What is a VPN and what protocols does it use?

A Virtual Private Network, or VPN, creates an encrypted tunnel over a public network, allowing remote users or sites to communicate securely as if they were on a private network. Common VPN protocols include IPsec, which operates at the network layer and provides authentication and encryption through Authentication Header and Encapsulating Security Payload; TLS VPN, which operates at the transport layer and is commonly used for remote access through web browsers; and WireGuard, a modern protocol using state-of-the-art cryptography with minimal attack surface.