Wednesday, January 16, 2013

Cryptography and Cyphers

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Now, it’s been some time now….we are all familiar with the word Cryptography.  Yeah, you guessed it right. It’s the art of encryption and decryption of data. Cryptography maybe a technology of the 21 century, but its roots are from the medieval period. In fact the Alexander the Great himself used a type of cryptography known as Cypher.  

Cryptography or cryptology is derived from a Greek word, ‘crypto’ means ‘hiding’ and graph means ‘writing’ or ‘data’. Therefore the art of concealing the data or information is called as Cryptography. In terms of computers, Cryptography is the practice and study of techniques for secure communication in the presence of third parties. More generally, it is about constructing and analysing protocols that overcome the influence of third parties and which are related to various aspects in information security such as data confidentiality, data integrity and authentication. Modern cryptography intersects the fields of mathematics, computer science, and electrical engineering.

Cryptography before the modern age was effectively synonymous with encryption, the conversion of information from a readable state to nonsense. The originator of an encoded message shared the decoding technique needed to recover the original information only with intended recipients, thereby forbidding unwanted persons to do the same. Since World War I  and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application is more far-flung.

Modern cryptography is to a great extent based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in practice by any adversary. It is theoretically possible to break such a system but it is infeasible to do so by any known practical means. These schemes are therefore termed computationally secure; theoretical advances and faster computing technology require these solutions to be continually adapted. There exist information-theoretically secure schemes that provably cannot be broken even with unlimited computing power-an example is the one-time pad -but these schemes are more difficult to implement than the best theoretically breakable but computationally secure mechanisms.

The art of protecting information by transforming it into an unreadable format, called cipher text. Only those who possess a secret key can decipher the message into plain text . Encrypted messages can sometimes be broken by cryptanalysis, also called codebreaking, although modern cryptography techniques are virtually unbreakable. 

As the Internet  and other forms of electronic communication become more prevalent, electronic security  is becoming increasingly important. Cryptography is used to protect e-mail  messages, credit card information, and corporate data. One of the most popular cryptography systems used on the Internet is Pretty Good Privacy  because it's effective and free. 

Cryptography systems can be broadly classified into symmetric-key systems  that use a single key that both the sender and recipient have, and public-key  systems that use two keys, a public key known to everyone and a private key that only the recipient of messages uses.
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