'The Origins of Cryptology: The Arab contributions', by Ibrahim A Al-Kadi Cryptologia, volume 16, no 2 (April 1992), pages 97-126. A discussion of recently discovered Arab manuscripts. http://www.networkcomputing.com/netdesign/1007part1comp.html Ever since man started communicating with one another, there has been a need to keep secrets. Cryptography is defined as the principles, means, and methods for rendering information unintelligible, and for restoring the encrypted information back into intelligible form. In other words, cryptography is the science of writing in secret. Examples of cryptography have been discovered in the writings of Egyptians over 4,000 years ago. The ancient Greek, Chinese, and Roman civilizations used surprisingly advanced cryptography techniques. The use of cryptography, and the analysis of cryptography (cryptoanalysis), flourished in the Arab world during the Middle Ages. While lovers and theologians have long made use of secret messages, the overwhelming use of secret writing has historically been in diplomacy and the military. http://www.nytimes.com/books/99/11/07/reviews/991107.07ossermt.html The first big breakthrough in decipherment was made in the ninth century by the Arab philosopher al-Kindi in a treatise only recently rediscovered. For a thousand years or more, a message coded in a random monoalphabetic cipher was considered undecipherable unless one had the key to the code. Remember, 'algorithm' and 'algebra' are Arabic in origin. -- Tiarnán Ó Corráin <ocorrain@esatclear.ie/ocorrain@yahoo.com> Alliance: In international politics, the union of two thieves who have their hands so deeply inserted in each other's pocket that they cannot separately plunder a third. -- Ambrose Bierce