Question

7. Is the set of all monoalphabetic substitutions a group? Find two keys M1,M2 and a message w such that M1(M2(tv))メM2(M1(w)). Is it possible to find two Caesar keys K1, K2 and a message m such that K1(K2(m))メK2(X1(m))? 8. Find two different English messages w, w2, and a monoalphabetic key k such that Mk(wn)w2. The longer the message, the better. Suppose that Alice sends ui to Bob (encrypted with a Monoalphabetic substitution). What problem does this present for Eve?

Answer 1

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