title: Trench code
Tony Fasson
Kiss (cryptanalysis)
Hill cipher
Gilbert Vernam
Letter frequency
Colin Grazier
Enigma machine
BEAR and LION ciphers
Playfair cipher
sentences: Trench Codes (a form of cryptography) were codes used for secrecy by field armies in World War I.
 Originally, the most commonly used codes were simple substitution codes, but due to the relative vulnerability of the classical cipher, trench codes came into existence.
 Important messages generally used mathematical encryption for extra security, though.
 The use of these codes required the distribution of codebooks to military personnel, which proved to be a security liability since these books could be stolen by enemy forces.
Lieutenant Francis Anthony Blair Fasson, {'1': ", '2': ", '3': ", '4': "} (17 July 1913 – 30 October 1942), known as Tony Fasson, was a British Royal Navy officer.
 He was posthumously awarded the George Cross "for outstanding bravery and steadfast devotion to duty in the face of danger" when on 30 October 1942 in action in the Mediterranean Sea he captured codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking  .
In cryptanalysis, a kiss is a pair of identical messages sent using different ciphers, one of which has been broken.
 The term was used at Bletchley Park during World War II.
 A deciphered message in the breakable system provided a "crib" (piece of known plaintext) which could then be used to read the unbroken messages.
 One example was where messages read in a German meteorological cipher could be used to provide cribs for reading the difficult 4-wheel Naval Enigma cipher.
In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra.
 Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was practical (though barely) to operate on more than three symbols at once.
 The following discussion assumes an elementary knowledge of matrices.
Gilbert Sandford Vernam (3 April 1890 – 7 February 1960) was a Worcester Polytechnic Institute 1914 graduate and AT&T Bell Labs engineer who, in 1917, invented an additive polyalphabetic stream cipher and later co-invented an automated one-time pad cipher.
 Vernam proposed a teleprinter cipher in which a previously prepared key, kept on paper tape, is combined character by character with the plaintext message to produce the ciphertext.
 To decipher the ciphertext, the same key would be again combined character by character, producing the plaintext.
The frequency of letters in text has been studied for use in cryptanalysis, and frequency analysis in particular, dating back to the Iraqi mathematician Al-Kindi (c. 801–873 AD), who formally developed the method (the ciphers breakable by this technique go back at least to the Caesar cipher invented by Julius Caesar, so this method could have been explored in classical times).
 Letter frequency analysis gained additional importance in Europe with the development of movable type in 1450 AD, where one must estimate the amount of type required for each letterform, as evidenced by the variations in letter compartment size in typographer's type cases.
Able Seaman Colin Grazier, GC was posthumously awarded the George Cross for the "outstanding bravery and steadfast devotion to duty in the face of danger" which he displayed on 30 October 1942 in action in the eastern Mediterranean when capturing codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking  .
The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-20th century to protect commercial, diplomatic and military communication.
 Enigma was invented by the German engineer Arthur Scherbius at the end of World War I.
 Early models were used commercially from the early 1920s, and adopted by military and government services of several countries, most notably Nazi Germany before and during World War II.
 Several different Enigma models were produced, but the German military models, having a plugboard, were the most complex.
 Japanese and Italian models were also in use.
The BEAR and LION block ciphers were invented by Ross Anderson and Eli Biham by combining a stream cipher and a cryptographic hash function.
 The algorithms use a very large variable block size, on the order of 2 to 2 bits or more.
 Both are 3 round generalized (alternating) Feistel ciphers, using the hash function and the stream cipher as round functions.
 BEAR uses the hash function twice with independent keys, and the stream cipher once.
 LION uses the stream cipher twice and the hash function once.
 The inventors proved that an attack on either BEAR or LION that recovers the key would break both the stream cipher and the hash.
The Playfair cipher or Playfair square or Wheatstone-Playfair cipher or Wheatstone cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher.
 The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the use of the cipher.

Question: Question: Who invented the cipher that was breakable with the codebooks Tony Fasson recovered? 

 Your answer will be verified with exact match score. To ensure correct verification, only provide the answer within the <answer> </answer> tags. Do not put any sentences or reasoning process within the <answer> </answer> tags. 

Supporting Information: Paragraph 0 

 Lieutenant Francis Anthony Blair Fasson, {'1': ", '2': ", '3': ", '4': "} (17 July 1913 – 30 October 1942), known as Tony Fasson, was a British Royal Navy officer.
 He was posthumously awarded the George Cross "for outstanding bravery and steadfast devotion to duty in the face of danger" when on 30 October 1942 in action in the Mediterranean Sea he captured codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking  . 

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Paragraph 1 

 In cryptanalysis, a kiss is a pair of identical messages sent using different ciphers, one of which has been broken.
 The term was used at Bletchley Park during World War II.
 A deciphered message in the breakable system provided a "crib" (piece of known plaintext) which could then be used to read the unbroken messages.
 One example was where messages read in a German meteorological cipher could be used to provide cribs for reading the difficult 4-wheel Naval Enigma cipher. 

--------------------------------

Paragraph 2 

 In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra.
 Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was practical (though barely) to operate on more than three symbols at once.
 The following discussion assumes an elementary knowledge of matrices. 

--------------------------------

Paragraph 3 

 Gilbert Sandford Vernam (3 April 1890 – 7 February 1960) was a Worcester Polytechnic Institute 1914 graduate and AT&T Bell Labs engineer who, in 1917, invented an additive polyalphabetic stream cipher and later co-invented an automated one-time pad cipher.
 Vernam proposed a teleprinter cipher in which a previously prepared key, kept on paper tape, is combined character by character with the plaintext message to produce the ciphertext.
 To decipher the ciphertext, the same key would be again combined character by character, producing the plaintext. 

--------------------------------

Paragraph 4 

 Able Seaman Colin Grazier, GC was posthumously awarded the George Cross for the "outstanding bravery and steadfast devotion to duty in the face of danger" which he displayed on 30 October 1942 in action in the eastern Mediterranean when capturing codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking  . 

--------------------------------

Paragraph 5 

 The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-20th century to protect commercial, diplomatic and military communication.
 Enigma was invented by the German engineer Arthur Scherbius at the end of World War I.
 Early models were used commercially from the early 1920s, and adopted by military and government services of several countries, most notably Nazi Germany before and during World War II.
 Several different Enigma models were produced, but the German military models, having a plugboard, were the most complex.
 Japanese and Italian models were also in use. 

--------------------------------

Paragraph 6 

 The BEAR and LION block ciphers were invented by Ross Anderson and Eli Biham by combining a stream cipher and a cryptographic hash function.
 The algorithms use a very large variable block size, on the order of 2 to 2 bits or more.
 Both are 3 round generalized (alternating) Feistel ciphers, using the hash function and the stream cipher as round functions.
 BEAR uses the hash function twice with independent keys, and the stream cipher once.
 LION uses the stream cipher twice and the hash function once.
 The inventors proved that an attack on either BEAR or LION that recovers the key would break both the stream cipher and the hash. 

--------------------------------

Paragraph 7 

 The Playfair cipher or Playfair square or Wheatstone-Playfair cipher or Wheatstone cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher.
 The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the use of the cipher. 

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Answer: Arthur Scherbius