F. W. Chesson SW\CODE.HTM
144 Fiske Street,
Waterbury, CT 06710 Rev: 7-27-00
SECRET WIRES
*
Civil War Cryptology
Origins of Secret Messages on Open Wires
Secret Communication was around as soon as there was human
communication. Tribal dialects and regional differences in basic
speech patterns were enough to separate clans and larger social
groups. Even within a tribe, jargon and special words, as well
as non-verbal gestures and body language, all served to define
status and leadership roles.
Cryptology, our name for all forms of secret communication,
whether written, electronically transmitted, or verbal, comes
from the Greek Kryptos meaning hidden, to which is appended
ology, meaning a discipline or systematic study, as in Theology
or Graphology. From the latter comes Cryptography, the Art of
Secret Writing. A sub-branch of cryptography is Steganography,
which seeks to conceal the very existence of a message, whether
it be plainly written (in the clear, as "plaintext") or already
made secure (in code, or enciphered.) Invisible Ink was a classic
vehicle for steganography, already two centuries old at the time
of the Civil War and still formidable during World War One.
When an intercepted message is analyzed for its meaning, it
is said to be subjected to Cryptanalysis. During the Civil War,
the U. S. Military Telegraph had no official code-breaking staff
and certainly no more than a half dozen of its top staff engaged
in part-time cryptanalysis of intercepted Confederate secret mail
and telegrams. By contrast, during the Cold War, the National
Security Agency probably employed well over one thousand dozen
specialists.
The history of cryptology has been covered in many works.
Of particular value are Chapters 2 through 7 of The Codebreakers,
by David Kahn. (Macmillan Company, New York, 1967) Manuscripts
in Arabic are known from the 14th century, while printed works on
cryptology were written in the early 1500s, when Giovanni Soro
and other cipher masters made Venice a Renaissance bastion of
diplomatic cryptology.
When writing arrived, it was appropriated in nearly every
developing society by the elite. Only reluctantly did priestly
scribes surrender their Sacred Art to the growing royal
bureaucracy and commercial classes.
One interesting example of practical cryptography was discovered
on an ancient Tigris River site. A Selucian scribe of 1500 B.C.
employed rarely-used cuneiform characters to protect the written
formula for a valuable pottery glaze. In India, the Artha-
sastra, a scholarly work on diplomacy, mentions secret writing
for the bureaucracy's vast spy system. And in another, more
familiar classic, the erotic Kama-sutra lists secret writing as
one of the 64 yoga arts that an enlightened woman should be
accomplished in.
Cryptanalysis began with the Arabs, and indeed our word
cipher comes from the Arabic. As early as 855 AD, a book on magic
listed several cipher alphabets, presumably for protecting
sensitive incantations. Interest continued to grow, until
cryptography was accorded its own section in a massive, 14-volume
encyclopedia of the early 15th Century.
This wisdom filtered down to the West, or was discovered
independently, for in 1401 the Italian Duchy of Mantua was
corresponding with its secret agents using cipher alphabets
having more than one symbol for commonly used letters, a
practical step to make code-breaking more difficult.
Basically, cryptography has two main branches, Code and
Cipher, both applicable to telegraphy. The Morse dot and dash
alphabet was, of course, a true code, and anyone intercepting a
transmission, or even seeing a register tape, for the first time,
would be quite confused as to the actual content.
With enough material, however, a statistical count of the
code symbols would soon reveal their meaning and make past and
future interceptions an open book...until the code was changed.
(Codebreakers, Chapter 20, "The Anatomy of Cryptology.") In
general, then, Code is a batch process, like Morse's early
port-rule transmitter, with information segments arranged in a
sequence.
Cipher, unlike code, is a linear process, with each letter
(rarely letter pairs or triads) being individually processed.
As for the telegraph, its electrical impulses were subjected
to privacy-producing techniques from its inception. Morse,
himself, had originally conceived his brainchild as being above
public participation, reserved for the most critical of
government communications. Towards this end, he spent long
hours devising a codebook, with numerical combinations
representing a variety of words, phrases and subjects. For
efficiency, a code book should be in two parts, one section for
encoding and another for decoding, just as multi-lingual
dictionaries have, for example; English-Spanish, and
Espanol-Englisa sections.
