## On the Subject of the Stunted Blind Polybius CM

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

The following diagrams will be used:

 1 2 3 4 1 2 3 4
 ? ? ? ? ? ? ? ?

Create a key using the keyword on screen 1 and the Boolean Expression on screen A using the letters between A–P, discarding the letters between Q–Z. Fill in the Stunted Polybius square (left) with the key you made in reading order.

Label the rows and columns of the Blind Polybius Square (right). The columns are labeled with numbers 1–4 in an order based on the first 4 letters of the keyword on screen 1. Label these letters 1–4 in alphabetical order. In case of recurring letters, label those from left to right. Proceed similarly to label the rows with numbers 1–4 in an order based on the last 4 letters of the keyword.

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

#### Encrypt Instructions

• Write the encrypted word in Unified English Braille (using only single-letter codes, no shortcuts). Stack the Braille patterns on top of one another.
• Convert the first X×2 rows of dots, one 2×2 tile at a time, to new letters. X is equal to the length of the encrypted word.
• Find each 2×2 tile in the Blind Polybius Square and observe its row and column labels, then find the new letter in the Stunted Polybius Square using the matching row and column numbers.
• Observe the right column of dots in the last X rows. For each filled dot, Caesar-shift the new letter in the same position forward by 13 (ROT-13).

#### Decrypt Instructions

• Concatenate the encrypted word with the letters on screen 2 in that order.
• Find the Nth letter of the encrypted word in the Stunted Polybius Square and determine its row and column.
• Then find the dot pattern in the Blind Polybius Square using the matching row and column numbers.
• Stack the dot patterns on top of one another, then re-divide them into blocks of three rows each, and read the result as Unified English Braille to obtain the decrypted word.

#### Example 1

Encrypted Word: KSDVI
Keyword: REFERRED
Using Encrypt Rules

 1 2 3 4 1 A B C G 2 H I J K 3 L M N O 4 P E F D
 4 1 3 2 3 4 2 1

K →
S →
D →
V →
I →

→ R3C1 → L
→ R2C1 → H
→ R4C1 → P
→ R2C2 → I
→ R4C4 → D

LHPID + 01100 → LUCID

Decrypted Word: LUCID

#### Example 2

Encrypted Word: JCOPNF
Keyword: PROVIDED
Using Decrypt Rules

 1 2 3 4 1 A B C F 2 G H J K 3 L M N P 4 O I D E
 2 3 1 4 4 1 3 2

J → R2C3 →
C → R1C3 →
O → R4C1 →
P → R3C4 →
N → R3C3 →
F → R1C4 →
N → R3C3 →
B → R1C2 →
F → R1C4 →

→ R
→ E
→ N
→ T
→ E
→ R

Decrypted Word: RENTER