If you do not have SFTP, you might wan to consider using SCP for secure file transfer. SCP (means secure copy) means secure file transfer thru secure shell (SSH) channel. Thru ssh channel, data packet will be transfer in encrypted form and this will secure your file transfer process.
Below is the scp example for secure file transfer under Mac and Linux:-
SCP Command example:-
$ scp -P port_no /from/location/filename.tar.gz /to/location/filename.tar.gz
For example, now i wan to transfer abc.zip from my desktop to my server (IP: 18.104.22.168, ssh port: 22) under username â€˜myremoteuserâ€™:-
$ scp -P 22 /home/mydesktop/abc.zip firstname.lastname@example.org:/home/myuser/abc.zip
For Windows user, you may try out WinSCP for secure file transfer.