Puzzles
#21
Solving Section III
The following is 100% stolen from this site.

The key is 0362514 (KRYPTOS).
And the encryption process is Route Transposition followed by a Keyed Columnar Transposition.

Step 1, Route Transposition:

First we pad the message fitting it into a 86xN box.
Why padding it? To make the text in all the columns line up leaving columns of only two different lengths for the person decrypting to deal with, who is expected to know exactly how many of them there are and which ones they are. We are just being considerate of the guy with the key on the other end.

How many letters to add? The message length is 336 and we are fitting it into a box of width 86. 86 mod 7 = 2.
It means that every line except for the last one will have 2 extra columns. 336 mod 86 = 78.
The last line will be 78 letters long and 78 mod 7 = 1.
And since the number of the last line's "extra" columns has to be the same as the first lines to make the columns line up, we only need one extra Q to make it 2 for all the lines. Clear enough?

Now to the transposition itself:
In by Rows backwards into 86x4, Out by Columns in groups of 7 which is the length of the key:
SLOWLYDESPARATLYSLOWLYTHEREMAINSOFPASSAGEDEBRISTHATENCUM
BEREDTHELOWERPARTOFTHEDOORWAYWASREMOVEDWITHTREMBLINGHAND
SIMADEATINYBREACHINTHEUPPERLEFTHANDCORNERANDTHENWIDENING
THEHOLEALITTLEIINSERTEDTHECANDLEANDPEEREDINTHEHOTAIRESCA
PINGFROMTHECHAMBERCAUSEDTHEFLAMETOFLICKERBUTPRESENTLYDET
AILSOFTHEROOMWITHINEMERGEDFROMTHEMISTXCANYOUSEEANYTHINGQ?
->
?QGNIHTYNAEESUOYNACXTSIMEHTMORFDEGREMENIHTIWMOOREHTFOSLIATEDYLTNESERPTUBREKCILFOTEMALF
EHTDESUACREBMAHCEHTMORFGNIPACSERIATOHEHTNIDEREEPDNAELDNACEHTDETRESNIIELTTILAELOHEHTGNI
NEDIWNEHTDNARENROCDNAHTFELREPPUEHTNIHCAERBYNITAEDAMISDNAHGNILBMERTHTIWDEVOMERSAWYAWROO
DEHTFOTRAPREWOLEHTDEREBMUCNETAHTSIRBEDEGASSAPFOSNIAMEREHTYLWOLSYLTARAPSEDYLWOLS
What makes me think it was written backwards? Because the extra space is not at the end of the message but before the first letter. Who would bother calculating the position of the first letter and start writing the message beginning with the 7th column just to make it fill up the rectangle perfectly at the end?
I think it is easier to simply fill out the rectangle backwards if you are doing it with pen and paper.
Either way, it is 86x4 with 7 spaces in front of the first letter.
?QGNIHT YNAEESU OYNACXT SIMEHTM ORFDEGR EMENIHT IWMOORE HTFOSLI ATEDYLT NESERPT UBREKCI LFOTEMA LF
EHTDESU ACREBMA HCEHTMO RFGNIPA CSERIAT OHEHTNI DEREEPD NAELDNA CEHTDET RESNIIE LTTILAE LOHEHTG NI
NEDIWNE HTDNARE NROCDNA HTFELRE PPUEHTN IHCAERB YNITAED AMISDNA HGNILBM ERTHTIW DEVOMER SAWYAWR OO
DEHTFOT RAPREWO LEHTDER EBMUCNE TAHTSIR BEDEGAS SAPFOSN IAMEREH TYLWOLS YLTARAP SEDYLWO LS
Whichever way the text was written initially, after we restack it into 7 columns, it will result in:
?QGNIHT
EHTDESU
NEDIWNE
DEHTFOT

