The PIA iOS app uses IPsec to connect to our network of VPN servers. Many users wonder why we chose IPsec instead of OpenVPN as the underlying protocol.
iOS ships with a couple of built-in VPN protocols like L2TP and IPsec. Apple currently only allows a select few VPN hardware and software vendors to implement their own custom VPN protocols, which does not include service providers.
Nevertheless, when correctly configured IPsec and OpenVPN protocols offer similar levels of protection against eavesdropping. Many experts also agree that neither is decisively better than the other when it comes to security. Thus at this time, IPsec is the strongest VPN protocol natively supported by iOS.
If you would rather use OpenVPN on your iOS device, this is also certainly possible to setup. To configure OpenVPN on your iOS device, you can follow the steps in this article.