Keep Talking and Nobody Explodes Mod Rozier CM

On the Subject of the Rozier CM

A machine that knows no bounds when it comes to ciphers.

The table on page 2 will be referred to as the Tabula Recta.

If the Submit Button is white, follow the instructions under Encrypt Instructions. Otherwise follow the instructions under Decrypt Instructions.

Encrypt Instructions

  • Use the Nth letter of the encrypted word as the column in the Tabula Recta.
  • Find the Nth letter of the keyword on screen 1 within the column.
  • Find the (N + 1)th letter of the keyword on screen 1 within the row.
  • The column you ended up on becomes your Nth decrypted word.

Decrypt Instructions

  • Use the Nth letter of the encrypted word as the column in the Tabula Recta.
  • Find the (N + 1)th letter of the keyword on screen 1 within the column.
  • Find the Nth letter of the keyword on screen 1 within the row.
  • The column you ended up on becomes your Nth decrypted word.

Do this for each letter of the encrypted word and the keyword to get your decrypted word.

When you reach the end of the keyword, treat it as if it wraps around to the beginning of the keyword.

Example 1

Encrypted Word: LWOX
Keyword: WOMAN
Using Encrypt Rules

L + WO → D
W + OM → U
O + MA → C
X + AN → K

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Keep Talking and Nobody Explodes Mod Rozier CM

Example 2

Encrypted Word: NDYJ
Keyword: CAP
Using Decrypt Rules

N + CA → P
D + AP → O
Y + PC → L
J + CA → L

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZA
BCDEFGHIJKLMNOPQRSTUVWXYZAB
CDEFGHIJKLMNOPQRSTUVWXYZABC
DEFGHIJKLMNOPQRSTUVWXYZABCD
EFGHIJKLMNOPQRSTUVWXYZABCDE
FGHIJKLMNOPQRSTUVWXYZABCDEF
GHIJKLMNOPQRSTUVWXYZABCDEFG
HIJKLMNOPQRSTUVWXYZABCDEFGH
IJKLMNOPQRSTUVWXYZABCDEFGHI
JKLMNOPQRSTUVWXYZABCDEFGHIJ
KLMNOPQRSTUVWXYZABCDEFGHIJK
LMNOPQRSTUVWXYZABCDEFGHIJKL
MNOPQRSTUVWXYZABCDEFGHIJKLM
NOPQRSTUVWXYZABCDEFGHIJKLMN
OPQRSTUVWXYZABCDEFGHIJKLMNO
PQRSTUVWXYZABCDEFGHIJKLMNOP
QRSTUVWXYZABCDEFGHIJKLMNOPQ
RSTUVWXYZABCDEFGHIJKLMNOPQR
STUVWXYZABCDEFGHIJKLMNOPQRS
TUVWXYZABCDEFGHIJKLMNOPQRST
UVWXYZABCDEFGHIJKLMNOPQRSTU
VWXYZABCDEFGHIJKLMNOPQRSTUV
WXYZABCDEFGHIJKLMNOPQRSTUVW
XYZABCDEFGHIJKLMNOPQRSTUVWX
YZABCDEFGHIJKLMNOPQRSTUVWXY
ZABCDEFGHIJKLMNOPQRSTUVWXYZ
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Keep Talking and Nobody Explodes Mod Rozier CM

Alternative Method

If the Submit Button is white, follow the instructions under Encrypt Instructions. Otherwise follow the instructions under Decrypt Instructions.

Encrypt Instructions

  • Take the sum of the alphabetic position (A1Z26) of the Nth letter of the encrypted word and X.
  • X is equal to the alphabetic position (A1Z26) of the (N + 1)th letter of the keyword on screen 1, minus the alphabetic position (A1Z26) of the Nth letter of the keyword.
  • If the resulting number falls out of the range of 1 - 26, add/subtract 26 until it is.
  • Turn the number back into a letter to get your Nth decrypted word (A1Z26).

Decrypt Instructions

  • Subtract the alphabetic position (A1Z26) of the Nth letter of the encrypted word by X.
  • X is equal to the alphabetic position (A1Z26) of the (N + 1)th letter of the keyword on screen 1, minus the alphabetic position (A1Z26) of the Nth letter of the keyword.
  • If the resulting number falls out of the range of 1 - 26, add/subtract 26 until it is.
  • Turn the number back into a letter to get your Nth decrypted word (A1Z26).
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Keep Talking and Nobody Explodes Mod Rozier CM

Example 1

Encrypted Word: LWOX
Keyword: WOMAN
Using Encrypt Rules

L + (O - W) → 4 → D
W + (M - O) → 21 → U
O + (A - M) → 5 → C
X + (N - A) → 37 - 26 → 11 → K

Decrypted Word: DUCK

Example 2

Encrypted Word: NDYJ
Keyword: CAP
Using Decrypt Rules

N - (A - C) → 16 → P
D - (P - A) → -11 + 26 → 15 → O
Y - (C - P) → 38 - 26 → 12 → L
J - (A - C) → 12 → L

Decrypted Word: POLL

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