SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary.
SSH is typically used to log into a remote machine and execute commands, but it also supports tunneling, forwarding arbitrary TCP ports and X11 connections. SSH uses a client-server protocol.
SSH uses private/public key pairs to log into another host. Users no longer have to supply a password every time they log on to a remote host.
Depending on your requirements for X-Window jobs, you can choose either bsub -XF (recommended) or bsub -IX. Both options encrypt the X-Server and X-Clients.