YNAEESU
ACREBMA
HTDNARE
RAPREWO

OYNACXT
HCEHTMO
NROCDNA
LEHTDER

SIMEHTM
RFGNIPA
HTFELRE
EBMUCNE

ORFDEGR
CSERIAT
PPUEHTN
TAHTSIR

EMENIHT
OHEHTNI
IHCAERB
BEDEGAS

IWMOORE
DEREEPD
YNITAED
SAPFOSN

HTFOSLI
NAELDNA
AMISDNA
IAMEREH

ATEDYLT
CEHTDET
HGNILBM
TYLWOLS

NESERPT
RESNIIE
ERTHTIW
YLTARAP

UBREKCI
LTTILAE
DEVOMER
SEDYLWO

LFOTEMA
LOHEHTG
SAWYAWR
LS

LF
NI
OO
Now write the key on top and proceed with...

Step 2, The Keyed Columnar Transposition:
KRYPTOS    KOPRSTY
0362514 -> 0123456

?QGNIHT    ?HNQTIG
EHTDESU    ESDHUET
NEDIWNE    NNIEEWD
DEHTFOT    DOTETFH
YNAEESU    YSENUEA
ACREBMA    AMECABR
HTDNARE    HRNTEAD
RAPREWO    RWRAOEP
OYNACXT    OXAYTCN
HCEHTMO    HMHCOTE
NROCDNA    NNCRADO
LEHTDER    LETERDH
SIMEHTM    STEIMHM
RFGNIPA    RPNFAIG
HTFELRE    HRETELF
EBMUCNE    ENUBECM
ORFDEGR    OGDRREF
CSERIAT    CARSTIE
PPUEHTN    PTEPNHU
TAHTSIR    TITARSH
EMENIHT    EHNMTIE
OHEHTNI    ONHHITE
IHCAERB    IRAHBEC
BEDEGAS    BAEESGD
IWMOORE    IROWEOM
DEREEPD    DPEEDER
YNITAED    YETNDAI
SAPFOSN    SSFANOP
HTFOSLI    HLOTISF
NAELDNA    NNLAADE
AMISDNA    ANSMADI
IAMEREH    IEEAHRM
ATEDYLT    ALDTTYE
CEHTDET    CETETDH
HGNILBM    HBIGMLN
TYLWOLS    TLWYSOL
NESERPT    NPEETRS
RESNIIE    RINEEIS
ERTHTIW    EIHRWTT
YLTARAP    YAALPRT
UBREKCI    UCEBIKR
LTTILAE    LAITELT
DEVOMER    DEOERMV
SEDYLWO    SWYEOLD
LFOTEMA    LMTFAEO
LOHEHTG    LTEOGHH
SAWYAWR    SWYARAW
LS        L  S 
LF        L  F 
NI        N  I 
OO        O  O 
Now to the last...

Step 3, Out by columns downwards, left to right resulting in:
?ENDYAHROHNLSRHEOCPTEOIBIDYSHNAIACHTNREYULDSLLSLLNO
HSNOSMRWXMNETPRNGATIHNRARPESLNNELEBLPIIACAEWMTW
NDITEENRAHCTENEUDRETNHAEOETFOLSEDTIWENHAEIOYTEY
QHEENCTAYCREIFTBRSPAMHHEWENATAMATEGYEERLBTEEFOASFIO
TUETUAEOTOARMAEERTNRTIBSEDDNIAAHTTMSTEWPIEROAGR
IEWFEBAECTDDHILCEIHSITEGOEAOSDDRYDLORITRKLMLEHA
GTDHARDPNEOHMGFMFEUHEECDMRIPFEIMEHNLSSTTRTVDOHW
Reminds you of anything? ;)

The decryption process requires knowing the key and the rectangle size for the route transposition:

KRYPTOS and 86.

First we determine the line lengths to split the message:
86 mod 7 = 2. It means that two of the columns are going to be longer.

Which two and by how much?
The first two in our system (they are 0 and 3 for the person decrypting the message), with lengths 51 and 47.
The difference between those lengths will be the same (4) for 86 mod 7 regardless of the message length.
You may want to find out why as an excercise.

