What is the HNS handshake protocol?

Could you please elaborate on the HNS handshake protocol? I'm curious to understand its purpose, functionality, and how it fits into the broader cryptocurrency and blockchain ecosystem. Specifically, how does the HNS handshake protocol ensure secure and efficient communication between nodes, and what sets it apart from other protocols in the industry? Additionally, could you provide some real-world applications or use cases for the HNS handshake protocol?