Spiromania #43
This is a puzzle cache. So the cache is not at the posted coordinates. As is usual in this series the solution will be represented in the shortened UTM format as VKabcdefghij standing for UTM: 15T E 4abcde N 49fghij. As in UTM, abcde is referred to as the easting and fghij as the northing.
To find the cache you must first decrypt this message:
KBUFYFMF601DAD07VRDOT059O
This is an example of a route encryption. The plaintext is written in horizontal lines across a grid, in this case a diamond-shaped grid. Then some other route through the grid is taken to provide the encrypted text. We will use spirals of course. Both the sender and the receiver know the form of the grid as well as the route through it. It is intended to be easy to encrypt in the field and easy to decrypt if you know the details, but not so easy otherwise.
This method is exemplified below. Let the plaintext just be the first 25 letters of the alphabet laid out horizontally. Tracing the inward-directed, counter-clockwise spiral on the left beginning at the top the encrypted message becomes "ABDGKPTWYXVS0JFCEHLQURNIM". Using the spiral on the right beginning in the middle the message would be "MQURNIEHLPTWYXVSOJFCABDGK". In this format how many different spirals are possible? There are four corner points. The spirals can be clockwise or counter-clockwise and inward- or outward-directed. So there are 16 possibilities. But you might find some short-cuts. The empty diamonds in the background might be useful for scratch work. Carry on, MacDuff.
Some small errors may be possible, so round both the easting and the northing to the nearest 5 meters, and enter your solution into the coordinate checker in the form VKabcd5fghi5.
You can validate your puzzle solution with certitude.
Congrats to the first ten solvers:
1. PackADad Thu, 23 Apr 2020 11:16:02
2. pfalstad Thu, 23 Apr 2020 16:34:45
3. salsman Thu, 23 Apr 2020 16:46:44
4. kcmcacher Thu, 23 Apr 2020 17:24:47
5. NYWanderer Thu, 23 Apr 2020 17:53:35
6. foundinthewild Thu, 23 Apr 2020 20:00:41
7. Pippin and Merry Fri, 24 Apr 2020 22:42:15
8. Boreal Walker Mon, 27 Apr 2020 16:05:28
9. kkmk Mon, 27 Apr 2020 20:21:11
10. fish2007 Fri, 1 May 2020 20:16:47