OpenVPN already sort of supports this: https://community.openvpn.net/openvpn/wiki/Hardening#Useof--tls-auth https://community.openvpn.net/openvpn/wiki/Hardening

OpenVPN already sort of supports this: https://community.openvpn.net/openvpn/wiki/Hardening#Useof--tls-auth https://community.openvpn.net/openvpn/wiki/Hardening#Useof--... While it does not provide additional encryption, it does prevent clients who do not know the secret from initiating connections (and thus interacting with the TLS state machine/etc).