FTP and S FTP connectors difference
FTP is not secured where as SFTP - is secured - google will provide more information.
SFTP runs over SSH only and is therefore secure. You can't switch that off. Also, if you want to use private key authentication, you need a local Atom.
Cloud Atom won't support private key infrastructure? Just plain authentication?
Yep. See SFTP connection documentation
Using a private key to identify a user is an alternate method for logging onto a server instead of using a password. This method is not available if you are using a Dell Boomi Atom Cloud. Examples of private keys are RSA and DSA.
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