Nowadays, the automobile industry is integrating many new features into vehicles. To provide these features, various electronic systems are being added. These systems are coordinated by different ECUs (Electronic Control Unit). Vehicle ECUs are internally connected through multiple communication buses. Any ECU connected to the bus can read or send data to other ECUs. As a result, if an adversary can compromise one of the ECUs, then the adversary will be able to access and exploit the data of other important ECUs. Moreover, an adversary can modify the stored data of an important ECU, if it is compromised. To solve these problems, we propose the use of symmetric key cryptography and elliptic curve-based Public Key Encryption (PKE) for ensuring confidentiality and the use of digital signature for ensuring integrity and authenticity. In addition, we propose the adoption of an identity-based access control to control the communication permissions. We also introduce a Blockchain-inspired mechanism to secure data stored in ECUs. Finally, we integrate a watcher to monitor the stored data and report if it is modified. We implement our concept using the ARM architecture-based Raspberry Pi Board and show that our approach can improve security in ECU communications and the watcher reports when an ECU data is modified.