A hybrid algorithm for robust image steganography

In this work, a novel hybrid algorithm has been developed for achieving imperceptible and robust image steganography for secure data communication. The novelty of the work lies in the careful manipulation of higher frequency coefficient of Discrete Cosine Transform (DCT) to maintain the perceptual quality of the image followed by embedding secret bits in the controlled DCT coefficients using random locations identified by deterministic Coupled Chaotic Map (CCM). The randomness of the CCM map is confirmed by National Institute of Standards and Technology, DIEHARD, ENT and TestU01 test suites. The experimental results demonstrate that the proposed technique has excellent stego-image quality keeping zero Bit Error Rate at maximum embedding capacity (EC). The proposed method has capability to withstand against malicious users as well as outperforms existing steganography techniques in terms of EC, and Peak Signal to Noise Ratio. The security of the proposed technique is subsequently examined by the key length, key sensitivity parameter and histogram analysis.