So we...

Step 1, Split the input as follows:
0 ?ENDYAHROHNLSRHEOCPTEOIBIDYSHNAIACHTNREYULDSLLSLLNO
1 HSNOSMRWXMNETPRNGATIHNRARPESLNNELEBLPIIACAEWMTW
2 NDITEENRAHCTENEUDRETNHAEOETFOLSEDTIWENHAEIOYTEY
3 QHEENCTAYCREIFTBRSPAMHHEWENATAMATEGYEERLBTEEFOASFIO
4 TUETUAEOTOARMAEERTNRTIBSEDDNIAAHTTMSTEWPIEROAGR
5 IEWFEBAECTDDHILCEIHSITEGOEAOSDDRYDLORITRKLMLEHA
6 GTDHARDPNEOHMGFMFEUHEECDMRIPFEIMEHNLSSTTRTVDOHW
Step 2, Write it in columns... (i omitted it to make Step 3 clearer, hence the following text is on its side)

Step 3, Reorder the columns according to the key:

0 ?ENDYAHROHNLSRHEOCPTEOIBIDYSHNAIACHTNREYULDSLLSLLNO
3 QHEENCTAYCREIFTBRSPAMHHEWENATAMATEGYEERLBTEEFOASFIO
6 GTDHARDPNEOHMGFMFEUHEECDMRIPFEIMEHNLSSTTRTVDOHW
2 NDITEENRAHCTENEUDRETNHAEOETFOLSEDTIWENHAEIOYTEY
5 IEWFEBAECTDDHILCEIHSITEGOEAOSDDRYDLORITRKLMLEHA
1 HSNOSMRWXMNETPRNGATIHNRARPESLNNELEBLPIIACAEWMTW
4 TUETUAEOTOARMAEERTNRTIBSEDDNIAAHTTMSTEWPIEROAGR
Step 4, Chop them into 86-letter long lines
(in groups of 4 of course, since 337/86 is > 3 but is <= 4)
0 ?END YAHR OHNL SRHE OCPT EOIB IDYS HNAI ACHT NREY ULDS LLSL LNO
3 QHEE NCTA YCRE IFTB RSPA MHHE WENA TAMA TEGY EERL BTEE FOAS FIO
6 GTDH ARDP NEOH MGFM FEUH EECD MRIP FEIM EHNL SSTT RTVD OHW
2 NDIT EENR AHCT ENEU DRET NHAE OETF OLSE DTIW ENHA EIOY TEY
5 IEWF EBAE CTDD HILC EIHS ITEG OEAO SDDR YDLO RITR KLML EHA
1 HSNO SMRW XMNE TPRN GATI HNRA RPES LNNE LEBL PIIA CAEW MTW
4 TUET UAEO TOAR MAEE RTNR TIBS EDDN IAAH TTMS TEWP IERO AGR
Step 5, Read the resulting 4 lines of the message backwards (reverse of the Step 1 of encryption). Done.

If the same key KRYPTOS=0362514 was used to encrypt the 4th part, the decryption process would be as follows:

Let's say the number of columns for the route transposition was 49 or 21...

Step 1:
?OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR
->
?OBKRUOXOGHULB
SOLIFBBWFLRVQQ
PRNGKSSOTWTQSJ
QSSEKZZWATJKLU
DIAWINFBNYPVTT
MZFPKWGDKZXTJC
DIGKUHUAUEKCAR
Step 2:
?SPQDMD
OORSIZI
BLNSAFG
KIGEWPK
RFKKIKU
UBSZNWH
OBSZFGU
XWOWBDA
OFTANKU
GLWTYZE
HRTJPXK
UVQKVTC
LQSLTJA
BQJUTCR
Step 3:
KOPRSTY    KRYPTOS
0123456 -> 0362514
               
