Consider a block cipher based on Feistel structure. The operation of a round is shown in...

 

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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 R₁. Ro R₁-1 R₁ R₁. 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. 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 R₁. Ro R₁-1 R₁ R₁. 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 the full answer