell OptiPlex 360MT with an Intel Core Core (TM) 2 Duo E7400 (2.8 GHz) and 1 GB RAM. In the environment of Ubuntu 9.04 and NS2.30, KeLiu was selected. The version of GPSR protocol is used as a blueprint for simulation. The selected scene is 100 nodes randomly distributed in a 500×500 square area with a maximum movement speed of 30 m/s, a simulation time of 400 s, and CBR data transmission with a dwell time of 0. s. This article selects the above parameters to generate 10 scenarios files, which simulates both the security and non-security environments, and compares the quantitative indicators of the original GPSR protocol and the trusted and secure GPSR routing protocol. 2. 3 experimental metrics With reference to RFC2501, this article uses the following nine indicators to measure performance: 1 average end-to-end throughput; 2 packet data packet loss rate; 3 packet data delivery rate; 4 delay jitter; 5 end-to-end average delay; 6 routing efficiency; Simulation time comparison table; 8 neighborhood location comparison table; 9MD5 value table. 2.4 Experimental data comparison 1) Examine the situation where there is no malicious node. Since the Trusted Security GPSR routing protocol does not add any additional information packets, when judging the neighbor nodes, it also uses the vector difference and energy range of the two node coordinate positions to judge. Therefore, the GPSR protocol based on the TPM chip has the same with the original GPSR protocol. The same network throughput, packet data packet loss rate and delivery rate, delay jitter, end-to-end average delay, and routing efficiency only consume time and resources on a single node for integrity verification and operational correctness judgment (the original GPSR The routing efficiency of the protocol was 65.68, the simulation time was 45.592 s, and the simulation time of the trusted GPSR protocol was 123.858 s). The MD5 value of the original GPSR protocol gpsr.cc is df969bcc6e164a7cfbcff99ca67122ed , gpsr_neighbor. The MD5 value of cc is f532145fb66e330ed0d192 df6ea7a124. The MD5 value of trusted security GPSR protocol gpsr.cc is e7c963af7bca2dea15e 199bdb7c15f08, and the MD5 value of gpsr_neighbor.cc is 3cc4aca792c6 d496 1aea4ce4fd0ad6a7. Analysis and implementation of trusted nodes and trusted routing in onboard ad hoc networks 2) Analyzing the existence of malicious nodes. In the scenario, 20 nodes are randomly set as malicious nodes. Malicious behavior includes dropping packets, adding neighbor nodes, and deleting normal neighbor nodes. It can be seen from the end to end that the average end-to-end throughput of the GPSR routing protocol based on the TPM chip is larger than that of the original GPSR routing protocol, while the average packet loss rate is low (33.11 % 54.52%); delay jitter The average delay of the original GPSR is 0. 002 199 s. The average delay of the GPSR protocol based on the TPM chip is 0. 002. 238 s. Combined with 1 data, the simulation time is slightly increased, and the routing efficiency is slightly reduced. 1 Comparison of routing efficiency and simulation time 3 Conclusion As the biggest challenge in VANET security, route security has received extensive attention. However, these security solutions are simply improved on the protocol layer and it is difficult to provide reliable security for the VANET routing protocol. This paper takes GPSR routing protocol as a blueprint, introduces TPM chip, proposes a new trusted and secure routing protocol model, provides comprehensive security protection for GPSR protocol, and can effectively prevent the destruction of internal malicious nodes. Further work will focus on how to make this trusted secure routing protocol model a general solution, and how to use this model in a real environment to serve public transportation security.
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