Keep Talking and Nobody Explodes Mod Mechanus Cipher

On the Rewording of Mechanus Cipher

Bring a plane of order with this cipher designed to balance the chaos.

Original Manual

The module displays two rows of lettered panels, an extra lettered panel, a submit panel, and two lettered gears.

You can press any of the panels on a row to flip that row. The top row shows an encrypted word, a keyword and a binary string. The bottom row shows two sets of numbers and a second keyword. The items on both rows are displayed in the mentioned order. The extra panel shows a key letter.

To solve the module, decrypt the word following the steps below and submit it using the gears. To submit, press the gears to turn them, and press the submit button when you want to enter the selected letter. You can flip the panels to clear your input.

Step 0 - Creating your key

For steps 2 and 3 you need a key. To make this key, take your keyword from the top row and repeat it until you have 26 letters. Then, for all letters in this string in reading order, if a letter has already occurred previously, shift it forward in the alphabet until this is not the case.

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZ

Example: Setting Up the Key

TROUPER -> TROUPERTROUPERTROUPERTROUP

Marking out letters used in TROUPER:

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZ

Example continues on the next page.

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Example: Setting Up the Key (Continued)

Duplicate Letter Adjustment

TROUPE [R] TROUPERTROUPERTROUP -> TROUPE [S] TROUPERTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN--Q-S--VWXYZ

TROUPES [T] ROUPERTROUPERTROUP -> TROUPES [V] ROUPERTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN--Q----VWXYZ

TROUPESV [R] OUPERTROUPERTROUP -> TROUPESV [W] OUPERTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN--Q-----WXYZ

TROUPESVW [O] UPERTROUPERTROUP -> TROUPESV [Q] UPERTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN--Q------XYZ

TROUPESVWQ [U] PERTROUPERTROUP -> TROUPESVQ [X] PERTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN---------XYZ

⋮

TROUPESVWQXY [E] RTROUPERTROUP -> TROUPESVQXY [F] RTROUPERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCD-FGHIJKLMN-----------Z

⋮

TROUPESVWQXYZABCD [U] PERTROUP -> TROUPESVWQXYZABCD [G] PERTROUP

ABCDEFGHIJKLMNOPQRSTUVWXYZ
------GHIJKLMN------------

⋮

Result after many iterations: TROUPESVWQXYFZABCDGHIJKLMN

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Step 1 - Pancake Transposition

Take your encrypted word from the top row and the two number strings on the bottom row. From the two number strings, pair each digit in the same position to get 7 pairs. For each pair, reverse all letters that are within in those positions. Positions from the pairs of digits are inclusive.

Example: Pancake Transposition

Encrypted Word: EOISDYN Number Strings: 1223236 2456565

1223236 2456565 -> 12 24 25 36 25 36 65

[EO] ISDYN + 12 -> [OE] ISDYN

O [EIS] DYN + 24 -> O [SIE] DYN

O [SIED] YN + 25 -> O [DEIS] YN

OD [EISY] N + 36 -> OD [YSIE] N

O [DYSI] EN + 25 -> O [ISYD] EN

OI [SYDE] N + 36 -> OI [EDYS] N

OIED [YS] N + 65 -> OIED [SY] N

Result: OIEDSYN

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Step 2 - Binary Gear Cipher

Take your encrypted word from previous step, the key from step 0, the key letter on the extra panel and the binary string on the top row. Make a row of your key’s letters and a row of decreasing 4-bit binary numbers starting from 1111 (F). Start at 0000 (0) on the binary row and start at your key letter on the key row. Then move left both rows simultaneously, wrapping around if necessary, until you hit the first letter of your encrypted word. Note down the current value from the binary row upon landing. Repeat this for the other letters, starting from where you just ended. Append all these binary numbers into one big string and split it into four equal groups and set it up as a table.

Obtain seven 4-bit binaries, from left to right, by reading each column of the binary from top to bottom. Starting from the place where you previously ended, move left both rows until you hit this binary. If the first digit of the binary string is a 1, keep moving left until you hit it again. The letter you land on is your new letter. Repeat this movement with the rest of the 4-bit binaries until you receive 7 letters, starting at the ending location of the previous letter and binary.

Example: Binary Gear Cipher

Key From Step 0:

TROUPESVWQXYFZABCDGHIJKLMN

Encrypted word from Step 1: OIEDSYN

Letter on Extra Panel: A

Top Row Binary String: 1100000

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

A -> O = 1100 (C)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

O -> I = 0100 (4)

Example continues on the next page.

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Example: Binary Gear Cipher (Continued)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

I -> E = 0011 (3)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

E -> D = 0001 (1)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

D -> S = 1100 (C)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

S -> Y = 0001 (1)

TROUPESVWQXYFZABCDGHIJKLMN
FEDCBA9876543210

Y -> N = 1101 (D)

Binary obtained: 1100010000110001110000011101

Split into columns of 4:
1100010
0001100
0111000
0011101

Read in columns from left to right: 1000, 1010, 0011, 0111, 0101 1000, 0001

Example continues on the next page.

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Example: Binary Gear Cipher (Continued)

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

1101 (D) -> 1000 (8), N -> A (1) -> M

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

1000 (8) -> 1010 (A), M -> K (1) -> S

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

1010 (A) -> 0011 (3), S -> L (0) -> L

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

0011 (3) -> 0111 (7), L -> H (0) -> H

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

0111 (7) -> 0101 (5), H -> E (0) -> E

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

0101 (5) -> 1000 (8), E -> O (0) -> O

FEDCBA9876543210
TROUPESVWQXYFZABCDGHIJKLMN

1000 (8) -> 0001 (1), O -> H (0) -> H

Result: MSLHEOH

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Keep Talking and Nobody Explodes Mod Mechanus Cipher

Step 3 - Strangely Elusive Letter Cipher

Take your encrypted word from previous step, the key from step 0 and the keyword on the bottom row. Append a # at the end of the key, and create a 3×3×3 grid by splitting the key into 3 groups, and creating 3 squares consisting of the letters in those groups in reading order. Pair each letter in the keyword with each letter in the encrypted word and follow the procedure here to get your decrypted word:

  1. Obtain their positions corresponding to where the letter is in the grid. X will refer to the row of the square the letter is found in, Y being the column of the square the letter is found in, and Z being the actual square found in. For convenience, the left-most column is 1 for X, the top-most row is 1 for Y, and the first square consisting of those 9 letters is 1 for Z.
  2. Compare the values of X, Y, and Z, as a group, to obtain the position of the decrypted letter.
    • If the 2 values corresponding to that group is distinct, the decrypted letter will have a third value in that group.
    • Otherwise, the decrypted letter will have the same value in that group.
  3. If the letter obtained in that position is #, use the encrypted letter as the decrypted letter instead.

Example: Strangely Elusive Letter Cipher

Encrypted Word: MSLHEOH
Keyword: CHIMERA
Grid used:

z=1z=2z=3
TROQXYGHI
UPEFZAJKL
SVWBCDMN#

M + C -> (3,1,3); (3,2,2) -> (3,3,1) -> W
S + H -> (3,1,1); (1,2,3) -> (2,3,2) -> A
L + I -> (1,3,3); (2,3,3) -> (3,3,3) -> # -> L
H + M -> (1,2,3); (3,1,3) -> (2,3,3) -> L
E + E -> (2,3,1); (2,3,1) -> (2,3,1) -> E
O + R -> (1,3,1); (1,2,1) -> (1,1,1) -> T
H + A -> (1,2,3); (2,3,2) -> (3,1,1) -> S
Decrypted word: WALLETS

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