Ah the joys of childish toys Mystery Cache

Ah the joys of childish toys.

Playing Fair with Playfair

I first encountered the Playfair Cypher in my youth, in grade school, when I purchased a TAB book titled "Secret Codes and Ciphers."  A couple of friends and I became quite enamored of the Playfair Cypher, viewing it as the perfect way to pass secret messages -- quite trivial secrets but still secret messages -- which no-one could intercept.  Thus, in memory of a youth not entirely misspent (not misspent at all, really), I decided to use this toy to present you with a puzzle challenge.

However, before you decide that this challenge is too complex, you should know that history reports that the Playfair Cypher was originally rejected -- in the 1850's -- by the British Foreign Office as too complex.  When the developer, Charles Wheatstone, offered to demonstrate that three out of four boys in a nearby school could learn to code and decode using the Playfair Cypher in less than a quarter hour, the immediate response from the Under Secretary of the Foreign Office was (perhaps accurately): "That is very possible ... but you could never teach it to attachés."

Now, are you smarter than a Foreign Office attaché?  

Or, more important, are you smarter than a fifth grader?

For the complete story on the Playfair Cypher, go here 

You can also try the cypher tool found here 

Note: since the Playfair Cypher is British in origin, I prefer the British spelling (cypher) over the American spelling (cipher).

One Additional Note: Using A Playfair Cypher For Numbers

While the original Playfair Cypher made no specific provisions for numbers, adding digital encryption to the cypher is quite simple; let 1 = 'A', 2 = 'B', etc., so that 0 = 'K' (since 'I' and 'J' are the same in this cypher) and use the null -- 'X' -- character for spaces and decimals.  Thus, a number such as 3.1415 is translated to CX AD AE and this is then encrypted in the same fashion as any other text.  Likewise, coordinates such as N 48 45.678 W 122 34.567 become NX DH XD EX FG HX WX AB BX CD XE FG (before encryption).

1   2   3   4   5   6   7   8   9   0

A   B   C   D   E   F   G   H  I/J  K

An Example of the Playfair Cypher

Using the keyword "Playfair" for the cypher, we get the key "PLAYFIR", by dropping the second 'A' and produce the table following:

Using this grid, we can encypher the very important secret message "All your base are belong to us", beginning with the digraphs:

Al lx yo ur xb as ex ar ex be lo ng xt ox us

And these encypher as: 

YAYVLS VIWCYQ KULBKU IHRVOE ZSSVXN

So, there you are, a key phrase, a key, a Playfair table and a fully encrypted message.  See how easy it is?

Please note: "Playfair" is NOT the keyword used to solve this puzzle.  You should, however, be able to guess at the appropriate key ... particularly if I tell you that it is an ten letter word with two duplicate characters (yielding an eight-character key) and it is perfectly appropriate for the sport you are engaged in. 

However, to be completely fair, using the real key, I've also encrypted two messages following: "All your base are belong to us." and "3.1415" (CXADAE) which, respectively become OPSOXC QSYNOU OWEUOW ICSNHO YSNOQT and OYDPGO.  Now, if you can decypher these two samples, then you'll know you have the correct keyword to decypher the real puzzle.

And now for the real puzzle

QBNRYO GAIGWN XOOZPO QEOWAG LCQPPO EONZFM OURBOY DESWOD NZNRVN NHIALO CUOLZN HAWOOZ FHNZSV XYCDNY HIVOIH

GNYZOR VSVNDU MZYOGA INHOVS

Congratulations to fishiam for decoding the message (FTD) in spite of being too distant to seek the cache. And also a thank you for catching an error in one digraph (now corrected).

Congratulations to Priates of the Yukon and sidetrackin for a co-FTF