The communication with the File Transfer Server can be made secure through HTTPS. When doing so, the files transferred between client and server are protected against eavesdroppers and man-in-the-middle attacks.
Based on your configuration, different steps have to be taken:
Step 1. Set up HTTPS for Enterprise Server as described in Using SSL in Enterprise Server.
Step 2. (Optional) When Enterprise Server and the Transfer Server run on separate machines, set up multiple certificates.
Note about certificates: When Enterprise Server and the File Transfer Server are both running on the same machine, nothing extra needs to be done. This is because the Transfer Server reuses the secured connection setup for Enterprise Server. Therefore, the very same certificate used to secure the Enterprise Server connection is used by the Transfer Server connection. This is regardless of whether the Transfer Server runs within Enterprise Server or separately on the same machine.