a) A ciphertext has been generated with an affine cipher, which is defined as follows: C = (a × P + b) mod 26 where C = ciphertext, P = plaintext, a & b are the key Adversary has the following knowledge: the most frequent letter of the ciphertext is sum of characters in your last name module 26, and the second most frequent letter of the ciphertext is sum of characters in your first name module 26. Break this cipher. If it is not breakable, provide an appropriate justification.   (b) If the cipher is redefined as follows: C = (a × b + P) mod 26 where C, P, a & b are as defined before, and adversary has the same knowledge as before, discuss with appropriate justification whether this new cipher is breakable. ONLY DO PART B.

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Q: 8

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