Until the early 1970s, the subject of cryptography remained in the shadows of the US National Security Apparatus, being mostly the province of the highly secretive National Security Agency. The NSA had exercised a monopoly over cryptographic research in the United States, largely because the industry for civilian applications of cryptography remained small. Throughout the late 20th and early 21st century the secure flow of electronic data has become an increasingly vital engine of economic growth, and cryptography has become critical industry beyond the confines of merely securing vital military and intelligence traffic. Because of this, the NSA's monopoly on encryption policy has begun to loosen. The ability of the NSA to exercise a monopoly on managing the security of the US communication infrastructure has been further eroded by the revelation of the NSA's abuses of its statutory authority during the Cold War by conducting systematic spying of domestic communications. .
First, I will briefly describe the basics of cryptography and history; second, cryptographic schemes and a single key cryptosystems; and finally, the anticipate future of cryptography. .
Basics of Cryptography.
Cryptography has become a generic term that refers to both cryptography the making of codes to encrypt information, and cryptology the breaking of the codes and the decrypting of information by entities other than the intended target of the communication. I use the term cryptography to refer to both throughout this paper. Entymologically speaking the word cryptography is, derived from the Greek kryptos, meaning "hidden", and graphos, meaning "writing" , and cryptology is from the Greek logos, meaning "word" or "speech" (Foerstel, 1993). .
History.
Cryptography has been systematically used to hide communication for at least the last 2500 years if not 4000 years (Office of Technology Assessment, 1994).