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The Rat: This one got more favorites than I expected, but I think it has run its course. I have removed the container.


Route Cipher

A cache by The Rat Send Message to Owner Message this owner
Hidden : 06/23/2011
3.5 out of 5
1.5 out of 5

Size: Size:   micro (micro)

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Geocache Description:

The cache is not at the posted coordinates but is within two miles.

A popular puzzle type that I haven't used in some time is an instructional cipher puzzle. This one is the Route Cipher as used in the American Cryptogram Association (ACA) (except my rectangle is bigger than indicated in the ACA guidelines). There is nothing particularly tricky about it, but it can be quite a bit of work to solve, especially by paper and pencil. There are exactly 48 routes allowed in the ACA: rows, columns, diagonals and spirals. Spirals can be clockwise or counterclockwise, and can start in a corner or near the center. The others can alternate directions (like a snake or "S" path). Here is a description of the cipher.

ACA cipher type: Route

I have appropriately started you at the intersection of Route 85 and Route 82. Solve the Route cipher below and find the cache. In order to solve it you must first reverse the route used to take off the ciphertext. This means first guessing the dimensions of the rectangle. There are several possibilities. Unless you are a programmer who can knock out the code to brute force all rectangle/route possibilities, you have to start trying by writing out the text in various routes in the rectangle you have guessed. The best way to solve a Route is to use a "crib," i.e. a known word in the plaintext, to verify whether the route and rectangle you chose allow for reading the crib via a separate route. I'll give you a head start. The message in the cipher below contains the word FIVE. That's your crib. There is only one V in the ciphertext. So when you start writing the ciphertext into the rectangle, when you come to the V, continue to fill in the rectangle until you have filled in all the squares adjacent to the V. If the adjacent letters do not contain an I and an E then that cannot be the right route/rectangle combination because the word FIVE cannot be read out from that V horizontally, vertically, diagonally, or in a spiral. You can stop and try another route or rectangle size. If there is an adjacent I and E then you have to check the letters adjacent to the I to see if there is an F that follows one of the accepted routes.

Here is the ciphertext:


You can validate your puzzle solution with certitude.

Congratulations to Nylimb on the FTS. Since this isn't getting the usual rush of solutions, I'll add another tip. Every route has a valid reciprocal route that begins at the end point and follows the same route back to the first letter in the first square. This means you can begin at either end of the ciphertext when writing the letters into the rectangle. Starting at the end here will get you to the V sooner and thus reduce the amount of writing necessary to eliminate a bad route.

Additional Hints (No hints available.)

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