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In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). That is, the order of the characters is changed. Mathematically a bijective function is used on the characters' positions to encrypt and an inverse function to decrypt. The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κÏυπτός kryptós hidden, and the verb γÏάφω gráfo write) is the study of message secrecy. ...
In cryptography, plaintext is information used as input to an encryption algorithm; the output is termed ciphertext. ...
In mathematics, a bijection, bijective function, or one-to-one correspondence is a function that is both injective (one-to-one) and surjective (onto), and therefore bijections are also called one_to_one and onto. ...
In mathematics, an inverse function is in simple terms a function which does the reverse of a given function. ...
Following are some implementations.
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 and grid 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 The key might specify "spiral inwards, clockwise, starting from the top right". That would give a cipher text of:
EJX CTE DEC DAE WRI ORF EON ALE VSE
(The clerk has broken this ciphertext up into blocks of three to help avoid errors).
Route ciphers have many more keys than a rail fence. In fact, for messages of reasonable length, the number of possible keys is potentially too great to be enumerated even by modern machinery. However, not all keys are equally good. Badly chosen routes will leave excessive chunks of plaintext, or text simply reversed, and this will give cryptanalysts a clue as to the routes.
An interesting variation of the route cipher was the Union Route Cipher, used by Union forces during the American Civil War. This worked much like an ordinary route cipher, but transposed whole words instead of individual letters. Because this would leave certain highly sensitive words exposed, such words would first be concealed by code. The cipher clerk may also add entire null words, which were often chosen to make the ciphertext humorous. See [1] for an example. Combatants United States of America (Union) Confederate States of America (Confederacy) Commanders Abraham Lincoln, Ulysses S. Grant Jefferson Davis, Robert E. Lee Strength 2,200,000 1,064,000 Casualties 110,000 killed in action, 360,000 total dead, 275,200 wounded 93,000 killed in action, 258,000 total...
In the context of cryptography, a code is a method used to transform a message into an obscured form, preventing those not in on the secret from understanding what is actually transmitted. ...
Columnar transposition In a columnar transposition, the message is written out in rows of a fixed length, and then read out again column by column, and the columns are chosen in some scrambled order. Both the length of the rows and the permutation of the columns are usually defined by a keyword. For example, the word ZEBRAS is of length 6 (so the rows are of length 6), and the permutation is defined by the alphabetical order of the letters in the keyword. In this case, the order would be "6 3 2 4 1 5".
In a regular columnar transposition cipher, any spare spaces are filled with nulls; in an irregular columnar transposition cipher, the spaces are left blank. Finally, the message is read off in columns, in the order specified by the keyword. For example, suppose we use the keyword ZEBRAS and the message WE ARE DISCOVERED. FLEE AT ONCE. In a regular columnar transposition, we write this into the grid as:
6 3 2 4 1 5 W E A R E D I S C O V E R E D F L E E A T O N C E Q K J E U Providing five nulls (QKJEU) at the end. The ciphertext is then read off as: EVLNE ACDTK ESEAQ ROFOJ DEECU WIREE In the irregular case, the columns are not completed by nulls: 6 3 2 4 1 5 W E A R E D I S C O V E R E D F L E E A T O N C E This results in the following ciphertext: EVLNA CDTES EAROF ODEEC WIREE To decipher it, the recipient has to work out the column lengths by dividing the message length by the key length. Then he can write the message out in columns again, then re-order the columns by reforming the key word.
Columnar transposition continued to be used for serious purposes as a component of more complex ciphers at least into the 1950's.
Double transposition A single columnar transposition could be attacked by guessing possible column lengths, writing the message out in its columns (but in the wrong order, as the key is not yet known), and then looking for possible anagrams. Thus to make it stronger, a double transposition was often used. This is simply a columnar transposition applied twice. The same key can be used for both transpositions, or two different keys can be used. An anagram (Greek ana- = back or again, and graphein = to write) is a type of word play, the result of rearranging the letters of a word or phrase to produce other words, using all the original letters exactly once. ...
As an example, we can take the result of the irregular columnar transposition in the previous section, and perform a second encryption with a different keyword, STRIPE, which gives the permutation "564231":
5 6 4 2 3 1 E V L N A C D T E S E A R O F O D E E C W I R E E As before, this is read off columnwise to give the ciphertext: CAEEN SOIAE DRLEF WEDRE EVTOC During World War I, the German military used a double columnar transposition cipher. The system was regularly solved by the French, naming it Übchi, who were typically able to find the key in a matter of days after a new one had been introduced. However, the French success became widely-known and, after a publication in Le Matin, the Germans changed to a new system on 18 November 1914. Combatants Allied Powers: Russian Empire France British Empire Italy United States Central Powers: Austria-Hungary German Empire Ottoman Empire Bulgaria Commanders Nicholas II Aleksei Brusilov Georges Clemenceau Joseph Joffre Ferdinand Foch Robert Nivelle Herbert Henry Asquith Sir Douglas Haig Sir John Jellicoe Victor Emmanuel III Luigi Cadorna Armando Diaz Woodrow...
Le Matin is a daily newspaper published by Edipresse in Lausanne, Switzerland. ...
November 18 is the 322nd day of the year (323rd in leap years) in the Gregorian Calendar. ...
1914 (MCMXIV) was a common year starting on Thursday (see link for calendar). ...
