Ridlon Road Crypto Cache
In Maine, United States
How Geocaching Works
As the name implies, this cache is located near Ridlon Road in Berwick Maine. The latitude and longitude of the cache are provided in the cryptogram below. However, this cryptogram has not been enciphered by the simple, single cipher alphabet system normally used for geocache hints. Instead, it has been encoded using the polyalphabetic Vigenere system. As a result, a bit of research and possibly a trip into the field may be necessary before you will be ready to try to locate this cache.
The Vigenere system was invented by Blaise de Vigenere in the 16th Century. It uses a set of 26 cipher alphabets, with each alphabet being identified by a single letter. When using the this system, each letter in a message is enciphered using a different Vigenere alphabet choosen based on the letters of a keyword. If you know the keyword on which a Vigenere cryptogram is based, deciphering it is a relatively easy task. Without that knowledge however, decrypting such a cipher can be very difficult and time consuming.
For this reason, the Vigenere cipher was called 'Le Chiffre Indechiffrable' (i.e., The unbreakable cipher) for over 300 years. But all good things come to an end. In 1863 a retired Prussian army officer, Friedrich Kasiski, published a general method of solving Vigenere type ciphers. Further, in the 1920's, William Friedman developed 'Index of Coincidence' methods which have made this cipher type even less secure. As a result, Vigenere type ciphers are no longer in general use except as puzzles.
Today, American Cryptogram Association (ACA) members regularily solve Vigenere ciphers for fun with no cribs (hints) being provided. But what can a poor geocacher do if his/her cryptanalytic skills are not up to ACA standards and he/she doesn't know an ACA member? Fortunately, a non-cryptanalytic method has been provided for obtaining the keyword used to encipher the cryptogram. The coordinates posted with this log are the position of a monument to a local patriot family. The name of that family is the ciphers keyword. With this information, and an understanding of how the cipher works (Obtainable from the references below), a geocacher should be able to crack 'Le Chiffre Indechiffrable'.
To encourage individuals to solve the cipher and find the cache I am offering two first to find prizes:
(1) First To Find (FTF) by any means: A copy of Simon Singh's book 'The Code Breakers' has been included in the cache for the FTF.
(2) FTF by purely cryptanalytic means: For the first to find the cache by solving the cryptogram without resort to the 'monument shortcut', a years membership in the ACA. Persons claiming this prize must contact me and describe in detail the method (e.g., Kasiski method, Index of Coincidence, Method of the Probable Word, etc...) they used to solve the cipher.
The cache is an ammo box and contains both cryptological literature for all finders and the usual trade items.
Gaines, Helen Fouche, "Cryptanalysis: A Study of Ciphers and Their Solutions", Dover Publications Inc., New York, 1956.: The classic elementary text for those wishing to learn to solve ciphers. Several chapters are devoted to the solution of Vigenere type ciphers.
Kahn, David, "The Code Breakers", Scribner, New York, 1996.: The definitive history of codes and ciphers from ancient times until about 1960. Pick this up after you have used the other references.
Singh, Simon, "The Code Book", Doubleday, New York, 1999.: An excellent short history of Cryptography which devotes the better part of a chapter to the Vigenere cipher.
(visit link) : An excellent primer on the Vigenere cipher. This page provides sufficient information to allow anyone to decode a Vigenere cipher by hand once the keyword is known.
(visit link) : Provides the 'Cipherclerk' applet which can be used to enciphering/decipher numerous historical ciphers, including the Vigenere. I recommend you use this applet once you have the ciphers keyword if you don't want to do the work by hand.
(visit link) : An excellent interactive tutorial on the Vigenere cipher. Be warned, the enciphering/deciphering tool provided does not allow the use of spaces in the cipher/plain text.
The Cryptogram in ACA standard format (Note, the spaces are for analysis purposes only, they do not represent word divisions):
Vigenere. Ridlon Road Crypto Cache location. MSCREP
LBPNI XHRAM WZKVT RVUEQ WPRGZ LPPLZ GEWYD ZVZEV YBEAW
DNGKC IKMMO MWLZX QIUGW MYZZO HNFXK PZJSR NYYKM MOQWA
CPMNF VNYEH WKOVF NDTFO WBKYG PVHIA MNPDE ZSGYI ZOTPC
Feel free to contact me if you need help or clarification. Sunny ciphering and good luck caching.
Sbe gur pelcgbtenz: Cebonoyr cuenfr vf 'ybpngrq ng'.
Sbe gur pnpur: Ybbx nebhaq gur pbeare sebz gur gbzo bs gur haxabja fbyqvre.
Last Updated: on 12/8/2012 3:32:42 PM (UTC-08:00) Pacific Time (US & Canada) (11:32 PM GMT)
Coordinates are in the WGS84 datum