the AES cipher begins and ends with a(n) _________ stage because any other stage, applied at the beginning or end, is reversible without knowledge of the key and
Would add no security.
A)Substitute bytes
B)AddRoundKey
C)MixColumns
D)ShiftRows

Question

Quizplus · Accepted Answer

The AES cipher begins and ends with an AddRoundKey stage because this operation directly incorporates the cipher key into the data block. This is essential for security, as without the key, reversing this step is not feasible, unlike the other stages which could be reversible without the key, thus not adding any security if placed at the beginning or end.

The AES Cipher Begins and Ends with A(n) _________ Stage