Re: Civil War Crypto Question... (fwd)

Forwarded message:

> Date: Sun, 21 Dec 97 21:46:22 PST
> From: jim@mentat.com (Jim Gillogly)
> Subject: Re: Civil War Crypto Question...
> 
> Jim Choate skribis:

> > On pp. 43 - 44 [of Hagerman's "The American Civil War..."]
> > ... a 'cipher disk' whereby the Union was able to
> > change their telegraph codes on an hourly schedule. It was apparently very
> > effictive in dealing with taps and such.
> > 
> > Anyone know of another source that discusses this disk? I looked in Applied
> 
> There's a very brief mention of a disk in "Masked Dispatches: Cryptograms
> and Cryptology in American History, 1775-1900", available from the NSA
> Central Security Service.  (Series 1, Pre-World War 1, Volume 1, United
> States Cryptologic History), Center for Cryptologic History, by Ralph
> E. Weber, 1993.

Thanks for the reference.

> On page 110 he says: "The North, on the other hand, adopted a handy "on-line"
> means of changing the basic flag code by prearrangement or at will, even within
> the act of transmission.  This was done with a disk, in which the alphabet on
> the inner disk revolved against an outer ring of flag combination, enabling an
> instant change of code."
> 
> My impression from this and from the chapter summary is that the disk was
> used for flag codes but not telegraphy.  For telegraphy the Union apparently
> used a word-based route transposition that Friedman found unimpressive.

Actualy it was used for telegraphy and flags. You see Mahan, the inventor of
the disk had also just invented the first ever alphabetic flag system.
Because of this system, instead of the wig-wag system others used, McClellan
was the first general in history to change his orders of attack 3 times in 3
days *and* win the battle. The problem on the Peninsula was the land was too
flat and the woods too thick to use it (see my original references around the
same few pages).

Friedman? Who the hell is Friedman? None of my references has anyone by that
named listed, let alone involved.

McClellan was the general in charge of the Army of the Potomac. Meyer was in
charge of the Signal Corp, which at the time was responsible for tactical
communications for McClellan. Originaly Meyer intended to use his new flag
system but because the terrain, flat and wooded, on the Peninsula they found
they weren't reliable. They were also using the balloons from the Union
Aeronautic Department under Lowe. They were quite effective, haven't found
out if they used Meyer's signal system. The flip side was the fully civilian
Military Telegraph under Stager which handled strategic telegraphy was
fighting Meyer for control of the various communications along technological
boundaries. At this time, while they were fighting the South and each other,
they brought in some Beardslee equipment (a rail-based portable telegraph
system) which apparently didn't work well at all. The Beardslee system was
the first use by an American army of portable telegraph equipment, it ran
between McClellan's headquarters to Stoneman's at Mechanicsville. Apparently
one of the chief problems was that wagons and people kept cutting the lines. 

Merry Christmas!


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On Mon, Dec 22, 1997 at 09:21:05AM -0600, Jim Choate wrote:
> 
> Friedman? Who the hell is Friedman? None of my references has anyone by that
> named listed, let alone involved.

Tsk, Tsk, A cyppherpunk not knowing who Wiliam F. Friedman was?  Author of many
texts on cryptography, ... was a master at cryptanalysis during the two World
Wars and could be called the father of American cryptography.

around 1917, became the head of the Department of Ciphers. During this time
America became engaged in World War I. Intercepted messages were given to
Friedman and he was successful in breaking each and every one of them. 

Probably wrote analysis of early US military crypto systems that the
reference was drawn from.
-- 
Tom Porter                                       txporter@mindspring.com
------------------------------------------------------------------------
   "I do believe that where there is a choice only between cowardice and
    violence, I would advise violence." Mahatma Gandhi

At 09:21 AM 12/22/1997 -0600, Jim Choate wrote:
>> My impression from this and from the chapter summary is that the disk was
>> used for flag codes but not telegraphy.  For telegraphy the Union apparently
>> used a word-based route transposition that Friedman found unimpressive.
...
>Friedman? Who the hell is Friedman? None of my references has anyone by that
>named listed, let alone involved.

Friedman was the WWII / Korean War cryptographer who wrote some of the
main surveys of crypto at the time.  In particular, he wrote a 4-volume set
of books, some of which were declassified, and some which became declassified
after a lawsuit by John Gilmore.
				Thanks! 
					Bill
Bill Stewart, bill.stewart@pobox.com
PGP Fingerprint D454 E202 CBC8 40BF  3C85 B884 0ABE 4639