?SPQDMD    ?QDPMSD
OORSIZI    OSIRZOI
BLNSAFG    BSGNFLA
KIGEWPK    KEKGPIW
RFKKIKU    RKUKKFI
UBSZNWH    UZHSWBN
OBSZFGU    OZUSGBF
XWOWBDA    XWAODWB
OFTANKU    OAUTKFN
GLWTYZE    GTEWZLY
HRTJPXK    HJKTXRP
UVQKVTC    UKCQTVV
LQSLTJA    LLASJQT
BQJUTCR    BURJCQT
Step 4:

For 49 columns:
?QDPMSD BSGNFLA RKUKKFI OZUSGBF OAUTKFN HJKTXRP LLASJQT
OSIRZOI KEKGPIW UZHSWBN XWAODWB GTEWZLY UKCQTVV BURJCQT
For 21 columns:
?QDPMSD UZHSWBN HJKTXRP
OSIRZOI OZUSGBF UKCQTVV
BSGNFLA XWAODWB LLASJQT
KEKGPIW OAUTKFN BURJCQT
RKUKKFI GTEWZLY
Step 5:

For 49:
TQCJRUBVVTQCKUYLZWETGBWDOAWXNBWSHZUWIPGKEKIOZRISOTQJSALLPRXTKJHNFKTUAOFBGSUZOIFKKUKRALFNGSBDSMPDQ?
For 21:
YLZWETGIFKKUKRTQCJRUBNFKTUAOWIPGKEKTQJSALLBWDOAWXALFNGSBVVTQCKUFBGSUZOIOZRISOPRXTKJHNBWSHZUDSMPDQ?
Step 6: Breaking the cipher (most probably the same double-key Vigenere) and reading the message.
 
The final decrypted message
SLOWLYDESPARATLYSLOWLYTHEREMAINSOFPASSAGEDEBRIST
HATENCUMBEREDTHELOWERPARTOFTHEDOORWAYWASREMOVEDW
ITHTREMBLINGHANDSIMADEATINYBREACHINTHEUPPERLEFTH
ANDCORNERANDTHENWIDENINGTHEHOLEALITTLEIINSERTEDT
HECANDLEANDPEEREDINTHEHOTAIRESCAPINGFROMTHECHAMB
ERCAUSEDTHEFLAMETOFLICKERBUTPRESENTLYDETAILSOFTH
EROOMWITHINEMERGEDFROMTHEMISTXCANYOUSEEANYTHINGQ
Add in a sprinkling of punctuation, and it comes out to be
Slowly, desparatly slowly, the remains of passage debris that encumbered the lower
Part of the doorway was removed. With trembling hands i made a tiny breach in the upper
Lefthand corner and then widening the hole a little i inserted the candle and peered
in. The hot air escaping from the chamber caused the flame to flicker but presently
Details of the room within emerged from the mist x can you see anything q?

The above solution's came from the University of California, San Diego Math Dept.
https://www.math.ucsd.edu/

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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#22
My brain blew a gasket after 5 mins of trying to get some things figured out.

It's beyond my abilities. Scratchinghead I'm still gonna look at it and re-read your posts but I know it's not gonna help lol.

You got any word search puzzles? I'm a whiz at that. Chuckle
And the Lord spake, saying, "First shalt thou take out the Holy Pin. Then, shalt thou count to three. No more. No less. Three shalt be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count, nor either count thou two, excepting that thou then proceed to three. Five is right out. Once the number three, being the third number, be reached, then, lobbest thou thy Holy Hand Grenade of Antioch towards thy foe, who, being naughty in My sight, shall snuff it."
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#23
(02-13-2021, 11:32 PM)Debauchery Wrote: My brain blew a gasket after 5 mins of trying to get some things figured out.

It's beyond my abilities. Scratchinghead I'm still gonna look at it and re-read your posts but I know it's not gonna help lol.

You got any word search puzzles? I'm a whiz at that. Chuckle

They aren't supposed to be easy. If they were easy, no one could exchange secrets over a distance with another. Some moroon would figure it out and your message would be toast.

