The SPF tool uses IIS web service as server. The SSL is a security certificate of a web server and client communication. It is the standard security technology to establish an encrypted connection between server and browser. The SSL is used in most of the web portal worldwide and is one of the most trusted encryption. Many ecommerce portals usually use the SSL Encryption certificate.
Secure Sockets Layer (SSL) is the cryptographic protocol to communicate securely over internet. SSL encrypt the segments of network connections at the Application Layer for the Transport Layer, using asymmetric cryptography for key exchange, symmetric encryption for confidentiality, and message authentication codes for message integrity.
Under the criteria of layman's understanding, the server sends various details to the client, like serial, Public key, and valid to (for SPF these information is enough. Although there are more info sent by the server to client). The client receives the information, provides the input, and the inputs are scrambled. Like if I provide the use the username as Bhaskar, and password as IdontKnow, user name can be sent as #%M09^&(!!!!!#R7u><} and password as #%&&&-^&*(#>Pu8*R7u><}. The scrambled information is delivered to the server and is decrypted over there. This way the data can remain safe. This way, if a customer is provided the web portal access, it will be highly secured to the satisfaction of customers.
Hope this little info was helpful anyway. See you soon…