A security administrator must implement a secure key exchange protocol that will allow company clients
to autonomously exchange symmetric encryption keys over an unencrypted channel. Which of the
following MUST be implemented?

A.
SHA-256

B.
AES

C.
Diffie-Hellman

D.
3DES

Explanation:
Diffie-Hellman key exchange (D-H) is a means of securely generating symmetric encryption keys across an
insecure medium.
Incorrect Answers:
A: SHA-256 can used to detect violations of data integrity. It will not, however, allow company clients to
autonomously exchange symmetric encryption keys over an unencrypted channel.B: AES is a specification for the encryption of electronic data. It will not, however, allow company clients
to autonomously exchange symmetric encryption keys over an unencrypted channel.
D: 3DES is symmetric-key algorithm for the encryption of electronic data. It will not, however, allow
company clients to autonomously exchange symmetric encryption keys over an unencrypted channel.

Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, p. 336
https://en.wikipedia.org/wiki/SHA-2
https://en.wikipedia.org/wiki/Advanced_Encryption_Standard
https://en.wikipedia.org/wiki/Triple_DES