Chuckle

Just figuring out what kind of cypher it is, is a big deal.

Just look at it and enjoy it.

Go back up to post #3 ?, anyway, back in the thread and, look at ROT 13 and try it. Encrypt a phrase and then, decrypt it.

All these codes can be cracked. The only really safe method is a One Time Pad. A Jefferson wheel pair is a close second. I'll find some stuff on both and post it when I have time.

Drinks

Hope you're feeling better. max


Edit

@Debauchery check this site(s) out..

http://www.ciphersbyritter.com/LEARNING.HTM

https://thebestvpn.com/cryptography/

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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#24
Section III Stuff

Route Transposition


Route cipher

In a route cipher, the plaintext is first written out in a grid of given dimensions, then read off in a pattern given in the key. For example, using the same plaintext that we used for rail fence:

W R I O R F E O E
E E S V E L A N J
A D C E D E T C X

https://en.wikipedia.org/wiki/Transposition_cipher

https://crypto.interactive-maths.com/route-cipher.html


Route Cipher

The Route Cipher is a transposition cipher. It rearranges the plaintext letters based on a shape of an imaginary path drawn on a grid.
Usage

The Route Cipher is a simple transposition cipher that can be performed manually, without the need of using additional equipment. It was quite popular throughout centuries, and used to protect information when more sophisticated ways were not available.

Currently, the Route Cipher is usually used with a piece of paper. The letters fill the grid which has dimensions defined by the secret key.

Good examples
http://www.crypto-it.net/eng/simple/route-cipher.html




Transposition cipher(s)

1 Rail Fence cipher
2 Scytale
3 Route cipher
4 Columnar transposition
5 Double transposition

    5.1 Cryptanalysis

6 Myszkowski transposition
7 Disrupted transposition
8 Grilles
9 Detection and cryptanalysis
10 Combinations
11 Fractionation

Snip
In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext (which are commonly characters or groups of characters) are shifted according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed (the plaintext is reordered). Mathematically a bijective function is used on the characters' positions to encrypt and an inverse function to decrypt.

The Rail Fence cipher is a form of transposition cipher that gets its name from the way in which it is encoded. In the rail fence cipher, the plaintext is written downwards and diagonally on successive "rails" of an imaginary fence, then moving up when we get to the bottom. The message is then read off in rows. For example, using three "rails" and a message of 'WE ARE DISCOVERED FLEE AT ONCE', the cipherer writes out:

W . . . E . . . C . . . R . . . L . . . T . . . E
. E . R . D . S . O . E . E . F . E . A . O . C .
. . A . . . I . . . V . . . D . . . E . . . N . .

Then reads off:

WECRL TEERD SOEEF EAOCA IVDEN

The cipher has broken this ciphertext up into blocks of five to help avoid errors. (see the Numbers Station post #26 below)
This is a common technique used to make the cipher more easily readable. The spacing is not related to spaces in the plaintext and so does not carry any information about the plaintext.)

https://en.wikipedia.org/wiki/Transposition_cipher

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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  • Heir
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#25
HOLDER

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
Like Reply
#26
Numbers stations


A numbers station is a shortwave radio station characterized by broadcasts of formatted numbers, which are believed to be addressed to intelligence officers operating in foreign countries.[1] Most identified stations use speech synthesis to vocalize numbers, although digital modes such as phase-shift keying and frequency-shift keying, as well as Morse code transmissions, are not uncommon. Most stations have set time schedules, or schedule patterns; however, other stations appear to have no discernable pattern and broadcast at random times. Stations may or may not have set frequencies in the HF band.[2]

The first known use of numbers stations was during World War I, with the numbers transmitted in Morse code. Numbers stations were most prolific during the Cold War era, yet many continue to broadcast and some long-time stations may have been taken over by different operators.[3] The Czech Ministry of the Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage,[4][5][6] with declassified documents proving the same. Few QSL responses have been received from numbers stations[7] by shortwave listeners who sent reception reports, to stations that identified themselves or to entities the listeners believed responsible for the broadcasts, which is the expected behaviour of a non-clandestine station.[8][9]

One well-known numbers station was the E03 "Lincolnshire Poacher",[10] which is thought to have been run by the British Secret Intelligence Service.[11] It was first broadcast from Bletchley Park in the mid-1970s but later was broadcast from RAF Akrotiri in Cyprus.

