- make a strong ssh key
$ [ssh-keygen](https://en.wikipedia.org/wiki/Ssh-keygen) -t rsa -b 4096 -f ~/.ssh/id_rsa
- turn to RFC 4716
$ ssh-keygen -e -f ~/.ssh/id_rsa.pub
- add to
~/.ssh/authorized_sftpkeys
on destination host - try out:
$ [curl](http://curl.haxx.se/) -u "<username>:" --key ~/.ssh/id_rsa --pubkey ~/.ssh/id_rsa.pub -T <file to upload> sftp://<target host>/<target path>/
$ [lftp](http://lftp.yar.ru/) -u <username>,xx ... sftp://<target host>