|
A Few Words on Secret
Writing
———
BY EDGAR A. POE.
———
As we can scarcely imagine a time
when there did
not exist a necessity, or at least a desire, of transmitting
information
from one individual to another, in such manner as to elude general
comprehension;
so we may well suppose the practice of writing in cipher to be of great
antiquity. De La Guilletiere, therefore, who, in his "Lacedaemon
Ancient
and Modern," maintains that the Spartans were the inventors of
Cryptography,
is obviously in error. He speaks of the scytala as being the
origin
of the art; but he should only have cited it as one of its earliest
instances,
so far as our records extend. The scytalae were two wooden
Cylinders,
prccisclv similar in all respects. The general of an army, in going
upon
any expedition, received from the ephori one of these cylinders, while
the other remained in their possession. If either party had occasion to
communicate with the other, a narrow strip of parchment was so wrapped
around the scytala that the edges of the skin fitted
accurately
each to each. The writing was then inscribed longitudinally, and the
epistle
unrolled and dispatched. If, by mischance, the messenger was
intercepted,
the letter proved unintelligible to his captors. If he reached his
destination
safely, however, the party addressed had only to involve the second
Winder
in the strip to decipher the inscription. The transmission to our own
times
of this obvious mode of cryptography is due, probably, to the historical
uses
of the scytala, rather than to anything else. Similar means of
secret
intercommunication must have existed almost contemporaneously with the
invention of letters.
It may be as well to remark, in
passing, that in
none of the treatises on the subject of this paper which have fallen
under
our cognizance, have we observed any suggestion of a method
— other
than
those which apply alike to all ciphers — for the solution
of the cipher
by scytala. We read of instances, indeed, in which the
intercepted
parchments were deciphered; but we are not informed that this was ever
done except accidentally. Yet a solution might be obtained with
absolute
certainty in this manner. The strip of skin being intercepted, let
there
be prepared a cone of great length comparatively — say six feet
long — and
whose circumference at base shall at least equal the length of the
strip.
Let this latter be rolled upon the cone near the base, edge to edge, as
above described; then, still keeping edge to edge, and maintaining the
parchment close upon the cone, let it be gradually slipped towards the
apex. In this [column 2:] process, some of those
words,
syllables, or letters, whose connection is intended, will be sure to
come
together at that point of the cone where its diameter equals that of
the scytala upon
which the cipher was written. And as, in passing up the cone to its
apex,
all possible diameters are passed over, there is no chance of a
failure.
The circumference of the scytala being thus ascertained, a
similar
one can be made, and the cipher applied to it.
Few persons can be made to believe that it is not quite
an easy thing
to invent a method of secret writing which shall baffle investigation.
Yet it may be roundly asserted that human ingenuity cannot concoct a
cipher
which human ingenuity cannot resolve. In the facility with which such
writing
is deciphered, however, there exist very remarkable differences in
different
intellects. Often, in the case of two individuals of acknowledged
equality
as regards ordinary mental efforts, it will be found that, while one
cannot
unriddle the commonest cipher, the other will scarcely be puzzled by
the
most abstruse. It may be observed, generally, that in such
investigations
the analytic ability is very forcibly called into action; and, for this
reason, cryptographical solutions might with great propriety be
introduced
into academies, as the means of giving tone to the most important of
the
powers of mind.
Were two individuals, totally unpractised in
cryptography, desirous
of holding by letter a correspondence which should be unintelligible to
all but themselves, it is most probable that they would at once think
of
a peculiar alphabet, to which each should have a key. At first it
would,
perhaps, be arranged that a should stand for z, b for y, c for
x, d for
w, &c. &c.; that is to say, the order of the letters would be
reversed.
Upon second thoughts, this arrangement appearing too obvious, a more
complex
mode would be adopted. The first thirteen letters might be written
beneath
the last thirteen, thus:
n o p q r s t u v w x y z
a b c d e f g h i j k I m;
and, so placed, a might stand for n and n for a, o for
b
and b for a, &c. &c. This, again, having an air of regularity
which
might be fathomed, the key alphabet might be constructed absolutely at
random.
