The output of the encryption function is fed back to the shift register in Output Feedback mode,whereas in ___________ the ciphertext unit is fed back to the shift register.
A)Cipher Block Chaining mode
B)Electronic Codebook mode
C)Cipher Feedback mode
D)Counter mode

Question

Quizplus · Accepted Answer

In Cipher Feedback (CFB) mode, the ciphertext output is fed back to the shift register. This results in the encryption of the plaintext as well as the output of the previous encryption. This feedback mechanism provides a way to create a stream cipher from a block cipher. In Output Feedback (OFB) mode, the output is used as a keystream to encrypt the plaintext rather than being fed back to the shift register. Therefore, Cipher Feedback mode is the correct choice in this scenario.

The Output of the Encryption Function Is Fed Back to the Shift