I understand key authentication is viable with user accounts created within the ServU app. For compliance requirements, all our user accounts need to be active directory accounts. I have contacted support about this a couple of years ago, and we attempted a solution that did not work. I have a few clients waiting for this feature, and over time that pressure increases.
I've managed secure file transfer for a couple of decades. This is my fourth hosting package, and I like it better than any I've used before. But this one Achilles Heal is in my face and I really need it to go away.