OpenVPN Support Forum

What kind of encryption does openvpn use? Does it use some kind of RSA or another type of asynchronous encryption to exchange keys and after key exchange is complete, it uses one synchronous key for the whole session? What does Diffie–Hellman option does to the openVPN security?

Also what happens if I didn't use Diffie–Hellman when setting up my openVPN?
What is the role of this algorithm? And what benefits does it do?
Am I right that even without the Diffie–Hellman there will be some RSA-esq kind of key exchange?

Use elliptic curve, it's faster.