Bacon's cipher
Encyclopedia
Bacon's cipher or the Baconian cipher is a method of steganography
(a method of hiding a secret message as opposed to a true cipher
) devised by Francis Bacon
. A message is concealed in the presentation of text, rather than its content.
is replaced by a group of five of the letters 'A' or 'B'. This replacement 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.
The writer must make use of two different typeface
s for this cipher. After preparing a false message with the same number of letters as all of the As and Bs in the real, secret message, two typefaces are chosen, one to represent As and the other Bs. Then each letter of the false message must be presented in the appropriate typeface, according to whether it stands for an A or a B.
To decode the message, the reverse method is applied. Each "typeface 1" letter in the false message is replaced with an A and each "typeface 2" letter is replaced with a B. The Baconian alphabet is then used to recover the original message.
Any method of writing the message that allows two distinct representations for each character can be used for the Bacon Cipher.
Bacon himself prepared a Biliteral Alphabet for handwritten capital and small letters with each having two alternative forms, one to be used as A and the other as B. This was published as an illustrated plate in his De Augmentis Scientiarum (The Advancement of Learning).
Because any message of the right length can be used to carry the encoding, the secret message is effectively hidden in plain sight. The false message can be on any topic and thus can distract a person seeking to find the real message. Many people still use Bacon's cipher today.
To encode a message each letter of the plaintext is replaced by a group of five of the letters'A' or 'B' .
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
disproved 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).
Steganography
Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message, a form of security through obscurity...
(a method of hiding a secret message as opposed to a true cipher
Cipher
In cryptography, a cipher is an algorithm for performing encryption or decryption — a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. In non-technical usage, a “cipher” is the same thing as a “code”; however, the concepts...
) devised by Francis Bacon
Francis Bacon
Francis Bacon, 1st Viscount St Albans, KC was an English philosopher, statesman, scientist, lawyer, jurist, author and pioneer of the scientific method. He served both as Attorney General and Lord Chancellor of England...
. A message is concealed in the presentation of text, rather than its content.
Cipher details
To encode a message, each letter of the plaintextPlaintext
In cryptography, plaintext is information a sender wishes to transmit to a receiver. Cleartext is often used as a synonym. Before the computer era, plaintext most commonly meant message text in the language of the communicating parties....
is replaced by a group of five of the letters 'A' or 'B'. This replacement 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.
The writer must make use of two different typeface
Typeface
In typography, a typeface is the artistic representation or interpretation of characters; it is the way the type looks. Each type is designed and there are thousands of different typefaces in existence, with new ones being developed constantly....
s for this cipher. After preparing a false message with the same number of letters as all of the As and Bs in the real, secret message, two typefaces are chosen, one to represent As and the other Bs. Then each letter of the false message must be presented in the appropriate typeface, according to whether it stands for an A or a B.
To decode the message, the reverse method is applied. Each "typeface 1" letter in the false message is replaced with an A and each "typeface 2" letter is replaced with a B. The Baconian alphabet is then used to recover the original message.
Any method of writing the message that allows two distinct representations for each character can be used for the Bacon Cipher.
Bacon himself prepared a Biliteral Alphabet for handwritten capital and small letters with each having two alternative forms, one to be used as A and the other as B. This was published as an illustrated plate in his De Augmentis Scientiarum (The Advancement of Learning).
Because any message of the right length can be used to carry the encoding, the secret message is effectively hidden in plain sight. The false message can be on any topic and thus can distract a person seeking to find the real message. Many people still use Bacon's cipher today.
Baconian Cipher Example
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
Bacon and Shakespeare
Some people have suggested that the plays attributed to William ShakespeareWilliam Shakespeare
William Shakespeare was an English poet and playwright, widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's national poet and the "Bard of Avon"...
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
Elizabeth Wells Gallup
Elizabeth Wells Gallup was an American educator and exponent of the Baconian theory of Shakespearian authorship....
attempted to find such messages by looking for the use of Bacon's cipher in early printed editions of the plays.
However, American cryptologists
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
William
William F. Friedman
William Frederick Friedman was a US Army cryptographer who ran the research division of the Army's Signals Intelligence Service in the 1930s, and parts of its follow-on services into the 1950s...
and Elizebeth Friedman
Elizebeth Friedman
Elizebeth Smith Friedman was a cryptanalyst and author, and a pioneer in U.S. cryptography. The special spelling of her name is attributed to her mother, who disliked the prospect of Elizebeth ever being called "Eliza." She has been dubbed "America's first female cryptanalyst".Although she is...
disproved 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).
Further reading
- Francis Bacon's Ciphers at the Philosophical Research SocietyPhilosophical Research SocietyThe Philosophical Research Society is an American nonprofit organization founded in 1934, by the prolific author and scholar Manly Palmer Hall, which provides learning and development of a philosophy of life which embraces conciliation of religion and science and higher understandings of life...
website. - William Friedman and Elizabeth Friedman, The Shakespearian ciphers examined, Cambridge University PressCambridge University PressCambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...
, 1957