This short tutorial explains how to setup SSH to use key based authentication, by default on CentOS this is disabled. To start with follow our guide on how to generate SSH key pairs and copy the key over.
Configure SSH to enable Public Key Based Authentication
Open up /etc/sshd_config in vi and find the following lines:
#PubkeyAuthentication yes
#AuthorizedKeysFile .ssh/authorized_keys
And un-comment them so it reads:
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys
Restart SSH Server with:
/etc/init.d/sshd restart
You should now be able to login over SSH using public key based authentication.