A NUMERICAL ENCODING TABLE
Word or Phrase Code Number
--------------------------------------------------------------
Alabama 123
Ammunition 278
Annapolis 222
Appear 650
Arrangement(s) 729
Atlanta 503
Aware of 413
Baltimore 507 etc.
DECODING TABLE
Code Number Word or Phrase
---------------------------------------------------------------
100 Can you communicating with...?
110 Wheat shipments
116 Custom House receipts
120 Hartford
123 Alabama
129 Replying to your letter of....
131 Steamship(s)
150 Interference
222 Annapolis etc.
Note the appearance of Alabama and its equivalent, 123, and
Annapolis, 222, in both tables.
Francis "Fog" Smith, Morse's early promoter and later adversary,
took advantage of the first code book and produced his own version in
1845; "The Secret Corresponding Vocabulary; Adapted to Morse's Electro-
Magnetic Telegraph." He pointedly informed the reader that; "Secrecy
in correspondence is by far the most important consideration." He
added letters to the Morse numerical lists and produced configurations
like ALONE = A.1645, for example.
At about the same time, one Henry Rogers melded the older
semaphore system to the new electrical art and came up with a work
entitled; "The Telegraph Dictionary and Seaman's Signal Book, Adapted
to Signals by Flags or Other Semaphores; and Arranged for Secret
Correspondence, Through Morse's Electro-Magnetic Telegraph."
It was not long, however, before telegraph users saw the true value
of the code book, Economy. As early as 1847, John Wills' "Telegraphic
Congressional Reporter" appeared and was appreciated wherever lengthy
orations had to be transmitted to the Great American Public.
By 1860, a large number of commercial codes were in use, partly
for secrecy but mainly for cost-saving reasons. The now-giant Western
Union Telegraph Company introduced a numerical phrase-list for its
operators back in 1859. Some of these abbreviations have come down to
the present day in commercial and amateur radio transmissions, in voice
and code. Among the most familiar and enduring are "73...Accept My
Compliments" and the most final number of all; "30...The End...."
With the laying of the successful Atlantic Cable in 1866, code
book vocabularies became more and more extensive, to save on toll
charges, which even now seem costly, of $5.00 per word.
Many codes were compiled to meet the special needs of railroads
and various industries and private enterprises. Most were first built
around the standard dictionaries of the day, wherein a single word
could represent another word, a phrase, or an entire sentence. Thus,
TURTLE might inform its decoding recipient: "The market is falling,
sell at once."
While these code words were useful, care had to be taken, less an
omitted or garbled word cause an entirely new meaning to be deciphered.
For example, if SHEEP stood for BUY, and SLEEP for SELL, the garbling
of H for L could spell nothing but big trouble!
As the art matured, codes were compiled so as to reduce such garbles
as much as possible. One method was to always use two different letters
in each code word. For example, if QWERTY stood for BUY NOW, a change of
both W and R to QSENTY could validly represent SELL NOW, but single-letter
alterations to QSERTY, QWERTI or NWERTY would all be invalid. Techniques
were also developed so that a mutilated code word might be determined by
the numerical values assigned to its letters.
The development of commercial codes reached into every facet of
American business life, from accounting to fireworks to mining equipment
to shoes to zoological supplies. It was a mirror of a nation's commercial
life during its heydays of the early 20th century. (Codebreakers, Ch 22)
Such large code books with their thousands of phrases for every
possible product or contingency were convenient only in businesses with
central head-quarters and established branch offices, or for governments
communicating with scores of far-flung embassies and consular offices.
Traveling salesmen and roving officials could not be burdened by large
tomes and relied on pocket-sized code digests. These limited-scope
editions were easier to print and distribute whenever a current volume
was lost, stolen, or routinely replaced.
Yet, ideally, a simple but relatively secure encipherment was desired
for speedy transmission of sensitive information. A device or routine which
could be easily carried or composed, easily learned and easily modified
when needed, was to be met by the other main branch of the Cryptography
Tree; Cipher.
