Cryptology Some Notes on Early History

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Antiquity

Simple monoalphabetic substitutions or transpositions are used in:

• Egypt
• Mesopotamia
• Israel (»Atbash cipher« [Wikipedia])
• Greece (external: »Skytale«, »Polybius Square)
• Rome (»Caesar cipher«)
• India (Kama Sutra)

Some antique scriptures are not ciphers in the proper sense but of cryptologic interest. Some of them are unsolved even today. Deciphering them is more or less a kind of cryptanalysis. The following ones are solved:

• Egyptian Hieroglyphs by Jean-François Champollion 1822
• Mesopotamian Cuneiform (ca 2900 BC until 50 AD) for several languages, deciphered from 1802 on by Georg Friedrich Grotefend
• Minoic Linear B (ca 1400 BC) by Michael Ventris 1952

• Proto-Elamite Script (Iran, ca 3050 until 2900 BC)
• Indus Script (ca 2500 until 1900 BC)
• Minoic Linear A (ca 1750 until 1450 BC)
• Olmec Script (Mexiko, ca 900 until 400 BC)
• Rongorongo tablets from Easter Island (until ca 1800 AD).

Cryptology as a Science in the Arabic-Islamic Middle Ages

... and the invention of cryptanalysis of monoalphabetic substitutions.

The word »cipher« derives from the arabic word »sifr« for »zero«, as well as the word »zero« in several languages.

The most important cryptologists:

• Al-KHALIL (718–786)
  • Full name: Abu Abd al-Rahman al-Khalil ibn Ahmad ibn Amr ibn Tamman al Farahidi al-Zadi al Yahmadi.
  • His book: Kitab al Mu'amma (Book of Cryptographic Messages) is lost.
  • Treats the method of probable word.
• Abu BAKR (?–?)
  • Full name: Abu Bakr Ahmad ben Ali ben Whshiyya an-Nabati.
  • His book: Kitab shauq al-mustaham fi ma'rifat rumuz al-aqlam from 855 (Book of the Frenzied Devotee's Desire to Learn About the Riddles of Ancient Scripts) is also lost.
  • Several cipher alphabets.
• Al-KINDI (801–873)
  • Full name: Abu Yusuf Yaqub ibn Is-haq ibn as Sabbah ibn 'omran ibn Ismail Al-Kindi.
  • Book: Risalah fi Istikhraj al Mu'amma (Treatise on Decrypting Cryptographic Messages), ca 850 AD, the oldest existent book on cryptology.
  • Introduces frequency analysis—this makes Al-Kindi the prime father of mathematical statistics.
  • Treats also transposition ciphers.
• Ibn ADLAN (1187–1268)
  • Full name: Afif ad-Din ibn Adlan ibn Hammad ibn Ali al-Mousili an-Nahwi al-Mutarjim.
  • Book: Al-Mu'allaf lil-Malik al-Ashraf (Written for King al-Ashraf)—rediscovered in 1987.
  • Comprehensive instructions for cryptanalysis.
• Ibn DUNAINIR (1187–1229)
  • Full name: Ibrahim ibn Mohammad ibn Dunainir.
  • Book: Maqasid al-Fusul al-Mutarjamah an Hall at-Tarjamah (Comprehensive Instructions for Solving Cryptograms)—rediscovered in 1987.
  • Introduces algebraic ciphers (replace letters by numbers, transform them by arithmetic operations).
• Ibn AD-DURAIHIM (1312–1361)
  • Full name: Taj ad-Din Ali ibn Muhammad ibn Abdul'aziz ibn ad-Duraihim.
  • Book: Miftah al-Kunuz fi Idah al-Marmuz (Key to Uncovering Secret Writings)—rediscovered in 1987.
  • Classification of ciphers, frequency analysis for many languages, Trithemius (Vigenère) table, grille, arithmetic mod n.
• QALQASHANDI (1355–1418)
  • Full name: Shihab al-Din abu l-Abbas Ahmad ben Ali ben Ahmad Abd Allah al-Qalqashandi.
  • 14 volume encyclopedia Subh al-asha 1412.
  • Contains a chapter on cryptology.

A comprehensive treatment is given in:

• Ibrahim A. Al-Kadi, Origins of cryptology: The Arab contributions. Cryptologia 16 (1992), 97 - 126.
• Mohamad Mrayati, Yahya Meer Alam, M. Hassan at-Tayyan (eds.): Arabic Origins of Cryptology. King Faisal Center for Research and Islamic Studies, Riyad.
  • Vol 1: Al-Kindi's Treatise on Cryptanalysis, 2003.
  • Vol 2: Ibn Adlan's Treatise al-muallaf lil-malik al-Asraf, 2004.
  • Vol 3: Ibn ad-Duryahim's Treatise on Cryptanalysis, 2004.
  • Vol 4: Ibn Dunaynir's Book, Expositive Chapters on Cryptanalysis, 2005.
  • Vol 5: Three Treatises on Cryptanalysis of Poetry, 2006.

»The best treatises on cryptography are works of pagan scholars.«
(Umberto Eco, The Name of the Rose)

Renaissance

Beginning with the Late Middle Ages also in Europe cryptography became a subject of interest.

• Roger Bacon (1214–1294?) described several ciphers in his Epistola de Secretis Operibus Artis et Naturae, et de Nullitate Magiae (Secret Works of Art and the Nullity of Magic).
• In 14th Century cryptographers in Venice and France refined the monoalphabetic substitution and introduced the nomenclator, an early instance of a codebook.
• In 15th Century polyalphabetic substitution started with ALBERTI.
• In 1474 and around 1500 Francesco SIMONETTA (1410–1480) in Milan and Giovanni SORO (?–1544) in Venice composed the first written treatises on cryptology in Europe. Both were famous as competent cryptanalysts.

Note that historical facts stated in these lecture notes are taken from David Kahn's book unless otherwise stated.

See also the timeline of cryptography in Wikipedia.

Concerning the use of classical cryptography the article

Benedek Láng
Shame, love, and alcohol: Private ciphers in early modern Hungary
Cryptologia 39 (2015), 276-287

Despite the fact that the majority of the surviving sources are from the field of politics (e.g., diplomacy, envoy's reports, military correspondence), cryptography extended beyond central diplomacy to be used by various social layers on day-to-day basis. It was not necessarily a privilege of men; several sources testify that women connected to politics in this way or another used claves, too. Apparently, the only criterion for cipher use was literacy. Just as the users were not all politicians, the purpose of ciphering was not necessarily political either: Private life, love affairs, extremely intimate relationsships, shame, excessive drinking, fear, fanily feuds, and moral sins were all topics that cried for enciphering.