In 2001, the United States tried the Cuban Five on the charge of spying for Cuba. That group had received and decoded messages that had been broadcast from the "Atención" station in Cuba.[12] Also in 2001, Ana Belén Montes, a senior US Defense Intelligence

Snip
It has been reported that the United States has used numbers stations to communicate encoded information to persons in other countries.[12] There are also claims that State Department-operated stations, such as KKN50 and KKN44, used to broadcast similar "numbers" messages or related traffic, although these radio stations have been off the air for many years.[15][16]

https://en.wikipedia.org/wiki/Numbers_station

https://www.youtube.com/watch?v=SQbQTv3aMkU

https://www.youtube.com/watch?v=jib-857c7GE

https://www.youtube.com/watch?v=we1uIOgNAFg

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
Like Reply
#27
O T P

[Image: AZjJyte.png]

A format of one-time pad used by the U.S. National Security Agency, code named DIANA. The table on the right is an aid for converting between plaintext and ciphertext using the characters at left as the key

In cryptography, the one-time pad (OTP) is an encryption technique that cannot be cracked, but requires the use of a one-time pre-shared key the same size as, or longer than, the message being sent. In this technique, a plaintext is paired with a random secret key (also referred to as a one-time pad). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using modular addition.

The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met:[1][2]

    The key must be truly random.
    The key must be at least as long as the plaintext.
    The key must never be reused in whole or in part.
    The key must be kept completely secret.


It has also been proven that any cipher with the property of perfect secrecy must use keys with effectively the same requirements as OTP keys.[3] Digital versions of one-time pad ciphers have been used by nations for critical diplomatic and military communication, but the problems of secure key distribution have made them impractical for most applications.

https://en.wikipedia.org/wiki/One-time_pad

https://www.khanacademy.org/computing/co...tic-cipher

https://www.cryptomuseum.com/crypto/otp/index.htm

http://users.telenet.be/d.rijmenants/en/onetimepad.htm

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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#28
For practical Cryptography, The Book Cipher is maybe my favorite.

The use of a book or publication is necessary. The Bible is a popular choice as, it's easy to find a popular edition like the Gideon Bible, that was often found in hotel rooms.

Snip
A book cipher, or Ottendorf cipher, is a cipher in which the key is some aspect of a book or other piece of text. Books, being common and widely available in modern times, are more convenient for this use than objects made specifically for cryptographic purposes. It is typically essential that both correspondents not only have the same book, but the same edition.[1]

Traditionally book ciphers work by replacing words in the plaintext of a message with the location of words from the book being used. In this mode, book ciphers are more properly called codes.

This can have problems; if a word appears in the plaintext but not in the book, it cannot be encoded. An alternative approach which gets around this problem is to replace individual letters rather than words. One such method, used in the second Beale cipher, replaces the first letter of a word in the book with that word's position. In this case, the book cipher is properly a cipher — specifically, a homophonic substitution cipher. However, if used often, this technique has the side effect of creating a larger ciphertext (typically 4 to 6 digits being required to encipher each letter or syllable) and increases the time and effort required to decode the message.

https://en.wikipedia.org/wiki/Book_cipher


The Book Cipher Algorithm


By Dejan Ristanovic and Jelica Protic, September 24, 2008
5-6 minutes

The Book cipher algorithm uses letters of subsequent words in some text or book as a key to encode messages.

