ArpON is a Proactive based solution and it defines the policies between all hosts on preventing Man In The Middle through ARP spoofing, ARP Cache Poisoning or ARP Poison Routing (APR).
ArpON don't use a centralized server or encryption. It uses an authentication of type cooperative between the hosts based on the policies that all hosts with ArpON must respect. These policies allow exactly total protection by these attacks for all hosts that use ArpON.
To understand these policies, you need to understand the final algorithm called HARPI and HARPI is like a puzzle. To understand HARPI, you need to understand the pieces of SARPI and DARPI. Finally, HARPI combines SARPI and DARPI in an one protocol solution.