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A CHALLENGE IN HIDING ENCRYPTED MESSAGE IN LSB AND LSB+1 BIT POSITIONS IN VARIOUS Cover Files

Joyshree Nath, Sankar Das, Shalabh Agarwal and Asoke Nath

The present work basically shows us how one can hide information in encrypted form to any cover file such as .exe files, Microsoft office files, .dbf files, image files, audio files and video files. However, the size of the hidden message must be very small in comparison to cover file which is an executable file. So far no one has tried to hide information inside any executable file. To make the system fully secured we first encrypt the secret message using MSA algorithm (Nath et al.(1)) and then we hide the encrypted message inside the cover file. introduced a new method for hiding any encrypted secret message inside a cover file. For encrypting secret message we have used new algorithm proposed by Nath et al(1). For hiding secret message we have changed both LSB and LSB+1 bits of each byte of the cover file. A generalized method was proposed by Nath etal(2) where they embed the secret message without going for any encryption.. The MSA(1) algorithm introduced a new randomization method for generating the randomized key matrix to encrypt plain text file and to decrypt cipher text file. The MSA (1) method also incorporates the multiple encryption and decryption process. To initiate the MSA algorithm the user has to enter a text_key, which can be of 16 characters long. This text_key is used to calculate the randomization number and the encryption number from the given text_key. The size of the encryption key matrix is 16x16 and the total number of matrices can be formed from 16 x 16 is 256! which is quite large and the MSA algorithm ensures that any of the pattern may be used for encryption as well as decryption process. To hide encrypted secret message in the cover file we have inserted the 8 bits of each character of encrypted message file in 4 consecutive bytes of the cover file such that only LSB and LSB+1 bits are changed depending on the bit pattern of the encrypted secret message. To make system further secured one has to enter a password before the actual steganography process starts. We propose that our new method could be most appropriate for hiding any file in any non-standard cover file such as executable file, compiler, MS-Office files, Data Base files such as .DBF, text editor such as notepad plus the standard cover files such as image, audio, video files etc. The size of the secret message be very small in comparison to the executable cover file. The present method may be implemented in mobile network, Bank data transactions in government sectors, in police department.