## 3 Blockchain-Enhanced Security and Operational Efficiency in VANETs
### System Operational Behavior  
Figure 9 delineates a schematic representation of the system's behavior, thereby encapsulating the sequence of transactions and the interplay between the constituent entities. A detailed exposition of the workflow is as follows:  
1. Network Initiation and Trust Configuration: The trust authority, an overarching entity vested with the authority to oversee the issuance and management of cryptographic keys and credentials, orchestrates the foundational phase of the VANET's operation. It meticulously authenticates the vehicular nodes and establishes encrypted communication conduits, thereby underpinning a secure operational milieu. In the initialization phase, vehicular nodes entering the network for the first time are mandated to com  
Figure 9: A schematic depiction of the VANET system architecture delineating the integral roles of the constituent components and the chronological progression of transactions. municate their identifying credentials to the trust authority (TA). Upon successfully verifying the provided information, the TA responds by issuing a pseudonym and a corresponding digital certificate to the vehicular node. Furthermore, it generates a public-private cryptographic key pair using elliptic curve cryptography. All these constituents collectively facilitate the formal registration of the vehicle's identity within the system. This comprehensively assembled information is then immutably recorded in the blockchain ledger in the form of a cryptographic transaction. 2. Vehicular Data Dissemination: The vehicular nodes, epitomizing the network's mobile units, collate an array of pertinent data. Subsequently, these nodes disseminate the amassed data to the strategically positioned roadside units (RSUs), thus facilitating a confluence of vehicular information streams. 3. Data Collection by RSUs: The RSUs, stationed as pivotal nodal points within the network, aggregate vehicular data. They act as intermediaries that channel the vehicular data into the Blockchain stratum, thereby ensuring the data's subsequent validation and indelible recording. 4. Blockchain Data Verification: Upon acquisition of the data, the blockchain infrastructure executes a stringent validation protocol. Leveraging the prowess of advanced consensus algorithms and the automation afforded by smart contracts, the infrastructure meticulously ascertains the data's veracity and integrity. 5. Validation Response to Vehicular Nodes: Consequent to the Blockchain's validation process, the vehicular nodes receive feedback. This feedback, indicative of the blockchain's scrutiny, prompts the nodes to refine their data reporting protocols in alignment with the validation outcomes. 6. Ongoing Data Procurement: In a perpetual state of vigilance, the RSUs persist in their endeavor to procure updated vehicular data. This uncreasing data acquisition undergirds a spectrum of analytical and decision-making paradigms, which is quintessential for the holistic management of vehicular dynamics. The ongoing activities of the vehicular nodes within the network can be segmented into four major categories: 1. Event Observation: Upon detecting a relevant event, the vehicular node captures the pertinent information and relays it to the nearest roadside unit (RSU). The RSU, in turn, disseminates this information to proximal vehicular nodes for further observation and verification. 2. Observation Report Generation: Vehicles then produce observational reports by integrating multivariable data, which are normalized through cosine similarity measures. The direct trust score is subsequently inferred using Bayesian statistical methods. 3. Trust Exchange: Nodes within the network partake in cooperative communication to exchange direct trust metrics, which are then construed as indirect trust indicators. 4. Composite Trust Calculation: The cumulative trust level of a target vehicle is calculated by assimilating both the direct and indirect trust metrics. On the other hand, RSUs within the network are responsible for two main functions: 1.