Cryptology
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Editing Cryptology[[1]]
Cryptology :science concerned with communications in secure and usually secret form. It encompasses both cryptography and cryptanalysis. The term cryptology is derived from the Greek kryptós, "hidden," and lógos, "word." Security obtains from legitimate users, the transmitter and the receiver, being able to transform information into a cipher by virtue of a key--i.e., a piece of information known only to them. Although the cipher is inscrutable and often unforgeable to anyone without this secret key, the authorized receiver can either decrypt the cipher to recover the hidden information or verify that it was sent in all likelihood by someone possessing the key. Cryptography (from the Greek kryptós and gráphein, "to write") is the study of the principles and techniques by which information can be concealed in ciphers and later revealed by legitimate users employing the secret key, but in which it is either impossible or computationally infeasible for an unauthorized person to do so. Cryptanalysis (from the Greek kryptós and analýein, "to loosen" or "to untie") is the science (and art) of recovering information from ciphers without knowledge of the key. Cryptology is often--and mistakenly--considered a synonym for cryptography and occasionally for cryptanalysis, as in the popular solution of cryptograms or ciphers, but specialists in the field have for years adopted the convention that cryptology is the more inclusive term encompassing both cryptography and cryptanalysis. Cryptography was concerned initially with providing secrecy for written messages. Its principles apply equally well, however, to securing data flow between computers, to digitized speech, and to encrypting facsimile and television signals. Most communications satellites, for example, routinely encrypt the data flow to and from ground stations to provide both privacy and security for their subscribers. Because of this broadened interpretation of cryptography, the field of cryptanalysis has also been enlarged to include the recovery of information from ciphers concealing any form of data. This article discusses the basic elements of cryptology, delineating the principal systems and techniques of cryptography as well as the general types and procedures of cryptanalysis. It also provides a concise historical survey of the development of cryptosystems and cryptodevices. For additional information on the encoding and encryption of facsimile and television signals and of computer data, see telecommunications system and information processing. In War world II, cryptology was used by both sides in the warring States and responsible for many of the battle advantages, and it helped to develop machines such as the enigma and Ultra which gives the Allies the winning role in the war.
adopted from 1994-2000 Encyclopædia Britannica, Inc.
