Which of the following would MOST effectively enhance the security of a challenge-response based
authentication system?

A.
Selecting a more robust algorithm to generate challenge strings

B.
implementing measures to prevent session hijacking attacks

C.
increasing the frequency of associated password changes

D.
increasing the length of authentication strings

Explanation:
Challenge response-based authentication is prone to session hijacking or man-in-the-middle attacks. Security
management should be aware of this and engage in risk assessment and control design when they employ this
technology. Selecting a more robust algorithm will enhance the security; however, this may not be as important
in terms of risk when compared to man-in-the-middle attacks. Choices C and D are good security practices;
however, they are not as effective a preventive measure. Frequently changing passwords is a good security
practice; however, the exposures lurking in communication pathways may pose a greater risk.