Can someone explain why, in remote access scenarios, IKEv2 EAP password-based user auth combined with IKEv2 PUBKEY gateway auth is preferable over mixed IKEv2 PSK/PUBKEY auth using the same password on the user side and the same certificate on the gateway side?
There are a few reasons why EAP is preferred over PSK:
- PSK requires the use of a (relatively) low-entropy password, which is (relatively) easy to bruteforce.
- PSK requires the passphrase to be stored on the server, which may result in key theft.
- EAP allows clients to authenticate using different credentials in each direction, so a server might authenticate itself to the client with a completely type of credential than the client uses to authenticate itself to the server.
- EAP allows clients to authenticate using their own digital certificate, which is much more secure than a password. The user just has to unlock their certificate (or certificate store) using their password on the local device.
- IKEv2 supports EAP-only authentication, which theoretically allows any form of add-on authentication mechanism to be used.