Secure and covert communication using steganography by Wavelet Transform

Abstract

This paper presents a hybrid image steganography along with cryptography algorithm based on LS (Logical & Statistical) encryption scheme and lift wavelet domain of digital images. Currently, cryptography data can be easily intercepted by an intruder during transmission. So it may be treated as ineffectual in terms of security. In such a scenario, the proposed algorithm provides secured transmission by using cryptography and steganography techniques. In this algorithm a new LS encryption scheme is implemented for converting secret message into ciphertext. It is being done by using several parameters like 'data indicator', 'count indicator', 'gray code' and novel 'data conversion' techniques. The 'gray code' and novel 'data conversion' techniques are used to recover the inherent information at the receiver and to improve the security of the secret data. Moreover, it reduces the ciphertext length compared to the length of original secret data. Hence this scheme improves the payload capacity and helps to improve the quality metrics like Number of Pixels Change in Rate (NPCR), Peak Signal to Noise Ratio (PSNR), and Correlation (CORR) in the stego image. Furthermore, steganography scheme provides an ability to tackle the various attacks like noise, rotational, histogram and visual attacks. It is also shown that how the original message is recovered back from stego image successfully.