## On the Subject of the M-209 CM

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

This cipher uses 2 pages.

Create an M-209 machine by following the instructions below:

• 1: Write down 16 zeros for row 1, 13 zeros for row 2, 11 zeros for row 3, 9 zeros for row 4, 7 zeros for row 5, and 5 zeros for row 6.
• 2: For each letter on page 1 screen 1, replace the zero with a one with at row 1, at the column equal to the alphabetic position of the letter (A1Z26).
• 3: Repeat step 2 for row 2 using the letters on page 1 screen 2.
• 4: Repeat step 2 for row 3 using the letters on page 1 screen 3.
• 5: Repeat step 2 for row 4 using the letters on page 1 screen 4.
• 6: Repeat step 2 for row 5 using the letters on page 2 screen 1.
• 7: Repeat step 2 for row 6 using the letters on page 2 screen 2.
• 8: For each letter on page 2 screen 3, shift the Nth row to the left, equal to the alphabetic position of the Nth letter, minus 1 (A0Z25).
• 9: Turn each character on pages 1 and 2, screens A–D into a row/col pair using the table below.
• 10: For each row, the offset for the Nth row is equal to the number of N numbers you got from the previous step.

For each letter of the encrypted word, do the following:

• Subtract 27 by the alphabetic position of the Nth letter of the encrypted word (A1Z26).
• For each row of the M-209 machine, if the left most digit is a 1, add the offset of that row to the number.
• If the number is greater than 26, subtract 26 until it is between 1–26.
• Convert the number back to a letter to get your Nth decrypted letter (A1Z26).
• Shift all the rows of the M-209 machine to the left one.
123456
1ABCDEF
2GHIJKL
3MNOPQR
4STUVWX
5YZ0123
6456789

#### Example

Encrypted Word: GARSF
Page 1 Screen 1: BEGHKMNO
Page 1 Screen 2: ACDGHKM
Page 1 Screen 3: BEHIK
Page 1 Screen 4: BCFGI
Page 2 Screen 1: ADFG
Page 2 Screen 2: ACD
Page 2 Screen 3: FGJCFD
Pages 1–2 Screens A–D: JR7DHP5XJ5RIZXT

 0 1 0 0 1 0 1 1 0 0 1 0 1 1 1 0 1 0 1 1 0 0 1 1 0 0 1 0 1 0 1 0 0 1 0 0 1 1 0 1 0 1 1 0 0 1 1 0 1 1 0 0 1 0 1 1 1 0 1 1 0

Shifting the rows: FGJCFD

 0 1 1 0 0 1 0 1 1 1 0 0 1 0 0 1 1 1 0 0 1 0 1 1 0 1 1 0 0 0 1 0 1 0 0 1 0 0 1 1 1 0 0 1 1 0 1 0 1 1 1 1 0 0 1 0 1 0 1 0 1

JR7DHP5XJ5RIZXT → 426364142234266442626332254624

 1: 9: 4: 8: 1: 7: 0 1 1 0 0 1 0 1 1 1 0 0 1 0 0 1 1 1 0 0 1 0 1 1 0 1 1 0 0 0 1 0 1 0 0 1 0 0 1 1 1 0 0 1 1 0 1 0 1 1 1 1 0 0 1 0 1 0 1 0 1

G → 27 - 7 → 20 + 9 + 8 + 1 + 7 → 45 - 26 → 19 → S

 1: 9: 4: 8: 1: 7: 1 1 0 0 1 0 1 1 1 0 0 1 0 0 1 0 1 0 0 1 0 1 1 0 1 1 0 0 1 1 0 1 0 0 1 0 0 1 1 0 0 0 1 1 0 1 0 1 1 1 1 0 0 1 0 1 0 1 0 1 1

A → 27 - 1 → 26 + 1 + 9 + 4 + 1 → 41 - 26 → 15 → O

 1: 9: 4: 8: 1: 7: 1 0 0 1 0 1 1 1 0 0 1 0 0 1 0 1 0 0 1 0 1 1 0 1 1 0 0 1 1 0 1 0 0 1 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 1 0 0 1 0 1 1 1 0 1 1 0

R → 27 - 18 → 9 + 1 + 1 + 7 → 18 → R

 1: 9: 4: 8: 1: 7: 0 0 1 0 1 1 1 0 0 1 0 0 1 0 1 1 0 1 0 1 1 0 1 1 0 0 1 1 0 1 0 0 1 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 0 0 0 1 0 1 1 1 0 1 1 0 1

S → 27 - 19 → 8 + 4 + 8 → 20 → T

 1: 9: 4: 8: 1: 7: 0 1 0 1 1 1 0 0 1 0 0 1 0 1 1 0 1 0 1 1 0 1 1 0 0 1 1 0 0 0 0 1 0 0 1 1 0 1 0 1 1 0 1 0 1 1 0 0 1 0 1 0 1 1 1 0 1 1 0 1 0

F → 27 - 6 → 21 + 9 + 8 + 7 → 45 - 26 → 19 → S

Decrypted Word: SORTS