Two entities who share a key k decided to use a block cipher ENC in Cipher Feedback (CFB) mode and a fixed IV value (i.e. the IV does not change) to build a MAC scheme to authenticate messages they exchange. More concretely, to sign a single-block message M, the MAC tag is computed as T= MENCK (IV), where denotes XOR. Note that all messages contain one block only. Is this MAC construction existentially unforgeable? O Yes O No

Q: Suppose that you share a new (unused) random key of 128-bits with a recipient. You are considering…

A: For an n-bit block size are 2n possible different plaintext blocks and 2n possible different…

Q: A message authentication code, MAC, takes as input a key K and message M and outputs a tag T. In…

A: The answer is given in step 2.

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Q: Using the corresponding decryption rules, please write out P_0, P_1, P_2, respectively.

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A: The solution is given in the next step

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A:

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A: Solution for the above question,  Introduction:

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A: As per our Guidelines we are supposed to answer first question only.Kindly repost another question…

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A: Introduction:Here we given the following data as follows :

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Q: Pet

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A: The answer to the above-mentioned question is given below with an explanation.

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Q: The Caesar Cipher Algorithm was introduced in Week #1. Encryption is the act of encoding a message…

A: Python code is as follows:-

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Q: Use the CFB mode of operation to encrypt the plaintext 100011111.

A: Using CFB mode of operation to encrypt plaintext 100011111

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A: Solution

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A: To do: part C and D based on question

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Q: This question concerns block cipher padding. Suppose the block cipher has a block size of 16 bytes.…

A: ANSWER:-

Q: D). The cipher text rough some other r

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