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From David Kahn's
``The Codebreakers''
(Macmillan, 1967)

``It must be that as soon as a culture has reached a certain level, probably measured largely by its literacy, cryptography appears spontaneously -- as its parents, language and writing, probably also did. The multiple human needs and desires that demand privacy among two or more people in the midst of social life must inevitably lead to cryptology wherever men thrive and wherever they write. Cultural diffusion seems a less likely explanation for its occurrence in so many areas, many of them distant and isolated.'' [p. 84]

The invention of cryptography is not limited to either civilians or the government. Wherever the need for secrecy is felt, the invention occurs. However, over time the quality of the best available system continues to improve and those best systems were often invented by civilians. Again, from David Kahn:

``It was the amateurs of cryptology who created the species. The professionals, who almost certainly surpassed them in cryptanalytic expertise, concentrated on down-to-earth problems of the systems that were then in use but are now outdated. The amateurs, unfettered to those realities, soared into the empyrean of theory.'' [pp. 125-6]

In the table to follow, each description starts with (date; civ or govt; source). Sources are identified in full at the end.

[Thanks to Ben Brockert of Mediapolis Iowa for making this into a table.]

Date C or G Source Info
about 1900 BC civ Kahn p.71 An Egyptian scribe used non-standard hieroglyphs in an inscription. Kahn lists this as the first documented example of written cryptography.
1500 BC civ Kahn p.75 A Mesopotamian tablet contains an enciphered formula for the making of glazes for pottery.
500-600 BC civ Kahn p.77 Hebrew scribes writing down the book of Jeremiah used a reversed-alphabet simple substitution cipher known as ATBASH. (Jeremiah started dictating to Baruch in 605 BC but the chapters containing these bits of cipher are attributed to a source labeled ``C'' (believed not to be Baruch) which could be an editor writing after the Babylonian exile in 587 BC, someone contemporaneous with Baruch or even Jeremiah himself.) ATBASH was one of a few Hebrew ciphers of the time.
487 BC govt Kahn p.82 The Greeks used a device called the ``skytale'' -- a staff around which a long, thin strip of leather was wrapped and written on. The leather was taken off and worn as a belt. Presumably, the recipient would have a matching staff and the encrypting staff would be left home.

[Note: an article in the July 1998 issue of Cryptologia entitled ``The Myth of the Skytale'' makes the case that the cryptographic use of the skytale was a myth.]

50-60 BC govt Kahn p.83 Julius Caesar (100-44 BC) used a simple substitution with the normal alphabet (just shifting the letters a fixed amount) in government communciations. This cipher was less strong than ATBASH, by a small amount, but in a day when few people read in the first place, it was good enough. He also used tansliteration of Latin into Greek letters and a number of other simple ciphers.
0-400? civ Burton The Kama Sutra of Vatsayana lists cryptography as the 44th and 45th of 64 arts (yogas) men and women should know and practice. The date of this work is unclear but is believed to be between the first and fourth centuries, AD. [Another expert, John W. Spellman, will commit only to the range between the 4th century BC and the 5th century AD.] Vatsayana says that his Kama Sutra is a compilation of much earlier works, making the dating of the cryptography references even more uncertain.

Part I, Chapter III lists the 64 arts and opens with: ``Man should study the Kama Sutra and the arts and sciences subordinate thereto [....] Even young maids should study this Kama Sutra, along with its arts and sciences, before marriage, and after it they should continue to do so with the consent of their husbands.'' These arts are clearly not the province of a government or even of academics, but rather are practices of laymen.

In this list of arts, the 44th and 45th read:

