Why am I still getting a password prompt with ssh with public key authentication

• ssh-keygen -t rsa -b 2048 -f /path/to/key_name
• adduser --disabled-password --group --system user_name
• scp root@host:/home/user_name/.ssh/authorized_keys

Make sure the permissions on the ~/.ssh directory and its contents are proper. When I first set up my ssh key auth, I didn't have the ~/.ssh folder properly set up, and it yelled at me.

• Your home directory ~ and your ~/.ssh directory on the remote machine must be writable only by you: rwx------ and rwxr-xr-x are fine, but rwxrwx--- is no good, even if you are the only user in your group (if you prefer numeric modes: 700 or 755, not 775).
• Your private key file (on the local machine) must be readable and writable only by you: rw-------, i.e. 600.
• Your ~/.ssh/authorized_keys file (on the remote machine) must be readable (at least 400), but you'll need it to be also writable (600) if you will add any more keys to it.
• Also, if SELinux is set to enforcing, you may need to run restorecon -R -v ~/.ssh (see e.g.Ubuntu bug 965663 and Debian bug report #658675; this is patched in CentOS 6).