Which protocol is designed to provide encrypted links over network connections and is widely used to secure web traffic?

• A. Secure Sockets Layer (SSL)
• B. HTTP over TLS
• C. Secure File Transfer Protocol (SFTP)
• D. SSH

Answer: (A)

SSL is designed to create an encrypted link between a client and a server, which is the foundation for securing web traffic. It starts with a handshake where the server presents a certificate to prove its identity and to negotiate which encryption methods to use. Through this process, the two ends establish session keys, typically using asymmetric cryptography to exchange keys, and then switch to symmetric encryption for the actual data transfer. This setup provides confidentiality, integrity, and authenticity, so HTTP requests and responses travel over a protected channel when used as HTTPS. The other options involve secure methods for different purposes—HTTP over TLS is essentially the same idea applied specifically to web traffic, while SFTP and SSH are used for secure file transfer and secure remote administration, respectively, not for securing everyday web traffic.