A secured key-based digital text passing system through color image pixels
Soumik Das, Pradosh Bandyopadhyay, Atal Chaudhuri, Monalisa Banerjee · 2012
From thousands of years back our predecessors have invented several ways of passing information in hidden form with other objects like papyrus scroll, cryptex etc. As decades crossed through earth's vein we are getting matured and invented several steganographic systems for message passing. The availability of internet in every corner of the universe forced the user of steganographic systems to invent and implement a better secured algorithm for encryption and decryption of text. In this paper we are going to propose a framework for embed text string into digital color images and the text that is embedded is perceptually invisible to Human Visual System (HVS). Many text steganographic systems are available that are passing the text with digital media as a form of message digest that can be hacked easily. Here our algorithm supersedes the conventional algorithms. Instead of forming message digest first a 32-bit secret key will be provided by the encrypter and that will be applied on the text with a hash function. That gives us a pseudo byte stream. Now we embed that pseudo byte stream directly to image pixels and after that the text will become the physical property of the encrypted image. On the other end if an intruder tries to perform the extraction of the text with a wrong secret key, he will not be succeeded. In the proposed framework the information of Red (R), Green (G) & Blue (B) values of the pixels of the host color image are retrieved. Subsequently the text is converted into byte stream with respect to the ASCII values of the characters present in the text. Triggering that byte stream with the secret key and hash function produces the pseudo byte stream. Each bit of this byte stream will be embedded in to the LSBs of RGB bytes of the image pixels that ensure the invisibility of text in the encrypted image. The extraction of the text is blind i.e., except the secret key nothing is needed for text decryption.