You seem to have a bit of a misunderstanding about the different protocols. FTP is a file transfer protocol, TELNET is an interactive communications protocol (and doesn't provide a mechanism for transfering files), SSH is a secure shell protocol used for secure authentication. SSH is the one you want to use as the others transfer everything in plain ascii text, including passwords. SSH uses secure encryption in all of its communications. You will need to use scp or sftp to actually transfer files, while ssh allows you to connect to other machines in a manner that, on the surface, is similar to telnet.
I'm not sure if MDK comes with documentation (online or otherwise), but openssh has the very basics in its source package in the INSTALL file.
Read the man pages on ssh, ssh-keygen, and sshd.
Typically, you want to set up your host keys with ssh-keygen just once, using syntax like:
/usr/bin/ssh-keygen -t rsa1 -f /etc/ssh/ssh_host_key -N ''
/usr/bin/ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key -N ''
/usr/bin/ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N ''