What must be established before using SSL for secure communications?

Using SSL (Secure Sockets Layer) for secure communications necessitates the establishment of certificates for both the client and server. SSL works by using these certificates to create an encrypted connection, ensuring that the data transmitted between the two parties remains confidential and secure. The server must present its certificate to the client to establish its identity and create a secure session.

This process relies on a public key infrastructure (PKI), where each party's certificate includes a public key that can be used to encrypt data that only the corresponding private key can decrypt. The client verifies the server's certificate is valid and trusted, helping to prevent man-in-the-middle attacks.

In contrast, while a secure internet connection, compatible operating systems, and a public IP address may be important in broader contexts of networking and connectivity, they are not prerequisites for establishing secure SSL communications specifically. The presence of valid certificates for both parties is the primary requirement to ensure trust and security in the communication process.