[ale] [OT] speaking of british (motorcycle thread) - interesting crypto info circa 1940

Charles Shapiro hooterpincher at gmail.com
Sat Aug 10 19:53:03 EDT 2013


Alan Turing is one of my personal heroes.  What the English did to him
after the war was shameful. An excellent biography of him ( David Leavitt's
_The_Man_Who_Knew_Too_Much_ (
http://www.barnesandnoble.com/w/man-who-knew-too-much-david-leavitt/1102002740?ean=9780393329094
) is still available  I believe.  He was one of the greatest mathematicians
of the 20th century, and all of us use his ideas every day.

-- CHS



On Sat, Aug 10, 2013 at 5:35 PM, Jay Lozier <jslozier at gmail.com> wrote:

> **
> It did help that the Allies also occasionally captured the current code
> books for the U-boots. One the U-boots was actually captured (U505) and is
> now in Chicago.
>
> From what I read the German Navy and Army had very good code discipline
> and rarely provided any cribs to the Allies. The Luftwaffe was apparently
> fairly sloppy and tended to provide cribs to the Allies.
>
> One of the more important tactics was direction finding and then home in
> on the signal
>
> On Sat, 10 Aug 2013 17:05:27 -0400, Boris Borisov <bugyatl at gmail.com>
> wrote:
>
> In my high school ages I had a book ( probably still have it ) about
> Enigma and how it works. My mind got wrecked by the complexity of
> mathematics involved!
>
>
> On Sat, Aug 10, 2013 at 4:54 PM, Ron Frazier (ALE) <
> atllinuxenthinfo at techstarship.com> wrote:
>
>> Hi all,
>>
>> I may have mentioned this here before, years ago, but considering the nsa
>> stuff, I thought it would be interesting to share.
>>
>> Last night I dug up a movie from a rarely used box I have and watched it.
>>  It's called Enigma.
>>
>> http://www.amazon.com/Enigma-Dougray-Scott/dp/B00006FD9P
>>
>> It's about the British and American cryptanalysis and code breaking
>> project during WWII circa 1940 - 1945.  The movie is R rated, and I could
>> do without the parts that make it so.  However, the other core content of
>> the movie is fascinating, and is based on truth.  I am not a history buff,
>> but I do like this movie.
>>
>> After watching the movie, I read about 29 pages from the following
>> wikipedia articles about Bletchly Park and Bombes.  Yes that last thing is
>> spelled correctly, as I will explain.
>>
>> http://en.wikipedia.org/wiki/Bletchly_Park
>> http://en.wikipedia.org/wiki/Bombe
>>
>> The articles state that the efforts of the code breakers in Britain and
>> the US reduced the length of the war by 2 - 4 years and that the outcome of
>> the war without their efforts would have been in question.  A caption in
>> the movie says these endeavors saved millions of lives.  None of this was
>> disclosed to the public until the 1970's.
>>
>> The main concern (relevant to this topic) of the British and later the US
>> was the German Enigma machine.  This is a brilliant little piece of
>> engineering.  It had an alphanumeric keyboard, a series of movable and
>> rotatable rotors, and a plug board where wires could be attached in various
>> combinations.  The operator would type a plaintext letter on the keyboard,
>> and a corresponding ciphertext letter would light up on a lamp board.  That
>> ciphertext would be transmitted by U-Boats, etc. by radiotelegraph.  Gears
>> inside would rotate the rotors, so, the next time you pressed the same
>> plaintext letter, you would get a different ciphertext letter.
>>
>> Even though the allies had some captured enigma machines or clones of
>> them, unless the rotor sequence, rotor position, and plug board wires were
>> set up properly, they would not be able to decrypt the enemy's messages.
>>  The 4 rotor Enigma machine had 18x10^19 different ways of being set up.
>>  If my math is right, that's more than the permutations of a 66 bit binary
>> key.  Decrypting the German U-Boat signals was critical to protect convoys
>> of allied ships from being sunk by the U-Boats.  This was a VERY
>> sophisticated cipher scheme for it's time.  There are comments in the
>> articles to the effect that, if the system had been properly used, it would
>> have probably been unbreakable.
>>
>> Alan Turing, sometimes known as the father of computer science, helped
>> the British develop the bombe machines, which were 1 - 2 TON
>> electromechanical monsters which replicated the function of 2 or more
>> enigma machines, with large numbers of rotating drums (or later relays),
>> but which could be driven at high speed by motors.  If the British or
>> American cryptanalysts could get a crib, a piece of known plaintext with a
>> matching piece of known ciphertext, like a weather report where the format
>> and data was known, they could use that as a baseline to set up the bombe.
>>  Using the known data, the bombe machines would try various possible
>> combinations of enigma setup sequences at high speed until a possible
>> option was found that could possibly decipher the other ciphertext messages
>> for which there was no crib.  The cryptanalysts would further analyze this
>> data, and eventually select a few possible setup sequences.   Those would
>> be tested by trying to decrypt the German communications.  If the result
>> came out German, then the allies could read the German comm traffic FOR A
>> DAY OR TWO.  The next day, they had to figure out the code again.  This
>> went on for years, and the allies eventually decrypted thousands of German
>> messages.  At one point in time, there were 12,000 employees at Bletchly
>> Park.
>>
>> So, you might say the Bitish and American code breakers saved our
>> collective butts.
>>
>> There is a simplified description of of how all this works, with
>> examples, in the articles.  Now, I've never claimed to be a math wizard.
>>  But, this stuff, even from 1940, makes my eyes cross.  I'm glad someone
>> understands it, and I'm sure modern crypto systems are much more complex.
>>
>> Anyway, hats off to the cryptographers for what they do, WHEN it's in the
>> best interest of society.
>>
>> I just thought you all would find this interesting, as I did, even though
>> history is not usually my thing.
>>
>> Sincerely,
>>
>> Ron
>>
>>
>> --
>>
>> (PS - If you email me and don't get a quick response, you might want to
>> call on the phone.  I get about 300 emails per day from alternate energy
>> mailing lists and such.  I don't always see new email messages very
>> quickly.)
>>
>> Ron Frazier
>> 770-205-9422 (O)   Leave a message.
>> linuxdude AT techstarship.com
>> Litecoin: LZzAJu9rZEWzALxDhAHnWLRvybVAVgwTh3
>> Bitcoin: 15s3aLVsxm8EuQvT8gUDw3RWqvuY9hPGUU
>>
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org
>> http://mail.ale.org/mailman/listinfo/ale
>> See JOBS, ANNOUNCE and SCHOOLS lists at
>> http://mail.ale.org/mailman/listinfo
>>
>
>
>
>
> --
> Jay Lozier
> jslozier at gmail.com
>
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ale.org/pipermail/ale/attachments/20130810/11de334c/attachment-0001.html>


More information about the Ale mailing list