Bacon's cipher

From Wikipedia, the free encyclopedia
Jump to: navigation, search


Cipher details[edit]

To encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'. This replacement is a binary encoding and is done according to the alphabet of the Baconian cipher, shown below.

a   AAAAA   g     AABBA   n    ABBAA   t     BAABA
b   AAAAB   h     AABBB   o    ABBAB   u-v   BAABB
c   AAABA   i-j   ABAAA   p    ABBBA   w     BABAA
d   AAABB   k     ABAAB   q    ABBBB   x     BABAB
e   AABAA   l     ABABA   r    BAAAA   y     BABBA
f   AABAB   m     ABABB   s    BAAAB   z     BABBB

Note: A second version of Bacon's cipher uses a unique code for each letter. In other words, I and J each has its own pattern.





Baconian cipher example[edit]

The word 'steganography', encoded with padding, where text in italics represents "typeface 2" and standard text represents "typeface 1":

To encode a message each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'.

Bacon and Shakespeare[edit]

Some people have suggested that the plays attributed to William Shakespeare were in fact written by Francis Bacon, and that the published plays contain enciphered messages to that effect. Both Ignatius L. Donnelly and Elizabeth Wells Gallup attempted to find such messages by looking for the use of Bacon's cipher in early printed editions of the plays.

However, American cryptologists William and Elizebeth Friedman refuted the claims that the works of Shakespeare contain hidden ciphers that disclose Bacon's or any other candidate's secret authorship in their The Shakespeare Ciphers Examined (1957).


  1. ^ Helen Fouché Gaines, Cryptanalysis: a Study of Ciphers and Their Solutions (1989), page 6]
  2. ^ Biliteral can mean: "written in two different scripts", Oxford English Dictionary

Further reading[edit]

External links[edit]