Similar to ISO 26262, the new ISO/SAE 21434 looks at the entire development process and life cycle of a vehicle. It follows the V-model. During all phases, including requirements engineering, design, specification, implementation, test, and operations, security aspects need to be taken into consideration.
ISO/SAE 21434 follows the V-model.
It must be ensured that the production of a safe vehicle requires a safety-conscious requirements analysis and a corresponding design and product specification.
However, if you are hoping for specific recommendations of security technologies or appropriate countermeasures by ISO/SAE 21434, we must disappoint you, as these will not be part of the standard. Instead, it is recommended that you conduct a structured threat analysis and risk assessment.