AB Cipher
AB Cipher is compatible with Snow Leopard (10.6) and higher.

Brief Description:
AB Cipher is based on a method used by Sir Francis Bacon to encipher messages. His method was published in "De Augmentis Scientarium" in 1623 and described by Jason Fagone in his book about Elizebeth Friedman (and her husband, William) in "The Woman Who Smashed Codes".

When you launch AB Cipher you see the AB Cipher Window which is used to encipher and decipher Secret Messages in a Host Message.


On the left half you see controls for enciphering messages and on the right half you see controls for deciphering messages.


Let's encipher a simple message. You can type or paste a message in the top left field, or click the "Load Test Message" button to use the Test Message. Above you see that the User clicked on the "Load Test Message" and the Test Message (Send Money) has been added to the Secret Message field. The "Delete" button can be used to clear the field and start over.

Each letter in the Secret Message is translated to a five letter group composed of a's and b's using the following Translation Table:


Notice that the letters "i" and "j" are combined and the letters "u" and "v" are combined.

So, the word "To" is translated into "baaba abbab". A space is placed between groups to make it easy to tell where a group starts and stops.

Each letter in a group indicates if the Host Message letter is to be
italicized or not. An "a" indicates that the Host Message letter is to be Normal and a "b" indicates that the Host Message letter is to be italicized.

Secret and Host Messages may use upper/lower case letters, commas, periods and spaces.
Commas, periods, and spaces are ignored.


Above you see the User clicked the "Make AB Format" button to display the AB groups for Send Money. The Secret Message has nine letters so nine AB groups are generated.


Above you see that the User clicked the "Load Test Host" button. Noticee that there is a message to the right saying that the Host Message is too short because each Secret Message letter requires at least five Host Message letters.


Above you see that the User added a few words to the Host Message and now the warning is gone.


Above you see the enciphered Host Message.


Above you see that the User wants to decipher the same message so the enciphered Host Message is pasted into the top right hand field.


Above you see that the User clicked on the "Make AB Format" button and the AB Groups are displayed.


Finally, you can see the User clicked on the "Decipher Message" button and the Deciphered Message is displayed. The three A's at the end of the Secret Message are a result of the Host Message being slightly longer than necessary.

here to download Version 1.0.0 (1.6 MB) for Macintosh OS 10.6 or later (zip).