Robust stego-key directed LSB substitution scheme based upon cuckoo search and chaotic map

High capacity image steganography using Least Significant Bit (LSB) substitution greatly impaires visual quality of the stego image. In addition, most of steganographic schemes consider direct embedding of secret message without considering its security concern over public channel transmission. To address this problem, we have introduced a novel stego-key directed LSB substitution scheme which not only offers high embedding capacity but also resilient against stego image distortion. The aim of this work is to consider this problem as search and optimization. High embedding capacity is achieved through optimal utilization of search domain using proposed LUDO scan scheme. Optimal Stego-key is determined through cuckoo search optimization where Lévy flight is used for obtaining new Stego-key. In addition, secret message is encrypted before embedding using chaotic map generated through random key. Large key space of Stego-key offer high resistance against various crypt analytic attacks. Proposed steganography scheme is evaluated over nine standard test images and competitive results are obtained. On an average, we achieved a Peak Signal-to-Noise Ratio (PSNR) of 44.09 and Structural Similarity Matrix (SSIM) of 0.97. Results demonstrate that the proposed steganography scheme not only outperforms state-of-the-art high embedding steganography schemes but also offers high payload capabilities with immunity against visual degradation.