Thus, a
might stand for p
b
" " " x
c
" " " u
d
" " " o, &c. [page
34:]
The correspondents, unless convinced
of their error
by the solution of their cipher, would no doubt be willing to rest in
this
latter arrangement, as affording full security. But if not, they would
be likely to hit upon the plan of arbitrary marks used in place of the
usual characters. For example, ( might be employed
for a
. "
"
" b
: "
"
" c
; "
"
" d
) "
"
" e &c.
A letter composed of such characters would have an
intricate
appearance unquestionably. If, still, however, it did not give full
satisfaction,
the idea of a perpetually shifting alphabet might be conceived, and
thus
effected. Let two circular pieces of pasteboard be prepared, one about
half an inch in diameter less than the other. Let the centre of the
smaller
be placed upon the centre of the larger, and secured for a moment from
slipping; while radii are drawn from the common centre to the
circumference
of the smaller circle, and thus extended to the circumference of the
greater.
Let there be twenty-six of these radii, forming on each
pasteboard
twenty-six spaces. In each of these spaces on the under circle write
one
of the letters of the alphabet, so that the whole alphabet be written
—
if at random so much the better. Do the same with the upper circle. Now
run a pin through the common centre, and let the upper circle revolve,
while the under one is held fast. Now stop the revolution of the upper
circle, and, while both lie still, write the epistle required; using
for
a that letter in the smaller circle which tallies with a in the larger,
for b that letter in the smaller circle which tallies with b
in
the larger &c. &c. In order that an epistle thus written may be
read by the person for whom it is intended, it is only necessary that
he
should have in his possession circles constructed as those just
described,
and that he should know any two of the characters (one in the under and
one in the upper circle) which were In juxta-position when his
correspondent
wrote the cipher. Upon this latter point he is informed by looking at
the
two initial letters of the document, which serve as a key. Thus, if he
sees a m at the beginning, he concludes that, by turning his
circles
so as to put these characters in conjunction, he will arrive at the
alphabet
employed.
At a cursory glance, these various
modes of constructing
a cipher seem to have about them an air of inscrutable secrecy. It
appears
almost an impossibility to unriddle what has been put together by so
complex
a method. And to some persons the difficulty might be great; but to
others — to
those skilled in deciphering — such enigmas are very simple indeed. The
reader should bear in mind that the basis of the whole art of solution,
as far as regards these matters, is found in the general principles of
the formation of language itself, and thus is altogether independent of
the particular laws which govern any cipher, or the construction of its
key. The difficulty of reading a cryptographical puzzle is by no [column
2:] means always in accordance with the labor or ingenuity
with
which it has been constructed. The sole use of the key, indeed, is for
those au fait to the cipher; in its perusal by a third party,
no
reference is had to it at all. The lock of the secret is picked. In the
different methods of cryptography specified above, it will be observed
that there is a gradually increasing complexity. But this complexity is
only in shadow. It has no substance whatever. It appertains merely to
the
formation, and has no bearing upon the solution, of the cipher. The
last
mode mentioned is not in the least degree more difficult to be
deciphered
than the first — whatever may be the difficulty of either.
In the discussion of an analogous
subject, in one
of the weekly papers of this city, about eighteen months ago, the
writer
of this article had occasion to speak of the application of a rigorous method
in
all forms of thought — of its advantages — of the extension of its use
even
to what is considered the operation of pure fancy — and thus,
subsequently,
of the solution of cipher. He even ventured to assert that no cipher,
of
the character above specified, could be sent to the address of the
paper,
which he would not be able to resolve. This challenge excited, most
unexpectedly,
a vend lively interest among the numerous readers of the journal.
Letters
were poured in upon the editor from all parts of the country; and many
of the writers of these epistles were so convinced of the
impenetrability
of their mysteries, as to be at great pains to draw him into wagers on
the subject. At the same time, they were not always scrupulous about
sticking
to the point. The cryptographs were, in numerous instances, altogether
beyond the limits defined in the beginning. Foreign languages were
employed.
