New Data Hiding Algorithm in MATLAB Using Encrypted Secret Message

In the present work the authors have introduced a new method for hiding any encrypted secret message inside a cover file. For encrypting secret message the authors have introduced a new bit exchange algorithm. For hiding secret message Nath et al(1,2,3) have already proposed various methods. Here the authors modified the steganographic method. Instead of changing the LSB of the cover file at a stretch the authors proposed to change LSB and LSB+3 bits and changing alternate bytes of the cover file. It means to hide one byte of secret message the authors used 8 bytes of the cover file but out of 8 bytes 4 bytes were modified in LSB and LSB+3 bit positions and the alternate bytes remain unchanged. The secret message was encrypted by using a simple bit exchange method before the actual embedding process starts. The number of times the secret message to be encrypted using bit exchange method can be controlled by the user. The proposed bit exchange method is reversible that means the way the encryption done the decryption to be done in reverse way. The entire work was done in MATLAB. The authors applied the present steganography algorithm on different cover files such as image file, audio file, video file, word file, Excel file, Power point file,.exe file and in every case the result found was satisfactory. To embed any secret message inside a cover file the user has to enter a password and the same password to be used to unhide the secret message. The authors propose that this method could be most appropriate for hiding any file in any standard or non standard cover file such as word, excel, .ppt, .exe, image, audio, video files. The hidden message is encrypted using some bit exchange method and hence it will be almost impossible for the intruder to unhide the actual secret message from the embedded cover file. This method may be used for sending some secret key to someone over mail as the intruder may not be able to unhide and to decrypt the secret message.