Which protocol operates on port 443 and encrypts web pages using TLS or SSL?

The protocol that operates on port 443 and encrypts web pages using TLS (Transport Layer Security) or SSL (Secure Sockets Layer) is Hypertext Transfer Protocol Secure, commonly known as HTTPS. This is the secure version of HTTP and is essential for protecting the integrity and privacy of data exchanged between a web browser and a server.

Using HTTPS, data sent over the Internet is encrypted, which prevents eavesdropping, tampering, and forgery, thereby ensuring a secure connection. This is particularly important for transactions involving sensitive information, such as online banking or shopping.

The other protocols mentioned do not perform encryption for web traffic or operate on port 443. HTTP, for instance, operates on port 80 and transmits data in plaintext, making it vulnerable to interception. ICMP is primarily used for error messaging and diagnostics rather than web traffic. FTP is a protocol used for transferring files and typically operates on ports 20 and 21, not involving encryption by default. Consequently, HTTPS is specifically designed to create a secure communication channel, making it the correct answer in this context.