Words and sentences were run together without interval. Several
alphabets
were used in the same cipher. One gentleman, but moderately endowed
with
conscientiousness, inditing us a puzzle composed of pot-hooks and
hangers
to which the wildest typography of the office could afford nothing
similar,
went even so far as to jumble together no less than seven distinct
alphabets, without
intervals between the letters, or between the lines. Many of
the
cryptographs were dated in Philadelphia, and several of those which
urged
the subject of a bet were written by gentlemen of this city. Out of,
perhaps,
one hundred ciphers altogether received, there was only one which we
did
not immediately succeed in resolving. This one we demonstrated to
be an imposition — that is to say, we fully proved it a jargon of
random
characters, having no meaning whatever. In respect to the epistle of
the
seven alphabets, we had the pleasure of completely nonplus-ing its
inditer by a prompt and satisfactory translation.
The weekly paper mentioned, was, for
a period of
some months, greatly occupied with the hieroglyphic and
cabalistic-looking
solutions of the cryptographs sent us from all quarters. Yet with the
exception
of the writers of the ciphers, we do not believe that any individuals
could
have been found, among the readers of the journal, who regarded the
matter
in [page 35:] any other light than in that of a
desperate
humbug. We mean to say that no one really believed in the authenticity
of the answers. One party averred that the mysterious figures were only
inserted to give a queer air to the paper, for the purpose of
attracting
attention. Another thought it more probable that we not only solved the
ciphers, but put them together ourselves for solution. This having been
the state of affairs at the period it was thought expedient to decline
farther dealings in necromancy, the writer of this article avails
himself
of the present opportunity to maintain the truth of the journal in
question — to
repel the charges of rigmarole by which it was assailed — and to
declare,
in his own name, that the ciphers were all written in good faith, and
solved
in the same spirit.
A very common, and somewhat too
obvious mode of secret
correspondence, is the following. A card is interspersed, at Irregular
intervals, with oblong spaces, about the length of ordinary words of
three
syllables in a bourgeois type. Another card Is made exactly coinciding.
One is in possession of each party. When a letter is to be written, the
key-eard is placed upon the paper, and words conveying the true meaning
inscribed in the spaces. The card is then removed and the blanks filled
up, so as to make out a signification different from the real one. When
the person addressed receives the cipher, he has merely to apply to it
his own card, when the superfluous words are concealed, and the
significant
ones alone appear. The chief objection to this cryptograph is the
difficulty
of so filling the blanks as not to give a forced appearance to the
sentences.
Differences, also, in the handwriting, between the words written in the
spaces, and those inscribed upon removal of the card, will always be
detected
by a close observer.
A pack of cards is sometimes made the
vehicle of
a cipher, in this manner. The parties determine, in the first place,
upon
certain arrangements of the pack. For example: it is agreed that, when
a writing is to be commenced, a natural sequence of the spots shall be
made; with spades at top, hearts next, diamonds next, and clubs last.
This
order being obtained, the writer proceeds to inscribe upon the top card
the first letter of his epistle, upon the next the second, upon the
next
the third and so on until the peek is exhausted, when, of course, he
will
have written fifty-two letters. He now shuffles the pack according to a
preconcerted plan. For example: he takes three cards from the bottom
and
places them at top, then one from top, placing it at bottom, and so on,
for a given number of times. This done, he again inscribes fifty-two
characters
as before, proceeding thus until his epistle is written. The pack being
received by the correspondent, he has only to place the cards in the
order
agreed upon for commencement, to read, letter by letter, the first
fifty-two
characters as intended. He has then only to shuffle in the manner
pre-arranged
for the second perusal, to decipher the series of the next fifty-two
letters — and
so on to the end. The objection to this cryptograph lies in the nature
of the missive. A pack of cards, sent [column 2:]
from one partly to another, would scarcely fail to excite suspicion;
and
it cannot be doubted that it is far better to secure ciphers from being
considered as such, than to waste time in attempts at rendering them
scrutiny-proof,
when intercepted. Experience shows that the most cunningly constructed
cryptograph, if suspected, can and will be unriddled.
