 ## On the Subject of The Inverted Forest Cipher

Trees, shrubs, wildlife and ... rotations?

On the module, you will see 3 screens, a keyboard, 2 arrows, and a submit button that displays the current page you’re on.

Pressing the right arrow takes you to the next page. Pressing the left arrow takes you to the previous page. There is a total of 2 pages.

Once you finally have your deciphered word, you can submit it. Once you start typing, all the screens will go black and the bottom screen will show what you are typing.

To clear it, just click one of the arrows. This goes to one of the pages and clears any input you put in. It will not let you go over 6 letters on input.

Once you are satisfied with your input, press the button labeled "SUB" to submit your answer. On a strike, the module will go back to the first page of the module, but it does not regenerate.

### Step 1: Monoalphabetic Rubik’s Cube Cipher

This step uses the encrypted word from the top screen on page 1 and the keywords on the middle (keyword A) and bottom (keyword B) screens on page 2.

First, create an alphabet key from keyword A. Append the full alphabet to it, then remove all duplicate letters (retain first occurrences).

Create two 3×3×3 cubes. The first, cube A, should be filled with letters A–Z as shown in the diagrams below (note that the center cubelet is omitted). The second, cube B, must be filled with the alphabet key in the order in which the below diagrams have the letters KENVMPABCDFGHIJLOQRSTUWXYZ. (Mnemonic: fill the face centers first in the below order, then the rest of front, middle and back layers in reading order as seen from the front.)

For each letter of keyword B, perform one of the below rotations on cube B (meaning: cycle the eight highlighted letters in the indicated direction, which is always clockwise when looking toward the relevant face of the cube) a number of times as given by the table underneath.

 Letter from keyword B Number of cycles AEIMQUY BFJNRVZ CGKOSW DHLPTX 1 3 5 7

Finally, find each letter of the encrypted word in cube A and replace it with the letter in the same position in cube B. When completed, you obtain a new encrypted word.

#### Example

Encrypted word: IJNCIM
Keyword A: REVEALED → key: REVALDBCFGHIJKMNOPQSTUWXYZ
Keyword B: MATE → rotations: 1×B, 1×U, 7×L, 1×F

I → H
J → C
N → V
C → F
I → H
M → L

New Encrypted Word: HCVFHL

### Step 2: Semaphore Rotation Cipher

For this step, you need the encrypted word obtained from step 1 and the keyword from the top screen on page 2.

Convert each letter of the encrypted word to semaphores using the table below. Then rotate each letter clockwise by 45° times the alphabetic position of the corresponding letter in the keyword.

 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Convert the result from semaphores back into a letter.

#### Example

Encrypted word: HCVFHL; keyword: MARSHY

 H C V F H L M585° A45° R810° S855° H360° Y1125° Z K M I H R

New Encrypted Word: ZKMIHR

### Step 3: Chain Bit-Rotation Cipher

For this step, you will need the encrypted word from step 2 and the keyword on the bottom screen on page 1. If the keyword is shorter than 6 letters, append a repetition of it to it.

Carry out the following steps for every letter of the encrypted word in backwards order (right to left):

• Convert the letter to a 5-digit binary number (A = 00001 ... Z = 11010). Append these 5 bits to the end of the number (or start with this 5-bit number if this is the first iteration).
• Cycle the number to the left by m bits. Here, m is the alphabetic position of the letter in the keyword in the same position. (Make sure to cycle all bits including leading zeros; you’re always cycling a multiple a 5 bits.)

Now convert the number back into 6 letters by repeating the following process:

• Take the number modulo 26. This yields the alphabetic position of the next decrypted letter. If the result is 0, your next letter is Z.
• Divide the number by 26, rounding down.

Ignore any surplus after 6 iterations. Finally, reverse the decrypted word.

#### Example

Encrypted word: ZKMIHR; keyword: QUARTERS

Append R=10010, cycle left by E=5: 10010
Append H=01000, cycle left by T=20: 1001001000
Append I=01001, cycle left by R=18: 100100001001100
Append M=01101, cycle left by A=1: 00100001001100011011
Append K=01011, cycle left by U=21: 1011001000010011000110110
Append Z=11010, cycle left by Q=17: 001101101101010110010000100110

229991462 % 26 = 12 = L | 229991462 / 26 = 8845825
8845825 % 26 = 1 = A | 8845825 / 26 = 340224
340224 % 26 = 14 = N | 340224 / 26 = 13085
13085 % 26 = 7 = G | 13085 / 26 = 503
503 % 26 = 9 = I | 503 / 26 = 19
19 % 26 = 19 = S

LANGIS → reverse → Decrypted Word: SIGNAL