File Permissions
SORT
# public key moved to server auth file and priv key on client
cd ~/.ssh/
/home/donald/.ssh
ssh -i fplabs test.fullproxylabs.com
sudo chmod 600 key
sudo chmod 644 key.pub
sudo nano /etc/ssh/sshd_config
PasswordAuthentication no
PubkeyAuthentication yes
sudo systemctl restart sshd
ref;
http://permissions-calculator.org/