CISSP – Information Systems Security Architecture Professional (ISSAP) — Question 14

Which of the following encryption modes has the property to allow many error correcting codes to function normally even when applied before encryption?

Answer options

• A. OFB mode
• B. CFB mode
• C. CBC mode
• D. PCBC mode

Correct answer: A

Explanation

OFB mode is designed to produce a stream of key bits that are independent of the plaintext and ciphertext, allowing error correction codes to work properly. In contrast, CFB, CBC, and PCBC modes are more dependent on the previous ciphertext block, which can disrupt the functionality of error correction codes when applied before encryption.