Unless you're a professional cryptanalyst, writing cryptography code means meddling with "powers" you cannot fully comprehend, and seemingly insignificant slips can be fatal. During World War II, for instance, Polish and British mathematicians broke Germany's Enigma code only because the same message-key was enciphered twice at the beginning of every message. The Germans did this to avoid mistakes caused by radio interference, but at the same time, it ruined their carefully planned cryptosystem. And how many slips are there in the code that multiply big numbers, look for 1000-digits primes, and encrypt the fixed header of your document?

With the Book cipher algorithm, you're safe from these kinds of errors because it is simple enough that you can code it in a few lines of C that are completely understandable, but still extremely secure. The so-called Beale ciphers (unmuseum.org/beal.htm), which point to a location of buried treasure somewhere in Bedford county, were coded in 1885, but still have not been decoded. This secret (or maybe hoax) has occupied some of the best cryptanalytic minds. Likewise, when Simon Singh gave 10 problems in the appendix of The Code Book, problem #5 (Book cipher) was the most difficult one for the winners of the £10,000 prize (www.simonsingh.com/Cipher_ Challenge.html). Still, the Book cipher has probably never been used in commercial software.
Book Cipher Algorithms

Basically, the Book cipher algorithm uses letters of subsequent words in some text or book as a key to encode a message. Figure 1 is the simplest form, usually called the "running key cipher." In this case, text (usually from a book) is used to provide a very long key stream. The book used is agreed upon in advance, while the passage used is chosen randomly for each message and secretly indicated somewhere in a previous message. In this example, we agreed to use J.K. Rowling's Harry Potter and the Order of the Phoenix and to start on page 335, line 28, with the sentence, "Hermione bit her lip and did not answer." We write this text under the plaintext and use it as the running key. The particular message to send is "DRDOBBS." We XOR the corresponding characters of the message and the running key to get the ciphertext 12 23 22 2 11 13 29.

Plaintext        D  R  D  O  B  B  S
Plaintext (hex)  44  52  44  4F  42  42  53
Running key      H  E  R  M  I  O  N
Running key (hex) 48  45  52  4D  49  4F  4E
Ciphertext (hex)  0C  17  16  02  0B  0D  1D
Ciphertext        12  23  22  2  11  13  29

Hex converter (many hand held scientific calculators do this)
https://learn.sparkfun.com/tutorials/hex...alculators

https://www.calculator.net/hex-calculator.html

https://www.eevblog.com/forum/reviews/ha...yhexlogic/


MORE
https://www.drdobbs.com/security/the-boo.../210603676

https://www.cs.miami.edu/home/burt/journ...ookcipher/

My choice..
[Image: 517AKNlBQvL._SX306_BO1,204,203,200_.jpg]

ISBN-13: 978-0553213119
ISBN-10: 9780553213119


@Debauchery @Heir

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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#29
PGP 1dunno1


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[Image: 3FTRPrR.png][Image: on1tkoS.png]
https://web.archive.org/web/201310032204...gacy.info/
Celebrating Over 30 Years as a " Designated Paper Terrorist "
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#30
(02-14-2021, 02:25 PM)Heir Wrote: PGP  1dunno1


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PGP is fine for most things over a cyber net. My mail is encrypted with a PGP variant. But, for use over a radio or using the posta mail system, it's not the best.

Plus, PGP can't be run by hand, you need a computer. The above methods are simple. I converted base 10 to hex by hand for years, before I had a calculator that would do it.

And both, a OTP and Book Cipher are stronger encryption than PGP or RSA.

If you have a running computer, a carrier pigeon can easily transport a Micro SD Card. I wouldn't trust one to The  PO. The bad boys in the sand delivered all their data via hand delivered thumb drives.

[Image: 220px-SD_Cards.svg.png]
From top to bottom: SD, miniSD, microSD

Half the population at Base Camp was clinically delusional.
-- John Krakauer 1996 Everest Expedition.

Apophenia is : “the tendency to perceive a connection or meaningful pattern between unrelated or random things (such as objects or ideas)”
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  • Heir
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