4.3 WHAT’S THE ANSWER TO LIFE, THE UNIVERSE, AND EVERYTHING?

EXERCISE 4.3: WHAT’S THE ANSWER TO LIFE, THE UNIVERSE, AND EVERYTHING?

We have already talked about chosen plaintext attacks in the previous chapter. The same attack can be used here. Again assume the role of Eve, the WACKO agent. You’ve intercepted Bob’s public key in the newspaper, and you have access to the RSA encryption program. If you suspect you know what Alice is sending in her encrypted messages, explain or demonstrate how you would verify your guesses.

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If Eve has a guess of what Alice is sending to Bob, all she needs to do is encrypt her guess by using the Bob’s public key and the RSA encryption program. Then she compares the ciphertext that she generated with what came from Alice. If they are the same, then that means her guess was correct. Otherwise, incorrect.