Le chiffre de Beale / The Beale cipher
ENG : cryptography, Beale Papers, Beale Cipher, book cipher, treasure cipher
FR : cryptographie, chiffre de Beale, papiers de Beale, chiffre dictionnaire, trésor de Beale
The Beale cipher
is a famous irresolute code since more than one century. It is a dictionary code,
i.e. the key which makes it possible to decipher the figure is provided by a text. It is composed
of 3 papers, which I will call C1, C2 and C3. Only C2 was solved: the key text is the Declaration
of Independence of the United States (1776).
I wrote a program in language C which attacks the figure
by systematic test with a list of key texts. This analysis is original for two reasons; firstly
the texts key come from Internet and largely from the
Gutenberg Project, which provides a great
quantity of free texts; secondly an algorithm makes it possible to detect the clear words in a
deciphered text, to replace the aptitude of a human reader to discriminate between a random
text and a comprehensible text. Thus C2, which comprises faults of retranscription, is
understood to approximately 60% by the algorithm; in comparison a random text is understood
to 33% and one comprehensible text with 90%. The totality of the process reproduces the mechanism
of research of a person wanting to attack the code by test with all the texts at its disposal and
while controlling that the text obtained has a direction. This tiresome research which took months
and months in 1900 takes a few hours today.
For the moment, more than 8000 complete texts
of English language were tested on C1 and C3, without positive results. It very probable that
the key text is not a text running or is published. In spite of the strong presumptions to
the Beale cipher is a hoax
, this research is justified by work of Carl Hammer
that the figures C1 and C3 have all the characteristics of a true cipher.
More details in french.
"Signature Simulation and Certain Cryptographic Codes"
Hammer, Communications of the ACM, 14 (1), January 1971, pp. 3-14.
Washington : Computer Services UNIVAC.
A basic probe of the beale cipher as a bamboozlement - PART I.
Louis Kruh, Cryptologia, 6 (4) 378-382 (1982)
The history of book ciphers
Albert C.Leighton and Stephen M. Matyas
THE Beale Papers,
CONTAINING AUTHENTIC STATEMENTS
REGARDING THE TREASURE BURIED IN 1819 AND 1821,
NEAR BUFORDS, IN BEDFORD COUNTY, VIRGINIA,
AND Which Has Never Been Recovered.
LYNCHBURG: Virginian Book and Job Print, 1885.
Entered according to act of Congress, in the year 1885, by J. B. Ward,
in the Office of the Librarian of Congress, at Washington.
Ayrinhac Simon - 2007