An unusually secure mode of secret
intercommunication
might be thus devised. Let the parties each furnish themselves with a
copy
of the same edition of a book — the rarer the edition the better — as
also
the rarer the book. In the cryptograph, numbers are used altogether,
and
these numbers refer to the locality of letters in the volume. For
example — a
cipher is received commencing, 121-6-8. The party addressed refers to
page
121, and looks at the sixth letter from the left of the page in the
eighth
line from the top. Whatever letter he there finds is the initial letter
of the epistle — and so on. This method is very secure; yet it is possible
to
decipher any cryptograph written by its means — and it is greatly
objectionable
otherwise, on account of the time necessarily required for its
solution,
even with the key-volume.
It is not to be supposed that
Cryptography, as a
serious thing, as the means of imparting important information, has
gone
out of use at the present day. It is still commonly practised in
diplomacy;
and there are individuals, even now, holding office in the eye of
various
foreign governments, whose real business is that of deciphering. We
have
already said that a peculiar mental action is called into play in the
solution
of cryptographical problems, at least in those of the higher order.
Good
cryptographists are rare indeed; and thus their services, although
seldom
required, are necessarily well requited.
An instance of the modern employment
cipher is mentioned
in a work lately published by Messieurs Lea & Blanchard, of this
city — "Sketches
of Conspicuous Living Characters of France." In a notice of Berryer, it
is said that a letter being addressed by the Duchess de Berri to the
legitimists
of Paris, to inform them of her arrival, it was accompanied by a long
note
in cipher, the key of which she had forgotten to give. "The penetrating
mind of Berrver," says the biographer, "soon discovered it. It was this
phrase substituted for the twenty-four letters of the alphabet — Le,gouvernement
provisoire."
The assertion that Berryer "soon
discovered the keyphrase,"
merely proves that the writer of these memoirs is entirely innocent of
cryptographical knowledge. Monsieur B. no doubt ascertained the
key-phrase;
but it was merely to satisfy his curiosity, after the riddle had
been
read. He made no use of the key in deciphering. The lock was
picked.
In our notice of the book in question
(published
in the April number of this Magazine) we alluded to this subject thus
—
"The phrase 'Le, gouvernement
provisoire' is French,
and the note in cipher was addressed to Frenchmen. The difficulty of
deciphering
may well be supposed much greater, had the key been in a foreign
tongue;
yet any one who will take the trouble [page 36:]
may
address us a note, in the same manner as here proposed; and the
key-phrase
may be either in French, Italian, Spanish, German, Latin, or Greek, (or
in any of the dialects of these languages,) and we pledge ourselves for
the solution of the riddle."
This challenge has elicited but a
single response,
which is embraced in the following letter. The only quarrel we have
with
the epistle, is that its writer has declined giving us his name in
full.
We beg that he will take an early opportunity of doing this, and thus
relieve
us of the chance of that suspicion which was attached to the
cryptography
of the weekly journal above-mentioned — the suspicion of inditing
ciphers
to ourselves. The postmark of the letter is Stonington, Conn.
S — — — —
— — , CT., APRIL 21, 1841.
To the Editor of Graham's Magazine.
SIR:
— In
the April number
of your magazine, while reviewing the translation by Mr. Walsh of
"Sketches
of Conspicuous Living Characters of France," you invite your readers to
address you a note in cipher, "the key phrase to which may be either in
French, Italian, Spanish, German, Latin or Greek," and pledge yourself
for its solution. My attention being called, by your remarks, to this
species
of cipher-writing, I composed for my own amusement the following
exercises,
in the first part of which the key-phrase is in English —
in the second
in Latin. As I did not see, (by the number for May,) that any of your
correspondents
had availed himself of your offer, I take the liberty to send the
enclosed,
on which, if you should think it worth your while, you can exercise
your
ingenuity.
