Which of the following protocols is used to authenticate the client and server’s digital certificate?

A.
PEAP

B.
DNS

C.
TLS

D.
ICMP

Explanation:
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security
over a computer network. It uses X.509 certificates and hence asymmetric cryptography to authenticate
the counterparty with whom it is communicating, and to exchange a symmetric key.
Incorrect Answers:
A: Protected Extensible Authentication Protocol (PEAP) encapsulates EAP methods within a TLS tunnel
that provides authentication and potentially encryption.
B: Domain name system (DNS) is the hierarchical naming scheme used for public and private networks.
D: ICMP is a protocol that is commonly used by tools such as ping, traceroute, and pathping.

http://en.wikipedia.org/wiki/Transport_Layer_Security
Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 42, 47, 61