Which one of the following protocols is used for secure communication over computer network?

HTTPS (Hypertext Transfer Protocol Secure) is the correct answer as it is specifically designed for secure communication over a computer network. It is an extension of HTTP that uses TLS (Transport Layer Security) or its predecessor, SSL (Secure Sockets Layer), to encrypt the data exchanged between a web browser and a server. This encryption ensures data confidentiality and integrity, protecting against eavesdropping and tampering.

• HTTP: The standard protocol for transferring data, but it transmits information in plain text, making it insecure.
• DHCP: Used for automatically assigning IP addresses to devices on a network.
• SMTP: The standard protocol used for sending emails; while it can be secured (e.g., SMTPS), its primary function is mail transfer, not general secure web communication.