A VPN protocol is the set of instructions used to establish a secure connection between two computers (your device and the VPN server). Various VPN protocols exist, but Proton VPN supports OpenVPN, IKEv2, and WireGuard. OpenVPN -  A battle-tested VPN protocol that is still widely regarded as the last word when it comes to VPN security. IKEv2 - A more modern VPN protocol that is fast while also considered by experts to be very secure. L2TP/IPsec - Although believed compromised by the NSA, under most circumstances, this protocol is still considered secure. It has, however, been superseded by the superior IKEv2. PPTP - A highly insecure protocol that some providers continue to support for compatibility reasons.  WireGuard - A very new VPN protocol that, while fast and secure (at least in theory), is still experimental. Proton VPN is watching the development of WireGuard (now out of beta phase on Linux) with great interest and has helped to fund its development. Learn more about VPN protocols.