Backup over network to remote tape drive

I am currently using tar to backup a server that has 9gb of data.
This is fine and works fine, as part of this I send the backup to a remote tape on a remote server using rsh..

This is not very secure though is it?

Whats the best idea here - is there another way I should do this to be more secure?

You could replace your use of rsh with ssh, and use a private network for backup.