The Chaocipher Clearing House
Progress Report #22
Upcoming in January 2014 Cryptologia: Kruh and Deavours's
1990 Chaocipher challenge solved
Paper written by Jeff Calof et al describes the history, analysis,
and solution
Chaocipher researchers have puzzled over Cipher Deavours and Lou Kruh's
challenge messages in the July 1990 issue of Cryptologia. Now, at
long last, a paper authored by Jeff Calof (with co-authors Jeff
Hill and Moshe Rubin) entitled "Chaocipher
Exhibit 5: History, Analysis, and Solution of Cryptologia's 1990
Challenge" is scheduled for publication in the January 2014
issue of Cryptologia. Here is the article's abstract:
"Chaocipher is a
method of encryption invented by John F. Byrne in 1918 who, over the
next 40 years, unsuccessfully tried to interest various U.S. Government
Agencies and Private Industries in his cipher system. His 1953
biography included a series of challenge ciphers he labeled Exhibits 1
– 4. In 1990, John Byrne (son of John F. Byrne) revealed and
demonstrated the Chaocipher algorithm to Professor Cipher Deavours and
Louis Kruh. Without revealing the encipherment process, they in turn
published an article including a new series of challenge ciphers they
called Exhibit 5. Twenty-three years later, and three years after the
first public revelation of the Chaocipher algorithm, Exhibit 5 remained
unsolved. Following a 2013 visit to the National Cryptologic Museum
(NCM) in Ft. Meade, Maryland to research the recently donated Byrne
family materials on the Chaocipher, co-author Jeff Calof found two
documents prepared by Deavours & Kruh pertaining to Exhibit 5. One
document provides their encipherment schema and solution for the
published version, while the other is for an earlier draft whose
challenge ciphers differ markedly from that of the published article.
This paper presents a review of Exhibit 5’s creation, an analysis
of the restrictions placed on Deavours and Kruh when writing their
article, their enciphering schema and source material for the published
Exhibit 5, irregularities with the published ciphertext, and an
overview and comparison with their unpublished Exhibit 5 draft and
challenge ciphers."
John F. Byrne's Exhibits 2 and 3 in "Silent Years" are
finally solved!
Finnish math student Esa Peuha discovers the method used to
encipher Exhibits 2 and 3
To date, Chaocipher Exhibits 1 and 4 found in John F.
Byrne's autobiographical "Silent Years" have been
deciphered, analyzed, and written about. It has been found
that they both use the classic Chaocipher algorithm
On the other hand, Exhibits 2 and 3 have eluded Chaocipher
researchers to date. The NSA web site has provided links
to John F. Byrne's Exhibit 2 notes, but researchers were not able
to prove that the exhibit followed the same classical Chaocipher
method used in exhibits 1 and 4. Up until now no one
has been able to explain how they were enciphered.
On 18 September 2013 I received the following email from Esa Peuha, a
Finnish math student:
"I have figured out
how Byrne encrypted Exhibits 2 and 3. The attached file has the
details, but the short version is that only the first 52 letters of
Exhibit 2 are actual Chaocipher, the rest of it and all of Exhibit 3
use a simpler method that switches alphabets after every 52 letters.
Since your article in Cryptologia mentions a document from the National
Cryptologic Museum related to Exhibit 3, I was wondering if you have
scans of it (and any other possibly relevant material) that you would
be willing to share?"
Esa attached a two-page PDF document briefly describing how Chaocipher
Exhibits #2 and #3 were enciphered. It did not take me long to
verify that Esa had indeed cracked the encipherment of both Exhibits 2
and 3. Esa's initial paper showed how Byrne enciphered the
exhibits, making use of Byrne's work sheets found on the NSA web
site, but some more work was required to determine the keywords used to
generate successive alphabets. This information was ultimately
provided by material photographed by Jeff Calof during his recent trip
to the National Cryptologic Museum.
Be sure to read Esa
Peuha's analysis of Exhibits 2 and 3. Here are links pointing
to some of the references in Esa's paper:
Copyright
(c) 2012-2013 Moshe Rubin
Created: 4 October 2013