During World War II, the double transposition cipher was used by Dutch Resistance groups, the French Maquis and the British Special Operations Executive (SOE). It was also used as an emergency cipher for the German Army and Navy. Preamble to the War During the period between the first and second World Wars the Netherlands, like other countries, suffered from the effects of the Great Depression after the Stock market crash of 1929. ...
Members of the Maquis in La Tresorerie For other uses, see Maquis. ...
The Special Operations Executive (SOE), sometimes referred to as the Baker Street Irregulars after Sherlock Holmess fictional group of spies, was a World War II organization initiated by Winston Churchill and Hugh Dalton in July 1940 as a mechanism for conducting warfare by means other than direct military engagement. ...
Until the discovery of the VIC cipher, double transposition was generally regarded as the most complicated cipher that an agent could operate reliably under difficult field conditions. The VIC cipher was a pencil and paper cipher used by the Soviet spy Reino Hayhanen, codenamed VICTOR. It was arguably the most complex hand-operated cipher ever seen. ...
Myszkowski transposition A variant form of columar transposition, proposed by Émile Victor Théodore Myszkowski in 1902, requires a keyword with recurrent letters. In usual practice, subsequent occurrences of a keyword letter are treated as if the next letter in alphabetical order, e.g., the keyword TOMATO yields a numeric keystring of "532164."
In Myszkowski transposition, recurrent keyword letters are numbered identically, TOMATO yielding a keystring of "432143."
4 3 2 1 4 3 W E A R E D I S C O V E R E D F L E E A T O N C E Plaintext columns with unique numbers are transcribed downward; those with recurring numbers are transcribed left to right: ROFOA CDTED SEEEA CWEIV RLENE
Disrupted transposition In a disrupted transposition, certain positions in a grid are blanked out, and not used when filling in the plaintext. This breaks up regular patterns and makes the cryptanalyst's job more difficult.
Detection and cryptanalysis Since transposition does not affect the frequency of individual symbols, simple transposition can be easily detected by the cryptanalyst by doing a frequency count. If the ciphertext exhibits a frequency distribution very similar to plaintext, it is most likely a transposition. This can then often be attacked by anagramming - sliding pieces of ciphertext around, then looking for sections that look like anagrams of English words, and solving the anagrams. Once such anagrams have been found, they reveal information about the transposition pattern, and can consequently be extended. Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so. ...
In statistics, a frequency distribution is a list of the values that a variable takes in a sample. ...
An anagram (Greek ana- = back or again, and graphein = to write) is a type of word play, the result of rearranging the letters of a word or phrase to produce other words, using all the original letters exactly once. ...
Simpler transpositions also often suffer from the property that keys very close to the correct key will reveal long sections of legible plaintext interspersed by gibberish. Consequently such ciphers may be vulnerable to optimum seeking algorithms such as genetic algorithms. A genetic algorithm (or short GA) is a search technique used in computing to find true or approximate solutions to optimization and search problems. ...
Combinations Transposition is often combined with other techniques. For example, a simple substitution cipher combined with a columnar transposition avoids the weakness of both. Replacing high frequency ciphertext symbols with high frequency plaintext letters does not reveal chunks of plaintext because of the transposition. Anagramming the transposition does not work because of the substitution. The technique is particularly powerful if combined with fractionation (see below). A disadvantage is that such ciphers are considerably more laborious and error prone than simpler ciphers. In cryptography, a substitution cipher is a method of encryption by which units of plaintext are substituted with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. ...
Fractionation Transposition is particularly effective when employed with fractionation - that is, a preliminary stage that divides each plaintext symbol into several ciphertext symbols. For example, the plaintext alphabet could be written out in a grid, then every letter in the message replaced by its co-ordinates (see Polybius square). Another method of fractionation is to simply convert the message to Morse code, with a symbol for spaces as well as dots and dashes. In cryptography, the Polybius square is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist. ...
1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information by using standardized sequences of variously spaced short and long elements for the characters and words in a message. ...
When such a fractionated message is transposed, the components of individual letters become widely separated in the message, thus achieving Claude E. Shannon's diffusion. Examples of ciphers that combine fractionation and transposition include the bifid cipher, the trifid cipher, the ADFGVX cipher and the VIC cipher. Claude Elwood Shannon (April 30, 1916 - February 24, 2001) has been called the father of information theory, and was the founder of practical digital circuit design theory. ...
In cryptography, confusion and diffusion are two properties of the operation of a secure cipher which were identified by Shannon in his paper, Communication Theory of Secrecy Systems published in 1949. ...
In classical cryptography, the bifid cipher is a cipher which combines the Polybius square with transposition, and uses fractionation to achieve diffusion. ...
In classical cryptography, the trifid cipher is a cipher invented around 1901 by Felix Delastelle, which extends the concept of the bifid cipher to a third dimension, allowing each symbol to be fractionated into 3 elements instead of two. ...
In cryptography, the ADFGVX cipher was a field cipher used by the German Army during World War I. ADFGVX was in fact an extension of an earlier cipher called ADFGX. Invented by Colonel Fritz Nebel and introduced in March 1918, the cipher was a fractionating transposition cipher which combined a...
The VIC cipher was a pencil and paper cipher used by the Soviet spy Reino Hayhanen, codenamed VICTOR. It was arguably the most complex hand-operated cipher ever seen. ...
On a final note you could replace each letter with its binary representation, transpose that and then convert the new binary string into the corresponding ASCII characters. If you loop the scrambling process on the binary string multiple times before changing it into ASCII characters it will make it harder to break into
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