Which network protocol is used to provide secure access and communication over an unsecured network?

• A. Secure Shell (SSH)
• B. Secure Sockets Layer (SSL)
• C. Transport Layer Security (TLS)
• D. Internet Protocol Security (IPsec)

Answer: (A)

SSH provides authenticated, encrypted remote access to a system over an insecure network. It creates a secure channel between client and server, protecting confidentiality and integrity of everything typed or returned during a login session. SSH uses public-key cryptography for strong authentication and negotiates a session key so commands and data are encrypted in transit, enabling safe remote administration and file transfers even over untrusted networks.

SSL/TLS secures application-layer communications such as web traffic, but isn’t typically used to provide interactive remote login sessions. IPsec protects IP packets at the network layer—great for VPNs between networks or hosts—but it isn’t designed to offer an interactive shell or remote command execution session.