22-10-2014, 12:04 PM
Abstracts: Steganography is the art of covered or hidden writing. The purpose of steganography is covert communication-to hide the existence of a message from a third party. The powerfulness of steganography, especially hidden in such objects, comes from the fact that we can hide information into almost all types of digital files. It can be image file formatted either in tif, png, bmp, jpeg etc. More powerful idea is that we can use steganographic methods to hide an already encrypted data -- thus making it more difficult for crypto analysts to obtain the original message. Many different carrier file formats can be used, but digital images are the most popular because of their frequency on the Internet. For hiding secret information in images, there exists a large variety of steganographic techniques some are more complex than others and all of them have respective strong and weak points. Different applications have different requirements of the steganography technique used. For example, some applications may require absolute invisibility of the secret information, while others require a larger secret message to be hidden. Information hiding in JPEG compressed gray scale images are investigated in this report. The challenges of covert communication in this state of the art image codec are analyzed and a steganographic scheme is then proposed to reliably embed high-volume data into the JPEG bit stream. Steganography is not intended to replace cryptography but rather to supplement it. If a message is encrypted and hidden with a steganographic method it provides an additional layer of protection and reduces the chance of the hidden message being detected. Steganography is still a fairly new concept to the general public although this is likely not true in the world of secrecy and espionage.