General View on Techniques Used In Image Steganography

The Steganography is getting its importance due to the increase in secret communication of computer users over the internet. It can also be express as an invisible communication that actually deals with the ways of hiding the presence of the secrete message from the image. Generally that data embedding is achieved in the communication, text, image, multimedia, voice content for copyright, military communication, authentication and for many other purposes. In the image Steganography, secret communication is achieved to hide a message into the cover image. The secret message is embedded inside the cover image in encrypted format by using some hiding algorithm and it send to a receiver over a network. The receiver then it decrypted the message by applying the reverse process on the cover data and reveals the secret data. Steganography means is not to vary the structure of secret message, but hides it inside a carrier-object (cover object). After hiding process cover object and stego-object (object which contain secrete information) are similar. This paper is about to showthe two different techniques that is used in the image steganography. There are two techniques that we study in this paper are Wavelet Transform and spread spectrum.