NationMaster - Encyclopedia: ADFGVX cipher

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 modified Polybius square with a single columnar transposition. The cipher is named after the six possible letters used in the ciphertext: A, D, F, G, V and X. These letters were chosen deliberately because they sound very different from each other when transmitted via morse code. The intention was to reduce the possibility of operator error. 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 ÎºÏÏ…Ï€Ï„ÏŒÏ‚ kryptÃ³s hidden, and the verb Î³ÏÎ¬Ï†Ï‰ grÃ¡fo write) is the study of message secrecy. ... This article is about algorithms for encryption and decryption. ... This article or section is in need of attention from an expert on the subject. ... 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 Herbert Henry Asquith Douglas Haig John Jellicoe Victor Emmanuel III Luigi Cadorna Armando Diaz Woodrow Wilson John Pershing Franz... Colonel (IPA: or ) is a military rank of a commissioned officer, with the corresponding ranks existing in nearly every country in the world. ... Year 1918 (MCMXVIII) was a common year starting on Tuesday of the Gregorian calendar (see link for calendar) or a common year starting on Wednesday of the Julian calendar. ... In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). ... In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). ... In cryptography, the Polybius square is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist. ...

Operation of ADFGX

Suppose we need to send the plaintext message, "Attack at once". First, a secret mixed alphabet is filled into a 5 × 5 Polybius square, like so: The plain text term has a different meaning. ... 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. ...

i and j have been combined, to make the alphabet fit in a 5 × 5 grid. The labels of the columns and rows were chosen simply as characters which were difficult to confuse in the Morse code, to minimise errors in transmission. 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information, using standardized sequences of variously spaced short and long elements for the letters, numerals, punctuation, special characters and words of a message. ...

Next, the fractionated message is subject to a transposition similar to (but not quite the same as) the standard columnar. We write out the message in rows under a transposition key:

Then it is read off in columns, in keyword order, yielding the ciphertext: This article is about algorithms for encryption and decryption. ...

In practice, the transposition keys were about two dozen characters long. Both the transposition keys and fractionation keys were changed daily.

ADFGVX

In June 1918, an additional letter, V, was added to the cipher. This expanded the grid to 6 × 6, allowing 36 characters to be used. This allowed the full alphabet (instead of combining I and J), plus the digits from 0 to 9. This mainly had the effect of considerably shortening messages which contained a large number of figures. Year 1918 (MCMXVIII) was a common year starting on Tuesday of the Gregorian calendar (see link for calendar) or a common year starting on Wednesday of the Julian calendar. ... In mathematics and computer science, a numerical digit is a symbol, e. ...

Cryptanalysis

ADFGVX was cryptanalysed by French Army Lieutenant Georges Painvin. The work was exceptionally difficult by the standards of classical cryptography, and Painvin became physically ill during it. His method of solution relied on finding messages with stereotyped beginnings, which would fractionate the same, then form similar patterns in the positions in the ciphertext that had corresponded to column headings in the transposition table. (Considerable statistical analysis was required after this step had been reached — all done by hand.) Cryptanalysis (from the Greek kryptÃ³s, hidden, and analÃ½ein, 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. ... Lieutenant is a military, naval, paramilitary, fire service or police officer rank. ... Georges Painvin in 1914 Georges Jean Painvin (1886-1980) was a French cryptanalyst during the First World War. ...

This meant it was only effective during times of very high traffic — but, fortunately for the cryptanalysts, that was also when the most important messages were sent.

Painvin broke the ADFGX cipher in April 1918, a few weeks after the Germans launched their Spring Offensive. As a direct result, the French army discovered where Ludendorff intended to attack. The French concentrated their forces at that point and stopped the Spring Offensive. The 1918 Spring Offensive or Kaiserschlacht was a series of German attacks along the Western Front during the First World War, which marked the deepest advance by either side since 1914. ... Ludendorff in 1918 Erich Ludendorff (sometimes given incorrectly as Erich von Ludendorff) (April 9, 1865 â€“ December 20, 1937, Tutzing, Bavaria, Germany) was a German Army officer, noted as a general during World War I. // Ludendorff was born in Kruszewnia near Posen, Prussia (now PoznaÅ„, Poland). ...

Note: the claim that Painvin's breaking of the ADFGX cypher stopped the German Spring Offensive of 1918, while frequently made, does not seem to agree with two historical facts. The 1918 Spring Offensive or Kaiserschlacht was a series of German attacks along the Western Front during the First World War, which marked the deepest advance by either side since 1914. ... Year 1918 (MCMXVIII) was a common year starting on Tuesday of the Gregorian calendar (see link for calendar) or a common year starting on Wednesday of the Julian calendar. ...