Cipher, in turn, has two main branches: Substitution and Transposition.
Substitution replaces each individual letter, or letter group, by other
letters or numbers. Thus, E becomes X, or THE becomes NXPF....
This cipher had become popular for recreational purposes in pre-Civil
War America, especially after the publication of Edgar Allan Poe's "The
Gold Bug" in June of 1843. Earlier, Poe had solved challenge cryptograms
sent to him by readers of Alexander's Weekly Messenger in 1840, continuing
when he became editor of Graham's Magazine, also in Philadelphia.
Transposition mixes letters or words about in a particular pattern
or route. Some enciphering systems include both operations, like the
current Data Encryption Standard (DES), although increased manipulations
mean a greater chance for errors to creep in.
It was word transposition which formed the heart of the United States
Military Telegraph's cipher system. In this crypto-system, the normal word
order of the message is shuffled about, according to a pattern which may
be readily memorized and changed at will. The method dates back to at
least 1685, when the Duke or Argyle used it in his abortive uprising
against James II of England. One hundred seventy-five years later, it
would be used again in putting down another nation's internal uprising...
the American Civil War.
Transposition's advantage in telegraphy is that real words are used,
thus leading to fewer transmission errors. Its disadvantage is that short
messages are easier to break. For example, the order to "Attack at dawn."
cannot be hidden, no matter how the three words are arranged. In this case,
even a simple encipherment into XZZXER XZQXYL gives far greater security,
as does the use of a code word like TURTLEDOVE.
There is evidence that journalists were already using this system
before the war's official outbreak. The reporters needed encipherment
to protect valuable news items in transmission, lest a rival newspaper
"scoop" them and appear first on the streets with that big EXTRA!
Code books would be both bulky to carry about and subject to loss
and theft. Hence, for the foot-loose reporter of that turbulent era,
the answer was the Word-Transposition Cipher. Cost could be another big
factor, with plain words charged at a lower rate than unpronounceable
letter combinations or numeric groups.
That just such a system was already in use at the opening of
hostilities is attested by the following telegram, which was seized with
others by Federal authorities in a Baltimore telegraph office on May 20,
1861...
(Pritchard to Craig April 19, 1861)
D. H. Craig
Vandalia to have letter find abusive ill man if to barter
so go to the assistance out refers to do practically Charleston
I your try. Pritchard
25/DH SG
When initially deciphered, the text reads:
abusive Assistance
I'LL TRY FIND OUT THE
MAN YOUR LETTER REFERS TO
IF I HAVE TO GO
TO CHARLESTON TO DO SO
barter VANDALIA practically
Full Text: "I'll try (to) find out the man you refer to (even) if I
have to go to Charleston to do so."
VANDALIA: Key for a Five Column, Four Line Transposition Block, with
the following Route: Up 3, Down 1, Up 5, Down 4, Up 2.
Null Words, Abusive, Barter, Assistance, Practically, are inserted at
the end of each column, except the last.
Daniel H. Craig was President of the Associated Press in 1861.
Pritchard was apparently one of his field correspondents.
Had the Duke of Argyle been involved on the side of the Confederacy,
he would have found an entirely different crypto-system in use, but one
probably known to him. This was the Vigenere, or Court Cypher, which
dated back to the 1500s. It had been employed in palace intrigues and
mini-state diplomacy up through the dynastic convulsions of the Holy
Roman Empire to the rise of Europe's modern states.
The Vigenere was based upon letter-substitution, wherein each letter
in the message was replaced by another. The process was governed by the
KEY, a word or group of letters of any length, even the message itself.
While this system had a vastly greater potential for security than
the route transposition, in practice it was often compromised by the
users' tendency to encipher only the most sensitive parts of the text,
and by protracted use of the same key.
For example, for the entire life of the Confederacy, only three main
keys, all of fifteen letters in length, were in use. And the last one,
"COMERETRIBUTION," was introduced early in 1865, when the need for secret
communications was about to become as academic as the Southern Cause itself. *
Below is the table or Tableau of the Vigenere Cipher, with
instructions for its use.