I am yours, respectfully,
S. D. L.
No. 1.
Cauhiif and ftd sdBtirf ithot tacd
wade rdchfdr tin
fuaefshffheo fdoudf hetiusafhie tuis fed herhchriai fi aciftdu wn sdaef
it iuhfheo hiidohwid wn acn deodsf ths tin iris hf iaf iahoheaiin
rdffhedr;
aer Ad auf it ftif fdoudfin oissichoaPheo hefdiihodeod taf wade
odeduaiin
fdusdr ounsfiouastn. Sacn fsdohdf it fdoudf iuhfheo idud weiie fi ftd
aeohdeff;
fisdDhsdf, A fiacdf tdar iaf ftacdr aer ftd ouiie iuhffde isle ihtt
fisd
herdhwid oiiiuheo tiihr, atfdu ithot tahu wdheo sdushffdr fi ouii
aoahe,
hetiusafbie oiiir wd fuaefshffdr ihEt ihffid raeodu ftaf rhfoicdun
iiiir
hefid iefhi ftd aswiiafiun dshffid fatdin udaotdr hff rdffheafhie.
Ounsfiouastn
tiidcdu siud suisduin dswuaodf Stied sirdf it iuhfLeo ithot and
uderdudr
idohwid iein wn sdaef it fled desiaeafiun wdn ithot sawdf weiie ftd
udai
fhoehthoafhie it ftd onstduf dssiindr fi hff siffdffiu.
No. 2.
Ofoiioiiaso ortsiii sov eodisoioe
afduiostifoi fit
iftvi si tri oistoiv oiniafetsorit ifeov rsri inotiiiiv ridiiot, irio
riwio
eovit atrotfetsoria aioriti iitri If oitovin tri aetifei ioreitit sov
usttoi
oioittstifo dfti aSdooitior trso ifeov tri dfit otftSeov softridi
fitoistoiv
oriofiforiti suitteii viireiiitifoi fit tri iarfoisiti, iiti trir net
otiiiotiv
uitfti rid lo tri eoviieeiiiv rfasueostr fit rii dftrit tfocei.
In the solution of the first of these
ciphers we
had little more than ordinary trouble. The second proved to be
exceedingly
difficult, and it was only by calling [column 2:]
every
faculty into play that we could read it at all. The first runs thus.
"Various are the methods which have
been devised
for transmitting secret information from one individual to another, by
means of writing, illegible to any except him for whom it was
originally
designed; and the art of thus secretly communicating intelligence has
been
generally termed cryptography. Many species of secret writing
were
known to the ancients. Sometimes a slave's head was shaved, and the
crown
written upon with some indelible coloring fluid; after which the hair
being
permitted to grow again, information could be transmitted with little
danger
that discovery would ensue until the ambulatory epistle safely reached
its destination. Cryptography, however, pure, properly embraces those
modes
of writing which are rendered legible only by means of some explanatory
key which makes known the real signification of the ciphers employed to
its possessor."
The key-phrase of this cryptograph
is — "A word to
the wise is sufficient."
The second is thus translated —
"Nonsensical phrases and unmeaning combinations
of words, as the learned lexicographer would have confessed himself,
when
hidden under cryptographic ciphers, serve to perpdex the
curious
enquirer, and baffle penetration more completely than would the most
profound apothems of
learned philosophers. Abstruse disquisitions of the scholiasts, were
they
but presented before him in the undisguised vocabulary of his mother
tongue
"
The last sentence here (as will be
seen) is broken
off short. The spelling we have strictly adhered to. D, by mistake, has
been put for I in perplex.
The key-phrase is — "Suaviter ir, mode, fortiter I'll
ret"
In the ordinary cryptograph, as will be seen in
reference to most of
those we have specified above, the artificial alphabet agreed upon by
the
correspondents, is employed, letter for letter, in place of the usual
or
natural one. For example: — two parties wish to communicate
secretly.
