Digital watermarking encryption algorithm based on synthetic key and wavelet decomposition

This paper presents a novel image encryption method that combines symmetric and asymmetric encryption with a watermark embedding extraction algorithm based on wavelet transform. The algorithm ensures the invisibility and robustness of the watermark, providing the first layer of encryption. The second layer of encryption is implemented by leveraging the efficiency of symmetric encryption and the security of asymmetric encryption. The integrity of the watermarking is evaluated using MEB(%), PSNR(dB), and SSIM(%), while the algorithm's efficiency is assessed through the encryption time T(ms). Experimental results show that the watermark achieves a PSNR of 59.671dB and an SSIM of 99.9, confirming its integrity and robustness. Furthermore, the synthetic encryption process takes only 50 seconds, ensuring both security and efficiency without increasing the time complexity. In conclusion, the proposed synthetic encryption algorithm demonstrates excellent performance in terms of efficiency and security.