Cryptology People

This page is a listing of some of the more important people in the history of cryptology. It is neither complete or definitive. And the descriptions are deliberately brief. For a more complete reference you should acquire "The CodeBreakers" by David Kahn, Signet [1967]. Or check my on-line pointers given in cryptographic references. Any glaring errors or omissions can be reported by using the comments button at the bottom of the page.

Polybius [c.200-118 B.C.E.]

The noted Greek philosopher, historian and writer Polybius arranged the alphabet into a squared grid or matrix. By numbering the rows and columns, letters could be transformed into other paired characters. The Polybius square's features of spliting a character into two parts, reducing the number of characters needed and ability to convert letters into numbers is still used in modern algorithms.

Caesar [100-44 B.C.E.]

The great Roman general and emperor Julius Caesar used a simple shifted monoalphabet (a becomes d, b becomes e, etc.) to disguise his messages to political friends such as Cicero. Although this algorithm is easily 'broken' today, it was sufficient in a time of very limited literacy.

Alberti [1404-1472]

The Italian architect, painter and writer Leon Battista Alberti is noted for creating the first cryptology literature, recognizing the power of polyalphabecy making the cipher disk, and developing algoithms using enciphered code.

Trithemius[1462-1516]

The German cleric Johannes Trithemius authored 'Polygraphiae', the first printed book on cryptology. He also developed the 'tabula recta' or square table polyalphabet. Trithemius also introduced regular alphabet changes as part of the enciphering algorithm.

Belaso [1553]

The otherwise obscure Italian Giovanni Battista Belaso wrote a pamphlet which mentioned using a countersign or keyword for alphabet selection.

Cardano [1501-1576]

The Italian physician, mathematician and writer Girolamo Cardano used plaintext as its own key (autokey). However it required that the decypherer figure out the first few characters on his own. This defeated the system! Cardano also developed a mechanical grill system or steganographic device for hiding messages within plaintext messages.

Vigenère [1523-1596]

The French diplomat and writer Blaise de Vigenère improved Cardano's autokey sytem by providing a priming key for the first letter.

Jefferson [1743-1826]

The American plantation owner and politician Thomas Jefferson designed a 'code-wheel' device for encyphering/decyphering messages.

Wheatstone [1802-1875]

The British scientist Sir Charles Wheatstone developed the Playfair Code, a table system that was easy to use. Although not difficult to analyse, it did muddle character frequency techniques by the use of digraphs (coding two letters at a time).

Kerckhoffs [1835-1903]

The French teacher and writer Auguste Kerckhoffs contributed greatly to both cryptography and cryptanalyse. He formulated procedures for long-term diplomatic codes as well as inventing the superpositioning technique for code breaking.

Yardley [1889-1958]

The American civil servant and poker player Herbert Yardley was the first head of MI8, organized in 1917. At war's end he created the 'American Black Chamber' which worked on Japanese codes through the 20's. His book 'The American Black Chamber' (aka 'Secret Service in America') revealed the inner workings of crypanalysis organizations and was very well received in Asia ;-] ;-].

Friedman [1891-1969]

The American geneticist William Frederick Friedman headed the cryptology department at Riverbank, a private research institute. He devised two major techniques and described them in 'The Index of Coincidence and its Application to Cryptology', a mathematical theory tome. One technique was used to reconstruct cypher alphabets without guesswork. The second was to treat frequency distributions as entities (causual order rather than historical). This second breakthrough is still used today! Friedman also was a enlightened instructor of cryptology as his training text 'Elements of Cryptanalysis' demonstrates. His wife and teammate Elizebeth also did significant cryptanalysis work including 'cracking' the codes of the Prohibition era rumrunners.

Turing [1912-1954]

The British mathematician, computer scientist and philosopher Alan Turing solidified the mathematical approach to cryptanalysis. His WW2 work at Bletchley Park allowed reading the German ULTRA code, generated by the Enigma machine. His design of the device 'the bombe' further sped decrypting of naval messages that led to winning 'the Battle of the Atlantic'.

Flowers [1905-1998]

The British engineer Tommy Flowers built Collossus (the world's first programmable electronic computer) to help Bletchley Park crack German codes.