  • The art of understanding writing in cipher, and the writing of words in a peculiar way.
  • The art of speaking by changing the forms of words. It is of various kinds. Some speak by changing the beginning and end of words, others by adding unnecessary letters between every syllable of a word, and so on.
200's civ Kahn p.91 ``The so-called Leiden papyrus [...] employs cipher to conceal the crucial portions of important [magic] recipes''.
725-790? govt/(civ) Kahn p.97 Abu `Abd al-Rahman al-Khalil ibn Ahmad ibn `Amr ibn Tammam al Farahidi al-Zadi al Yahmadi wrote a (now lost) book on cryptography, inspired by his solution of a cryptogram in Greek for the Byzantine emperor. His solution was based on known (correctly guessed) plaintext at the message start -- a standard cryptanalytic method, used even in WW-II against Enigma messages.
855 civ Kahn p.93 Abu Bakr Ahmad ben `Ali ben Wahshiyya an-Nabati published several cipher alphabets which were traditionally used for magic.
--- govt Kahn p.94 ``A few documents with ciphertext survive from the Ghaznavid government of conquered Persia, and one chronicler reports that high officials were supplied with a personal cipher before setting out for new posts. But the general lack of continuity of Islamic states and the consequent failure to develop a permanent civil service and to set up permanent embassies in other countries militated against cryptography's more widespread use.''
1226 govt Kahn p.106 ``As early as 1226, a faint political cryptography appeared in the archives of Venice, where dots or crosses replaced the vowels in a few scattered words.''
about 1250 civ Kahn p.90 Roger Bacon not only described several ciphers but wrote: ``A man is crazy who writes a secret in any other way than one which will conceal it from the vulgar.''
1379 govt/civ Kahn p.107 Gabrieli di Lavinde at the request of Clement VII, compiled a combination substitution alphabet and small code -- the first example of the nomenclator Kahn has found. This class of code/cipher was to remain in general use among diplomats and some civilians for the next 450 years, in spite of the fact that there were stronger ciphers being invented in the meantime, possibly because of its relative convenience.
1300's govt Kahn p.94 `Abd al-Rahman Ibn Khaldun wrote "The Muqaddimah", a substantial survey of history which cites the use of ``names of perfumes, fruits, birds, or flowers to indicate the letters, or [...] of forms different from the accepted forms of the letters'' as a cipher among tax and army bureaus. He also includes a reference to cryptanalysis, noting ``Well-known writings on the subject are in the possession of the people.'' [p.97]
1392 civ Price p.182-7 "The Equatorie of the Planetis", possibly written by Geoffrey Chaucer, contains passages in cipher. The cipher is a simple substitution with a cipher alphabet consisting of letters, digits and symbols.
1412 civ Kahn p.95-6 Shihab al-Din abu `l-`Abbas Ahmad ben `Ali ben Ahmad `Abd Allah al-Qalqashandi wrote "Subh al-a `sha", a 14-volume Arabic encyclopedia which included a section on cryptology. This information was attributed to Taj ad-Din `Ali ibn ad-Duraihim ben Muhammad ath-Tha`alibi al-Mausili who lived from 1312 to 1361 but whose writings on cryptology have been lost. The list of ciphers in this work included both substitution and transposition and, for the first time, a cipher with multiple substitutions for each plaintext letter. Also traced to Ibn al-Duraihim is an exposition on and worked example of cryptanalysis, including the use of tables of letter frequencies and sets of letters which can not occur together in one word.
1466-7 civ Kahn p.127 Leon Battista Alberti (a friend of Leonardo Dato, a potifical secretary who might have instructed Alberti in the state of the art in cryptology) invented and published the first polyalphabetic cipher, designing a cipher disk (known to us as the Captain Midnight Decoder Badge) to simplify the process. This class of cipher was apparently not broken until the 1800's. Alberti also wrote extensively on the state of the art in ciphers, besides his own invention. Alberti also used his disk for enciphered code. These systems were much stronger than the nomenclator in use by the diplomats of the day and for centuries to come.
1473-1490 civ Kahn p.91 ``A manuscript [...] by Arnaldus de Bruxella uses five lines of cipher to conceal the crucial part of the operation of making a philosopher's stone.''
1518 civ Kahn p.130-6 Johannes Trithemius wrote the first printed book on cryptology. He invented a steganographic cipher in which each letter was represented as a word taken from a succession of columns. The resulting series of words would be a legitimate prayer. He also described polyalphabetic ciphers in the now-standard form of rectangular substitution tables. He introduced the notion of changing alphabets with each letter.
1553 civ Kahn p.137 Giovan Batista Belaso introduced the notion of using a passphrase as the key for a repeated polyalphabetic cipher. (This is the standard polyalphabetic cipher operation mis-named ``Vigenère'' by most writers to this day.)
1563 civ Kahn p.138 Giovanni Battista Porta wrote a text on ciphers, introducing the digraphic cipher. He classified ciphers as transposition, substitution and symbol substitution (use of a strange alphabet). He suggested use of synonyms and misspellings to confuse the cryptanalyst. He apparently introduced the notion of a mixed alphabet in a polyalphabetic tableau.
1564 civ Kahn p.144(footnote) Bellaso published an autokey cipher improving on the work of Cardano who appears to have invented the idea.
1585 civ Kahn p.146 Blaise de Vigenère wrote a book on ciphers, including the first authentic plaintext and ciphertext autokey systems (in which previous plaintext or ciphertext letters are used for the current letter's key). [Kahn p.147: both of these were forgotten and re-invented late in the 19th century.] [The autokey idea survives today in the DES CBC and CFB modes.]
1623 civ Bacon Sir Francis Bacon described a cipher which now bears his name -- a biliteral cipher, known today as a 5-bit binary encoding. He advanced it as a steganographic device -- by using variation in type face to carry each bit of the encoding.
1790's civ/govt Kahn p.192, Cryptologia v.5 No.4 pp.193-208 Thomas Jefferson, possibly aided by Dr. Robert Patterson (a mathematician at U. Penn.), invented his wheel cipher. This was re-invented in several forms later and used in WW-II by the US Navy as the Strip Cipher, M-138-A.
1817 govt Kahn p.195 Colonel Decius Wadsworth produced a geared cipher disk with a different number of letters in the plain and cipher alphabets -- resulting in a progressive cipher in which alphabets are used irregularly, depending on the plaintext used.
1854 civ Kahn p.198 Charles Wheatstone invented what has become known as the Playfair cipher, having been publicized by his friend Lyon Playfair. This cipher uses a keyed array of letters to make a digraphic cipher which is easy to use in the field. He also re-invented the Wadsworth device and is known for that one.
1857 civ Kahn p.202 Admiral Sir Francis Beaufort's cipher (a variant of what's called ``Vigenère'') was published by his brother, after the admiral's death in the form of a 4x5 inch card.
1859 civ Kahn p.203 Pliny Earle Chase published the first description of a fractionating (tomographic) cipher.
1854 civ Cryptologia v.5 No.4 pp.193-208 Charles Babbage seems to have re-invented the wheel cipher.
1861-1980 civ Deavours
``A study of United States patents from the issuance of the first cryptographic patent in 1861 through 1980 identified 1,769 patents which are primarily related to cryptography.'' [p.1]
1861 civ/(govt) Kahn p.207 Friedrich W. Kasiski published a book giving the first general solution of a polyalphabetic cipher with repeating passphrase, thus marking the end of several hundred years of strength for the polyalphabetic cipher.
1861-5 govt Kahn p.215 During the Civil War, possibly among other ciphers, the Union used substitution of select words followed by word columnar-transposition while the Confederacy used Vigenère (the solution of which had just been published by Kasiski).