In the Beginning.
- From: adacrypt <austin.obyrne@xxxxxxxxxxx>
- Date: Fri, 22 Oct 2010 01:19:52 -0700 (PDT)
Kasiski and Babbage both broke the Vigenere cipher that had lasted for
two centuries and was thought to be totally impregnable for all time.
Very simply they both realised, independently and at different times
according to historians, that every language has linguistic probably
that they could use to crack the ciphertext of that language. The
ploy was simple in concept, i.e.establish the frequency of occurrence
of every character in a large general piece of casual text in the
language and then by superimposing this frequency of the language
sample onto the ciphertext, that would enable a very close guess to be
made at what that particular ciphertext was concealing as plaintext.
The upshot of their work was to say that languages have innate
structure that can be found by inspection and can be used to
cryptanalyse ciphertext of that language.
Major Joseph Mauborgne, who was head of cryptographic research for the
US army in 1920, realised that the antidote to a Kasiski / Babbage
attack on ciphertext was to destroy all structure in the key
ingredients that created it first day. Ciphertext itself is never
random by definition i.e the string of ciphertext is never random but
the key elements that make it up originally can be made to have equal
probability of being the correct one in the blind retrieval system
that a crypanalyst is forced to use, even if the cryptanalyst has full
knowledge of what the key string might be and have full knowledge of
the correct inverting procedure that turns ciphertext back into
plaintext. He might as well just sit down and compose an essay as
being the plaintext message.
This was scientific randomness being used for the first time in
cryptography – a major advance that was totally misunderstood by
writers of cryptography of the day (if there were any) and culpably,
by other writers 50 years later on who had by now inherited the
enormous power of computer science. They went down a completely wrong
road instead that produced complexity-theoretic cryptography as block
ciphers of binary digits and one failed attempt at a mathematical one-
way function, to wit, DES, AES and RSA. Randomness was totally
eschewed due to lack of understanding. The RSA cipher is a laudable
attempt at a mathematical one-way function but unfortunately it fails
because it can be blown by factoring of very large numbers that have
to keep on getting larger with time just to stay ahead of the posse.
The almost cult following that all of this cryptography enjoys today
in this news group cannot hide the fact that this cryptography is
computer-dependent and could crash quite suddenly at any time in the
future. It is time to bite the bullet and admit this instead of
spooning reassuring bits of jargon to each other as pen pals do in
posts but living in a fools’ paradise of insularity meanwhile.
Taking sides in any argument to the contrary is simply deluding
oneself that all is tickety-boo and there is no cause for concern,
there is instead good reason to be concerned at the level of say the
NSA and other national agencies of other countries. But that is not
the point being made here.
The extraordinary thing about the misunderstanding of Joseph
Mauborgne’s cryptography is the total failure of even the best writers
in the business to understand the scientific randomness of his
cryptography and instead castigate his One-time Pad Cipher on the
grounds that it would be impossible to provide the randomness in the
OTP that it required, based on their wrong understanding i.e. the
completely wrong haphazard notion of randomness instead of the
scientific version of what randomness in cryptography really is. This
can only be called crass ignorance.
Joseph Mauborgne's work was metaphorically a case of ‘pearls before
Sadly, the same ignorance goes on even to day.
Joseph Mauborgne’s name was assigned to the Hall of Fame of US army
intelligence. His contribution to cryptography is still not
understood properly, unfortunately. He is one of the great people in
cryptography. It is quite hard to find any others that could stand
next to him, Vigenere perhaps? none of the modern names can hold a
candle to these two giants.
Enjoy - adacrypt