Advanced dual layered encryption for block based approach to image steganography

Image steganography is a method of concealing information using an image as a medium. The most prominent approach for image steganography is the Least Significant Bit Algorithm (LSB). In this the least significant bit of all pixels of an image is used to hide information in them. The flaw of this algorithm is that it becomes very easy for an attacker to extract information from this algorithm. In that context an approach has been developed to help increase the security of the algorithm. For the proposed approach we consider the entire data to form one big block of information. The first step is to encrypt this information. This is done using the famous Advanced Encryption Standard (AES) algorithm. The key to encrypt this information is then hidden using the RSA algorithm. This adds an extra layer of security to the algorithm. Next the encrypted block of data is broken down to ‘n’ blocks, where ‘n’ is chosen by the user. ‘n+1’ images are then chosen at random and each block is hidden using LSB with an image. The images are sent in random. However, the sequence is stored in a hash table which is hidden in the extra image. All the ‘n+1’ images are sent, the first ‘n’ in a random order. The sequence is extracted using the hash table and then the decryption of key is first then and then the entire data.