The Chaocipher Clearing House
Progress Report #9
Hill submits research paper entitled "Chaocipher: Analysis and Models"A
few days ago Jeff Hill submitted another, more recent, internal paper
of his entitled "Chaocipher: Analysis and Models". This paper is
mandatory reading for anyone interested in Chaocipher research.
In his thorough, clear, and original manner, Jeff gives a clear
summary of observed Chaocipher phenomena. He follows up with an
incisive analysis of these phenomena in terms of Markov processes,
which leads him to propose several original and thought-provoking
hypothetical models that explain the observed traits.
opinion, this is the most comprehensive and advanced theory about
Chaocipher in the open literature today, and will be of general
interest to any cryptanalyst. I highly recommend fellow
researchers to read this excellent paper.
paper also contains important historical information. He provides
quotes from letters by William F. Friedman to Byrne which clarify the
relationship between them vis-a-vis Chaocipher. It shows
conclusively that Byrne obstinately refused to provide Friedman with a
set of messages as per the Army's standard requirements from cipher
inventors. Apparently Byrne had no one to blame but himself for
the fact that Chaocipher was not adopted by the US agencies.
Once again, I
want to thank Jeff for agreeing to sharing his hard-earned knowledge of
Chaocipher with the cryptologic community at large via the
Chaocipher Clearing House.
(c) 2009 Moshe Rubin
16 April 2009
Updated: 22 April 2009