A 2002 review of Sophie de Lastours' book on this subject, La France gagne la guerre des codes secrets 1914-1918, in the Journal of Intelligence History, (Journal of Intelligence History: volume 2, Number 2, Winter 2002) states:

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References

Category: Classical ciphers The Affine cipher is a special case of the more general substitution cipher. ... The Alberti Cipher was the first ever Polyalphabetic Cipher. ... Atbash is a simple substitution cipher for the Hebrew alphabet. ... A tabula recta for use with an autokey cipher An autokey cipher is a cipher which incorporates the message (the plaintext) into the key. ... In classical cryptography, the bifid cipher is a cipher which combines the Polybius square with transposition, and uses fractionation to achieve diffusion. ... A book cipher is a cipher in which the key is the identity of a book. ... The action of a Caesar cipher is to replace each plaintext letter with one a fixed number of places down the alphabet. ... The Four-square cipher is a manual symmetric encryption technique. ... Hills cipher machine, from figure 4 of the patent In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. ... A keyword is a monoalphabetic substitution. ... -1... In classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation. ... The pigpen cipher uses graphical symbols assigned according to a key similar to the above diagram. ... The Playfair system was invented by Charles Wheatstone, who first described it in 1854. ... A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. ... In cryptography, the Polybius square is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist. ... The Rail Fence Cipher is a form of transposition cipher that gets its name from the way in which it is encoded. ... The Reihenschieber was a hand cipher system used by Germany. ... Reservehandverfahren (RHV) (German: Reserve Hand Procedure) was a German Naval World War II hand-cipher system used as a backup method when no working Enigma machine was available[1]. The cipher had two stages: a transposition followed by bigram substitution. ... ROT13 replaces each letter by its partner 13 characters further along the alphabet. ... In classical cryptography, the runnning key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide a very long key stream. ... This article is about the encryption device; for the Dune character, see Scytale (Dune). ... The Smithy code is series of letters embedded, as a private amusement,[1] within the April 2006 approved judgement of Mr Justice Peter Smith on the The Da Vinci Code copyright case. ... The Solitaire cryptographic algorithm was designed by Bruce Schneier for use in Neal Stephensons Cryptonomicon (where it was initially called Pontifex). ... In cryptography, a straddling checkerboard is a device for converting an alphabetic plaintext into digits whilst simultaneously achieving fractionation (a simple form of information diffusion) and homophony (a simple method for suppressing peaks of the frequency distribution). ... 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. ... It has been suggested that the section The code from the article Smitty Harris be merged into this article or section. ... In classical cryptography, a transposition cipher changes one character from the plaintext to another (to decrypt the reverse is done). ... 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. ... The Two-square cipher is a manual symmetric encryption technique. ... 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. ... The VigenÃ¨re cipher is named for Blaise de VigenÃ¨re (pictured), although Giovan Batista Belaso had invented the cipher earlier. ... In mathematics, physics and signal processing, frequency analysis is a method to decompose a function, wave, or signal into its frequency components so that it is possible to have the frequency spectrum. ... In cryptography, coincidence counting is the technique (invented by William F. Friedman) of putting two texts side-by-side and counting the number of times that a letter appears next to itself in both copies. ... A cryptogram is a short piece of text encrypted with a simple substitution cipher in which each letter is replaced by a different letter. ... Bacons cipher or the Baconian cipher is a method of steganography (a method of hiding a secret message as opposed to a true cipher) devised by Francis Bacon. ... In cryptography, the Polybius square is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist. ... This article is about the encryption device; for the Dune character, see Scytale (Dune). ... In cryptography, a straddling checkerboard is a device for converting an alphabetic plaintext into digits whilst simultaneously achieving fractionation (a simple form of information diffusion) and homophony (a simple method for suppressing peaks of the frequency distribution). ... Tabula recta In cryptography, the tabula recta is a square table of alphabets, each one made by shifting the previous one to the left. ... 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 ÎºÏÏ…Ï€Ï„ÏŒÏ‚ kryptÃ³s hidden, and the verb Î³ÏÎ¬Ï†Ï‰ grÃ¡fo write) is the study of message secrecy. ... The history of cryptography dates back thousands of years. ... Cryptanalysis (from the Greek kryptÃ³s, hidden, and analÃ½ein, 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. ... This article is intended to be an analytic glossary, or alternatively, an organized collection of annotated pointers. ... Symmetric-key algorithms are a class of algorithms for cryptography that use trivially related cryptographic keys for both decryption and encryption. ... Encryption Decryption In cryptography, a block cipher is a symmetric key cipher which operates on fixed-length groups of bits, termed blocks, with an unvarying transformation. ... The operation of A5/1, a LFSR-based stream cipher used to encrypt mobile phone conversations. ... A big random number is used to make a public-key pair. ... In cryptography, a cryptographic hash function is a hash function with certain additional security properties to make it suitable for use as a primitive in various information security applications, such as authentication and message integrity. ... A cryptographic message authentication code (MAC) is a short piece of information used to authenticate a message. ... A cryptographically secure pseudo-random number generator (CSPRNG) is a pseudo-random number generator (PRNG) with properties that make it suitable for use in cryptography. ...

Contents

Operation of ADFGX

ADFGVX

Cryptanalysis

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References

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