Talk:Cryptography/Introduction

Ist usage of the word 'Cryptography' occured in 1658 in Sir Thomas Browne's 'The Garden of Cyrus. ..quote ....'WE might abate the strange CRYPTOGRAPHY of Gaffarel in his Starrie Booke of heaven'.

Cryptanalysis Classes
Four classes of cryptanalysis;

A) Ciphertext-only. Only the ciphertext is known and the key and/or message must be found from this.

B) Known plaintext. The ciphertext and part of the message is known.  The key and/or the rest of the message must be found from this.

C) Chosen plaintext. The analysist can chose the plaintext to encrypt.  The key must be found from this.

D) Chosen ciphertext. Public key ciphers only, the analysist can chose the ciphertext to decrypt.  The key must be found from this.

Backup of some prior segments
While this could be left to page history, for now I'll leave some bits here so that people can see what major chunks were lifted out and replaced. wikipedia:User:PolyGnome

Prior intro, part 1
Cryptography is generally understood to be the study of the principles and techniques by which information is converted into an encrypted version that is difficult (ideally, impossible) for any unauthorized person to convert to the original information, while still allowing the intended reader to do so. In fact, cryptography covers rather more than merely encryption and decryption. It is, in practice, a specialized branch of information theory with substantial additions from other branches of mathematics. And perspective and approaches, because of the inherent conflict between those authorized, and those not, to see the information / interfere in the exchange / pretend to be other than they are / etc, from such sources as Machiavelli, Sun Tzu, and Karl von Clausewitz.

Unsurprisingly, the study of hiding the meaning of messages from others by encrypting them has been accompanied by the study of how to read such messages when one is not the intended receiver; this area of study is called cryptanalysis. People involved in such work, and with cryptography in general, are known as cryptographers (or for some of those in the other lexigraphic school, cryptologists).

The original unencrypted information being sent from one person (or organization) to another is usually called the plaintext. Encryption is the process of converting the plaintext into some unreadable form (ideally one undistinguisable from random gibberish), and decryption converts this back to the plaintext. Encryption includes two major classes of technique: encoding (yielding codetext) and enciphering (yielding ciphertext). The exact operation of the encryption and decryption, for all schemes with any pretense to security, is controlled by one or more keys.

My intent with the introduction is to try to cover the basic understanding and texture of cryptography without bogging down the reader. Although it will obviously have to be refined after the other modules have been completed. wikipedia:User:PolyGnome

Just a note
Would it be possible to cite a couple books on cryptography? There are several good ones, and I think it's a good idea to refer to something a little more concrete.

Interesting Typos
I discovered some interesting typos, such as "Bprivately" and the like, I don't know why they were there, but it reads better now, I also changed "cypher" in the body to "cipher", to match the introduction

Tyler.szabo 01:54, 6 October 2005 (UTC)