Current smart traffic lights (STLs) can provide access to a traffic signal, which a vehicle, such as an emergency vehicle, can manipulate through a Cooperative Awareness Message (CAM) object. However, researchers have demonstrated that STLs can be easily hacked using an abusive CAM object. To address such a weakness, techniques are presented herein that secure a STL with auxiliary data that is attached to a CAM object, which can be used by a vehicle on-board unit (OBU) and smartphones. Aspects of the presented techniques reduce the encryption and decryption overhead that is incurred when attaching a security header as part of a CAM message. Further aspects of the presented techniques ensure that the authenticity and integrity of a CAM message can be validated through a roadside infrastructure (e.g., Roadside Units (RSUs)) and STLs with the help of a central server