Encrypted digital watermarking algorithm for quick response code using discrete cosine transform and singular value decomposition

There is a trade-off relationship between the imperceptibility of a watermark and the robustness of a digital watermarking algorithm; to overcome this, we propose a robust digital watermarking encryption algorithm for quick response (QR) code images based on discrete cosine transform (DCT) and singular value decomposition (SVD) through dual scrambling using Josephus ring and cellular automata. Experimental results show that watermark can still be identified from a seriously distorted QR code. The proposed scheme maintains satisfactory image quality, with great robustness to noise, filters, JPEG compression, rotation, cropping, contrast variation attacks, print/scan attacks, and so on. This algorithm can achieve further reform for QR code, which can be widely used to protect the copyright of digital works.