improve my SDN networking project by adding encryption feature

My project goal is to improve my SDN networking project by adding advanced encryption features. This requires the initial knowledge of using the ARP Protocal And ARP Spoofing Attack as the existing network project is 70% completed BY me, you just need to complete the project and ADD encryption to the project . Security requirements are set to a high standard and must meet advanced criteria. after we complete the project , it will be needed to measure the network Security improvment and maintain top performance.
if you look to the attachment you will have initial idea of the project