Code 50 : Bacon Code

Bacon Code

Background

Sir Francis Bacon (* 1561; † 1626) developed a method to encode a secret message in such a way, that it does not even appear as a message to an outsider. This is called steganography, the science of hiding information.

Principle

Each character from the plaintext is encoded by a word composed of 5 characters. This word only contains the characters a and b.

Plaintext	Code		Plaintext	Code		Plaintext	Code
A	aaaaa		I/J	abaaa		R	baaaa
B	aaaab		K	abaab		S	baaab
C	aaaba		L	ababa		T	baaba
D	aaabb		M	ababb		U/V	baabb
E	aabaa		N	abbaa		W	babaa
F	aabab		O	abbab		X	babab
G	aabba		P	abbba		Y	babba
H	aabbb		Q	abbbb		Z	babbb

Tab. 1: Bacon encryption

The word "SECRET" for example, would be encoded like this:
"baaab aabaa aaaba baaaa aabaa baaba"
Now, a sentence is formed which serves as inconspicuous carrier of the message and the code is hidden in this message. Many alternatives are possible. One possibility would be to write capital letters for letters which represent a coded "a".The message could be hidden in the sentence "So I never meant to cause you trouble" in such a way:
baaab aabaa aaaba baaaa aabaa baaba 
sOINe VErME ANTtO cAUSE YOuTR oUBlE
sO I NeVEr MEANT tO cAUSE YOu TRoUBlE
Another possibility which would be much more inconspicuous but also requires more creativity, would be to encode an a by a word with the starting characters A-K and a b by a word with the starting characters L-Z. According to this principle, we could encode the message "SECRET" like this:
"Let Ana and Britta stay at home. They are ill and can’t go to Daphne’s party. Don’t be angry girls, it is really better, and we can go there alone."

 

Security

As soon as the principle is known, security is practically nonexistent. The purpose of this method is to hide the fact that a text even contains an important message so that no outsider would even try to search for the hidden message. This is achieved by hiding the message inside a meaningful sentence, which does not appear to be suspicious. On the other hand, this method could also be used to spread false information by hiding the message "we will attack from the north" in a sentence, which implies that the actual attack will happen from the south.

Weblinks

http://shakespeareauthorship.com/bacpenl.html (Englisch)