## On the Subject of the Differential CM

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

Turn the letter on screen A to a Value via the Value Table, modulo it by the length of the encrypted word. This is your Shift Offset.

Shift the encrypted word to the left a number of times equal to the Shift Offset.

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

#### Encrypt Instructions

- 1: Take the Nth digit on screen 1 and multiply it by 26.
- 2: Then take the alphabetic position (A1Z26) of the (N + 1)th letter of the encrypted word and subtract from it the alphabetic position (A1Z26) of the Nth letter of the encrypted word, modulo 26.
- 3: Sum the 2 numbers you got from steps 1 and 2 to get a 2 digit number. Append this number to any previous digits.
- 4: Repeat steps 1 - 3 for each digit displayed on screen 1.
- 5: Split the string of digits into 2 equal halves, placing the 2nd half of digits under the 1st half.
- 6: Let D be a string of letters, containing only the first letter of the encrypted word.
- 7: Read the Nth column top-to-bottom as a two-digit number.
- 8: Sum the alphabetic position (A1Z26) of the last letter of D and the number you got from step 7, modulo 26, and turn the resulting number into a letter (A1Y25Z0). Append this letter to D.
- 9: Repeat steps 7 - 8 for each column in the digit string.
- 10: Finally, shift the letters in D to the right by the Shift Offset to get your decrypted word.