Directions for Use
Cut this card in two along the line.
In order to send messages in this cipher, a key-word (or sentence) must be agreed on between the correspondents: this should be carried in the memory only.
To translate a message into cipher, write the key-word, letter for letter, over the message, repeating it as often as may be necessary: slide the message-alphabet along under the other, so as to bring the first letter of the message under the first letter of the key-word, and copy the letter that stands over ‘a’: then do the same with the second letter of the message and second letter of the key-word, and so on.
Translate the cipher back into English by the same process. [T. O.
For example, if the key-word be ‘war,’ and the message ‘meet me at six,’ we write it thus:—
| { | w | a | r | w | a | r | w | a | r | w | a | } | |||
| m | e | e | t | m | e | a | t | s | i | x | |||||
| k | w | n | d | o | n | w | h | z | o | d |
The cipher sent, ‘kwndonwhzod,’ may be re-translated by the same process.
| KEY-ALPHABET. | ||||||||||||||||||||||||||
| 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 | |
| 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 | a |
| MESSAGE-ALPHABET. | ||||||||||||||||||||||||||