Exercise 4.1 Let P be a plaintext and let f(P) be the length of P in bytes. Let b be the block size of the block cipher in bytes. Explain why the following is not a good padding scheme: Determine the minimum number of padding bytes necessary in order to pad the plaintext to a block bo undary. This is a number n which satisfies 0 is a multiple of b. Pad the plaintext by appending n bytes, each with value n.

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