Blind Invisible Watermarking Technique in DT-CWT Domain Using Visual Cryptography Meryem Benyoussef, Samira Mabtoul, Mohamed El Marraki, and Driss Aboutajdine Mohammed V-Agdal University, Faculty of Science, Department of Physics LRIT Associated Unit to the CNRST-URAC N 29 benyoussef.meryem@yahoo.fr Abstract. A method for digital image copyright protection is presented in this paper. The proposed method is a blind invisible and robust image watermarking scheme based on Dual Tree Complex Wavelet Transform (DT-CWT) and Visual Cryptography concept (VC). This method does not require that the watermark to be embedded into the original image which leaves the marked image equal to the original one. In the concealing and extracting process, the image is transformed in the complex wavelet domain to generate a secret and a public share respectively, using LL sub-band features and a VC codebook. To extract the watermark from the attacked image, the secret and public shares are stacked together. To improve the visual quality of the extracted watermark, a post process called reduction procedure is also proposed. The experimental results show that the proposed method can withstand several image processing attacks such as cropping, filtering and compression etc. . . Keywords: Robust Blind Watermarking, Visual Cryptography, Complex Wavelet Transform, Copyright Protection. 1 Introduction Visual Cryptography (VC) was first introduced by Moni Noar and Shamir at Eurocrypt’94 [1]. VC is described as a secret sharing scheme of digital images. It involved breaking up the image into n shares using a codebook. Those shares are binary images usually presented in transparencies; so that each participant can hold a transparency (share). The act of decryption is to simply stack shares and view the secret image that appears on the stacked shares. The decoding of the secret image by the Human Visual System (HVS) is the interesting feature that has attracted the researchers in adapting this concept for several applica- tions including watermarking. In accordance with cryptography, the security of a crypto-system does not reside in the algorithm, but resides in the secret key; that is, the security will maintain well even if the algorithm has been published. Digital image watermarking is the technique of embedding a secret image, called also “watermark pattern”, into a cover image, to protect intellectual prop- erty. The watermark pattern in the cover image can be either visible [2] or invis- ible [3]. However the visible watermarking techniques destroy the image quality A. Petrosino (Ed.): ICIAP 2013, Part I, LNCS 8156, pp. 813–822, 2013. c  Springer-Verlag Berlin Heidelberg 2013