## On the Subject of the Porta CM

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

Do the following instructions:

• Use the Nth letter of the keyword as the row in the table below.
• If the Nth letter of the encrypted word is between A–M, use the letter as the column for the chart. Then the intersection of the row and column of the 2 letters will give you a decrypted letter.
• Otherwise, find the Nth letter of the encrypted word in the same row as the Nth letter of your keyword. The column of that letter will give you a decrypted letter via the A–M row of the chart.

Do this for each letter of the encrypted word and the keyword to get a decrypted word.

If you reach the end of the keyword, treat it as if it wraps around to the beginning of the keyword.

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 O P Q R S T U V W X Y Z N P Q R S T U V W X Y Z N O Q R S T U V W X Y Z N O P R S T U V W X Y Z N O P Q S T U V W X Y Z N O P Q R T U V W X Y Z N O P Q R S U V W X Y Z N O P Q R S T V W X Y Z N O P Q R S T U W X Y Z N O P Q R S T U V X Y Z N O P Q R S T U V W Y Z N O P Q R S T U V W X Z N O P Q R S T U V W X Y

#### Example

Encrypted Word: CBNRRF
Keyword: AMEN

C + A → P
B + M → U
N + E → L
R + N → L
R + A → E
F + M → Y

Decrypted Word: PULLEY