Abstract
The idea of digitizing documents to be archived or shared has given rise to a variety of new data types such as 3D meshes. The sharing of this data type between remote users, using high-speed computer networks and remote multimedia databases, poses great security problems. As a solution, we propose, in this paper, a new crypto watermarking algorithm. The originality of this work lies in joining cryptography with digital watermarking to secure 3D multiresolution meshes. To this end, three steps should be executed. The first is the watermark preparation. It consists, firstly, in applying the Secure Hash Algorithm 1 algorithm to generate an electronic signature of the mesh source. Secondly, the logo undergoes an encryption using Advanced Encryption Standard algorithm. To end this step, the signature and the encrypted logo pass through a convolutional encoder to obtain a codeword. As for the second step, it is called mesh preparation and it consists in applying a spiral scanning method to the mesh to split it into Groups Of Triangles. For each Group Of Triangles, a wavelet transform is applied to generate the corresponding Wavelet coefficients vector. Finally, embedding data occurs using the cylindrical coordinate system, a modulation and the least Significant Bit method. The experiment of our algorithm proves that it allows a very high insertion rate without influencing the mesh quality. Our algorithm also minimizes the amount of memory used. Moreover, it is robust against the most popular attacks. Our results show that our algorithm presents an improvement in comparison with recently published results.