## On the Subject of the Chaocipher CM

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

Create a key using the keyword on screen 1 and the Boolean Expression on screen A. This will be referred to as Key A.

Create a key using the keyword on screen 2 and the Boolean Expression on screen B. This will be referred to as Key B.

Write Key A above Key B and place an asterisk above the 14th letter of the keys.

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

#### Encrypt Instructions

• Find the Nth letter of the encrypted word in Key A. This will be called Character A.
• Replace it with the letter in Key B. This will be called Character B.
• Shift Key A so that the last letter of the key is Character A. Take out the 3rd letter of Key A and place it back in at the position of the asterisk.
• Shift Key B so that the 1st letter of the key is Character B. Take out the 2nd letter of Key B and place it back in at the position of the asterisk.

#### Decrypt Instructions

• Find the Nth letter of the encrypted word in Key B. This will be called Character B.
• Replace it with the letter in Key A. This will be called Character A.
• Shift Key A so that the last letter of the key is Character A. Take out the 3rd letter of Key A and place it back in at the position of the asterisk.
• Shift Key B so that the 1st letter of the key is Character B. Take out the 2nd letter of Key B and place it back in at the position of the asterisk.

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

#### Example 1

Encrypted Word: MFBGY
Key A: BARGINCDEFHJKLMOPQSTUVWXYZ
Key B: BCFGHJKLOPQRSUVWXYZDEMNTIA
Using Encrypt Rules

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

M → V

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

F → O

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

B → I

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

G → C

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

Y → E

Decrypted Word: VOICE

#### Example 2

Encrypted Word: SZFZZ
Key A: ABCDEFGHJKMNOPQSUVWXYZTRIL
Key B: GUESTABCDFHIJKLMNOPQRVWXYZ
Using Decrypt Rules

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

S → D

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

Z → A

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

F → N

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

Z → C

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

Z → E

Decrypted Word: DANCE