There once was a man from Peru,
Whose limericks all stopped at line two.
Rpl xcjd jfi yfo,
Cw hzhyywh ot iojet,
Fdy ovjyu ozmn tdz spg yxz oet yxmgybm.

Can you figure out what cipher this limerick is using and how to decode it so that we can find out exactly what is written after the limerick was stopped?

Or, perhaps the word lengths are enough for you to determine what the words are?

The key is a place that the man could also have been from for this limerick to make sense.

  • $\begingroup$ Some observations: the encrypted words are mostly short; there are many "x" and "y" (probably they're vocals) $\endgroup$
    – leoll2
    Commented Apr 23, 2015 at 15:57

1 Answer 1


The encoded words are:

But then one day,
He decided to stray,
And wrote this one all the way through.

The Vigenere key is qvsevf. Shifting back by one letter provides a key of Purdue. So the cipher is Z-based, not A-based.

  • $\begingroup$ My Vigenère key is Z-based, not A-based, so you need to shift your letters back by 1. $\endgroup$
    – user88
    Commented Apr 23, 2015 at 16:11
  • $\begingroup$ But otherwise you're correct! $\endgroup$
    – user88
    Commented Apr 23, 2015 at 16:11
  • $\begingroup$ @Len How did you get to the solution? Brute-force? If so, using your own program or any online tool? $\endgroup$
    – leoll2
    Commented Apr 23, 2015 at 16:16
  • $\begingroup$ There are online tools to help you crack Vigenère ciphers, yes - that's how I encoded this one in the first place. $\endgroup$
    – user88
    Commented Apr 23, 2015 at 16:17
  • 1
    $\begingroup$ @leoll2 - This solver tool worked this time (but doesn't always work). This program works well but not this time. ;-) $\endgroup$
    – Len
    Commented Apr 23, 2015 at 16:22

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