Which protocol provides encryption, authentication, and integrity for secure communications over a network?

• A. SSL/TLS
• B. SSH
• C. IPsec
• D. PKI

Answer: (A)

Encryption, authentication, and integrity in network communications are provided by a security protocol that creates a protected channel between two endpoints. TLS (the modern form of SSL) does exactly that: it establishes a secure session, authenticates the communicating parties (typically the server, and optionally the client), and protects all transmitted data from eavesdropping and tampering.

• Encryption ensures the data remains confidential so that interceptors can’t read it.

• Authentication verifies who you are communicating with, preventing impostors from pretending to be the server (and optionally the client).

• Integrity guarantees that any tampering with the data would be detected, since the recipient can verify that the message hasn’t changed in transit.

TLS is widely used to secure web traffic (HTTPS) and many other protocols that require secure channels. Other options don’t fit this exact role: SSH is tailored for secure remote login, IPsec operates at the IP layer for VPNs, and PKI provides the infrastructure for issuing and managing certificates but isn’t itself a protocol that secures a channel.