Can one use a public key/private key authentication to use Fling?

[Lemond2021]

Can one use a public key/private key authentication to use Fling?

[Jsalgado]

Are you referring to the user name and password?: 

Before you set up Fling, you should have the following information:

● The FTP server. This can be in dotted IP form (e.g., 69.10.42.210) or in domain form (e.g., ftp.nchsoftware.com).

● Your username and password.

● The directory to load files to your web server. This could be something like /home/yourco/www/html or /var/www/html.

[Lemond2021]

Thank you.

• I mean "can one use ssh keys"?
• Also can one use sftp instead of ftp?
• Can one ftp for a directory above public_html?