Library

 

The Codebreakers: The Story of Secret Writing by David Kahn. Book review by Roger Pineau

codes and code breaking, history of,
Previous Next

OFFICIAL USE ONLY

Recent Books: Cryptology

After this dramatic opening the reader is treated to a pageant of cryptography through the centuries, beginning with the earliest known deliberate transformation of a writing about 1900 B.C., found in the tomb of Klmumhotep II. Cryptographic developments of the ensuing 3,000 years are traced through India, Mesopotamia, Babylonia, and Assyria, in Greek and Roman writings, in Persia, Egypt, AngloSaxon Britain, and Scandinavia.
To this point the story is simply of cryptography, the rendering of a message unintelligible by some transformation of the plain text. The cryptanalysis side of crvptology begins with the Arabs, who in the seventh century were the first to discover and record methods of analyzing the frequency and juxtaposition of letters. The author describes with examples and anecdotes the developments from this beginning to the sudden rise of secret writing with the Renaissance in western civilization and the work of Geoffrey Chaucer and Roger Bacon.   Thirty centuries is a long period to cover in some thirty pages of text, but seven pages of notes on this chapter indicate that Kahn has rather thoroughly plowed the field.
Next the spread of political cryptography is pursued from rudimentary beginnings in the early 13th century through Venice, Rome, the Vatican, the secular principalities of Italy, and throughout Europe. The growth of cryptology paces evenly the flowering of modern diplomacy. Kahn's examples range from the well to the little known and from the simple to the recondite in each period and stage of development.
The development of the modern system of polyalphabetic substitution, described in a chapter called "On the Origin of a Species," began in the 17th century with the work of four amateurs who adopted a mixed alphabet, the principle of letter-by-letter encipherment, and an easily changed key.   A further improvement came in the use of grilles and tableaux to govern the enciphered sequence.   These successes were not achieved without pitfalls and pratfalls, which Kahn recounts with clarity and gaiety, including an example of Casanova's use of cryptanalysis as a key to seduction.
In spite of the advance to polyalphabetic substitution, the nomenclators system of cryptography first developed for Pope Clement 11 in the late 14th century continued to flourish in Europe. Kahn at
100

OFFICIAL USE ONLY


Previous Next

Posted: May 08, 2007 08:18 AM
Last Updated: Aug 05, 2011 01:39 PM