sbamaty (3/11/2013)
I don't think any file transfer utility/software automatically encrypts the file during file transfer process. Vendor/provider needs to encrypt it.
SFTP does that (see MIT licensed PuTTy's PSFTP client) (see also GPL licensed Filezilla[/url] client and server).
It's best to both encrypt the file either with a symmetric encryption (passphrase/key), or with asymmetric public key encryption (certificate), prior to sending, even if you're using SFTP. That way two compromises are required, not just one, to intercept in transit.