## On the Subject of the Hill CM

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

The 2 numbers on screen 1 are labeled A and B and the 2 numbers on screen 2 are labeled C and D

If the Submit Button is white, use Matrix A. Otherwise, use Matrix B.

Split the encrypted word into pairs of letters. If there is an odd amount of letters, leave the last letter as the odd letter.

Turn each pair of letters into its alphabetic position (A1Y25Z0).

Take each pair of numbers and do the following:

- Multiply the 1st number with the top left number of the matrix.
- Multiply the 2nd number with the top right number of the matrix.
- Sum the 2 numbers together, modulo 26, and turn it back to a letter (A1Y25Z0).
- Do the same 3 steps using the 1st number with the bottom left number of the matrix and the 2nd number with the bottom right number of the matrix.
- You should have a decrypted pair of letters.

#### Matrix A

A | B |

C | D |

#### Matrix B

Ai | Bi |

Ci | Di |

The instructions to determine Ai, Bi, Ci, and Di are written on the next pages.