## On the Subject of the Portax CM

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

If there is a number on screen A, take out the letter at that position in the encrypted word. Set aside this letter to be put back in at a later step. Take the key from screen 1, and write the encrypted word underneath it so that it fits in the columns of the key. This will be referred to as the Portax Grid.

The following cipher table will be referred to as the Portax Table.

ABCDEFGHIJKLM
NOPQRSTUVWXYZNOPQRSTUVWXY
ACEGIKMOQSUWYACEGIKMOQSUW
BDFHJLNPRTVXZBDFHJLNPRTVX

Do the following instructions:

• Move the 1st row of the Portax Table so that the letter A aligns with the letter on the 3rd/4th row that is the same letter as the Nth letter of the 1st row of the Portax Grid.
• Find the Nth letter on the 2nd row of the Portax Grid in the 1st/2nd row that is within the area of the 1st row of the Portax Table.
• Find the Nth letter on the 3rd row of the Portax Grid in the 3rd/4th row that is within the area of the 1st row of the Portax Table.
• If the 2 letters are in the same column, replace the Nth letter on the 2nd row of the Portax Grid with the letter that is above/below the top most letter within the 1st/2nd row of the Portax Table and the replace the Nth letter on the 3rd row of the Portax Grid with the letter that is above/below the bottom most letter within the 3rd/4th row of the Portax Table.
• Otherwise, replace the Nth letter on the 2nd row of the Portax Grid with the letter in the same row as the top most letter but in the same column as the bottom most letter in the Portax Table. And replace the Nth letter on the 3rd row of the Portax Grid with the letter in the same row as the bottom most letter but in the same column as the top most letter in the Portax Table.

Do this with each letters in the 1st, 2nd, and 3rd row of the Portax Grid. Then read the letters in reading order, ignoring the top row of the Portax Grid. If you took out a letter, insert that letter back into position equal to the number on screen A. You should now have an decrypted word.

#### Example

Encrypted Word: PWMEJEF
Key: ZSF
Screen A: 6

PWMEJEF + 6 → PWMEJF

 Z S F P W M E J F
 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z N O P Q R S T U V W X Y A C E G I K M O Q S U W Y A C E G I K M O Q S U W B D F H J L N P R T V X Z B D F H J L N P R T V X
 Z S F D W M F J F
 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z N O P Q R S T U V W X Y A C E G I K M O Q S U W Y A C E G I K M O Q S U W B D F H J L N P R T V X Z B D F H J L N P R T V X
 Z S F D R M F T F
 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z N O P Q R S T U V W X Y A C E G I K M O Q S U W Y A C E G I K M O Q S U W B D F H J L N P R T V X Z B D F H J L N P R T V X
 Z S F D R A F T D

DRAFTD + 6 + E → DRAFTED

Decrypted Word: DRAFTED