Kerberos authentication
Kerberos is a protocol that allows for secure authentication even over unsecure networks. It can be difficult to set up, but after it is fully working you have a very secure authentication system with the benefits of single sign-on.
It is usually a good idea to first create a working setup where the server uses username and password/LDAP authentication and a user directory in LDAP mode, and then proceed with switching from username and password/LDAP to Kerberos.
Note: Delegated Kerberos is not supported when running Web Player or
Automation Services on Linux.