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This question asks students to decrypt a message using a simple Caesar cipher, without giving them the key.

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Caesar wants to organise a secret meeting with Marc Anthony. He sends Marc-Antony the secret message {ciphertext} using a shift cipher. Where do Caesar and Marc Anthony meet (enter your answer in capital letters)?

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We do not have the key to decrypt the message, so we need to try every possible key and choose the answer that is intelligible.

\n

To apply a key $k$ to the string, each letter $x$ is substituted with $x+k\\pmod{26}$, where $x$ is the place of the letter in the alphabet. This gives us the strings {advice}

\n

Of those the only one that makes sense is the one for $k=\\var{26-shift}$, {plaintext}. Therefore this is where Caesar and Marc-Anthony will meet.

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