Network Security

Cryptography

Network Security

Written by VYGA V R Thursday, 18 March 2010 09:03

Cryptography is the art or science of keeping messages secret. It deals with transformations of message into coded form by encryption at the sender side and recovery of original messages by decryption at the receiver side. Cryptographic techniques allow a sender to encrypt data before transmitting so that an intruder can gain no information from intercepted data. The intended receiver only can recover or decrypt original data from encrypted data.

Suppose that someone wants to send a message to a receiver, and wants to be sure that no one else can read the messages. There is the possibility that someone else opens the letter or hears the electronic communication. But secure messaging is possible with the help of cryptology.

In cryptographic terminology, the message is called plain text or clear text. Encoding the contents of the message in such a way that hides its contents from outsiders is called encryption. The encrypted message is called the cipher text. The process of retrieving the plain text from the cipher text is called decryption. Encryption and decryption usually make use of a key, and the coding method is such that decryption can be performed only by knowing the proper key. Set of data transformations used to do encryption is called a cipher.

Cryptanalysis is the art of breaking ciphers, retrieving the plaintext with out knowing the proper key. People who do cryptography are cryptographers, and practitioners of cryptanalysis are cryptanalysts. Cryptology is the branch of mathematics that studies the mathematical foundation of cryptographic methods.