Review on Network Security and Cryptography

In  these days communication technology is very advanced. Digital communication has become very important to secure transmission of information between the sender and the receiver. Security for exchange is a very important feature because it protects information from interloper. In this paper we present a hierarchy of network security technologies such as privacy, authentication, non-rejection and honesty control. There are two popular security mechanisms, namely cryptography and steganography. Both are well known and widely used techniques. Cryptography is used to send data in an encrypted form using the encryption key. Encrypted data is transmitted through unsafe public media. Decryption algorithms are also used to decrypt messages when using decryption keys. Steganography is used to hide data in other cover media.