Data Hiding Algorithm using Variable Block Size in Cover Image File

Data hiding inside any standard or non standard cover file is now a common area of interest across the globe. Nath et al already developed several methods for hiding any secret message inside any standard or non standard cover file. In the present work the authors have introduced a new method of hiding any kind of small secret message such as text, image, audio file inside any cover file which is mainly .bmp file. The authors divide the entire cover file into number of blocks and then inserted the bits of the secret file after a series of shift operations on them in the RGB components of pixels of cover image file. After inserting any secret message inside a cover file it was found that there is no significant change in the stego file. The shifting operation on the bits of the secret file in addition to the random generation of blocks, and processing them in an order, where a definite number of bits of the secret file to embed are reserved for each block will make the entire process fully secured. The size of the cover image should be at least 10-20 times larger than the secret message file so that the entire process should be almost unbreakable. General Terms Block,embed,dembed