Security for internet transfers

Hi
I now use SFTP with SynchBack Pro to transfer files over the internet.. For security, I only let the SFTP server connect to the IP address that Synchback is using.. and the transfer is encrypted.
Does Synchback touch encrypt the transfer, and is there the option to allow it to only connect to 1 IP address? (I guess I could configure the firewall to do that but it is messy.

thanks