Mavericks update changes sshd_config? I normally use private key authentication to SSH into my mac via an iOS client. I recently upgraded to Mavericks, and started noticing the client prompting for a password rather than trying the private key first. My old /etc/sshd_config had disabled password authentication ("PasswordAuthentication no, ChallengeResponseAuthentication no"), but it looks like the upgrade process to Mavericks reset these two values to yes. 

Is anybody else seeing this change? Is there any documentation on this? It seems like a significant security issue to reenable SSH password authentication by default.
I had the same problem and found the answer here: Mavericks update broke ssh key-based authentication

Basically, you can't use authorized_keys2 anymore (an old default). Rename the file to "authorized_keys" and it should work again (it did so for me).

mv ~/.ssh/authorized_keys2 ~/.ssh/authorized_keys