Fractionated Morse Mystery Cache
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Difficulty:
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Terrain:
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Size: 
(regular)
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This cache is not at the indicated coordinates. The actual coordinates have been written in Morse Code and then encrypted using an enciphering method called ‘Fractionated Morse’.
11/16/07 - Please be mindful of private property. At its end, the road opens into a circular parking area. Do not continue up the private road. Park and enter the field just beyond the house on the right. The residents who surround this parking area know of the cache.
Here is an explanation of the methodology.
First, each letter of the plaintext is enciphered using Morse code, with an ‘x’ between letters and ‘xx’ between words. For example, the word ‘degrees’ becomes –
d e g r e e s
x x _ . . x . x _ _ . x . _ . x . x . x . . . x x
Next, the resulting series of dots, dashes and x’s are divided into groups of three, called trigraphs. Since there are 26 different possible trigraph combinations, each will be represented by a different letter of the alphabet in the related cipher text [CT] message.
The Resources section of the American Cryptogram Association’s website [‘cryptogram.org’] contains an example of the Fractionated Morse encryption method. As illustrated, the digraphs are matched with a ‘keyword’ alphabet that in the example is based on the word ‘roundtable.’ This alphabet is used to convert the trigraphs into the final cipher text.
Let’s assume that I have used the word ‘degrees’ in the cipher text that follows, and that I have used this same keyword [roundtable] alphabet. Let’s further assume that the digraphs are as follows:
Z U B F N S A U
\x x _ \. . x \. x _ \_ . x \. _ . \x . x \. x . \. . x \x
1 2 3 4 5 6 7 2
The word ‘degrees’ becomes ZUBFNSAU.
You will note that there are seven different digraphs used, and only one repetition. This pattern helps locate the possible locations of this word in the actual CT.
Actually, there are three different possible trigraph combinations for the word, depending on the text that precedes it in the enciphered message. Here are the other two patterns.
x\ x _ .\ . x . \x _ _ \. x . \_ . x \. x . \x . . \. x x
1 2 3 2 4 2 5 6
x x \_ . . \x . x \_ _ . \x . _ \. x . \x . x \. . . \x x
1 2 3 4 5 2 6
As a last step, the letters of the CT message are written in groups of five – ZUBFN SAU
The cache is a large camouflaged jug, and here is the key to its location:
UHYEI LZHCC RQROF ZAYCI RKOCS UHYEL TFSHY EYVUR
KSOGW ZBYAG XTTXK PVTAT QYYRG BYAXP TYJCH ZUBXE
CVKJY YVPZY JADHT ZHOFE CVKHM MTZSJ PZYJY ICZHF
YEYVU OFBHA ISUZB SPVER ZWUBA EWZBY AGCBD URKSO
GTZAV ZUCZT ICHE
Oh, yes…
I have used the trigraph sequence that is shown in the ACA example.
I have used a different ‘keyword.’
The word ‘indicated’ appears in the CT.
Checksum = 53.
Additional Hints
(No hints available.)