GF JB HC SUVCO CHOSCFCWU ENNAEKT
CDX PUJWA XNK UQYNE LJEL, NAYU XUN
OTF OPEE JFPYNEY GRMCYZXX WXITU
WPWE YFELW OTF.
One way to encrypt a secret message is to use a Date Shift Cipher.This cipher has the same advantage that keyword ciphers have. It results in random letter substitutions and the date key can be changed as often as needed.
First you need a date. The date to use in this puzzle is found on the plaque near a big oak tree near the parking coordinates. Another way to find this date is to look behind this document, or if you know when Western Australia was founded, you can work it out because the plaque at the old oak tree was planted for WA's sesquicentennial celebrations. The date you need is in the format MonthMonthYearYearYearYear so you get a six digit number. Dont forget to put a zero first if the month is only a single digit.
To help you decipher the code, write out the alphabet from left to right.
Above the code, write your six digit number over and over until you come to the end.
Now shift each letter of the code by the number of spaces indicated above it, TO THE LEFT. Note that for example if A shifts,you wrap around back to Z continuing to count to the left.
Write these deciphered letters below the code and the coordinates should appear.
The cache is a nano camouflaged in a larger outer. Please bring your own writing instrument.
You can check your answers for this puzzle on GeoChecker.com.