THE VIGENERE CIPHER TABLEAU
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
C D E F G H I J K L M N O P Q R S T U V W X Y Z A B
D E F G H I J K L M N O P Q R S T U V W X Y Z A B C
E F G H I J K L M N O P Q R S T U V W X Y Z A B C D
E F G H I J K L M N O P Q R S T U V W X Y Z A B C D
F G H I J K L M N O P Q R S T U V W X Y Z A B C D E
G H I J K L M N O P Q R S T U V W X Y Z A B C D E F
H I J K L M N O P Q R S T U V W X Y Z A B C D E F G
I J K L M N O P Q R S T U V W X Y Z A B C D E F G H
J K L M N O P Q R S T U V W X Y Z A B C D E F G H I
K L M N O P Q R S T U V W X Y Z A B C D E F G H I J
L M N O P Q R S T U V W X Y Z A B C D E F G H I J K
M N O P Q R S T U V W X Y Z A B C D E F G H I J K L
N O P Q R S T U V W X Y Z A B C D E F G H I J K L M
O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
P Q R S T U V W X Y Z A B C D E F G H I J K L M N O
Q R S T U V W X Y Z A B C D E F G H I J K L M N O P
R S T U V W X Y Z A B C D E F G H I J K L M N O P Q
S T U V W X Y Z A B C D E F G H I J K L M N O P Q R
T U V W X Y Z A B C D E F G H I J K L M N O P Q R S
U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
V W X Y Z A B C D E F G H I J K L M N O P Q R S T U
W X Y Z A B C D E F G H I J K L M N O P Q R S T U V
X Y Z A B C D E F G H I J K L M N O P Q R S T U V W
Y Z A B C D E F G H I J K L M N O P Q R S T U V W X
Z A B C D E F G H I J K L M N O P Q R S T U V W X Y
Sample Encipherment, using COME RETRIBUTION as key
Procedure: Write key letters under message letters. Look for the
message letter on top line of table, then move down until you reach
the row whose left-most letter is that of key letter.
Example; when L is extended down two rows to C of key, N is the
cipher letter.
Message: Longstreet to move at once into Petersburg defence.
Key: COMERETRIB UT IONC OM ERET RIBU TIONCOMERE TRIBUTI
Cipher: NCYKJXKVMU NH UCIG OF SEGX ZVUI IMHRTGNYIK WVNFHVM
Decipherment is in reverse; Go to Row C, move to cipher letter N,
then go straight up to top line to find L of the plain message.
For secret correspondence, Confederate agents used not only the
Vigenere, but also simple homophonic ciphers, a method which appeared
in Renaissance Italy, as far back as 1400. In this system, common
letters like E, T, A, O, I, N, etc., are given multiple substitutes,
usually in the form of exotic symbols.
For example, E = Q,Z,3,9,! A = K,X,2,# T = A,J,%,+
These were fairly easily solved, given enough material to work on, as
will be shown in a detailed examination of the strengths and weaknesses
of Confederate Cryptography, which in its own way was a mirror of the
Confederacy, itself.
Thus, like the differing political and social philosophies of
North and South, their cryptographic systems in the fratricidal struggle
just ahead were also divided and diverse:
Transposition versus Substitution....
* A seventeen-letter key; "My Old Kentucky Home" was mentioned in a
mid-1863 communication between generals.
APPENDIX
Anatomy of a United States Military Telegraph Cipher Message.
To examine how a Cipher Operator sent an encoded messages during
the war, let us examine the following example.
On the day of a battle, General Chatfield writes the following
status report and gives it to operator McCaine for transmission:
"We expect to engage the enemy soon. I am on left flank of
General Hawley with reserve artillery behind Turtle Creek. The bridge
is guarded by two companies. Signed, Chatfield."
McCaine first makes a word count of the cleartext and determines
it to be exactly thirty words. This calls for a 5 x 6 transposition
block of six columns wide and five lines deep.
From his USMT Codebook, he finds the codeword LONDON meeting
this specification and enters the text as shown:
1. 2. 3. 4. 5. 6.
