An enhanced LSB-based quantum audio watermarking scheme for nano communication networks

In recent years, digital multimedia including image, audio, and video are extended to quantum computation and quantum networks. Consequently, copyright protection of digital multimedia in quantum networks becomes a significant issue. As an important security technology, quantum watermarking is an appropriate solution, which embeds copyright information into the carrier signal. This work presents an enhanced least significant bit (LSB) based audio watermarking using reflected gray code. In the presented scheme, the watermark image is first scrambled using a new scrambling method presented in this paper, which modifies pixel values for scrambling instead of changing pixel positions. The scrambled image is then converted into a qubit sequence to comply with one-dimension audio signal, and the qubits are embedded into carrier quantum audio signal using an embedding key. In embedding phase, every four low qubit of target audio sample replaced with their nearest even or odd number in reflected gray code, based on the value of embedded qubit. For every procedure of the proposed scheme, the quantum circuit and complexity analysis is presented. Experimental results prove that the proposed scheme has good transparency, capacity and security.