Sending Files w/o Sending Clear Passwords?

Ambush_Bug asks: "I've done some googling around, but to no avail. I'm wondering if the Slashdot knows of a remote login protocol which exists in security space somewhere between ssh & rsh/ftp/telnet. Basically, the point is that I don't care if my data are encrypted, but I'd rather not send my password around as plaintext. I'm sending extremely large astronomical images which don't compress very well (noisy backgrounds...) and sftp is just too slow, but our sysadmin isn't fond of rcp, ftp and the like. Is there something in between?"