1. WE EXPECT TO ENGAGE THE ENEMY
2. SOON I AM ON LEFT FLANK
3. OF GENERAL SMITH WITH RESERVE ARTILLERY
4. BEHIND TURTLE CREEK THE BRIDGE IS
5. GUARDED BY TWO COMPANIES SIGNED CHATFIELD
For simplicity's sake, important words such as ENEMY, ENGAGE,
and ARTILLERY, which would normally have their own codewords, will
be left in the clear.
McCaine then notes the transposition route, or the pattern by
which the text will be enciphered. In the case of LONDON, it is:
Up-6, Down-1, Up-4, Down-2, Up-5, Down-3.
Commencing with CHATFIELD, at the bottom of column 6, he writes
the text going up the column. Following ENEMY, at the top of Column 6,
he adds a Null or Check-Word. This will enable the receiving cipher
clerk to cope with any garbling of the text should a word be omitted
or two words run together, such as where OVER and COME are merged
into OVERCOME. Originally, the nulls were obvious sequences of common
substances such as Lead, Gold, Silver, Iron....
While useful in quick error checking, such nulls could also give
away the basic structure of the transposition block, and so were soon
replaced by words more fitting the overall text. Here, an operator
could allow a little levity to enter his otherwise deadly serious
occupation, by selecting null words which when inserted in the break
between the columns would convey an often humorous as well as cryptic
sense to the cipher-text. In this case, McCaine chose FLEES to follow
ENEMY. Proceeding down Column 1, he follows the last word GUARDED
with the check-word HOPES. Going up Column 4, he adds BRAVELY after
ENGAGE.
Thus following the prescribed route and adding his own well-chosen
nulls, he arrives at the following cipher-text, ready for transmission
over wires that may well be tapped.
Any Confederate wire-tapper taking down the message would read the
following jumble:
To Eckert War Dept.
LONDON CHATFIELD IS ARTILLERY FLANK ENEMY FLEES WE SOON OF OF
BEHIND GUARDED HOPES COMPANIES THE WITH ON ENGAGE BRAVELY
EXPECT I GENERAL TURTLE BY THUNDER SIGNED BRIDGE RESERVE LEFT
THE FIELD TO AM HAWLEY CREEK TWO MILES.
McCaine
The use of codewords considerably adds to the security of the system.
If Artillery = PRINCESS, FLANK = WINDPIPE, Enemy = RAMPANT,
Company = SHYLOCK, Engage = WASP, Bridge = PLATE, and Reserve =
WINDOW...then the cipher-text becomes:
LONDON CHATFIELD IS PRINCESS WINDPIPE RAMPANT FEVER WE SOON OF
OF BEHIND GUARDED EVIL SHYLOCK THE WITH ON WASP NEST EXPECT I GENERAL
TURTLE BY THUNDER SIGNED PLATE WINDOW LEFT THE FIELD TO AM HAWLEY
CREEK TWO MILES.
If Generals Chatfield and Hawley were important enough to have
their own codewords, say MELON and PEACH, respectively, then the
telegram would have looked as follows:
LONDON MELON IS PRINCESS WINDPIPE RAMPANT FEVER WE SOON OF OF
BEHIND GUARDED EVIL SHYLOCK THE WITH ON WASP NEST EXPECT I GENERAL
TURTLE BY THUNDER SIGNED PLATE WINDOW LEFT THE FIELD TO AM PEACH
CREEK MILES
The choice of nulls by our Cipher Operator has given the
uninitiated some tantalizing, if irrelevant, pseudo-phrases:
Guarded Evil Shylock...On Wasp Nest...I General Turtle, By Thunder...
Left The Field....
Sometimes, merely the normal transposition operation could,
along with the substitution of code words, create curious and
humorous phrases, as shown by the following actual examples:
As Less Seems Funny...I Like You Satisfied...Not Many
Vouchers Burned...
May Angles Attend...The Auburn General Gave It...Swords In
Andes Hands...
Vomit Whole Limestone Rock...Move Dispositions For Them
Pretty Niggers....
This, then, is how the Union Army guarded some of the most
vital communications during the Civil War, as will presently be seen.
* * *
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