In multimedia steganocryptic system, the message will be first encrypted and then encrypted date will be hidden into an image file.  Cryptography converts message into an unreadable cipher.  Both these technologies provide security to data over unsecure communication channel against intruder attacks.  In order to minimize the threat of intrusion over communication channel there is a need of powerful high secure system than steganogcyptic or cryptography technologies. The features of cryptography, steganography and multimedia data hiding are combined in visual cryptographic steganography technology.  This combined technology is more secure when compared to that of steganography and cryptography technologies.

Overview:

Visual steganography is most secure forms of steganography technology which implemented in image files.  In multiple cryptography technology, the data will be encrypted into cipher and then cipher data will be hidden in multimedia image file.  The threat of an intruder to access secret information becomes the most painful concern in communication media. Many traditional technologies like cryptography, steganography exists but in order to face few more problems addressed by these technologies, a visual cryptographic steganography technology is emerged.  To achieve data encryption, traditional cryptographic techniques are used and to hide the encrypted data, visual steganography algorithms are used.

Visual cryptography uses a special encryption technique to hide information in images and which can be decrypted by the human vision with the correct key image used.  This technique uses two transparent images.  Among these two images, one image contains random pixels and the other contains secret information. It is not possible to get the secret information with one of the images. Only both images together can help to retrieve the secret information.

To implement visual cryptography there is a need to print the two layers onto a transparent sheet.  If visual cryptography is used for secure communication, there is need for the sender to distribute one or more random layers in advance to the receiver.  The system is unbreakable until and unless both the layers fall into wrong hands. If one of the both layers is intercepted then it is not possible to retrieve the encrypted information at any cost. 

Download  Seminar Report on Visual Cryptographic Steganography – Images for Computer Engineering Students .