QuantumFTP supports connections via FTPS and FTPES (FTP with SSL). SSL can be used to secure connections and provide authentication when connecting to a server.
Client certificates are supported in both implicit and explicit modes.
Explicit Mode - Also known as AUTH SSL or FTPES. A connection is established on port 21 as normal, but a secure channel is negotiated before any data is sent. RFC 4217 complient.
Implicit Mode - An encrypted connection is opened to port 990 and an SSL handshake is performed before any data is sent.
Client Certificate/Client Password - These fields are optional. A certificate can be used to authenticate to the server if necessary.