Question: Consider a block cipher based on Feistel structure. The operation of a round is shown in the following figure: Plaintext block Iterate times Ciphertext

Consider a block cipher based on Feistel structure. The operation of a round is shown in the following figure: Plaintext block Iterate times Ciphertext block Lo Li-1 Lr R. Ro R-1 R R. Lr (a) (4 points) Does the round function need to be invertible? Why? (b) (6 points) Does the compression function f need to be invertible? Why?\dows Go to Settings to activate Windows.

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The image you provided shows the structure of a Feistel cipher which is a symmetric structure used in block cipher algorithms A Feistel cipher splits ... View full answer

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