It
is arranged before parting that
|
( |
|
shall stand for
|
|
a |
|
) |
|
—————— " |
|
b |
|
— |
|
—————— "
|
|
c |
|
*
|
|
—————— "
|
|
d |
|
. |
|
—————— "
|
|
e |
|
’
|
|
—————— "
|
|
f |
|
; |
|
—————— "
|
|
g |
|
:
|
|
—————— "
|
|
h |
|
? |
|
—————— "
|
|
i or J
|
|
! |
|
—————— "
|
|
k |
|
&
|
|
—————— "
|
|
l |
|
0 |
|
—————— "
|
|
m |
|
‘
|
|
—————— "
|
|
n |
|
† |
|
—————— "
|
|
o |
|
‡
|
|
—————— "
|
|
p |
|
¶ |
|
—————— "
|
|
q |
|
![[R-hand]](zrhand12.jpg)
|
|
—————— "
|
|
r |
|
] |
|
—————— "
|
|
s |
|
[
|
|
—————— "
|
|
t [page
37:]
|
|
£ |
|
—————— "
|
|
u or v
|
|
$ |
|
—————— "
|
|
w |
|
¿
|
|
—————— "
|
|
x |
|
¡ |
|
—————— "
|
|
y |
|
![[L-hand]](zlhand12.jpg)
|
|
—————— "
|
|
z |
Now the following note is to be communicated —
"We must see you immediately upon a matter of great
importance. Plots have been discovered, and the conspirators are in our
hands. Hasten!"
These words would be written thus
$ 0 . £ ] [ ] . . ¡ † £ ? 0 0
. * ¿
) [ . & ¡ £ ‡ † ‘ ) 0 ) [ [ .
† ’ ;
. ) [ ? 0 ‡ †
[ ) ‘ — . ‡ & † [ ] : ) £ . ( . . ‘ * .
] — † £ .
. * ) ' * — † ‘ ] ‡ ?
) [ †
] )
. ?
? ‘ † £
: ) ‘ * ] : ) ] [ . ’
This certainly has an intricate appearance, and
would
prove a most difficult cipher to any one not conversant with
cryptography.
But it will be observed that a, for example, is never
represented
by any other character than ), b never by any other character
than
(, and so on. Thus by the discovery, accidental or otherwise, of any
one
letter, the party intercepting the epistle would gain a permanent and
decided
advantage and could apply his knowledge to all the instances in which
the
character in question was employed throughout the cipher.
In the cryptographs, on the other hand, which have been
sent us by our
correspondent at Stonington, and which are identical in conformation
with
the cipher resolved by Berryer, no such permanent advantage is to be
obtained.
Let us refer to the second of these puzzles. Its
key-phrase runs thus:
Surfeiter ire mono, fortiter in ret
Let us now place the alphabet beneath this phrase,
letter beneath letter —
S|u|a|v|i|t|e|r|i|n|m|o|d|o|f|o|r|t|i|t|e|r|i|n|r|e
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
We here see that
a
stands for — — —
— — — — — — — —
c
d
"
" — — — — —
— — — — — — m
e
"
" — — — — —
— — — — — — z
f
"
" g, u and
o
i
"
" — — — — —
— — — — — — w
m
"
" e, i, s and k
n
"
" j
and
x
o
"
" — — — — —
— — — — — — p
r
"
" h, q, v and y
s
"
" — — — — —
— — — — — — a
t
"
" — — — — —
— — — — — — t
u
"
" f, r, and b
v
"
" — — — — —
— — — — — — d
In this manner n stands for two letters, and e, o, and
t for
three each, while i and r represent each as many as four.
Thirteen
characters are made to perform the operations of the whole alphabet.
