Currently AF Table link only support username and password. With increasing security requirement this is becoming more and more problematic. AF table Link requires unattended connectivity, and updating password every 90 days is not practical. As a result a service account is usually used and the password is never changed.
We recently had a security incident and we were asked to reset our password for SAP SnowFlake. After the reset we found there's unidentified instance of connection that's using the same username. It was queueing the system frequently and cause the account getting locked out because it was still using the old password. We end up having to create a new username.
We were asked by the IT organization to switch to a Key-Pair authentication mechanism. This will support unattended connectivity and increase the security at the same time.
Actually I was able to get the Key-Pair authentication to work right now, so this is no longer relevant.