Which of the following types of security services are used to support authentication for remote users and
devices?

A.
Biometrics

B.
HSM

C.
RADIUS

D.
TACACS

Explanation:
RADIUS authentication phase takes place when a network client connects to a network access server
(NAS) and provides authentication credentials. The NAS will then make use of the authentication
credentials to issue a RADIUS authentication request to the RADIUS server, which will then exchange
RADIUS authentication messages with the NAS.
Incorrect Answers:
A: Biometrics refers to a collection of physical attributes of the human body that can be used as
identification or an authentication factor. Devices cannot use this.
B: HSM is a physical computing device that protects and oversees digital keys for strong authentication
and provides cryptoprocessing. It is not used for the authentication of remote users and devices?
D: TACACS was used for communicating with an authentication server, not the actual authentication.

http://cloudessa.com/products/cloudessa-radius-service/what-is-a-radius-server/Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, p. 285
http://en.wikipedia.org/wiki/Hardware_security_module
http://en.wikipedia.org/wiki/TACACS