The
result of such a key-phrase upon the cipher, is to give it the
appearance
of a mere medley of the letters e, o, t, r and i — the latter
character
greatly predominating, through the accident of being employed for
letters
which, themselves, are inordinately prevalent in most languages — we
mean e and i. [column 2:]
A letter thus written being
intercepted, and the
key-phrase unknown, the individual who should attempt to decipher it
may
be imagined guessing, or otherwise attempting to convince himself, that
a certain character (i, for example,) represented the letter e. Looking
throughout the cryptograph for confirmation of this idea, he would meet
with nothing but a negation of it. He would see the character in
situations
where it could not possibly represent e. He might, for
instance,
be puzzled by four i's forming of themselves a single word, without the
intervention of any other character; in which case, of course, they
could
not be all e's. It will be seen that the word wise might
be thus constructed. We say this may be seen now, by us, in
possession
of the key-phrase; but the question will, no doubt, occur, how, without
the
key-phrase, and without cognizance of any single letter in the cipher,
it would be possible for the interceptor of such a cryptograph to make
any thing of such a word as iiii?
But again. A key-phrase might easily
be constructed,
in which one character would represent seven, eight, or ten letters.
Let
us then imagine the word iiiiiiiiii presenting itself in a cryptograph
to an individual without the proper key-phrase; or, if this be
a
supposition somewhat too perplexing, let us suppose it occurring to the
person for whom the cipher is designed, and who has the
key-phrase.
What is he to do with such a word as iiiiiiiiii? In any of the ordinary
books upon Algebra will be found a very concise formula (we have
not the necessary type for its insertion here) for ascertaining the
number
of arrangements in which m letters may be placed, taken n at
a time. But no doubt there are none of our readers ignorant of the
innumerable
combinations which may be made from these ten i's. Yet, unless it occur
otherwise bv accident, the correspondent receiving the cipher would
have
to write down all these combinations before attaining the word
intended;
and even when he had written them, he would be inexpressibly perplexed
in selecting the word designed from the vast number of other words
arising
in the course of the permutation.
To obviate, therefore, the exceeding
difficulty of
deciphering this species of cryptograph, on the part of the possessors
of the key-phrase, and to confine the deep intricacy of the puzzle to
those
for whom the cipher was not designed, it becomes necessary that some order
should
be agreed upon by the parties corresponding — some order in reference
to
which those characters are to be read which represent more than one
letter — and
this order must be held in view by the writer of the
cryptograph.
It may be agreed, for example, that the f rat time an i occurs
in
the cipher, it is to be understood as representing that character which
stands against the first i in the key-phrase; that the second
time
an i occurs it must be supposed to represent that letter which stands
opposed
to the second i in the key-phrase, &c. &c. Thus the location
of each cipherical letter must be considered in
connexion with the
character itself, in order to determine its exact signification.
We say that some pre-concerted order of
this [page
38:] kind is necessary, lest the cipher prove too intricate
a lock to yield even to its true key. But it will be evident, upon
inspection,
that our correspondent at Stonington has inflicted upon us a
cryptograph
in which no order has been preserved; in which many
characters,
respectively, stand, at absolute random, for many others. If,
therefore,
in regard to the gauntlet we threw down in April, he should be half
inclined
to accuse us of braggadocio, he will yet admit that we have more than
acted up to our boast. If what we then said was not said suaviter
in
modo, what we now do is at least done fortiter in re.
In these cursory observations we have
by no means
attempted to exhaust the subject of Cryptography. With such object in
view,
a folio might be required. We have indeed mentioned only a few of the
ordinary
modes of cipher. Even two thousand years [column 2:]
ago, Æneas Tacticus detailed twenty distinct methods; and modern
ingenuity has added much to the science. Our design has been chiefly
suggestive;
and perhaps we have already bored the readers of the Magazine. To those
who desire farther information upon this topic, we may say that there
are
extant treatises by Trithemius, Cap. Porta, Vignere, and P. Niceron.
The
works of the two latter may be found, we believe, in the library of the
Harvard University. If, however, there should be sought in these
disquisitions — or in any — rules for the solution of cipher,
the seeker will be
disappointed. Beyond some hints in regard to the general structure of
language,
and some minute exercises in their practical application, he will find
nothing upon record which he does not in his own intellect possess. |
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