In this paper a new security technique aiming to ensure safe and reliable communications between different nodes on an automotive Controller Area Network (CAN) is presented. The proposed method relies on a robust authentication code using Blake-3 as a hash algorithm within an adapted structure that includes a monitor node. A prototype is implemented and run effectively to perform hardware simulations of real case-based security problems of automotive embedded CAN systems. As a result, data transfer can take place on a newly enhanced CAN bus according to the standard protocol without being intercepted nor tampered with by unauthorized parties thereby highlighting the effectiveness of the proposed technique.