Systems Security Certified Practitioner – SSCP – Question0743

Which of the following is not a DES mode of operation?

A. Cipher block chaining
B. Electronic code book
C. Input feedback
D. Cipher feedback

Correct Answer: C

Explanation:

Output feedback (OFB) is a DES mode of operation, not input feedback.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 149).