HTTPS (Hypertext Transfer Protocol Secure) is the protocol used for secure communication over a computer network and is widely used on the Internet. The security aspect of HTTPS is provided by layering the HTTP protocol on top of the Transport Layer Security (TLS) protocol or its predecessor, Secure Sockets Layer (SSL). When a client connects to a server via HTTPS, a TLS handshake occurs, which authenticates the server (and optionally the client) and establishes a shared secret key. All subsequent HTTP traffic is then encrypted using this key, ensuring confidentiality and integrity of the data exchanged between the client and the server.

A. IPSec: Operates at the network layer (Layer 3) to secure IP packets between endpoints, often for VPNs, not specifically for application-layer HTTPS connections.

B. SNMPv3: Is a protocol for secure network management. It provides encryption for management data, not for general web traffic as HTTPS does.

D. SSH: The Secure Shell protocol is used for secure remote administration, file transfers (SFTP), and tunneling, but it is not the underlying protocol that secures HTTPS.

1. CWNP, "CWISA-102 Certified Wireless IoT Solutions Administrator Official Study Guide," 2nd Edition. Chapter 3: Networking Services, under the "HTTP and HTTPS" section, states: "HTTPS uses an encryption protocol to encrypt communications. Originally, this was Secure Sockets Layer (SSL), but it has now been entirely replaced by Transport Layer Security (TLS)." (Page 68).

2. Internet Engineering Task Force (IETF), RFC 2818: HTTP Over TLS. The abstract states: "This memo describes how to use Transport Layer Security (TLS) to secure HTTP connections over the Internet." Section 1, "Introduction," further clarifies that "Conceptually, HTTP/TLS is very simple. The only difference between HTTP and HTTP/TLS is that HTTP/TLS runs over a secure TLS connection."

3. MIT OpenCourseWare, 6.858 Computer Systems Security, Fall 2014. Lecture 14 Notes: Web Security, Section 3, "HTTPS," explains: "HTTPS = HTTP on top of SSL/TLS. SSL/TLS provides a secure channel... It provides confidentiality, integrity, and server authentication." (Page 3).